United States Office of Water June 1981
Environmental Protection Regulations and Standards (WH-553) EPA-440 4-81 -019
Agency Washington DC 20460
Water '•
&EPA An Exposure
and Risk Assessment
for Dichlorobenzenes
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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.
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0372-101
REPORT DOCUMENTATION *• ^PORT NO. 2.
PAGE EPA-440/4-31-019
i. TKIa and Subtffla
An Exposure and Risk Assessment for Dichlorobenzenes
1 1,2-Dichlorobenzene 1,3-Dichlorobenzene 1,4-Dichlorobenzene
'. Authors Harris , J.; Coons, S.; Byrne, M. ; Fiksel, J.; Goyer, M. ;
Waaner. J.: and Wood. M. fADL) Moss. K. : Acurex Cornoration
i. Performing Organization Nam* and Addrasa
Arthur D. Little, Inc. Acurex Corporation
20 Acorn Park 485 Clyde Avenue
Cambridge, MA 02140 Mt. View, CA 94042
.2. Sponsoring Organisation Name and Addraa*
Monitoring and Data Support Division
Office of Water Regulations, and Standards
U.S. Environmental Protection Agency
Washington, D.C. 20460
3. Recipient's Accession Ho,
s. Report Data Final Revision
June 1981
6.
8. Performing Organization Rapt. No.
10. Proiaet/Taak/W«rk Unit No.
11. Contract(C) or Srant(G) No.
(a C-68-01-5949
C-68-01-6017
(G)
13. Typa of Raport A Period Covarad
Final
14.
Extensive Bibliographies
I*. Abatraet (Urn* 200 word*)
This report assesses the risk of exposure to 1,2-dichlorobenzene, 1,3-dichlorobenzene,
and 1,4-dichlorobenzene. 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 March 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 dichloro-
benzenes 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 dichloro-
benzenes for various subpopulations,
'. OoeuiMfit Anatyata a. Descriptor*
Exposure
Risk
Water Pollution
Air Pollution
b. IdantHloraVOpan Ended Terms
Pollutant Pathways
Risk Assessment
Effluents
Waste Disposal
Food Contamination
Toxic Diseases
Dichlorob.enzenes
1,2-Dichloro6enzene
1,3-Dichlorobenzene
1,4-Dichlorobenzene
U S Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevarjj, 12th Floor
60604-3590
c. COSAT, ™,«,oup Q6F Q6T W..^,,
Availability Statement
Release to Public
19. Security Class (This Reoort)
Unclassified
20. Security Class (This Page)
21. No. at 0a«ea
132
22. Price
Sea lamtruetloat an fteversa
OPTIONAL 7OMU 372 (4-771
(Formerly NTIS-3S)
Department at Commerce
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EPA-440/4-81-019
March 1981
(Revised June 1981)
AN EXPOSURE AND RISK ASSESSMENT FOR
DICHLOROBENZENES
1,2-Dichlorobenzene
1,3-Dichlorofaenzene
1,4-Dichlorob enzene
by
Judith Harris, Susan Coons,
Melanie Byrne, Joseph Fiksel,
Muriel Goyer, Janet Wagner
and Melba Wood
Arthur D. Little, Inc.
U.S. EPA Contract 68-01-5949
Kenneth Moss
Acurex Corporation
U.S. EPA Contract 68-01-6017
Gregory Kew
Project Manager
U.S. Environmental Protection Agency
Monitoring and Data Support Division (WH-553)
Office of Water Regulations and Standards
Washington, D.C. 20460
OFFICE OF WATER REGULATIONS AND STANDARDS
OFFICE OF WATER AND WASTE MANAGEMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
83926-36
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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 identification 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 ?nd 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
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TABLE OF CONTENTS
LIST OF FIGURES
LIST OF TABLES
ACKNOWLEDGMENTS
1.0 TECHNICAL SUMMARY 1-1
2.0 INTRODUCTION 2-1
3.0 MATERIALS BALANCE 3-1
3.1 Introduction 3-1
3.2 Production of Dichlorobenzenes 3-1
.3.2.1 Manufacture .3-2
3.2.2 Inadvertent Sources of Dichlorobenzene 3-5
3.3 Uses of Dichlorobenzenes 3-7
3.3.1 Overview' 3-7
3.3.2 1,2-Dichlorofaenzene 3-7
3.3.3 1,4-Dichlprobenzene 3-12
3.3.4 Minor Uses 3-13
3.4 Municipal Disposal of Dichlorofaenzenes . 3-15
3.4.1 POTWs 3-16
3.4.2 Urban Refuse 3-19
3.5 Summary and Conclusions 3-19
REFERENCES 3-22
4.0 FATE AND DISTRIBUTION IN THE ENVIRONMENT 4-1
4.1 Introduction 4-1
4.2 Pysiochemical Characteristics 4-1
4.3 Modelling of Environmental Distribution 4-5
4.3.1 Introduction 4-5
4.3.2 Mackay Equilibrium Partitioning Model 4-5
4.3.3 EXAMS Model 4-7
4.3.4 Comparison of MackayTs Equilibrium Model and
EXAMS 4-10
4.3.5 Volatilization 4-15
4.4 Monitoring Data 4-18
4.4.1 Introduction 4-18
4.4.2 Overviex* of Ambient and Effluent Water
Concantrations: STORET Data 4-13
4.4.3 Municipal Wastewater 4-20
4.4.4 Drinking Water 4-24
ill
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TABLE OF CONTENTS
(Continued)
4.4.5 Runoff
4.4.6 Ambient: Surface Waters
4.4.7 Atmosphere
REFERENCES 4-30
5.0 EFFECTS AND EXPOSURE—HUMANS 5-1
5.1 Human Toxicity 5-1
5.1.1 Human and Animal Studies 5-1
5.1.2 Metabolic Studies 5-7
5.1.3 Overview 5-8
5.2 Human Exposure 5-9
5.2.1 Introduction 5-9
5.2.2 Waterborne Exposure 5-11
5.2.3 Airborne Exposure 5-16
5.2.4 Summary 5-23
REFERENCES 5-24
6.0 EFFECTS AND EXPOSURE—AQUATIC BIOTA 6-1
6.1 Effects on Aquatic Biota 6-1
6.1.1 Introduction 6-1
6.1.2 Fish and Invertebrates 6-1
6.1.3 Other Organisms 6-1
6.1.4 Plants 6-1
6.1.5 Conclusions 6-7
6.2 Exposure of Aquatic Biota 6-7
6.2.1 Dichlorobenzene Levels in Aquatic Systems 6-7
6.2.2 Conclusions 6-9
REFERENCES 6-11
7.0 RISK CONSIDERATIONS 7-1
7.1 Introduction 7-1
7.2 Humans 7-1
7.2.1 Statement of Risk 7-1
7.2.2 Discussion 7-2
7.3 Aquatic Biota 7-9
APPENDICES
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LIST OF FIGURES
Page
3-1 Dichlorobenzene Materials Balance Flowsheet (.1978) 3~20
4-1 Temperature Dependence of Vapor Pressure for
Dichlorobenzenes 4-4
7-1 Acute Effect Levels and Daily Human Exposure for 1,2-
and 1,4-Dichlorobenzene 7~8
A-l Batch Production of Chlorobenzenes and Environmental
Release Points for Dichlorobenzenes A-2
A-2 Continuous Production of Chlorobenzene and Environmental
Release Points for Dichlorobenzene A-3
B-l Block Diagram for Toluene Diisocyanate Production B-4
B-2 Air and Water Pollution Control for Dye Carriers B-5
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LIST OF TABLES
Page
3-1 Dichlorobenzene Materials Balance: Production (1978) 3-3
3-2 Dichlorobenzene Materials Balance: Use (1978) 3-8
3-3 1978 Dichlorobenzene Emission Estimates from Pesticide
Manufacturers 3-14
3-4 Dichlorobenzene Distribution in POTWs, Sludge; Selected
Urban Sites 3-17
3-5 Dichlorobenzene Materials Balance: Municipal POTWs and
Refuse 3-18
4-1 Physical and Chemical Properties of Dichlorobenzenes 4-2
4-2 Values of Parameters Used for Calculating the Equilibrium
Distribution of 1,2-Dichlorobenzene Using the Mackay
Fugacity Model 4_6
4-3 Equilibrium Partitioning of 1,2-Dichlorobenzene Calculated
Using Mackay rs Fugacity Model 4-8
4-4 Input Parameters for EXAMS Modelling of the Fate of
1,2-Dichlorobenzene in Generalized Aquatic Systems 4-9
4-5 Steady-State Concentrations of 1,2-Dichlorobenzene in
Various Generalized Aquatic Systems Resulting from
Continuous Discharge at a Rate of 1.0 kg/hour 4-11
4-6 The Fate of 1,2-Dichlorobenzene in Various Generalized
Aquatic Systems 4-<-12
4-7 The Persistence of 1,2-Dichlorobenzene in Various
Generalized Aquatic Systems After Cessation of Loading
at 1 kg/hour 4-13
4-8 Comparison of Results from Mackay's Equilibrium Model
and EXAMS for 1,2-Dichlorobenzene in a Pond System 4-14
4-9 Percentage Distribution of Ambient and Effluent
Concentrations for Dichlorofaenzenes in STORET 4-19
4-10 Ambient Concentrations of Dichlorobenzenes in Surface
Water: Remarked and Unremarked Data in STORET 4-21
4-11 Concentrations of Dichlorobenzenes in Industrial
Effluents: Remarked and Unremarked Data in STORET -1-22
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LIST OF TABLES
(Continued)
Page
4-12 Concentrations of Dichlorobenzene Detected in Drinking
Water: National Organic Monitoring Survey, March 1976
through January 1977 4-25
4-13 Concentration of Dichlorobenzenes in Ambient Air Samples 4-27
4-14 Levels of Dichlorobenzenes Detected in Air at the
Kin-Buc Disposal Site, Edison, NJ 4-29
5-1 Adverse Effects of Dichlorobenzenes in Mammalian
Species 5-10
5-2 Volume and Geographic Distribution of Aquatic Releases
of 1,2-Dichlorobenzene 5-12
5-3 Volume and Geographic Distribution of Aquatic Releases
of 1,4-Dichlorofaenzene 5-13
5-4 Summary of Reported Aqueous Environmental Concentrations
of Dichlorobenzene . 5^-14
5-5 Estimated Human Exposure to Dichlorobenzenes by
Ingestion of Drinking Water 5-15
5-6 Volume and Geographic Distribution of Atmospheric .
Releases of 1,2-Dichlorobenzene 5^-17
5-7 Volume and Geographic Distribution of Atmospheric
Releases of 1,4-Dichlorobenzene 5^18
5-8 Summary of Reported Airborne Concentrations of
Dichlorofaenzenes 5-19
5-9 Estimated Size of U.S. Population Exposed to Point and
Area Source Atmospheric Concentrations of 1,2- and
1,4-Dichlorobenzene 5-20
5-10 Estimated Inhalation Exposures to Dichlorobenzenes 5^22
6-1 Acute Toxicity of Dichlorobenzenes for Freshwater Fish
and Invertebrates 5-2
6-2 Acute Toxicity of Dichlorobenzene for the Freshwater
Fathead Minnow Pimephalas promales^ for Different
Exposure Durations 5_2
6-3 Acute Toxicity or Dichlorobenzene for Marine Fish and
Invertedraces 5_3
vii
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LIST OF TABLES
(Continued)
Page
6-4 Effects of Dichlorobenzenes on Annelids and Other
Marine Biota g_4
Effects of Dichlorobenzenes on Freshwater Plants 6-5
Effects of Dichlorobenzenes on Marine Plants 6-6
6-7 Summary of STORET Data (Remarked and Unremarked) 6-3
6-8 Summary - Reported Fish Kills Due to Dichlorobenzene
(1970-1980) 6_10
7-1 Reported Dosages Associated with Acute Effects of
Dichlorofaenzenes in Mammals 7-3
7-2 Summary of U.S. Subpopulations Exposed to Varying
Levels of Dichlorobenzenes 7-4
7-3 Margins of Safety for 1,2-Dichlorobenzene Exposure
Scenarios 7_g
7-4 Margins of Safety for 1,4-Dichlorobenzene Exposure
Scenarios 7_7
7-5 Criteria and Standards for Dichlorobenzenes 7-1Q
A-l Dichlorobenzene Emission Factors " A—1
A-2 Patents Relating to Meta-Dichlorobenzene Manufacture A-4
A-3 National Organic Monitoring Survey, March 19 76-^
January 1977 ^-5
A-4 Ambient Levels of Dichlorobenzenes in Water A-6
B-l Frequency of Dichlorobenzene Detection in Industrial
Wastewaters B-l
B-2 3,4-Dichloroaniline Producers B.-2
B-3 o-Dichlorobenzene Emission from Toluene
Diisocyanate (TDI) Producers B-3
3-4 Dyestuffs Utilizing 1,2-Dichlorobenzene as a Reaction
Solvent B.-6
3-5 Ambient Levels of Dichlorobenzenes in Air 3-7
viii
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ACKNOWLEDGEMENTS
The Arthur D. Little, Inc., task managers for this study were Susan
Coons and Judith Harris. Major contributors to this report were Melanie
Byrne (Aquatic Effects and Exposure), Susan Coons (Human Exposure),
Joseph Fiksel (Risk Considerations), Muriel Goyer (Human Effects), Janet
Wagner (Environmental Fate), and Melba Wood (Monitoring Data). In addi-
tion Kenneth Schwartz assisted in the EXAMS analysis, Elizabeth Cole
provided input to the human effects section and Caren Woodruff contributed
to the discussion of volatilization. Preparation of the final draft
report involved Jane Metzger (editing), Nina Green (documentation) and
Alfred Wechsler (technical review).
The materials balance for the dichlorobenzenes (Chapter 3.0) was
produced 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. Kenneth Moss
was the task manager for Acurex, Inc. Patricia Leslie was responsible
for report production.
Gregory Kew, MDSD, was the project manager at EPA.
ix
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1.0 TECHNICAL SUMMARY
1.1 INTRODUCTION
The Monitoring and Data Support Division, Office of Water Regulations
and Standards, U.S. Environmental Protection Agency is conducting an on-
going program to identify the sources of and evaluate the exposure to the
129 oriority pollutants. This report assesses the exposure to and the
probable risk associated with exposure to 1,2-dichlorobenzene, 1,3-dichlo-
robenzene and 1,4-dichlorobenzene. The organization of this summary is
somewhat different from that of the report, focusing on the risk considera-
tions first since this section presents the major conclusions of the study.
1.2 RISKS TO HUMANS AND AQUATIC ORGANISMS
Dose levels at which acute effects have been observed in humans or
mammals are generally more than three orders of magnitude greater than
the typical levels of human exposure through inhalation and ingestion.
The potential chronic effects of dichlorobenzenes have yet to be deter-
mined. The dichlorobenzenes are considered by the Carcinogen Assessment
Group of the U.S. EPA to be of potential concern with respect to carcino-
genicity; however, the available data on carcinogenic, mutagenic or tera-
togenic effects are not sufficient at this time to permit a quantification
of these risks to humans. Existing health effects data from subchronic
studies in rats, when extrapolated to humans and coupled with estimated
exposure levels, suggest that the risk associated with dichlorobenzenes
in the environment is not unreasonable.
The U.S. EPA has set the ambient water quality criterion for total
dichlorobenzenes at 400 ug/1. This criterion is based on the highest
•long-term no-ofaserved-effect level of 13.42 mg/kg/day reported for rats
orally administered 1,2- or 1,4-dichlorobenzene for 5 to 7 months and a
safety factor of 1000, placing the acceptable human intake at 0.94 mg/day.
Exposure to the general population is well below this level. Inhalation
appears to be the most significant route of exposure. Drinking water
accounts for relatively low exposures, although heavily contaminated drink-
ing water in some local areas could possibly result in higher exposure
levels. Risk to certain subpopulations exposed to local, elevated concen-
trations of dichlorobenzenes in air may occur through use of deodorizers
or moth repellants containing 1,4-dichlorobenzene, or through proximity
to industrial manufacturing or waste disposal sites. Exposure to these
groups may approach 1 mg/day. Risk to occupationally exposed workers
could be considerably higher than risk to the general population.
There are very few data available on either the effects or exposure
of aquatic biota to dichlorobenzenes. Based on the monitoring data, there
appear to be few reports of environmental concentrations of dichlorobenzenes
at levels comparable to those causing adverse effects. In general, ambient
and affluent concentrations are two orders of magnitude lower than effects
levels. Aquatic biota may be at risk from accidental spilling or leakage
of large quantities of the chemicals; in these cases, the duration of the
exposure is expected to be short.
1-1
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1.3 HUMAN EFFECTS AND EXPOSURE
The dichlorohenzenes are rapidly absorbed by humans via the lungs
and gastrointestinal tract, and metabolized; they are also absorbed through
the skin. The major target systems include the liver, the reticuloendo-
thelial system, and the central nervous system.
Little specific information is available on the toxicity of dichloro-
benzenes to humans. Anecdotal reports have linked chronic exposure to
1,2- or 1,4-dichlorobenzene with a few cases of human leukemia. A cause
and effect relationship, however, cannot be reliably inferred from these
reports. Occupational exposure to 1,4-dichlorobenzene suggests that no
organic injury or adverse hematologic effects may be associated with air
concentrations of 500 mg/m3; concentrations greater than 960 mg/m^ are
intolerable, 400 mg/nr causes eye and nose irritation, and an odor is
detectable at 90-180 mg/m3. Exposure to concentrations up to 90 mg/nr3 of
1,2-dichlorobenzene caused no organic injury or adverse hematologic effects,
while 300 mg/nH was detectable and 600 mg/m3 produced irritation but no
serious effects.
*
One study reported that there was no notable hazard due to skin
irritation or dermal absorption of 1,4-dichlorobenzene, except under
extreme conditions. A case of allergic purpura following 24-48 hour
exposure to 1,4-dichlorobenzene and contact eczematoid dermatitis result-
ing from chronic skin exposure to 1,2-dichlorobenzene have been reported.
Existing health effects data from animal studies are limited. No
long-term studies beyond 7 months' duration have been completed. Data from
an ongoing study suggest that ingestion of 1,2-dichlorobenzene (86/mg/kg/
day) does not induce oncogenic effects in either rats or mice, but the
final decision on oncogenic potential should be deferred pending completion
of the National Cancer Institute study. Mutagenic data for the dichloro-
benzenes are inconclusive and limited to sub mammalian systems. Data on
reproductive effects of the dichlorobenzenes are not available.
Although available health effects data are inadequate to characterize
risk, sufficient subchronic data are available to estimate acceptable
exposure levels. Inhalation of 560 mg/m^ 1,4-dichlorobenzene 7 hours/day,
5 days /week for 6-7 months showed no noticeable effects in a number of
species of mammals. Oral LD5Q values for the dichlorobenzenes are gener-
ally in the 500 mg/kg range. The maximum tested oral dose of either 1,2-
or 1,4-dichlorobenzene that produced no observed adverse effects in rats
(13.42 mg/kg/day) was used by the EPA in establishing the water quality
criterion. The Russian literature reports a maximum no-detected effect
level in rats of 0.001 mg/kg/day. The reason for the discrepancy between
these two levels is unclear; exposure levels and their determinations were
not adequately addressed in the Russian literature.
Data on exposure to the dichlorobenzenes through ingestion are li
to those associated with consumption of drinking water. The maximum dichlo
robenzene concentration observed in drinking waters was almost two orders
1-2
-------
of magnitude lower than the water quality criterion; the mean of observed
values was lower by more than two orders of magnitude.
Human exposure to dichlorobenzenes through inhalation appears to be
much larger than that through ingestion. The largest environmental
releases are to the atmosphere, and estimated exposures through inhalation
of ambient air range from 2 ug/day to 90 ug/day. The maximum value was
reported for an urban location. Concentrations of dichlorobenzenes in
air around industrial sites or disposal sites result in higher exposures
to sufapopulations living near these sources. Data from one study suggest
that exposure associated with mothball usage (or possibly use of odor
control agents) could reach 1 mg/day 1,4-dichlorobenzene for some people,
but the extent to which these data are representative of widespread condi-
tions remains to be confirmed. Occupational levels possess the potential
for worker exposure significantly above that to the general population.
1.4 AQUATIC EFFECTS AND EXPOSURE
The lowest concentration of the dichlorobenzenes which was found to
be toxic to marine and freshwater organisms was 1000 ug/1. The most sensi-
tive species tested was the mysid shrimp with LC5QS of 1199-2850 yg/1.
There was not a consistent difference in the leyel of toxicity observed
for the three isomers, although Dalaemonetes pugio and Daphnia magna did
show an increased sensitivity to the 1,2-dichlorobenzene isomer.
The concentrations reported for ambient and effluent waters are
generally in the low ppb range C.<10 ug/1) ; only one unremarked observation
greater than 1000 ug/1 was reported in STORET for ambient water and one
for effluent water. Therefore, the exposure of biota to toxic levels in
ambient waters can be assumed to be quite low. Results of the EXAMS model
calculations suggest that removal of dichlorobenzenes from aquatic media
is rapid; volatilization is the major removal mechanism in quiescent.
systems, whereas advection is much more effective in river systems. Fish
kill data indicate that the accidental discharges of chemicals represent
a source of possible exposure of aquatic biota to toxic concentrations of
the dichlorobenzenes; the limited duration of the effects confirms the
findings of EXAMS.
1.5 MATERIALS BALANCE
The total amount of dichlorobenzenes released to the environment in
1978 has been estimated to be approximately 13,500 kkg, more than one-half
of the available U.S. supply (production minus exports plus imports).
Environmental releases during production totaled 96 kkg to air, 6.3 kkg
to land, and 230 kkg to water for 1,2-dichlorobenzene and 240 kkg to air,
7.7 kkg to land, and 290 kkg to water for 1,4-dichlorobenzene. These
losses occur in vent gases; liquid wasta screams from stills, wash tanks
and strippers; and sludges. Inadvertent sources of dichlorobenzenes,
such as Indus trial incineration and chlorination of drinking water, do noc
appear to release significant quanticitas to the environment.
-------
In general, uses of the dichlorobenzenes are responsible for the
^°S!eS C° thS •nvlroM*nt. Whereas manufacture accounts for only
^.a/. of the environmental releases, use accounts for over 95% The
largest environmental releases are atmospheric. Emissions of 1 2-dichlo-
robenzene (% 5,500 kkg) occur primarily during solvent usage [e.g? clean-
ing or process solvents during toluene diisocyanate (TDI) or 3,4-dichloro-
aniline production] while the 1,4-isomer (* 24,000 kkg) is released as
a result of use in mothballs and as a space deodorant. Most of these
applications (except TDI process solvent use) represent widespread dis-
persive uses, with the potential for exposure to the general public or
specific population subgroups as a normal consequence of use.
Of the estimated 440 kkg dichlorobenzenes entering POTWs, calcula-
tions indicate that approximately one-half is lost to the air and one-half
is discharged to water. The exact input of dichlorobenzenes to municipal
incinerators is unknown, yet these compounds are probably destroyed with
over 99.9% efficiency depending on conditions of temperature and residence
it*^ ^^Tff1?*1 facilic?' Dichlorobenzenes that are dispersed to
landfills (520 kkg) arrive there primarily as garbage deodorants or as
re
residue in used solvent containers.
1.6 ENVIRONMENTAL FATE
Most of the environmental discharges of dichlorofaenzenes are released
to the atmosphere; furthermore, the dichlorobenzenes released to aquatic
systems are not expected to persist in the water column at high concentra^
tions. The high vapor pressures and low water solubilities suggest that
volatilization will be very important. Under experimental laboratory
conditions, the half-life of 1,2-dichlorobenzene, as a function of vola-
tilization, was estimated to range from 1.6 to 6.7 hours, depending on
the current and wind velocities of the system. The octanol.-water parti-
tion coefficient suggests that adsorption onto soils and sediments will
also be a major pathway for removal from the water column. The rate of
biodegradation in the environment may also be sufficiently high that bio-
degradation would he a major fate process.
Results of the Mackay equilibrium partitioning model for 1,2-dichloro-
benzene indicate that in a system at equilibrium, 35% of the chemical will
be in the air compartment, 64% in the sediment, and 0.3% in the water
column. Aquatic fate was also modelled by use of EXAMS, which incorporates
some of the other fate processes to give a more complete estimate of the
behavior of the dichlorobenzenes in environmental systems. Three *eneral-
ized aquatic systems were modelled in EXAMS: a pond, an oligotrophic lake
and a river system. '
In the pond, 84% of the 1,2-dichlorobenzene is expected to be in the
sediment at steady state; volatilization will be the major removal process
trom water. Following suspension of the loading (1 kg/hour) , 33% of the
1,2-dichlorobenzene in the system will be removed within ?4 days Tn ^
oligosrophic Lake, aost of the chemical will reside in che watar'column
where it will be subject to rapid volatilization. Within 24 days of cessa-
tion of che loading, results of the EXAMS run predict chat 56% of ^he
-------
1,2-dichlorobenzene will have been removed from the system. Finally,
EXAMS was used to model the river system, the system most likely to receive
discharge of dichlorobenzene from an industrial source or from accidental
spills or leakage. In the river system, at steady-state, the chemical is
expected to be distributed between the water and sediment compartments as
follows: 75% in water, 25% in sediment. Volatilization is not the predom-
inant removal process in a dynamic system such as the river where other
processes (such as advection) are more important. After cessation of the
1 kg/hour loading, 76% of the 1,2-dichlorobenzene will be removed from the
system within 12 hours; 99.9% of the dissolved chemical will be lost from
the water, 2.33% removed from the sediment. These environmental fate data
support the observation that discharges of dichlorobenzenes (to river
systems) that were responsible for large fish kills affected the biota for
periods of only 1 day; the levels would have been substantially diminished
in less than 12 hours.
Monitoring data for the dichlorobenzenes are quite limited. Ambient
and effluent dichlorobenzene concentrations reported in the STORE! data
base were generally less than 10 ug/1. However, most of the data were
remarked, and the discussion is largely of detection limits. Drinking
water data indicated maximum levels less than 10 ug/l«
Air monitoring data indicate ambient levels of dichlorobenzenes
generally below 1 ug/m3. A Japanese study reported urban concentrations
up to 4.2 ug/m3 and suburban concentrations up to 2.4 ug/nr. Ambient air
near industrial or disposal sites in the U.S. was reported to contain up
to 46 ug/m3 of total dichlorobenzenes. Room concentrations associated
with mothball usage were measured at 105
1-5
-------
2.0 INTRODUCTION
The Office of Water Regulations and Standards, Monitoring and
Data Support Division, 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 on cultural
and environmental flows of specific priority pollutants and estimate
the risk based on receptor exposure to these substances. The results
are intended to serve as a basis for developing a suitable regulatory
strategy for reducing the risk if such action is indicated.
This report on the dichlorobenzenes includes separate discussions
of the three isomers whenever practical. The isomeric designations
used are 1,2-dichlorobenzene, 1,3-dichlorobenzene and 1,4-dichloro-
benzene; ortho-, meta- and para-dichlorobenzene are common alternative
designations for the three isomers. The 1,2- and 1,4-dichlorobenzene
isomers are the only ones produced and used in significant quantities.
Most of the data on exposure and effects are specific to these two
isomers so they are dealt with in more detail in the following chapters.
However, there are limited monitoring data for all three isomers.
The physiochemical data indicate that they are similar, but in making
a risk assessment, each should be considered a separate chemical.
This document is an assessment of the risks associated with ex-
posure to the dichlorobenzenes. Information on production, use, fate
and distribution of these chemicals is included in order to determine
the exposure associated with specific activities. The report is
organized as follows:
• Chapter 3.0 presents a materials balance for the dichlorobenzenes
that considers quantities of the chemical consumed or produced
in various processes, the amount of pollutant released to the
environment, the environmental compartment intially receiving
it, and, to the degree possible, the locations and timing of
releases.
• Chapter 4.0 describes the distribution of the dichlorobenzenes
in the environment by presenting available monitoring data for
various media and by considering the physiochemical and biological
fate processes that transform or transport the chemicals.
• Chapter 5.0 discusses the available data concerning the toxicity
of the dichlorobenzenes for humans and laboratory animals and
quantifies the likely level of human exposure via major known
axnosura routes.
2-1
-------
Chapter 6.0 presents the reported effects levels and estimated
exposure levels for aquatic biota.
Chapter 7.0 compares exposure conditions for humans and other
biota vith the available data on effects levels from
Chapters 5.0 and 6.0. The risks associated with various
exposures to the dichlorobenzenes are discussed.
Appendices A and B provide supporting information for Chapter
3.0.
-------
3.0 MATERIALS BALANCE
3.1 INTRODUCTION
One perspective from which exposure to a chemical may be evaluated
is that of a materials balance. Since the total mass of all materials
entering a system equals the total mass of all materials leaving that
system, excluding those materials the system accumulates or retains, a
materials balance may be performed around any individual operation that
may ultimately place a specific population at risk, (e.g., process
water discharges creating groundwater contamination). Each overall
materials balance, therefore, consists of a collection of smaller scale
ones, each of which is directed to specific releases to the environ-
ment. It is beyond the scope of this chapter to predict the fate of the
chemical following release.
The chapter reviews both published and unpublished data concerning
the production, use, and disposal of dichlorobenzenes within the United
States. Information from the available literature has-been critiqued
and compiled to present an overview of major sources of environmental
release of•dichlorobenzenes. Fully annotated tables have been included
to aid data evaluation. Since a negligible amount of 1,3-dichlorobenzene
is manufactured in this country, the major emphasis of this chapter is on
the distribution of releases of 1,2- and 1,4-dichlorobenzenes.
Section 3.2 discusses the production-of 1,2-dichlorobenzene and
1,4-dichlorobenzene; 1,3-dichlorofaenzene is not produced in significant
quantities, and is not discussed in detail. The numerous uses of the
dichlorobenzenes and the attendant environmental releases are reviewed
in Section 3.3. Section 3.4 presents a discussion of the disposition
of dichlorobenzenes discharged to municipal waste facilities, i.e.,
publicly-owned treatment works (POTWs) and urban refuse landfills or
incinerators. A materials balance flow sheet for the dichlorobenzenes
and a summary of the major findings are presented in Section 3.5.
3.2 PRODUCTION OF DICHLOROBENZENES
The three dichlorobenzene isomers are shown below:
Cl Cl Cl
1,2-dichlorobenzene
ortho-dichlorobenzene
o-dichlorobenzene
1,3-dichlorobenzene
meta-dichlorobenzene
m-dichlorobenzene
1,4-dichlorobenzene
para-dichlorobenzene
o-dichlorobenzene
3-1
-------
This section describes the manufacture of dichlorobenzenes . In
addition, environmental releases from manufacture are estimated using
available data, and the possible inadvertent sources of dichlorobenzene
release to the environment are discussed.
3.2.1 Manufacture
3.2.1.1 Overview
The 1978 production figures for 1,2- and 1,4-dichlorobenzenes were
available from two sources: U.S. International Trade Commission (USITC)
and an employee exposure report by Hull and Company (Hull 1980). The
two production totals differ considerably: 38,000 kkg were reported by
USITC and 60,000 kkg by Hull and Co. The data from the latter were
chosen for use in this materials balance because they were the result
of direct industry contacts. In addition, there apparently was a re-
porting error in production figures by one company to USITC (Hull 1980) .
(The identity of this facility could not be revealed for proprietary
reasons.) Table 3-1 summarizes location, production, and environmental
release data for 1,2- and 1,4-dichlorobenzene manufacture. The third
isomer, 1,3-dichlorobenzene, is not produced in significant; quantities,
although it has many potential uses (EPA, 1979d; see Sections 3.2.1 4
and 3.5).
Historically, 1,2- and 1,4-dichlorobenzene were produced largely as
byproducts of monochlorobenzene manufacture. However, demand for mono-
chlorobenzene has dropped in the last decade. In the future, therefore,
production facilities are expected to be shifted toward maximizing the
yield of dichlorobenzenes (EPA 1978a. Mannsville Chemical Products 1978
'Lewis 1975).
Chlorobenzenes are produced by direct chlorination of benzenes in
continuous or batch reactors. A combination process may be used in
which batch chlorination is followed by continuous product refining
(SRI 1979b). The product is a mixture of monochlorobenzene and 1,2-
and 1,4-dichlorobenzenes as major products, along with small amounts of
higher chlorinated benzenes (Kurtz and Smalley 1979). The major reactions
are:
C6H5C1 + HC1
C6H.C1 + C12 - ^C6H4C12 + HC1
The HC1 product, contaminated with benzene and chlorinated products,
passes overhead. The reactor bottoms are scrubbed with benzene or
Chlorobenzenes and passed to a neutralizer where they are washed with
aqueous sodium hydroxide to remove HC1 and most of the dichlorobenzenes,
thus forming a sludge and a supernatant. The sludge, rich in dichloro-
benzenes, is distilled into 1-4- and 1,2- fractions. Tne supernatant is
also distilled, to separate benzene, aonochlorobenzene. and 1,2- and 1,-i
dichlorobenzenes (Lowenheim and Moran 1975).
3-2
-------
Table 3-1. Dichlorobenzene Materials Balance: Production, 1978(kkg/yr)a
Producers and Location
1 .2-Oicnlorobenzene
Allied Chemical Corp.
Syracuse, NY
OOH Chemical Corp.
Midland. MI
Monsanto Company
Sauget. !L
PPS Industries, Inc.
Natrium. UV
Specialty Organics, Inc.
Irnindale, CA
Standard Chlorine Chemicals
Co. Inc.
Delaware City, OE
Keamy, NJ
Tota 1 s
1 . 4-0 1 eh 1 orobenzene
Allied Chemical Corp.
Syracuse, NY
Oow Chemical Corp.
Midland, MI
Monsanto Company
Sauget, IL
PPC Industries, Inc.
Natrium, WV
Specialty Organics, Inc.
Irxindalc, CA
Standard Chlorine Chemicals
Co. Inc.
Delaware City, OE
Keamy, NJ
Totals
Caoaci ty
•
1.300
14,000
7,300
9,100
910
23.000
7,300
63,000
1,300
14,000
5,500
14.000
910
34.000
6.300
77,000
Production2
770
6.000
3,100
3.900
390
9,800
3.100
27.000
770
6.000
2.400
6.000
390
15.000
2,900
33,000
Environmental 3el<
Air* «aterf
2.7
21
11
14
1.4
35
11
96
5.5
43
17
43
2.3
110
21
240
6.6
51
26
33
3.3
34
26
230
6.3
53
21
53
3.4
130
26
290
Land3
neg"
1.4
neg
neg
neg
2.3
neg
5.3
neg
1.4
neg
1.4
neg
3.5
nsg
7.7
a) All values rounded to two significant figures.
b) SRI, 1979b.
c) Total production: Hull, 1980. Breakdown by plant based on plant capacity.
d) Environmental releases distributed based on plant capacity,
e) See Table A-I (Appendix A) for emission factors; emissions distributed as process (651). storage (131), fugitive (21S).
f' rttUlSI.?:0037 k2 d1«h1««5«««"«»/k? monochlorobenzene produced. In water stream from dieh 1 orobenzene column; 1.4 x 105 kkg ™,no-
cftlorooenzene produced, 1978; proportion which 1s each isomer is based on production.
g) Based an 0.0001 kg diehlorobenzenes/kg nonochlorobenzene produced, land disposed from fractionating towers; Hull, 1930; EPA, 1977C.
h) Negligible; <1 kkg.
3-3
-------
3.2.1.2 Batch Chlorination
In the batch chlorination process (see Figure A-1, Appendix A,)
chlorine is bubbled into a reactor charged with benzene at a rate that
maintains a temperature of 40° to 60°C (Lowenheim and Moran 1975). The
top and bottom streams are treated as described above. At 100% chlor-
ination, the yield is about 80% monochlorobenzene, 15% 1,4-and 5% 1,2-
dichlorobenzene, with insignificant amounts of higher chlorinated ben-
zenes (Kurtz and Smalley 1979). The 1,2-dichlorobenzene is separated
from the 1,4-isomer by washing the 1,4-dichlorobenzene crystals with
methanol and heating at 100°C under vacuum (EPA 1977b). Two or three
kg of 1,4-dichlorobenzene are formed per kg of 1,2-dichlorobenzene (SRI
1979a). For high yields of 1,4-dichlorobenzene, either an aluminum
chloride catalyst is used or the mixed product stream is further chlor-
inated to convert 1,2-dichlorobenzene to trichlorobenzene, with sub-
sequent fractional distillation of 1,4-dichlorobenzene from the remain-
ing chlorobenzenes (Catalytic 1979).
3.2.1.3 Continuous Chlorination
Continuous chlorination is used to minimize the production of higher
chlorinated products, including the dichlorobenzenes (Lowenheim and Moran
1975; see Figure A-2, Appendix A). The reaction takes place in a series
of combined chlorination-fractionation chambers. The partially chlorinated
material is sent to a distillation unit, where the benzene is distilled and
returned to the chlorinator. Hydrogen chloride is then passed through one
or more towers in which the high boiling chlorobenzenes are used to remove
organic contaminants. The hydrogen chloride may be recovered as either
an anhydrous product or aqueous solution, with a carbon column being used
if flow organic specification is required. The other chlorinated products
are further fractionated into heavy tars (mostly dichlorofaenzenes) and mono-
chlorobenzene, which is neutralized as in batch chlorination (Lowenheim
and Moran 1975). Thus, monochlorofaenzene is immediately isolated and only
fresh benzene is exposed to chlorine (EPA 1975a), with a resultant yield
of up to 95% monochlorobenzene (EPA 1977a).
3.2.1.4 1,3-Dichlorobenzene
This isomer is not produced in commercially significant quantities
by direct chlorination (EPA 1977d). Alternative methods that have been
proposed include hydrogenolysis of trichlorobenzenes (Crowder and Gilbert
1958, Redman and Weimer 1960) and dechlorination of hexachlorocyclohexane
(lindane) (Allirot 1972). The usual method is isomerization of 1,2- and
1,4-dichlorobenzenes (EPA 1977d), generally at high temperature and
pressure (EPA 1977a, Pray 1958). Various patents relating to 1,3-di-
chlorobenzene manufacture are shown in Table A-2, Appendix A.
-------
3.2.1.5 Environmental Releases
Releases of the dichlorobenzenes occur at many stages during manu-
facture, in vent gases, liquid waste streams, or sludges. Table 3-1
shows calculated losses from production. Very low air emissions of
dichlorobenzenes occur through vents on the tail gas absorber, as by-
product HC1 is essentially free of organic compounds (Lewis 1975).
Overall emissions have been reported as 3.55 kg 1,2-dichlorofaenzene
lost/kkg produced and 7.24 kg 1,4-dichlorofaenzene lost/kkg produced
(EPA 1980e). The resultant 96 kkg and 240 kkg air emissions of the
respective isomers, subdivided into process, storage, and fugitive
losses, are distributed by individual plants, based on capacity, as
shown in Table 3-1.
Because 1,4-dichlorobenzene sublimes at room temperature, further
air emissions may eventually be expected from liquid and solid waste
streams (EPA 1979b). Liquid waste is discharged from stills, wash
tanks, and strippers involved in product refining (Catalytic 1979).
For the batch process, discharges from the dichlorobenzene column wash
stream have been estimated as 0.0037 kg/kg monochlorobenzene produced
(EPA 1975a). Based on 1.4 x 10^ kkg monochlorobenzene produced, 290
kkg of 1,4-dichlorobenzene are released to water, along with 230 kkg
1,2-dichlorobenzene (see Table 3-1).
Dichlorobenzene releases in 1,2-dichlorobenzene column waste have
been estimated as o.0001 kg/kg monochlorobenzene produced (EPA 1975a).
This amounts to 14 kkg of dichlorobenzenes discharged to land. In
addition, 0.044 kg of "polychlorinated aromatic resinous" sludge of
indeterminate composition is released per kg monochlorobenzene pro-
duced (EPA 1975a), totalling 6,200 kkg in 1978. As this sludge, dis-
charged to industrial and sanitary landfills, is rich in dichloro-
benzenes and is the major source of pollutant discharge (EPA 1979a), a.
much larger amount than 14 kkg of dichlorobenzenes could be disposed
of on land.
It is relevant to note that Brown _et_ _al_. (1975, as cited in EPA
1977a) have estimated losses to the environment (410 kkg 1,2-dichloro-
benzene and 540 kkg 1,4-dichlorobenzene) similar to the 330 kkg 1,2-
dichlorobenzene and 540 kkg 1,4-dichlorobenzene calculated as released
to all media in this materials balance. Another document estimated
total losses of dichlorobenzenes during production of monochlorobenzene
as 2,900 kkg to water and 3,100 kkg to land (EPA 1978b), but no rationale
was provided for these estimates.
3.2.2 Inadvertent Sources of Dichlorobenzene
Any human activity that unintentionally generates a chemical and
disperses it to the environment may be called an "inadvertent source"
of that chemical. The following considerations indicate chat inad-
vertant sources do not appear to contribute significant amounts of
3-3
-------
dichlorofaenzenes to the environment. Disposal p_er se_ (e.g., POTWs and
Urban Refuse) is discussed in Section 3.4.
•
While chemical plants are often inadvertent sources of chemicals-
due to production of byproducts, in this case these routes have been
considered in discussions of the production processes (Section 3.2.1.5).
Disinfection of drinking water or wastewater by chlorination is another
potentially important inadvertent source of chlorinated hydrocarbons
(see Section 3.4, Municipal Disposal of Dichlorobenzenes). Contamination
of municipal drinking waters has also been investigated in the National
Organic Monitoring Survey (NOMS), which examined 113 community water
supplies, representing all types of sources and treatment processes,
in three phases during a twelve month period (EPA, 1977f). As shown in
Appendix A (see Table A-3), dichlorobenzenes are detected neither fre-
quently nor in high concentration. Moreover, the source of dichloro-
benzenes, when they were found, is .not readily apparent, though the data
suggest that chlorination is not a significant source of dichlorobenzenes
found in these waters. A similar conclusion can be derived from another
study that found the highest levels of 1,2-, 1,4-, and 1,3-dichloro-
benzenes in drinking water to be only 1, 1, and <3 ug/1, respectively
(EPA, 1975b, see Table A-4, Appendix A).
EPA has summarized data on two other inadvertent sources, coal
mining and iron/ste.el manufacturing. The latter industry appears to
be the only source of significant loading, approximately 4 kkg of
1,4-dichlorobenzene per year in treated wastewater (EPA 1980f).
A final possible inadvertent source of dichlorobenzenes released
to the environment may be the incineration of polyvinyl chloride (PVC)
materials. A pilot-scale study on"combustion of PVC at temperatures
between 570° and 1100°C at various residence times and excess air levels
indicated emission factors of 0.10 mg to 22 mg of dichlorofaenzene(s) per
kg of PVC burned (Ahling jet al. 1978). The published data do not show
any consistent correlation between emission levels and combustion
conditions, so estimation of the significance of this possible source
of dichlorofaenzene emissions is difficult to make at this time. None-
theless, it should be noted that this source may be increasingly
important as incineration competes with land disposal for municipal
waste treatment.
An unresolved question at the present time is whether there are
any identifiable inadvertent sources of 1,3-dichlorobenzene. Moni-
toring data (Section 3.4.1) suggest that this isomer may be present
in the environment at levels that are comparable to the 1,2- and 1,4-
species, while the materials balance analysis indicates production and
use of 1,3-dichlorobenzene to be at least three orders of magnitude
lower than 1,2- and 1,4-dichlorobenzene.
j-o
-------
3.3 USES OF BICHLOROBENZENZS
3.3.1 Overview
The uses of dichlorobenzenes can be divided into the following
three major categories: (1) use as a reactant in chemical synthesis,
(2) use as a process solvent, and (3) use as a formulation solvent.
For the first two applications, the shipping destination represents
the point of most likely release to the environment. Release of
dichlorobenzene used as a formulation solvent, however, can occur
prior to, during and after the manufacturing process of formulation.
This section will examine the variety of specific uses of di-
chlorobenzenes, from mothballs to solvent uses and dye synthesis. The
1,2- and 1,4- isomers account for essentially 100% of the dichloro-
benzene used. Although 1,3-dichlorobenzene has a number of potential
uses, negligible commercial production is reported (Kao and Poffen-
berger 1979); therefore, this isomer is considered to have an insig-
nificant impact on the overall materials balance. A summary materials
balance for the total use categories is presented in Table 3-2, which
includes the limited quantitative data available on environmental
releases of the isomers discussed below. A table showing the frequency
of dichlorofaenzene detection in various industrial wastewater streams
has been included in Appendix B (see Table B-l).
3.3.2. 1,2-Dichlorobenzene
3.3.2.1. Overview
i
Total U.S. production of 1,2-dichlorobenzene in 1978 was estimated
to be 27,000 kkg (Hull 1980). While 3,200 kkg of this material were
exported that year, 210 kkg were also imported, for a net domestic
supply of about 24,000 kkg (U.S. Dept. of Commerce 1980, SRI 1979a).
It is estimated that the 1,2-dichlorobenzene domestic supply in 1978
was distributed as follows: 70% to organic synthesis (primarily 3,4-
dichloroaniline); 15% to toluene diisocyanate manufacture as a process
solvent; 8% to miscellaneous formulated solvent uses; 4% to dye manu-
facture and application; and 4% to other minor uses, primarily pesti-
cides manufacture (SRI 1979a). The following is a discussion of the
major uses (the minor uses will be covered together with 1,4-dichloro-
benzene minor uses in Section 3.3.4).
3-:
-------
Table 3-2. Oichlorobenzene Materials Balance: Use, 1978 (kkg/yr)a
Isomer
1 , 2- Di ch 1 orobenzene
1,3-Qichlorobenzene
1, 4-0 i chl orobenzene
Use Category
Synthesis of 3,4-Qichloroaniline
Toluene Diisocyanate Manufacture
Miscellaneous Solvents
Dye Manufacture
£
Others
Exports
Imports
Space Deodorant
Moth Control
Other^
Exports
Imports
Consumption
17,000
3,600
1,900
960
' 720
3.2009
neg
15,000
9,500
2,700
6.3003
Contained
in Products
17,000
960
650
2109 '
2.7QO
4309
Environmental Releases
Air tand Water
24C
3,600d negd
l,900e 20e 12a
neg°
70f
•
14,000h 500h 500h
9.5001 I1' I1'
5J
a) Numbers may not add due to rounding to two significant figures.
b) Input figures: Hull, 1980 (total); SRI, 1979a (percentage breakdown).
c) See Table A-l (Appendix A) for emission factor; negligible: <1 kkg.
d) Air: all assumed released to the atmosphere, EPA, I980e; Land: 558 kkg residue/TDI plant/yr, 100 ppm
ortho-dich1orobenzene in residue (nine plants) EPA, 1977a/b; Lewis, 1975.
e) Cleaning solvents: 99% released to air, 1% to land with containers, Simmons, 1980. Discharge of 12
kkg is from dye carrier use (see Section 3.4.1.4).
f) Partial survey of users for odor control in sewage: 70 kkg, Hull, 1980; 100% lost to the atmosphere.
Negligible (<1 kkg) loss from pesticide manufacture (see Table 3-3). Indeterminate amount used for
agricultural chemicals and laboratory supply.
g) U.S. Dept. of Commerce, 1980; SRI, 1979a. Placement of imports and exports in respective columns are
, for purposes of materials balance, not to imply that each goes solely to containment in a product or a
specific use.
h) 90% released to air, 10% to either water (toilet deodorizer) or land (garbage deodorizer), Willert,
1980.
i) All domestically-used mothballs assumed to release para-dichlorobenzene to the atmosphere during use
Environmental releases also include use in textile mTTTs (see Section 3.4.1.4).
j) Primarily pesticide manufacture (see Table 3-3 for emissions), plus: dye synthesis, aorasives -1
waxes ana finishes, and agricultural chemicals, SRI, 1979a; Hull, 1980.
oor
3-3
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3.3.2.2 Synthesis of 3,4-Dichloroaniline
The primary use of 1,2-dichlorobenzene, amounting to 17,000 kkg
in 1978 (SRI I979a), is the synthesis of 3,4-dichloronitrobenzene,
which is subsequently reduced to 3,4-dichloroaniline by the following
reactions:
HN03
This white, crystalline end product is used chiefly to manufacture urea
herbicides, the most important of which is propanil, a rice herbicide
(SRI 1979a). It also has minor applications in pesticides, bactericides,
and dyestuffs. The reaction step utilizing 1,2-dichlorobenzene is a
captive one, with most of the dichlorobenzene claimed to be either con-
sumed, recovered, or recycled (Zeftel 1980). The producers of 3,4-di-
chloroaniline , along with data on 1,2-dichlorobenzene emissions, are
listed in Table B-2.
3.3.2.3
Manufacture of Toluene Diisocvanate
The manufacture of toluene diisocyanate (TDI) consumes 15% or
3,600 kkg of the net 1,2-dichlorobenzene domestic supply (SRI 1979a).
Toluene diisocyanate is used in urethane polymers, primarily for flexible
foams in furniture cushions. The producers of toluene diisocyanate, plant
capacities, and '1,2-dichlorobenzene emissions are presented in Table B-3.
As shown schematically in Figure B-l, l,2r-dichlorobenzene is used
as a process solvent in which diaminotoluene is dissolved prior to re-
action with phosgene to produce crude toluene diisocyanate. The 1,2-
dichlorobenzene is recovered during distillation of unreacted phosgene
(which the solvent has absorbed) and during vacuum distillation of the
crude toluene diisocyanate. Although no specific data on emissions were
available, it has been estimated that virtually all (3,600 kkg) of the
1,2-dichlorobenzene utilized for TDI manufacture is eventually released
to the atmosphere (EPA 1980e), through vents, scrubbers and leaking
valves or pipes (see Table B-3). The distillation residue is incinerated
(Chadwick and Hardy 1967, Sato 1966) or often disposed of on land (EPA 1977a)
It has been estimated that 558 kkg of centrifuge residue are produced
per toluene diisocyanate plant per year from evaporator units for TDI
purification and solvent recovery, and that this residue contains no
more than a few hundred ppm 1,2-dichlorobenzene (EPA 1977a, EPA 1977b,
Lewis 1975). If the 1,2-dichlorobenzene concentration in the residue is
100 rug/kg,a total of <1 kkg should be discharged to land from the nine
plants producing toluene diisocyanate.
3-9
-------
3.3.2'.4 Miscellaneous Solvent Uses
As is the case for many chlorinated hydrocarbons, 1,2-dichloro-
benzene exhibits useful solvent properties which give it a wide range
of applications. An estimated 8% or 1,900 kkg of the annual 1,2-
dichlorobenzene net supply is consumed in the solvent market, which
includes automobile engine cleaners, fuel additives, and carburetor
cleaners.
The 1,2-dichlorobenzene isomer is also used as a solvent in
paint formulations, as well as in compounds for removing paints, inks,
varnishes, lacquers, resins, gums, waxes, heavy greases, acetylcell-
ulose, sulfur, organic sulfur compounds and oxides of nonferrous
metals. In addition, 1,2-dichlorobenzene is a very good solvent for
rubber and tar, and is frequently used to remove tarry residues in
stills and other processing equipment. Other solvent applications
include: shoe polish, metal polish, firearms, cleaners, rust pre-
ventatives, and other cleaning/polishing formulations, dissolving
pitch on papermaking felts, degreasing leather hides/woolen pelts,
and as a carrier solvent for preservatives/repellents in wood-pre-
serving compounds (SRI 1979a, Zacharias, 1980, Hull 1980, PPG, 1977).
In this study, all of the 1,2-dichlorobenzene used in miscella-
neous solvents is assumed to be discharged to the environment, due to
the number of small operations performed and the attendant economic
infeasibility of solvent recovery. Furthermore, 99% of the emissions
(1,880 kkg) are estimated to be released to the air, with the remaining
1% (20 kkg) discharged to land in containers (Simmons 1980; see Table
3-2).
3.3.2.5 Dyes; Synthesis and Application
The compound 1,2-dichlorobenzene serves a dual purpose in the dye
industry, in both manufacture and application of the dyestuffs. Approx-
imately 3% or 960 kkg of the net 1,2-dichlorobenzene supply is used
as a dye carrier, or as a process solvent or reactive intermediate in
dye synthesis (SRI 1979a).
Dye carriers, also called dye accelerants, are used to achieve
complete dye penetration of synthetic fibers, primarily polyester.
The carriers effectively loosen the interpolymer bonds of the fibers
to allow penetration of disperse dyes.' (Disperse dyes are water-
insoluble, nonionic dyes for application to hydrophobic fibers from
an aqueous suspension.) This process is not needed for natural tex-
tiles since they contain open, partially hollow structures, which are
easily penetrable by dyes.
Dying procedures vary according to the makeup of the textile
material. Almost all 100% polyester is pressure dyed, utilizing an
average of 2% by weight dye carrier to fabric. An atmospheric process
is used for blended materials (lass than 100% polyester) and requires
3-10
-------
a higher concentration of dye carrier, an average of 10% by weight
(Stone 1980). No exact figure is available for 1,2-dichlorobenzene
release from consumption as a dye carrier, but the compound does find
widespread use in this market [BASF Corporation, however, reports that a-
mixture of isomers acts as a'better carrier (Seizenger 1980)]. It
seems probable, that all of the dichlorobenzene used annually as a dye
carrier is eventually released into the environment. ( A possible
scheme for control of dichlorobenzene release from use as a dye
carrier is shown in Figure B-2.)
Contradictory information has been received on one use of
1,2-dichlorobenzene. Some references discuss the use of 1,2-dichloro-
benzene as a dye intermediate (EPA 1977c, Bannister ot_ al. 1979),
but industry representatives claim that use of the dichlorobenzenes
is limited to the role of pro-cess solvent rather than as reactive
precursors (Lonenzo 1980, Anderson 1980). Nonetheless, PPG Industries,
Inc. does mention the sulfonation of 1,2-dichlorobenzene to produce the
dyestuff 3,4-dichlorobenzene-sulfonic acid (PPG 1977) and the manu-
facture of 3,4-dichloroaniline, sometimes used as a dyestuff, has
already b.een discussed • (see Section 3.3.2.2). Specific dyes for which
1,3-dichlorobenzene use as a process solvent during production has been
documented are listed in Table B-4, along with the names and loca-
tions of the dye manufacturing plants. Dichlorobenzene used as a pro-
cess solvent may conservatively be assumed to be released to the environ-
ment in amounts equal to the annual usage for this application. The
releases to water,'land, and air can be estimated as described below.
Environmental release data for the dye industry are limited.
Levels of up to 380 ug/1 dichlorobenzene in raw wastewater and 32 yg/1
in final effluent have been found in one dye manufacturing plant
(Games and Hites 1977), but a total flow for the entire industry is
not presently available. Analysis of wastewater samples from textile
mills, where 1,2-dichlorobenzene might be used as a dye carrier,
revealed a maximum level of 290 yg/1 of 1,2-dichlorobenzene in raw
wastewater and 20 yg/1 in the treated water (EPA, 1980f). Using a
total annual wastewater volume of 600 x 10^ m^/yr (EPA, 1976b), a
total release of 12 kkg is estimated for treated effluent from this
industry. Releases of dichlorobenzene to land and air may be esti-
mated from the difference between these concentrations in raw and
treated wastewater and total industry flow and by use of the assumption
that the material removed from the water is either incorporated in or
absorbed onto sludge destined for land disposal, or volatilized to
the atmosphere. The resultant total is 160 kkg of 1,2-dichlorofaenzene.
The data describing the behavior of dichlorobenzenes in publicly-owned
treatment works (POTWs; see Section 3.4., Table 3-4) can serve as a
basis for assuming that 99% of this latter amount will end up in the
air and only 1% in sludge (see Table 3-2) . A similar calculation for
1,^-dichlorobenzene, using concentrations of 220 yg/1 for raw and 1.5 ug/1
for treated wastewater (EPA 1980f), gives an estimate of 0.9 kkg of
water, 130 kkg to air, and 1.3 kkg to land '(see Table 3-2).
3-n
-------
This isomer is used for moth-proofing of textiles (see Section 3.3.3.3)
and could possibly be an ingredient or impurity in some dye carriers
(EPA 1979b). These releases are included in the emissions reported
for use of 1,4-dichlorobenzene for moth control.
3.3.3 1,4-Dichlorobenzene
3.3.3.1 Overview
In 1978, 33,000 kkg 1,4-dichlorobenzene were produced, 6,300 kkg
exported and 430 imported (Hull 1980, U.S. Dept. of Commerce 1980).
As in most years, a significant percentage of the 27,000 kkg 1,4-di-
chlorobenzene remaining for domestic consumption was formulated into
blocks, balls, and cakes, devoted to space deodorants (55%) and moth
control (35%); the remaining 10% was comprised of minor uses (SRI 1979a)
This section discusses the two major uses of 1,4-dichlorobenzene, while
the minor uses will be covered along with those of 1,2-dichlorobenzene
in Section 3.3.4.
3.3.2.2 Odor Control
Space deodorizing is the largest volume market for 1,4-dichloro-
benzene, accounting for 55% (15,000 kkg) of the net domestic supply in
1978 (SRI 1979). This category includes deodorants for toilet bowls,
urinals, garbage and diaper pails (EPA 1977a). These products are
usually sold as 100% 1,4-dichlorobenzene blocks, although perfume is
often added. The predominant approach in public urinals has been to
use odor-masking agents, but a recent study has investigated the use of
a urease/1,4-dichlorobenzene composition to control the source of odor,
as well as alleviate odor (Weber 1977).
Of the 15,000 kkg of 1,4-dichlorofaenzene used in the category,
all is assumed to be released to the environment, by sublimation to
the atmosphere, flushing into sewers or land disposal with garbage.
It is estimated that approximately 90% (14,000 kkg) of the 1,4-dichlo-
robenzene used for this purpose is released to the air; the remaining
10% (1,000 kkg) is released to either land or water, depending upon
whether it is used as a garbage deodorant or toilet deodorant, respec-
tively (Wiliert 1980).
3.3.3.3 Moth Repellant
The 1,4- isomer has been used extensively in household mothballs
for many years. In 1978, this use consumed 9,500 kkg (35%) of the
1,4-dichlorobenzene available for domestic consumption (SRI 1979a,see
Table 3-2). With the increased use of synthetic fabrics, the market
for mothballs should decline.
Numerous brands of mothballs are available to the consumer, con-
taining ^_99% 1,4-dichlorobenzene (EPA 1980d) . Other examples of moth/
3-12
-------
insect control with 1,4-dichlorobenzene include preservation of glycerin-
treated dried flowers during shipment, moving and storage (vans and
warehouses), mothproofing of textiles during production, and possible
use by furriers (Hull 1980, EPA 1979b). For the purpose of this
materials balance, essentially all of the 1,4-dichlorobenzene used in
mothballs is assumed to be released to the atmosphere, with approx-
imately 1 kkg going to water and land from the textile industry (see
Section 3.3.2.5). Morita and Ohi (1975) found the following 1,4-di-
chlorobenzene levels in indoor air: inside wardrobe, 1,700 ug/m^; inr-
side closet, 315 ug/nr; bedroom, 105 ug/rn-^ (see Table B-5).
3.3.4 Minor Uses
3.3.4.1 Overview
The minor uses of 1,2- and 1,4-dichlorobenzene, though comprising
only a small percentage of total output, totalled approximately 3,400
kkg in 1978. These uses include: agricultural chemicals, abrasives,
odor control, laboratory applications, dye synthesis (1,4-dichloro-
benzene), and uses in various other formulated products. The miscella-
neous uses in this category (those other than pesticide manufacture)
are generally dispersive in nature (i.e., exposure results as a normal
consequence of use). Therefore, the small volume involved belies the
fact that the potential for high exposure levels to a specific consumer
population could exist.
3.3.4.2 Agricultural Chemical^
Both 1,2- and 1,4-dichlorofaenzene are listed in the Farm Chemicals
Handbook (1975) for various applications in the agricultural chemicals
industry. In addition, EPA's Pesticides Division maintains a list of
products that contain either of the two isomers (EPA 1980d). Estimates
of emissions from pesticide manufacture, distributed by geographic
region, are presented in Table 3-3.
Besides moth control, discussed in Section 3.3.3.3, 1,4-dichloro-
benzene can also be applied to tobacco seed beds for blue mold control,
for control of peach tree borers, and to combat mildew and mold on
leather and fabrics. The 1,2-dichlorobenzene isomer possesses a
slightly wider range of applications, including use as an herbicide,
insecticide, and soil fumigant. It has been used to control mites,
termites, peach tree borers, bark bettles and grubs, as well as
insects and mites in poultry houses and animal sleeping quarters (Farm
Chemicals Handbook 1975).
The exact amount of each isomer devoted to agricultural chemicals
was not available (see Table 3-2). Nonetheless, it is assumed that a
large portion of the amount used for this purpose is released co che
atmosD'nere.
3-13
-------
Table 3-3. 1978 Dichlorobenzene Emission Estimates from Pesticide Manaufacturers3
CO
I
I--1
keg ion
New England
Middle Atlantic
East North Central
West North Central
South Atlantic
East South Central
Uest South Central
Mountain
Pacific
Total
Number of
Sites per
Region
4
37
19
15
17
14
15
5
13
139
1,2 -dichlorobenzene
Emissions
(kg/yr)b
10
96
49
39
44
36
39
13
34
360
1 ,4 -dichlorobenzene
Emissions
(kg/yr)c
40
370
190
150
170
140
150 ,
50
130
1,400
a) Values rounded to two significant figures.
b) Average per site 2.6 kg/yr; see Table A-l for emission factor.
c) Average per site 10 kg/yr; see Table A-l for emission factor.
Source: EPA, 1980e.
-------
3.3.4.3 Abrasives Manufacture
A minor application of 1,4-dichlorobenzene, probably accounting
for <1 kkg annually (Richards 1980), is its use in the manufacture of
abrasive grinding wheels. Production involves the bonding of abrasive
grains (i.e., aluminum oxide, silicon carbide, diamond) to the wheel
shape, using a ceramic (vitrified) or resin (resinoid) matrix. The
1,4-isomer (as well as naphthalene) is used as an additive in the grain
and bond mixture to faciliate a more open spacing of the grains. The
additive vaporizes during the curing operations. The compound is
well-suited for this application, due to its hard crystalline nature,
ability to be crushed to definable grit sizes, and quick vaporization
at the curing temperatures (1,200*0 for the vitrified matrix and 150-
200°C for the resinoid matrix).
Although reference is made to the use of 1,4-dichlorobenzene in
resinoid-bonded wheels (Pinstone 1978), contact with industry repre-
sentatives suggests that, at least in this country, 1,4-dichlorobenzene
is used in vitrified bonding only (Richards 1980). Only one of the
three major abrasives manufacturers, Norton Company (Worcester, MA),
uses it (Richards 1980). All of the 1,4-dichlorobenzene used for this
purpose is assumed to be released to the atmosphere during curing
(Richards 1980 L.
3.3.4.4 Other Uses
The compound 1,4-dichlorobenzene is also used in chemical synthesis,
floor waxes and finishes, textiles, and extreme pressure lubricant (Hull
1980). As a reactive intermediate, 1,4-dichlorobenzene can be used to
manufacture the dyestuffs 2,5-dichloroaniline and 2,5-dichlorobenzene-
sulfonic acid, although a growing market is in the manufacture of poly-
phenylene sulfide resin, an engineering plastic produced by Phillips
Chemical Co. under the trade name Ryton®. The compound 1,2-dichloro-
benzene is sold for use in laboratories and was at one time formulated
as a heat-transfer medium (Dowtherm E® by Dow Chemical Co.), but that
product line has been discontinued (Seifert 1980). Specific data on
emissions from the formulation or use of dichlorobenzenes in these
applications were not available.
The compound 1,2-dichlorobenzene has also been mentioned in connection
with odor control in industrial wastewater plants and sewage treatment plants
(Hull 1980). One survey reported that approximately 70 kkg was used in deodor-
ant in sewage plants (Kopp 1980, Hull 1980), but that this did not represent
the entire market. Nonetheless, this 70 kkg can serve as a lower limit for
estimates of 1,2-dichlorobenzene release to the air from use in odor control
(see Table 3-2).
3.4 MUNICIPAL DISPOSAL OF DICHLQROBENZENES
This section deals with the ultimate disposition of dichlorobenzenes
discharged to municipal wasta facilities. These include publicly-owned
treatment works (POTWs) and urban refuse landfills or incinerators.
3-15
-------
3.4.1 POTWs
Input of dichlorobenzene to POTWs is largely dependent upon
variation in industrial discharges feeding the POTWs and the types of
industry in a particular municipal area. A recent EPA study of 20
selected urban POTW facilities with secondary treatment and varying
feed conditions produced a materials balance of dichlorobenzenes shown
in Table 3-4.
An overall materials balance for municipal disposal, presented in
Table 3-5. can be constructed using a total U.S. POTW flow of approxi-
mately lO11 I/day (EPA 1978d) and simple mean values of 8.3, 1.6, and
2.1 yg/1 (influent) and 2, 1.7 and 2 ug/1 (effluent) for 1,2-, 1,3- and
1,4-dichlorobenzene, respectively (from Table 3-4). For these calcu-
lations influent and effluent flow rates are assumed to be equal (i.e.
water loss from sludge removal and evaportion is small compared with
influent flows). Using these assumptions, 210 kkg total dichlorobenzes
were discharged from POTWs in 1978, while there was an input of 440 kks
(see Table 3-5). S
The amount of dichlorobenzene discharged in sludge can be estimated
from the dichlorobenzene concentration in sludge and the quantity of dry
sludge produced annually, 6.0 x 10<5 kkg (EPA 1979c). Assuming the simple
mean 1,2-, 1,3- and 1,4-dichlorobenzene concentrations of POTW wet sludge
_to be 59, 52 and 105 ug/1, respectively (see Table 3-4), 31 kkg of total
dichlorobenzene were released to land as a component of sludge (EPA 1979d).
The amount of dichlorobenzene released to the atmosphere may be
approximated by the difference in the above calculations, with the
following assumptions: (1) dichlorobenzene recycled within the activated
sludge process will eventually be "wasted"; (2) the dichlorobenzene bio-
logically degraded is negligible; and (3) the dichlorofaenzene is lost to
the atmosphere by mechanical stripping, or aeration (note: volatilization
is the primary environmental transport mode for dichlorobenzene). Thus,
an estimated 200 kkg of dichlorobenzene are released to the atmosphere from
POTWs.
It is of interest to note the presence of 1,3-dichlorobenze in
the POTW streams, despite the fact that negligible production of the
isomer is reported (Kao and Poffenberger 1979). Possible sources
include: contaminant of 1,2- or 1,4-dichlorobenzene-containing products,
or analytical errors and artifacts. The former is probably not a si*-
nificant source, as a contaminant would only be present at ppm levels°in
the product and not result in wastewater concentrations comparable to
the major isomers. The latter theory is a stronger one, due to the
similarity of physical properties among all three isomers. Finally,
it is important to point out the limited nature of the POTW data, in
chat 20 plants ara caken as representative of the entire U.S. Vastlv
dirrarent totals for influent (110 kkg) effluent (55 kkg), atmospheric '
emission (33 kscg) and sludge ralaases (negligible) of dichlorobenzenes
rasult ir median values are used in the calculations instead of simola
mean values.
3-16
-------
Table 3-4 Oichlorobenzene Distribution in POTWs. Sludge; Selected Urban Sites
Plant Average Flow
(106 I/day)
1
2
J
4
5
6
7
U
9
10
U
13
14
15
16
I/
Iti
19
20
Median
Simple Mean
Mow Weighted
340
30
42
320
83
27
190
87
200
87
160
150
64
53
27
550
57
240
260
450
Mean
1 .2-Uichlorobenzene
Influent Effluent Sludgeb
3 1
4 . 1
ND
105 6
<5 <5
Nfl
nu
3 <10
<2 <2
NO
3 <3
<10 ND
NO
NO
18 2
NO
7 5
<5 <5
2.5 1
8.3 2
15 2.8
<10C
<10
282
3
233
258
ND
ND
ND
300
88
NO
59
Concentration (pg/1)
1 ,3-Dichlorobenzene
Influent Effluent Sludgeb
1 1 «10
1 3 <10
„__ un ..
<5 <5 252
.............. un ......
3 <1 ND
<10 <10 35
<2 <2 475
1 <3 ND
NO
Nn
<3 <3 150
un
<5 <5 100
un.
1.6 1.7 52
2.1 2.2
1 ,4-Dichlorobenzerie
Influent Effluent Sludgeb
3
1
13
<5
1
<10
1
3
3
2
0.5
2.1
3.0
1
<10
HI)
2
<5
<\
<10
1
NU
<3
un
un
NU
NU
NU
NU-*--
NU
NU
2
un
0.5
2.0
1.8
<10
<10
1.128
15
ND
28
325
ND
1.217
190
ND
150
a) Ihe percent industry contribution to flow ranges from <5 to 50Z.
b) Combined primary and secondary sludge.
c) for calculation of means and medians,values preceded by < are taken as that number (upper limit) and NO as zero.
d) Not detected.
U'A, i'JIiOc.
-------
Table 3-5 Dichlorobenzene Materials Balance: Municipal POTWS1 and Refuse (kkg/yr)
Source Input Air Land Water
P01W 440b 200c 31d 210]
Urban
Incineration unknown neg-
Landfill 520 520f
iJ
oi a) Publicly owned treatment works.
b) Figures calculated from EPA data (see Table 3-4): based on 1011 I/day total POTW flow and simple mean
values for influent concentrations of; ortho-dichlorobenzene (8.3 viQ/1)» meta-dichlorobenzene (1.6 iig/1) and
p^ra-dichlorobenzene (2.1 »jg/l); effluent concentrations of: 2, 1.7 and 2 pg/l» respectively. See Section
3.4.1 for totals calculated from median values.
c) Mathematical difference between input and (Land and Water) values.
d) Based on simple mean values of 59 iig/1 (prtho-dichlorobenzene). 52 pg/1 (meta-dichlorobenzene) and 150 ng/1
(pjnra^dichlorobenzene) for wet sludge loading (see Table 3-4).
e) 99.9% efficiency of incineration; MacDonald ett aJU, 1977.
f) Dichlorobenzene in spent solvent containers and garbage pails (see Table 3-2).
-------
3.4.2 Urban Refuse
Three options for handling of urban refuse are available: energy
recovery (primarily by incineration), material recovery, and disposal
through incineration or landfills. Urban refuse can be divided into
two major components: 1) a combustible fraction (paper, cardboard,
plastics, fabrics, etc.); and 2) a noncombustible fraction (ferrous
and nonferrous metals, glass, ceramics etc.). There are no data,
however, concerning dichlorobenzene emissions from municipal incinera-
tion, but these compounds are probably destroyed with over 99.9%
efficiency (MacDonald _e_t al. 1977). Dichlorofaenzenes could be
disposed directly as municipal wastes, in formulated solvent containers
or as garbage deodorants. From Table 3-2, this total is 520 kkg (see
Table 3-5).
3.5 SUMMARY AND CONCLUSIONS
The chlorobenzenes are produced by direct chlorination of benzene
in continuous or batch reactors. The product is a mixture of monochloro-
benzene and 1,2- and 1,4-dichlorobenzenes as major products, along with
small amounts of higher chlorinated benzenes. In 1978, 27,000 kkg of
1,2- and 33,000 kkg of 1,4-dichlorobenzene were manufactured in the U.S.
Total dichlorobenzene exports were 9,500 kkg and imports totalled 640 kkg,
The total amount of dichlorofaenzene released to the environment
is estimated to be approximately 31,500 kkg, more than one-half of the
available U.S. supply. Environmental releases during production
totalled 96 kkg to air, 6.3 kkg to land, and 230 kkg to water'for
1,2-dichlorobenzene and 240 kkg, 7.7 kkg and 290 kkg for 1,4-dichloro-
benzene. The.se losses occur in vent gases; liquid waste streams from
stills, wash tanks and strippers; and sludges. Inadvertent sources of
dichlorobenzenes, such as industrial incineration and chlorination of
drinking water, do not appear to release significant quantities to the
environment.
In general, uses of the dichlorobenzene are responsible for the
major losses to the environment. Whereas manufacture accounts for only
2.8% of the environmental releases, use accounts for over 95%. A flow
diagram summarizing the dichlorobenzene materials balance is presented
in Figure 3-1.
The largest environmental releases are atmospheric, reflecting the
volatility of these chlorinated hydrocarbons. Emissions of 1,2-dichloro-
benzene (% 5,500 kkg) occur primarily during solvent usage [e.g.,
cleaning or process solvents during toluene diisocyanate (TDI) or 3,4-
dichloroaniline production] while the 1,4-isomer (% 24,000 kkg) is
released as a result of use in mothballs and as a space deodorant.
Most of these applications (except TDI process solvent use) represent
widespread, dispersive uses, with the potential for exposure to the
general public or specific population subgroups as a normal consequence
of use.
3-19
-------
Sources
Direct: Production
Uses
Environmental ^e'easas
Lane
1,2-Oicnlorobenzene
27.000
Net
Domestic
Supply
24,000
3,4-Oicnloroaniline
Production 17,000
Manufacture of Toluene
Diisocyanat* 3.600
-» 3,500
Miscellaneous Solvents
(9.3.. paint remover
da-inking) 1.900
1.900
96
Dye Synthesis 960
Minor Uses (e.g.,
pesticides, odor
control) 720
70
1,3-Qichlorobenzene
neg
neg
20
6.3
-neg-
12
230
1,4-01cn1orobenzene
33.000
Imoort
430
Net
Domestic
Supply
27,000
Space Deodorant IS,000 • — —» 14,000
otn Control 9,500
Minor Uses (e.g., pesti-
cide synthesis, abrasives,
textiles)
2,700
9,500
240
5
500
7.7
500
290
Indirect
200
31
210
neg
(Iron 5 Steel Manufacture
PVC Incineration - — — — — — — __ __
-neg-
neg
4
"Igure 3-1. Dicnlorooenzene .Materials Balance "lowsneet, 1978 (kkq/yr)a
a) Numoers iay not add aue to 'ounalng to two significant f-!gurss.
Inputs not Salsncsa 3y »nvironmentai releases are contained in products (see Taole 3-2)
3-20
-------
Of the estimated 440 kkg total dichlorobenzenes entering POTWs,
calculations indicate that approximately one-half is lost to the air
and one-half is discharged to water. The input of dichlorobenzenes to
municipal incinerators is uncertain, yet these compounds are probably
destroyed with over 99.9% efficiency. Dichlorobenzenes that are
dispersed to landfills (520 kkg) arrive there primarily as garbage
deodorants or as residue in used solvent containers.
A major goal of this materials balance was to establish a range
of uncertainty for the numbers presented. The conclusions are based
on a review of all known dichlorobenzene environmental release data.
It should be noted, however, that portions of this information are
tentative, and, in certain cases, limited to engineering judgement.
3-21
-------
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Chlorinated Aromatic Hydrocarbon Manufacture: Chlorobenzenes.
Washington, DC: Contract No. 68-03-2567; December, 1979.
Environmental Protection Agency, 1979b. Development Document for
Effluent Limitations Guidelines and Standards for the Textile Mills,
Point Source Category. Washington, DC: EPA 440/l-79/022b; 1979.
Environmental Protection Agency, 1979c. Comprehensive Sludge Study
Relevant to Section 8002(g) of the Resource Conservation and Recovery
Act of 1976. Washington, DC: EPA-SW-802; 1979.
Environmental Protection Agency, 1979d. Environmental Impact
Statement Criteria for Classification of Solid Waste Disposal
Facilities and Practices. Washington, DC: EPA SW-821; 1979.
Environmental Protection Agency, 1980a. Chlorinated Hydrocarbon
Manufacture: Preliminary Draft Report, An Overview. Washington, DC:
EPA Contract No. 68-02-2567; Februrary, 1980.
3-23
-------
Environmental Protection Agency, 198Qb. Development Document for
Effluent Limitations Guidelines and Standards for the Inorganic
Chemicals Manufacturing, Point Source category. Washington, DC:
EPA 440/1-79-007; June, 1980.
Environmental Protection Agency, 1980c. Fate of Priority Pollutants
in Publicly Owned Treatment Works, Interim Report. Washington, DC:
EPA 440/1-80/301; October, 1980.
Environmental Protection Agency, 1980d.- Data printout. (Pesticide
Division Systems Support Branch). Washington, DC: Pesticide
Division; 1980.
Environmental Protection Agency, 1980e. Human Exposure to Atmospheric
Concentrations of Selected Chemicals: A Summary of Data on
Chlorobenzene (para-dichlorobenzene and ortho-dichlorobenzene).
Research Triangle Park, NC: Office of Air Quality Planning and
Standards; EPA Contract No. 68-02-3066; May, 1980.
Environmental Protection Agency, 1980f. Treatability Manual, Vol. I:
treatability data. Washington, DC: EPA 600/8-80-042a; 1980.
Environmental Protection Agency, 1980g. Priority Pollutant Frequency
Listing Tabulations and Descriptive Statistics: memo from:
D. Neptune, Analytical Programs to R.B. Schaffer, Director of Effluent
Guidelines Division. January, 1980.
Farm Chemicals Handbook. Willoughby, OH: Meister Publication Co.;
1975. Pages D 149,152.
Games, L.M.; Hites, R.A. Composition, treatment efficiency, and
environmental significance of dye manufacturing plant effluents.
Analytical Chemistry 49(9):1433-1440;1977.
Hull and Co. Employee Exposure to Chlorobenzene Products. Greenwich,
CT: February, 1980.
Kao, C. and Poffenberger, N. Chlorinated benzenes, (In) Kirk-Othmer
Encyclopedia of Chemical Technology, 3rd ed. New York: John Wiley
and Sons; 5:797-808,1979.
Koop, T. (EPA, Office of Toxic Substances) Personal Communication,
1977; as cited in EPA, 1977a.
Kurtz, B.E.," Smalley, E.W. Chlorobenzene and dichlorobenzene, (In)
Encyclopedia of Chemical Processing and Design. New York: Marcel
Dakker; 8:117-135; 1979.
Lewis, P.F. (Department of Health, Education and Welfare, Public
Health Service, Division of Chemical Technology). Chlorinated
Benzenes; Rockville, MD: January 1975.
3-24
-------
Lonenzo, J. (Ciba-Geigy Corp.) Personal Communication, July 1980.
Lowenheim, F.A.; Moran, F.A. Chlorobenzene, dichlorobenzene (In)
Faith, Keyes and Clark, Industrial Chemicals, 4th ed. New York:
Wiley-Interscience; 1975.
MacDonald, L.P., Skinner, D.J.; Hopton, F.J.; Thomas, G.H. Burning
waste chlorinated hydrocarbons in a cement kiln. Ottawa, Canada:
Environmental Protection Service, Fisheries and Environment;
EPS-4-WP-77-2;1977.
Mannsville Chemical Product. Chemical Products Synopsis. Mannsville,
New York; 1978.
Morita, M. and Ohi, G. Para-dichlorobenzene in human tissue and
atmosphere in tokyo metropolitan area. Environment Pollution;
8:269-274,1975.
PPG Industries, Inc. 1977. PPG chlorinated benzenes. Chemical
Division, Pittsburgh, PA. 40 p.
Pinkstone, W. Abrasives (In) Kirk-Othmer Encyclopedia of Chemical
Technology. 3rd ed. New York: John Wiley and Sons: 1:26-52 ; 1978 .
Pagnotto, L.D. Walkley, J.E. Urinary dichlorophenol as an index of
para-dichlorobenzene exposure. Journal American Industrial Hygiene •
Association; 26:137-142; 1965.
Pray, B.O., inventory; Columbia-Southern Chemical Corp. assignee.
U.S. patent 2,819,321. 1956 January 7.
Redman, H.E. Weimer, P.E. Ethyl Corp., assignee. U.S. patent.
2,943,114. 1960 June 28.
Richards, T. (Norton Co.) Personal Communication, July, 1980.
Sato, K. Make more TDI and less polymer. Hydrocarbon Processing;
45(11):177-179;1966.
Seizenger, R. (BASF Corporation) Personal Communication, August, 1980.
Seifert, W. (Dow Chemical Company) Personal Communication, August,
1980.
Simmons, R. (Dow Chemical Company) Personal Communeiation, August.
1980.
3-25
-------
' ~'
Stanford Research Institute, 1979b. Montrose Chemical Corporation:
Monochlorobenzene Survey Report, Menlo Park, CA; 1979.
Stone, R. (Cotton, Inc) Personal Communication, August, 1980.
U.S. Department of Commerce. (Foreign Trade Division, Trade
Information Branch) Personal Communication, August, 1980.
Wannemacher, R; Demaria, R. Dye carriers (In) Kirk-Othmer
JohnWil.
1980.
, I. (Willert Home Products) Personal Communication, September,
Young, D.R.; Heesen, T.C.; McDermott-Erlich, D.J. Synoptic survey of
chlorinated hydrocarbon inputs to the sourthern California bight.
Draft Report to National Environmental Research Center, EPA
Corvallis, Oregon, June, 1976.
Zacharias, M. (National Paint and Coatings Association) Personal
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Zeftel, L. (e.i. du Pont de Nemours and Co., Inc.) Personal
Communication, July 1980.
3-26
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4.0 FATE AND DISTRIBUTION IN THE ENVIRONMENT
4.1 INTRODUCTION
This chapter characterizes the fate processes that determine the
ultimate distribution of the dichlorobenzenes in environmental media and,
therefore, the opportunities for exposure of humans and other biota.
The physiochemical characteristics of dichlorobenzenes are summarized
in order to identify the processes that transport or transform the
chemical upon its release to the environment (Section 4.2). Modelling
efforts undertaken to characterize the fate of dichlorobenzenes in
selected environmental scenarios are described (Section 4.3). Monitoring
data are presented from STORET and a limited number of surveys that
provide indications of concentrations actually detected in environmental
media (Section 4.4).
4.2 PHYSIOCHEMICAL CHARACTERISTICS
The three dichlorobenzene isomers have the following chemical
structures:
1,2-dichlorobenzene
(ortho- or o-dichlorobenzene)
1,3-dichlorobenzene
(meta- or m-dichlorobenzene)
Cl
1,4-dichlorobenzene
(para- or p-dichlorobenzene)
The general physical and chemical characteristics relevant to the environ-
mental behavior of these compounds are summarized in Table 4-1. An
examination of these data reveals both the similarities and the differ-
ences among the three isomers. The three compounds have little variation
in such properties as boiling point, density, and vapor pressure. Both
1,2- and 1,3-dichlorobenzene have low melting points (-17.0°C and -24.7°C,
-------
TABLE 4-1. PHYSICAL AND CHEMICAL PROPERTIES OF DICHLOROBENZENES
Dichlorobenzene Isomer
Property
llolscular Formula
lioiecular Weight
Halting Point (°C)
Boiling Point (°C
at 1 atm)
Density at 20°C
Vapor Pressure
(nn Hg at 25° C)
Saturated Vapor Cone.
(g/m3 at 25°C)
Water Solubility
(mg/i at 25°C)
Partition Coeff.
Qctanol:Water
Sediment:Water
Fish:Water
ilicrobial Degradation
Rate Const. (days~^)
Henry's Law Const.
(atin m3 mo.le"1)
1,2-
CgH^Clz
147.01
-17.0
180.5
1.3048
1.5
1.30
12
145
120
2500
2400
628
209
1.1
1.94xlO"3
1,3-
CbHuCl2
147.01
-24.7
173.0
1.2884
2.28
2.20
18
123
2400
—
—
—
2.63xlO~3
1,4-
C6&+C12
147.01
53.1
174.0
1.2475
1.18
—
9
79
79
2500
2500
612
205
1.2
2.72xlO"3
Reference
CRC Weast (1979)
CRC Weast (1979)
CRC Weast (1979)
CRC Weast (1979)
CRC Weast (1979)
Versar (1979)
Calc. Chiou, et.al.
(1977)
Calculated: PV=riRT
Verschueren (1977)
U.S. EPA (1980b)
U.S. EPA (1980b)
Calc.-Chiou, _ejt ol. (1977)
U.S. EPA (1980b)
U.S. EPA (1980b)
U.S. EPA (1980b)
U.S. EPA (1980c)
4-2
-------
respectively) and so are liquids at ambient temperatures; 1,4-dichloro
benzene, however, is a solid with a melting point of 53.1°C.
Some initial conclusions about the environmental fate of dichloroben-
zenes can be made from the physiochemical properties. The fact that the
octanol:water and the sediment:water partition coefficients are relatively
high tends to indicate that adsorption onto soils and sediments may be a
major fate process for dichlorofaenzenes discharged into aquatic media.
The dichlorobenzenes are only sparingly soluble in water compared with other
organic compounds, with saturation concentrations on the order of 100 mg/1
(100 ppm). Therefore, neither transport within water (for example,
advection), nor transport into the water medium (for example, from rain-
out, leaching, or runoff) is expected to be a major environmental fate
process. A moderate potential for bioaccumulation is indicated by the
fish:water partition coefficient.
The vapor pressures of the dichlorobenzenes are high, corresponding
to saturation concentrations in air at 25°C on the order of 0.1-0.2%
(v:v); even at 0"C, the dichlorobenzenes have vapor pressures >0.2 mm Hg.
The temperature dependence of the vapor pressure is indicated in Figure 4-1.
Volatilization is likely to be a major environmental process for dichloro-
benzenes in water.
The chemical reactivity of the dichlorobenzenes is expected to be
very low under environmental conditions. Although chlorobenzenes can be
hydrolyzed under stringent conditions (strong caustic, 300°C) (Morrison
and Boyd, 1959), the rate of hydrolysis in ambient water (pH 5-8, T<30°C)
will be essentially zero. Likewise, the rate of direct photolysis is
expected to be negligible, since the dichlorobenzenes do not absorb UV
light in the >290-nm wavelength region characteristic of solar radiation.
The possibility that dichlorobenzenes react with such reactive species
as hydroxyl radicals in the atmosphere or RC>2 radicals in aquatic media
cannot be ruled out; specific data that would allow estimation of the
rate of such reactions have not yet been found. The 1,2- and 1,4-dichloro-
benzene isomers were reported by Ware and West (1977) to be quite resistant
to autooxidation by the peroxy radical (R02O in water; they are also
resistant to autooxidation by ozone in the atmosphere. The'dichlorobenzenes
do, however, react with hydroxyl radicals (HO-) in air, with reported half-
lives on the order of 3 days (Ware and West 1977).
The rate of biodegradation of dichlorobenzenes in the environment
may be sufficiently high to suggest that biodegradation is a major
fate process for these chemicals in water. In one set of experiments
measuring degradation, a shake-flask culture using acclimated microbial
populations showed that within 7 days the 1,2-, 1,3- and 1,4-dichlorobenzenes
were 29%, 35% and 16% degraded, respectively. Under the same conditions,
benzene was reported to be 100% degraded in the same time period.
1-3
-------
3.0 _
2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
Key
O 1.2 Dichlorobenzene
E 1,3 Dicnlorobenzene
A 1,4 Dichlorobenzene
FIGURE 4-1 TEMPERATURE DEPENDENCE OF VAPOR
PRESSURE FOR DICHLOROBENZENES
4-4
-------
4.3 MODELLING OF ENVIRONMENTAL DISTRIBUTION
A.3.1 Introduction
Several modelling efforts were undertaken to describe important
aspects of the behavior of 1,2-dichlorobenzene in selected environmental
settings. This isomer was chosen because it is commercially produced
and used and because it has the highest water solubility of the three
isomers; other properties were quite similar for the three isomers.
The Mackay equilibrium model was used to predict the results of physical
transport processes on the partitioning of dichlorobenzenes in each
environmental compartment when all phases are in equilibrium. The EXAMS
(Exposure Analysis Modelling System) developed by the U.S. EPA was used
to study the fate of dichlorobenzenes in generalized aquatic environ-
ments, and the results were compared with those of the Mackay model.
Because volatilization is a major pathway for the dichlorobenzenes in
aquatic systems, volatilization half-lives for dichlorobenzene were cal-
culated for a range of wind and current velocities. The results of these
modelling efforts are described in this section.
/
4.3.2 Mackay Equilibrium Partitioning Model '
As an initial step in hazard or risk assessments for toxic chemicals,
in the planning of laboratory and field tests, and in the interpretation
of monitoring data, rough estimates as to the pollutant's environmental dis-
tribution can often be made by inspection of the chemical's properties.
A simple approach to an initial estimate of environmental partitioning
has recently been proposed based upon the fact that in a system at equili-
brium, the fugacity of the pollutant must be the same in all phases
(Mackay 1979).
In Mackay's Level I approach (the one used here), all environmental
compartments (phases) are assumed to be directly or indirectly connected
and-at equilibrium. The compartments considered are air, surface water,
suspended sediments, bottom sediments, sediment biota, and aquatic biota.
The Level I calculations require that these compartments be roughly des-
cribed (volumes, temperature, sediment and biota "concentrations," etc )
and the model output will clearly depend upon the nature of the
"environment" selected. Compartment-specific parameters chosen to
approximate the EXAMS pond environment are listed in Table 4-2. The
Level I calculations do not consider degradation or transport into or
out of the selected environment.
A relatively small number of chemical-specific parameters (also listed
in Table 4-2) are required to calculate equilibrium partitioning. If one
desires an absolute estimate of the equilibrium concentrations in each
phase, it is necessary to know the total amount of the chemical that is
likely to be in the selected environment. (Note that predicted concentra-
tion ratios between two phases will not be affected by"the number selected.)
Total amount is assumed to be 370 kg (2520 moles) to correspond to the"
pond accumulation predicted by the EXAMS Model based upon a"loading rate
4-5
-------
TABLE 4-2. VALUES OF PARAMETERS USED FOR CALCULATING THE EQUILIBRIUM
DISTRIBUTION OF 1,2-DICHLOROBENZENE USING THE MACKAY FUGACITY MODEL
CHEMICAL-SPECIFIC PARAMETERS (25°C)
Solubility (mg/1)
Henry's Law Constant
Adsorption Coefficients:
suspended sediments
sediment
biota
Total Amount in System
145
1.93 x 10
-3
628
628
209
370 kg (2520 moles)
COMPARTMENT-SPECIFIC PARAMETERS (258C)
Air:
area
depth
volume
Water:
area
depth
volume
biomass constant
suspended sediment
Sediment:
area
depth
volume
biomass content
wet sediment density
sediment dry weight=
1 x 104m2
3 x 103m
3 x 107m3
I x 10um2
2 m
2 x 10%3
12.9 mg/1
30 mg/1
1 x 10V
5 x lO^m
5 x 103m3
50.01 g/m3
1.85 g/cm3
100 x wet weight
137
4-6
-------
of 24 kg/day (see Section 4.3.3). Details of the calculated methods
are provided elsewhere (Mackay 1979) and are not repeated here. The
results are presented in Table 4-3.
4.3.3 EXAMS Model
The U.S. EPA Athens Environmental Research Laboratory has developed
an interactive system designated as EXAMS (Exposure Analysis Modeling
System) to carry out exposure analyses for organic chemicals in six
freshwater environments (Smith jst_ _al. 1977). In performing these analyses,
the model assumes "steady-state" behavior and considers the fate and
transport of the organic chemical as it passes through a system composed
of one or more water and sediment compartments. These compartments have
been assembled to represent a simple pond (one water and one sediment
compartment), a river (several water/sediment compartments in a row),
and a lake (containing "shallow" and "deep" water compartments). Within
the aqueous compartments, biota (fish, algae) may be assumed to exist
and the extent of bioconcentration of the organic chemical in the species
may be calculated.
Using the precompiled environments, plus chemical^specific input
parameters, EXAMS models the bulk transport of a chemical (between aqueous
compartments) and mixing, as well as the processes of volatilization (loss
to the atmosphere), adsorption on sediments and suspended solids (by
physical forces or ion exchange), hydrolysis (assumed first-order reaction),
photolysis (assumed first-order reaction), biodegradation (with and without
light), and dissociation (for organic acids, bases, complexes).
The physical and chemical properties of the three dichlorobenzene
isomers do not vary substantially. Therefore, the EXAMS model was run
only for 1,2-dichlorobenzene since this isomer is one that is produced
in substantial quantities and has the highest water solubility of the
three, a characteristic suggesting that it would have the most significant
aquatic exposure and effects. Initially, 1,2-dichlorobenzene was modeled
in all six of the EXAMS environments (pond, eutrophic lake, oligotrophic
lake, river, coastal river, and turbid river). The results showed similar
distributions for the three river systems and the three water bodies. On
the basis of these preliminary runs, it was decided that modelling of the
pond (high biological activity), the oligotrophic lake, and the river would
be sufficient to approximate the fate of the dichlorobenzenes in a range
of aquatic environments.
The data used as input to the EXAMS model are presented in Table 4-4.
Data in the materials balance (Chapter 3.0) indicate that 230 kkg/year
of 1,2-dichlorobenzene are released to water during production; releases attri-
butable to individual production plants range from 3.3 kkg/year to 84 kkg/year,
Based upon the above data, and with considerations toward ease of model
execution, tu« loading rate for 1,2-dichIorubeuzene was set at 2u kg/day
(1 kg/hour); compared with the 84 kkg/year discharge, this may be a low'
estimate. Another source has reported mean industrial dichlorobenzene
loadings in the range of 10"4 to 13 kg/day (EPA 1980c); based upon these
4-;
-------
TABLE 4-3. EQUILIBRIUM PARTITIONING OF 1,2-DICHLOROBENZENE CALCULATED
USING MACKAY'S FUGACITY MODEL
Partitioning at Equilibrium
Compartment Holes Concentration Percent
881. 4.32 mg/m3 35.2
Water 7.60 55.9 ug/1 0.30
Suspended Sediment 0.143 35 mg/kg 0.006
Sediment 1610 35 mg/kg 64.4
dry weight
Aquatic Biota 0.0206 18 mg/kg 0.0012
Biotic Sediment 0.0200 12 mg/kg 0.0008
4-3
-------
TABLE 4-4. INPUT PARAMETERS FOR EXAMS MODELLING OF THE FATE OF
1,2-DICHLOROBENZENE IN GENERALIZED AQUATIC SYSTEMS
Variable Explanation
MTW Molecular wt.(g/mole)
KVO Ratio of volatilization
to reareation rate
SOL Aqueous solubility (mg/1)
KPB Partition coefficient
biomassrwater (u2/g)/(mg/l)
HENRY Henry's Law Constant
(atm m3 mole 1)
KOW Partition coefficient
octanol:water
KBACW1 Second order bacterial
degradation rate constant
(in water) (ml/cell/hr)
QTBACW1 Increase in KBACW1 per 10°C
change in temperature
KBACS1 Second order bacterial
degradation rate constant
(in sediment) (ml/cell/hr)
QTBACS1 Increase in KBACS1 per 10°C
in temperature
LOAD Loading rate (kg/hr)
Input
Value
147.01
0.495
145
209
2500
1 x 10"10
2
2
1 x 10"10
Reference
Weast (1979)
SRI (1980)
Verschueren (1977)
U.S. EPA (1980b)
1.93 x 10~3 U.S. EPA (1980b)
U.S. EPA (1980b)
SRI (1980)
SRI (1980)
SRI (1980)
SRI (1980)
4-9
-------
data the actual exposure concentrations could be up to 100,000 times less
than those predicted using a 24 kg/day loading rate.
At chemical concentrations below solubility saturation, maximum
concentrations and accumulations will be proportional to loading; self-
purification times and percent disposals will be unaffected by changes
in loadings. Table 4-5 presents the dichlorobenzene concentrations
expected in the three simulated environments at steady-state conditions.
Water concentrations in the pond and lake were 3.0 mg/1 and 0.15 mg/1,
respectively; concentrations in the river systems were much lower
largely due to dilution factors. Sediment concentrations were varied;
sediment concentrations in the pond system, where there is considerable
sediment/water mixing, were almost three orders of magnitude higher
than in the other systems.
Table 4-6 gives data on the distribution and transformation of
dichlorobenzene in the three environments. The processes for removal
from sediment are not very efective. The persistence of 1,2-dichlorobenzene
in the pond is much greater than in the lake and river due to the static
nature of the pond and to the fact that most of the chemical is residing
in the sediment compartment. In the relatively static systems (pond and
lake), in which physical transport processses are negligible, volatiliza-
tion becomes the major removal mechanism, accounting for 91-94.6% of the
loss. In the river system, transport downstream is a major removal
process, responsible for the lower self-purification time.
A further insight into the impact of a pollutant in aquatic environ-
ments is given by examining the persistence of the chemical following
termination of the discharge (after the system has reached equilibrium).
Table 4-7 outlines the persistence of 1,2-dichlorobenzene following cessa-
tion of the 24 kg/day discharge. Within 24 days most of the aqueous
1,2-dichlorobenzene in all three systems will be removed; 99.96% will be
removed in one-half day from the water compartment of the river system.
4.3.4 Comparison of Mackay's Equilibrium Model and EXAMS
A pond was picked as the best environment to use in comparing EXAMS
results with a Level I Mackay calculation because a pond has the least
transport in and out of the environmental system. Comparable EXAMS and
Mackay results are summarized in Table 4-8. The total amount of
1,2-dichlorobenzene used in the Mackay model was taken to be equal to
the pond accumulation predicted from the EXAMS run with a 24 kg/day
loading rate.
In spite of the fact that the assumptions inherent in the two models
are different, a comparison of the two sets of data show 'the results to
be in general agreement. The concentrations predicted from the Mackay
model are all lower since a large proportion of the 370-kg accumulation
from EXAMS has been "removed" by volatilization in the Mackay tnodel.
Another major difference between the two models is that the Mackay model
is simply a partitioning model, whereas the EXAMS model considers the kinetic
data and processes that occur after the chemical has bean partitioned
4-10
-------
TABLE 4-5. STEADY-STATE CONCENTRATIONS OF 1.2-DICHLOROBENZENE IN VARIOUS GENERALIZED AQUATIC
SYSTEMS RESULTING FROM CONTINUOUS DISCHARGE AT A RATE OF 1.0 kg/hour"
System
Pond
O|igolrophic
f Lake
Ri ver
1.0
Maximum Concentrations
Loading
(kg/hr),
1.0
1.0
Water
Dissolved
(mg/D
3.0
0.15
Water
Total
(ing/ 11
3.0
0.15
Maximum in
Sediment
Deposits
(mg/kg)
460
0.73
Plankton
(Mg/g)
630
30
Benthos
(Mg/g)
610
3.3
Total
Steady-State
Accumulation
(kg)
370
410
Total
Dally
Load
(ka/(
24
24
0.00099 0.00099
0.21
0.048
1.2
24
"AN data simulated by EXAMS (U.S. EPA-SERL, Athens, Ga.) model (see text for further information).
-------
TABLE 4-6. THE FATE OF 1,2-DICHLOROBENZENE IN VARIOUS GENERALIZED AQUATIC SYSTEMS™
Percent Distribution
I
t-4
Ixj
System
Pond
Ol IguLropliic
Lake
River
Residing in
Water at
Steady-State
16.22
98.11
75.52
Residing in
Sediment at
Steady-State
83.78
1.89
24.48
Percent Lost by Various Processes
Transformed
Transformed by Lost Time for
by Chemical Biological by Other System Self-
Processes Processes Volatilized Processes^* Purification c'
0.0
0.0
0.0
0.05
0.0
0.0
91.91
94.64
1.44
8.05
5.36
98.56
282.8 days
83.78 days
18.19 days
"All data simulated by the EXAMS (U.S. EPA-SERL, Athens, Ga.) model (see text for further information).
Including loss through physical transport beyond system boundaries.
(!
Esl imate for removal of ca. 97% of the toxicant accumulated in system. Estimated from the results of
Hie half-lives for the toxicant in bottom sediment and water columns, with overall cleansing time
weighted according to the pollutant's initial distribution.
-------
TABLE 4-7. THE PERSISTENCE OF 1,2-DICHLOROBENZENE IN VAROUS GENERALIZED
AQUATIC SYSTEMS AFTER CESSATION OF LOADING AT 1 kg/hour)'"
Lost
Time from
Period % Lost % Lost Total
System (days) from Water from Sediment System
Pond 24 87.96 22.28 32.94
Oligotrophic 24 6fi>74 15>Q6 65>76
Lake
River 0.5 99.96 2.33 76.06
aAll data simulated by the EXAMS (U.S. EPA-SERL, Athens, Ga.) model.
See text for further information.
4-13
-------
TABLE 4-8. COMPARISON OF RESULTS FROM MACKAY'S EQUILIBRIUM MODEL AND
EXAMS FOR 1,2-DICHLOROBENZENE IN A POND SYSTEM
EXAMS Results
(Pond, 24 kg/day loading
370 kg steady state accumulation)
Maximum Concentrations
Water
Water Biota
Sediment Biota-
Sediment
3.0 mg/1
630 mg/kg
610 mg/kg
460 mg/kg
Mackay Results
(370 kg in system)
Water
Water Biota
Sediment Biota
Sediment
Concentrations
0.0559 mg/1
18 mg/kg
12 mg/kg
35 mg/kg dry
weight
Accumulation
% in Water
% in Sediment
16.22
83.78
Percent of Chemical per Compartment
% in Watera 0.30
% in Sediment 64.4
a.
Part of the initial aquatic load has been removed by volatilization.
4-14
-------
into a certain compartment. Both models predict that in an equilibrated
aquatic ecosystem, most of the 1,2-dichlorobenzene will accumulate in the
sediment; however, the Mackay model shows a higher sediment-to-water ratio
for the chemical. This apparent discrepancy may be due to the fact that
degradation pathways (biolysis, for example) are included in the EXAMS
model but are not included in the Mackay model. Once the chemical has
been partitioned into sediment in the Mackay model, no allowance is made
for degradation and other removal processes. Inclusion of biotransforma-
tion processes may also account for the fact that the EXAMS model predicts
much higher biotic concentrations for dichlorobenzene.
These data agree well with available monitoring data (presented in
Table 4-10). The average ambient water concentration (remarked and
unremarked) reported in the STORET Water Quality Information System for
1,2-dichlorobenzene was 29 ug/1; 94% of the unremarked observations were
< 100 ug/1. The maximum reported concentration in ambient water was
4660 ug/1.
Volatilization is the primary means of disposition from ponds and lakes
and largely controls the persistence of the chemical in these systems.
In more dynamic systems, such as rivers, "other" processes (such as
advection) are the primary means of disposition. The most significant
accumulation.is in the sediment, as evidenced by the high maximum •
concentrations in sediment and by the EXAMS prediction that, within the
same period of time, much lower percentages of chemical are lost from
the sediment compartment than from the water compartment. Biolysis may
be important since the maximum chemical concentrations in both plankton
and benthos are high, but this is a relatively minor means of disposition.
4.3.5 Volatilization
The rate of volatilization is dependent upon the chemical properties
of the given compound and the physical properties of the water body and
the atmosphere above it. For dichlorobenzene, the rate can be determined
by a mathematical model using interphase exchange coefficients based on
specific chemical and physical properties. The determination of the
volatilization rate involves several steps, as shown below.
a) Evaluation of Henry's Law Constant, H, where:
H - £l
S
where Pv « vapor pressure at 25°C
S - solubility at 25°C
4-15
-------
The values of PV, S and H for the three dichlorobenzene isomers are shown below.
Pv(atm)
S (g/1)
H/atm-m3\
\mole J
1,2-DCB
.002
.145
.002
1,2-DCB
.003
.123
.004
1, 4-DCB
.002
.079
.004
b) Compounds with a Henry's Law Constant of less than 3 x 10 atm-m /mole
.are often considered non-volatile. The value of this constant
for dichlorobenzene indicates that this chemical is highly volatile.
Using the dimensional form of the Henry's Law Constant, one can
determine the non-dimensional form from which interphase exchange
coefficients will be calculated. The non-dimensional Henry's Law
Constant, H*, is expressed as:
H* - H/RT
Where R » gas constant » 8.2 x 10" atm-m3 /mole-°K
T * temperature » 298°K (equivalent to 25°C)
The values for H* for the three dichlorobenzene isomers are given
below:
1,2-DCB1,3-DCB1,4-DCB
H* 8.2 x 10"2 1.6 x 10'1 1.6 x I0~l
c) The liquid phase exchange coefficient, K^, is based upon the current
speed, the depth of the body of water, and the speed of the wind
passing over the water surface. As these variables change, the rate
of volatilization will also change. For the present example:
-------
V - current speed « 1 in/ sec
V • wind speed » 2 m/sec
w
D « depth * 1 m
M « molecular weight » 147g
The liquid phase exchange coefficient, kj, , is expressed as (Southworth, 1579);
/v 0.969\
k* * 23'51( pO.673) N/"327JreO:526
-------
VOLATILIZATION HALF-LIVES FOR 1,2-DICHLOROBENZENE
Vw (m/sec)
V
c
4.4
4.4.
Cm/ sec)
1
2
3
MONITORING
2
6 . 7 hour
3 . 7 hour
. 2.5 hour
DATA
3
4. 1 hour
2. 3 hour
1. 6 hour
1 Introduction
Literature reviews and the STORET Water Quality System were the main
sources of monitoring data for the dichlorobenzenes under study. The
major problems in describing the environmental distribution of these
chemicals are the limited amount of literature and sparseness of STORET
monitoring data.
The STORET data are discussed first in order to present an overview
of the reported national distribution of dichlorobenzenes in the aqueous
environment. Subsequent sections of this chapter describe both water
and air levels that have been reported in monitoring studies in the published
literature.
4.4.2. Overview of Ambient and Effluent Water Concentrations;. STORET Data
At least 98% of the effluent concentrations and 94% of the observations
recorded for ambient concentrations of dichlorobenzenes are "remarked"
values. A remark indicates either that dicholorobenzenes were analyzed for
but not detected or that actual values are known to be less than those
recorded. Thus, the discussion that follows regarding STORET monitoring
data for dichlorobenzene is largely of concentrations not exceeding a
reporting (detection) limit rather than the actual concentrations in the
environment.
As of September, 1980 both ambient and effluent concentrations of the
dichlorobenzenes across the nation were reported to be quite low, with
most observations recorded at less than or equal .to 10 ug/1. For example,
ambient concentrations for the 1,2- isomer indicate that 88% of the 17
unremarked values and 95% of the 349 remarked values are no greater than
10 yg/1. With effluent concentrations for the 1,2-isomer, 58% of the
unremarked values and 96% of the 391 remarked values are less than or
equal to 10 ug/1. The percentage distribution of unremarked and remarked
values for both ambient and effluent concentrations for each isomer is
presented in Table 4-9. With so few data and so little definition in
the data, an overall trend of higher concentrations near production
plants, or other point sources, for instance, could not be discerned.
4-13
-------
TABLE 4-9. PERCENTAGE DISTRIBUTION OF AMBIENT AND EFFLUENT CONCENTRATIONS FOR DICIILOROBENZENES IN STORET
Percentage Jn Remarked
Percentage In Unremarked
Concentration Ranges (Mg/jO
1
1
1
1
]
1
AmbJeut Data
,2-dU'h lorobenzene
, 3-dichlovobenzene
, 4-d icli lorobenzene
Effluent Data
,2-d it'll lorobenzene
, 3-di ch lorobenzene
,4-d i cli lorobenzene
f
Obs.
17
16
24
7
6
9
12
13
33
29
17
33
1.1-10
76
81
63
29
33
56
10.1-100
6
0
0
14
17
11
\HF>» -I
100.1-1000
0
6
4
14
33
0
>1000
6
0
0
14
0
0
Obs.
349
375
390
391
394
508
1000
0
0
0
.5
0
0
Source: STORET Water Quality Information System, September 1980
-------
Table 4-10 exhibits the unremarked and remarked STORE! data for
maximum, minimum, and mean concentrations of dichlorobenzenes in ambient
waters. Of the 11 major basins with recorded data, the Missouri River
basin data reflect the highest maximum concentrations and the highest
mean. For the nation as a whole, the mean concentrations for 1,2-, 1,3-
and 1,4-dichlorobenzenes from both remarked and unremarked data were cal-
culated as 29 ug/1, 12 ug/1 and 14 ug/1, respectively.
Concentrations of dichlorobenzenes in well water samples generally
do not exceed 10 ug/1. Monitoring data from 14 water quality stations
in the states of Kansas, Washington, Kentucky, Oregon, and South Carolina
indicate that the pollutant was analyzed for but not detected, using
reporting limits up to 10 ug/1. Where detected, the actual values were
reported to be less than the quantification limits.
Table 4-11 displays all STORE! data on effluent concentrations in major
river basins for each dichlorobenzene isotner, along with a gross analysis.
Analysis of this limited data set suggests that maximum effluent levels
of 1,2-dichlorobenzene are found in the Northeast (960 ug/1), the
Southeast (2500 ug/1), and the Missouri River (316 yg/1) .basin. For
1,3-dichlorobenzene, the apparent maximum concentration areas are the
North Atlantic (670 ug/1), and the Southeast (2500 ug/1) river basins.
The Southeast river basin is also the location of the highest reported
level of 1,4-dichlorobenzene. Because the "data base is so restricted
and since most of the STORE! data are remarked, it would be unwise to
place much emphasis on the apparent isomer-specific or river basin-specific
distribution patterns.
In summary, the STORE! effluent data show national mean concentra-
tions centered on 17 ug/1 for 1,2-dichlorobenzene, 14 ug/1 for 1,3-
dichlorobenzene, and 9 ug/1 for 1,4-dichlorobenzene. It is somewhat
surprising, considering the production and use aspects of the materials
balance analysis, that the apparent mean concentrations of all three
dichlorobenzene isomers are so similar and that 1,3-dichlorobenzene
levels are occasionally higher than those for 1,4-dichorobenzene. This
may reflect, in part: experimental uncertainties in isomer designations
in analysis and reporting of data; possible differences in reactivities
and environmental degradation; or the possibility of some indirect and/or
inadvertent sources of the 1,3-dichlorobenzene isomer in the aquatic
environment.
4.4.3 Municipal Wastewater
A recent Arthur D. Little, Inc. study (Levins _et al. 1979) of
priority pollutants in municipal wastewater within defined drainage
areas found quantifiable levels of dichlorobenzenes in 13% of samples
from residential areas, 31% of samples from commercial areas, 57% of
[light] industrial area samples, and 56% of POTW influents. The analytical
techniques employed in this study gave incomplete resolution of the 3
isomers, and the results have been reported as dichlorobenzenes. The
mean concentrations and ranges observed for four U.S. cities were:
4-20
-------
TABLE ^ -10. AMBIENT CONCENTRATIONS OF DICHLOROBENZENES IN SURFACE WATER: REMARKED AND UNREMARKED DATA IN STORET
Concentration (ug/1)
Norlli Atlantic
Southeas t
Ohio River
Lake Erie
Upper Miss
Lake Michigan
Missouri River
i'o Lower Mississippi
Western Culf
I'arlfie Nort
Puerto Rico
UNITED STATES
Source: STORET Water Quality Information System, September 1980.
STORET Mean = average of all data points, remarked as well as unremarked.
l42-Dichlorobenzene
lias in //Obs.
ic 10
47
52
2
sippi 12
n 9
er 43
sippi 9
15
liwest 86
1
S 286
Max i
10
20
100
.10 .
5
1
4660
10
.00'
10
.00
4660
Min.
10
.00
.02
.10
2
.00
2
.00
.00
.00
.00
.00
Meana
10
13
9
.10
3
.33
148
3
.00
6
.00
29
1,
tfObs.
6
47
67
12
42
9
15
86
1
285
3-DIchlorobenzene
Max.
10
20
20
5
400
10
.00
10
.00
400
Min.
10
.00
.01
2
2
.00
.00
.00
.00
.00
Mean"
10
13
6
3
39
3
.00
6
.00
12
1,
/fobs.
10
4 7
66
2
12
3
44
9
15
86
1
295
4-Dichlorobenz<
Max. Min.
10
20
20
20
5
1
610
10
.00
10
.00
610
10
.00
.01
.20
2
1
2
.00
.00
.00
.00
.00
sr*-"
Mean
10
13
6
.2
3
1
58
3
.00
6
.00
14
-------
TABLE 4-M. CONCENTRATIONS OF DICHLOROBENZENS IN INDUSTRIAL EFFLUENTS: REMARKED AND UNREMARKED DATA
IN STORET
1,2-Dichlorobenzene
1,3-Dichlorobenzene
Major River Basin
Northeast
North Atlantic
Southeast
Tennessee River
Ohio River
Lake Erie
Upper Mississippi
10 Lake Michigan
Missouri River
Lower Mississippi
Colorado River
Western (!ulf
1'acilic Northwest
(,'a 1 i form' a
Creal Basin
Lake Superior
Virgin Islands
UNITED STATES
00bs .
101
71
52
8
8
16
1
32
,290
Max.
960
20
2500
10
100
4
316
.00
30
2500
Min. Mean"
.00 10
.00 .83
10 59
10 10
10 22
4 4
1 24
.00 .00
.00 4
.00 17
#0bs,
101
67
52
8
8
1
15
1
32
285
Max.
2
670
2500
10
10
4
5
.00
30
2500
Min. Mean"
.00 .12
.00 10
10 59
10 10
10 10
4 4
3 4
.00 .00
.00 5
.00 14
1,4-Dichlorobenzene
00bs. Max. Min. ITean"
117
78
62
9
17
6
9
1
26
11
4
7
39
8
1
1
1
397
57
20
2500
10
10
I
4
1
5
1
1
1
30
1
.00
1
1
2500
.10
.00
1
1
1
1
1
1
1
1
.00
.00
1
.00
1
1
.00
.75
1
49
9
5
1
1
1
3
1
1
.86
4
1
.00
1
I
9
STORET Water Quality Information System, September, 1980.
STORET mean is average of all data points, remarked as well as unremarked-
-------
SAMPLE SITE
Tap Water
Residential Areas
Commercial Areas
Industrial Areas
POTW Influent
TOTAL #
SAMPLES
12
47
42
21
18
% OCCURRENCE
OF DCB's
0
13
31
57
56 •
MEAN
ug/1
0
2.8 ± 5.5
7.5 * 11.3
376
33
RANGE
ug/1
not detected
0-20
0-26
0 - 2187
0-93
The level of industrial activity in each of the four cities studied had
a definite effect on the concentrations of dichlorobenzenes. The effluent
of one POTW was sampled for comparison with the POTW influent. Dichloro-
benzenes were measured in 5 of the 6 influent samples at an average con-
centration of 25 ug/1; they were not detected in any of the six effluent
samples. The detection limit was 10 ug/1.
Earlier work by Kopperman et_ al.(1975) and by Glaze and Henderson
(1975) had reported levels of'1,2- and 1,4-dichlorobenzene in chlorinated
wastewater from a Denton, TX facility as 10 ug/1 each. An EPA study
(Bellar et al.1974) showed an average concentration of 10.6 ug/1 of
dichlorobenzenes (all isomers) in POTW influents. That work reported
levels in POTW effluent of 5.6 ug/1 before chlorination and 6.3 ug/1
after chlorination. The difference in levels pre- and post-chlorination
is probably not significant compared with the uncertainty of the measure-
ment. The data suggest that wastewater chlorination is probably not a
major source of dichlorobenzenes in the aquatic environment.
Additional POTW data from a recent EPA study of 20 selected urban
POTW facilities with secondary treatment are presented in Chapter 3.0,
Table 3-4. The mean and median concentration for the three dichlorobenzene
isomers are summarized below:
i-23
-------
Concentration (ug/1)
Median
Simple Mean
Flow-weighted Mean
Median
Simple Mean
Flow-weighted Mean
Median
Simple Mean
Flow-weighted Mean
Influent
2.5
8.3
15
ND
1.6
2.1
0.5
2.1
3.0
1^2-Dichlorobenzene
Effluent
1
2
2.8
1 » 3-Dichlor obenzene
ND
1.7
2.2
1, 4-Dichlorobenzene
0.5
2.0
1.8
Sludge
ND
59
ND
52
ND
150
An investigation of chlorinated compounds in the major municipal
wastewaters of southern California was conducted by Young et al (1976)
Concentrations of 1,2-dichlorobenzene were recorded from 374 ^g"/l to
34 yg/1 (mean 12 ug/1) in the summer months and from 0.42 ug/1 to
230 yg/1 (mean 50 ug/1) in the fall season. Similarly for 1,4-dichlorobenzene
concentrations in the summer and fall seasons ranged from 1.9 ug/1 to
30 ug/1 (mean 8 ug/1) and from <0.01 ug/1 to 440 ug/1 (mean 92 ua/1) '
respectively. '
4.4.4 Drinking Water
The National Organic Monitoring Survey (Symons et al. 1975) found
1,2- and 1,3-dichlorobenzenes in fewer than 5% of the drinking water
samples analyzed (Table 4-12). The 1,4-dichlorobenzene isomer was
reported more frequently. Mean concentrations for positive results
were <2 ug/1, while median concentrations for all samples were <0.005 ug/1
for all isomers as indicated in Table 4-12. These data are consistent
with the results of an earlier U.S. EPA study (U.S. EPA 1975), which had
indicated 1 ug/1, <3 ug/1 and 1 ug/1 as the highest drinking water concen-
trations observed for 1,2-, 1,3- and 1,4-dichlorobenzene, respectively.
A more recent study (Coleman et. al. 1980) reports levels of 9 ng/1 and
11 ng/1 of 1,2-dichlorobenzene and 10 ng/1 and 27 ng/1 of 1,4-dichlorobenzene
in drinking water samples. Coleman et al. observe that the 'dichlorobenzenes
are reduced to below detectable levels by treatment with granular activated
carbon.
4.4.5 Runoff
Young (1976) has reported that a level of 0.05 ug/1 of dichlorobenzenes
is typical of Los Angeles storm water runoff.
-------
I
10
TABLE 4-12. CONCENTRATIONS OF DICHLOROBENZENE DETECTED IN DRINKING WATERS: NATIONAL ORGANIC
MONITORING SURVEY, MARCH 1976 THROUGH JANUARY 1977.
Number of Positive Analyses
per Mean Concentration (pg/l) Median Concentration (ug/1)
Is oilier Phasea Number of Analyses Positive Results Only All Results^
1,2-DCB
1,3 DC B
1,4 -DC 11
I II
0/113
0/113
2/111 20/113
III
4/110
2/110
29/110
I II III
1.5
0.10
2.0 0.14 0.07
I II
<0.005
<0.005
<1 <0.005
III
<0.005
<0.005
<0.005
Source: Acurex (1981)
UPhase I (March-April 1976) Samples shipped and stored at 2° to 8°C for 1 to 2 weeks prior to analyses.
I'luise II (May-July J976) Samples held at 20° to -25°C for 3 to 6 weeks prior to analyses permitting
reactions to proceed to end points.
Phase III (November 1976 - January 1977) Samples processed with or without chlorine reducing agent -
in these data, samples were processed without quenching a'dditive, so were permitted to react
to terminal values.
Those are minimum quantifiable limits.
-------
4.4.6 Ambient Surface Waters
Sheldon and Hites (1978) found dichlorobenzene (isomers unspecified)
at concentrations of 0.4 ug/1 in one out of five winter-time samples of
Delaware river water. No detectable levels were found in 11 summer
samples from the same source. Jungclaus et al. (1978) detected, but did
not quantify, dichlorobenzenes in both the wastewater and the receiving
water/sediments near a specialty chemical plant.
Schwarzenback et al.(1979) conducted a 1-year study of 1,4-dichloro-
benzene in the central basin of Lake Zurich, Switzerland. The compound
is introduced into the lake primarily from domestic sewage effluents.
The central basin receives effluent from 12 sewage treatment plants,
accounting for approximately 88 kg of 1,4-dichlorobenzene annually;
average residence time of water in the basin is 1.2 years. Estimates
of 1,4-dichlorobenzene from six vertical concentration profiles taken
between November 1977 and November 1978 at the central basin indicated
a total quantity of 9 - 13 kg at depths from 0 - 20 m and from 23 - 39 kg
between the depths of 20 and 136 m. Experimentation indicated mass
transfer to the atmosphere as the predominant elimination mechanism.
The average residence time of 1,4-dichlorobenzene in the central basin
was calculated at 5 months.
4.4.7 Atmosphere
Concentrations of dichlorobenzenes in ambient air samples collected
from various locations across the United States have been reported by
Pellizzari (1978). As indicated in Table 4-13, all of the reported
observations are <1 ug/tn3; in most instances, the dichlorobenzenes were
below detection limits (10-200 ng/m3 depending on size of air sample)
or were reported as "trace" (i.e., presence of chemical detected but at
levels too low to quantify). The 1,2- and 1,3- dichlorobenzene isomers
were detected most frequently, while 1,4-dichlorobenzene was almost never
observed. It should be noted that the data collected by Pellizzari were
for the purpose of method development rather than explicitly to monitor
dichlorobenzene levels in the environment. The reported concentration
levels are very low. Since the purpose of the sampling was not solely
to represent ambient concentration levels, sampling techniques may have
enhanced identification of the 1,3-dichlorobenzene isomer.
Holzer et al.(1977) reported the identification of 1,3-dichlorobenzene
in samples of urban and rural air from Alabama. Quantitative analyses
were not reported by Holzer et al. for this chemical but examination of
their chromatograms indicates a level of approximately lug/mj in the
urban air and considerably <1 ug/m3 in the rural air sample.
As part of the same study, Pellizzari examined samples from two
industrial locations and a waste disposal site. The air in an area
around an American Cyanamid plant in Linden, NJ was found to contain
4-26
-------
TABLE 4-13. CONCENTRATION OF DICHLOROBENZENES IN AMBIENT AIR SAMPLES'
. , 3,
Sampling
Location
NJ
Tulsa, OK
Houston, TX
Upland, CA
Magna, UT
Grand Canyon, AZ
Giesmar, LA
Baton Rouge, LA
Iberville Parish, LA
Pasadena, TX
Deer Park, TX
1,2-DCB
-------
2-74 ng/m3 of 1,2-dichlorobenzene and 1-30 ng/m3 of another dichloro-
benzene isomer. In the area around a DuPont de Nemours plant in
Deepwater, NJ, air concentrations of 1,2-dichlorobenzene ranged from
trace to 1,300 ng/m3, while levels of another isomer ranged from trace
to 1,200 ng/m3. Ambient air at the Kin-Buc disposal site at Edison,
Nev Jersey showed levels up to 46,000 ng/m^ of total dichlorobenzenes
(Table 4-14). Again, Pellizzari reports that the 1,2- and 1,3-isomers
were most abundant while 1,4- was rarely observed.
Pagnotto and Walkley (1965) report concentrations of 25-35 ppm
(150-210 mg/m3) and 70 ppm (420 mg/m3) 1,4-dichlorobenzene in work-
places associated with manufacture of that isomer. Levels of dichloro-
benzene (isomer not specified) less than 1 ppm were reported at a mono-
chlorobenzene manufacturing plant (SRI 1979).
In a study of dichlorobenzene levels in air in Tokyo, Morita and Ohi
(1975) reported 1,4-dichlorobenzene concentrations of 2.7-4.2 ug/m3 in
the central city and_1.5-2.4 ug/m3 in suburban areas. These levels are
10 to 100 times higher than the data reported by Pellizzari (1978)
(Table 4-13) for United States ambient air.
1-lorita and Ohi (1975) also report some data for indoor air levels of
I,4-dichlorobenzene. Concentrations were 1700 ug/m^ inside a wardrobe,
315 ug/m3 inside a closet, and 105 ug/m3 in a bedroom. These levels
suggest that use of 1,4-dichlorobenzene as a moth repellent leads to
high concentrations of this chemical within localized areas.
-------
TABLE 4-1.4. LEVELS OF DICHLOROBENZENES DETECTED IN AIR AT THE KIN-BUG
DISPOSAL SITE, EDISON, NJ
Concentration (ng/m r
Sampling Date
6/29/76
6/30/76
7/1/76
3/24/76-3/26/76
1,2-DCB
<53~- 1900
<40 - 940
<49 - 9900
<33 - 12,000
1,3-DCB
<53 - 34,000
<50 - 890
<48 - 3500
<33 - 27,000
1,4-DCB
<48 - <81
<36 - <65
<39 - 470
<10 - 7000
aRanges are for 4-6 observations at each location.
Indicates limit of detection.
^
-------
REFERENCES
Acurex Corporation; Dichlorobenzenes: an environmental materials balance
Arlington, VA: Acurex Corp.; 1981
Bellar, T.A.; Lichtenfaerg, J.J.; Kroner, R.C. The occurrence of organo-
halides in chlorinated drinking waters. J. Am. Waterworks Assoc. 66-
703-706; 1974
Chiou, G.T.; Freed, V.H.; Schmedding, D.W.; Kohnert, R.L. Partition co-
efficient and bioaccumulation of selected organic chemicals. Environ
Sci. Technol. 11(5):475-478; 1977 (As cited by Versar 1979).
Coleman, W.E.; Melton, R.G.; Slater, R.W., Kopfler, F.G.; 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.
Glaze, W.H.; Henderson, J.E. Formation of organochlorine compounds from
the chlorination of a municipal secondary effluent. Journal WPCF
. 47(10): 2511-2515; 1975.
Holzer, G.; Shanfield, H.; Zlatkis, A.; Bertsch, W.; Juarez, P.;
Mayfield, H.; Liebich, H.M. Collection and analysis of trace organic
emissions from natural sources. J. Chromatogr. 142:755-764; 1977.
.Jungclaus, G.A.; Lopez-Avila, V.; Hites, R.A. Organic compounds in
industrial wastewater: A case study of their environmental impact.
Environ. Sci. and Technol. 12(1):88-96; 1978.
Kopperman, H.L.; Kuehl, D.W.; Glass, G.E. Chlorinated compounds found
in waste treatment effluents and their capacity to bioaccumulate.
Proceedings of the conference on the environmental impact of water
chlorination. Oak Ridge, TN; 1975, October 22-24.
Levins, P.; Adams, J.; Brenner, P.; Coons, S.; Thrun, K.; Harris, G.;
Weschler, A. Sources of toxic pollutants found in influents to sewage
treatment plants. VI. Integrated interpretation part I. Contract No.
68-01-3657. Washington, D.C.: U.S. Environmental Protection Agency;
1979e.
Mackay, D. Finding fugacity feasible. Environ. Sci. Technol. 13: 1218-
1223;_1979.
Morita, M.; Ohi, G. Para-dichlorobenzene in human tissue and atmosphere
in Tokyo Metropolitan Area. Environ. Pollut. 8: 269-274; 1975.
Morrison, R.J.; Boyd, R.N.; Organic chemistry. Boston, MA: Allan and
Bacon, 1973.
-30
-------
Pagnotto, L.D.; Walkley, J.E. Urinary dichlrophenol as an index of
para-dichlorobenzene exposure. J. Am. Indust. Hyg. Assoc. 26:137-142;
1965 (As cited in Acurex 1981).
Pellizzari, E.D. Quantification of chlorinated hydrocarbons in previously
collected air samples.EPA 45013-751112, Washington, DC: U.S. Environmental
Protection Agency; 1978.
Schwartzenbach, R.P.; Molnar-Kubica, E.T.;Giger, W.; Wareham, S.G.
Distribution, residence time, and fluxes of tetrachloroethylene and
1,4-dichlorobenzene in Lake Aurich, Switzerland. Environ. Sci. Technol.
13(11):1367-1373; 1979.
Sheldon, L.S.; Hites, R.A. Organic compounds in the Delaware River.
Env. Sci. and Technol. 12(10): 1188-1194; 1978.
Smith, J.H.; Mabey, W.R.; Buhonoz, N.; Holt, B.R.; Lee, S.S.; Chou, T.-W.;
Bomberger, D.C.; Mill, T. Environmental pathways of selected chemicals
in freshwater systems. Part I. Background and Experimental Procedures.
Athens. GA: Office of Research and.Development, U.S. Environmental Protection
Agency; 1977.
Southworth, G.R. The role of volatilization in removing polycyclic
aromatic hydrocarbons from aquatic environments. Bull. Environ. Contain.
Toxicol. 21:507-514; 1979.
Stanford Research Institute (SRI). Montrose Chemical Corporation:
Monochlorobenzene survey report. Menlo Park, CA: Stanford Research
Institute: 1979 (As cited in Acurex 1981).
Stanford Research Institute (SRI). Estimates of physical-chemical
properties of organic priority pollutants. Preliminary draft. Washington,
D.C.: Monitoring and Data Support Division, U.S. Environmental
Protection Agency; 1980.
Symons, J.M.; Bellar, T.A.; Caldwell, J.K.; Krapp, K.L.; Robeck, G.G.;
Slocum, C.J.; Smith, B.L.; Stevens; A.A. National organics monitoring
survey for halogenated organics. J. Am. Waterworks Assoc. 67:634-636;
1975.'
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). Identification of organic
compounds in effluents from industrial sources. Washington, DC: Office of
Toxic Substances, U.S. Environmental Protection Agency; 1975.
U.S. Environmental Protection Agency (U.S.EPA). STORET water quality
information system. Washington, DC: U.S. Environmental Protection
Agency; 1980a.
4-31
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U.S. 'Environmental Protection Agency (U.S. EPA). Fate and transport of
hazardous waste. Appendix B of Background Document, Identification and
listing of hazardous waste, in support of Resource Conservation and
Recovery Act, Subtitle C regulations, prepared by U.S. EPA Environmental
Research Laboratory. Athens, GA: Office of Solid Waste, U.S. Environ-
mental Protection Agency; 1980b.
U.S. Environmental Protection Agency (U.S. EPA). National Pollutant
Discharge Elimination System (NPDES) - Availability of wastewater treat-
ment manual (Treatability manual). Washington, DC: Office of Research
and Development, U.S. EPA; 1980C. Available from: U.S. Government
Printing Office, Washington, DC; Stock No. 055-00-00190-1.
Versar, Inc. Water-related environmental fate of 129 priority pollutants.
Washington, DC: Office of Water Planning and Standards, U.S. Environ-
mental Protection Agency; 1979.
Verschuren, K. Handbook of environmental data on organic chemicals. New
York, NY: Van Nostrand Reinhold Co.; 1977 (As cited by Versar 1979).
Ware, S.; West, W.L. Investigation of selected potential environmental
contaminants: halogenated benzenes. EPA 560/2-77-004.. Washington, DC:
Office of Toxic Substances, U.S. Environmental Protection Agency; 1977. •
Weast, R. ed. Handbook of chemistry and physics. 55th ed. Cleveland,
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Young, D.R.; Heesen, R.C.; McDermott-Ehrlich, D.J. Survey of chlorinated
hydrocarbon inputs into the Southern California bight. Draft; 1976.
i-32
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5. 0 EFFECTS AND EXPOSURE—HUMANS
5.1 HUMAN TOXICITY
5.1.1 Human and Animal Studies
5.1.1.1 Carcinogenicity
Most available data concerning the carcinogenicity of the dichloro-
benzenes are inadequate for valid assessment of risk (IARC 1974) due to
small group size, relatively short duration of experimental testing, low
exposure levels and/or lack of detail. Girard et_ al. (1969) reported
five anecdotal cases of blood disorders in individuals exposed by chronic
inhalation and/or dermal contact to 1,2- or 1,4-dichlorobenzene. These
included two cases of chronic lymphoid leukemia, two cases of acute
myeloblastic leukemia, and one case of myeloproliferative syndrome.
However, as with other available data, these reports do not prove a
cause-effect relationship, nor do they permit a quantitative risk asses.s-
ment applicable to the general population.' The National Academy of
Sciences finds this lack of information "disturbing, in view of the
suspected role of p-dichlorobenzene in human leukemia and its apparent
_ability to undergo metabolic activation and covalent binding to tissue
"constituents" (HAS 1977).
A study in progress has yielded no evidence of tumor development in
B^F! mice or Fischer 344 rats (50/sex/species) after 18 months' oral
administration of 1,2-dichlorobenzene at 120 mg/kg doses, 5 days/week.
However, the treatment has not been completed and histologic examinations
have not been performed (L.F. Juodeika, Technical Information Resources
Section, Bioassay Program, NCI-NTP, December 3, 1980, personal communica-
tion) .
5.1.1.2 Adverse Reproductive Effects
No adequate studies are available concerning the embryotoxicity or
teratogenicity of the dichlorobenzenes. A potential for transplacental
toxicosis or developmental effects may be inferred from human studies
that demonstrated the transplacental migration and accumulation in blood
of the lower chlorinated benzenes, leading to effects on hormone
metabolizing systems. (Dowty and Laseter 1976, Ware and West 1977).
5.1.1.3 Mutagenicity
Data concerning any mutagenic effects of the dichlorobenzenes were
inconclusive and limited to submammalian systems. Prasad (1970) reported
that treatment of Aspergillus nidulans for I hour with a 200 jg/ml ether
solution of 1,2-, 1,3-, or 1,4-dichlorobenzene resulted in an increase
in the number of back mutations. Chlorination in the para-posicion
appeared to have special genetic significance, causing a greater fre-
quency of back mutations.
5-1
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Anderson _et_ al. (1972) found that 1,2-dichlorobenzene was non-mutagenic
in an in vitro point mutation test system with several strains of
histidine-requiring mutants of Salmonella typhimurium.
Griffin and Hill (1978) reported no statistically significant increase
in the in vitro DNA breakage rate of ColEl plasmid DNA from Escherichia
coli treated with a 1 mg/ml solution of dichlorobenzene in hexane.
5.1.1.4 _Qther Toxic Effects
Humans
Most cases of human poisoning from dichlorobenzenes have resulted from
long-term inhalation of vapors, although some cases due to ingestion or
dermal absorption have been reported. Toxic exposures have been primarily
occupational in nature but have also resulted from home use of 1,4-
dichlorobenzene or, less frequently, 1,2-dichlorobenzene. In 22 cases
of dichlorobenzene poisoning, target systems included the blood or reticulo-
endothelial system, including bone marrow and/or immune components (17
cases), kidney (1), liver (6), central nervous system (2), respiratory
tract (2), and integument (3). General toxic or irritative symptoms
were observed in 17 cases, while three cases involved allergy or sensitiza-
tion (U.S. EPA 1980). Relatively low water solubility and high lipid
solubility favor penetration of the dichlorobenzenes by diffusion through
most membranes, including pulmonary and gastrointestinal epithelium,
brain, hepatic parenchyma, renal tubules and placenta. This allows for
wide distribution and accumulation in the tissues leading to possible
toxic levels within the body and recirculation of these chemicals for
long periods of time (Ware and West 1977).
Three non-occupational cases of poisoning from ingestion of 1,4-dichloro-
benzene crystals or pellets have been reported. These include acute
poisoning of a 3-year old male (Hallowell 1959), and chronic toxicity to
19-year old (Frank and Cohen 1961) and 21-year-old (Campbell and Davidson
1970) females. The first two instances resulted in hemolytic anemia,
while the latter resulted in effects on the central nervous system. All
three cases indicated an appreciable absorption of the chemical from the
gastrointestinal tract, but no data concerning the quantitative efficiency
of the absorption were available.
Several cases of 1,4-dichlorobenzene poisoning have been attributed to
inhalation exposure, including one case of pulmonary granulomatosis in a
53-year-old white woman exposed to 1,4-dichlorobenzene crystals for 12-15
years. Macroscopic crystals present in lung lesions were physically
similar to those of 1,4-dichlorobenzene (Weller and Crellin 1953). 'A
case of aplastic anemia was reported in a 68-year-old black woman exposed
to 5.5-kg 1,4-dichlorobenzene nuggets and 7-kg naphthalene flakes
several hours/day for 3 weeks in a room with little air exchange and
under extreme heat conditions (Hardin and Baetjer 1978).
Other reports of toxicity attributed to the dichlorobenzenes include
six cases of various forms of anemia (Cotter 1953, Petit and Chamoeix
-------
1948, Perrin 1941, Wallgren 1953), five cases involving severe liver
pathology due to chronic inhalation of 1,4-dichlorobenzene vapors, and
two cases of anemia due to chronic inhalation of 1,2-dichlorobenzene
(Girard _et_ al. 1969, Gadrat et_ al. 1962). The details of these cases
were not given, and again, no data on quantitative efficiency of absorp-
tion were available.
Hollingsworth et al.(1956) found no organic injury or adverse hematologic
effects in workers exposed to average air concentrations of 500 mg/m3
1,4-dichlorobenzene. A concentration of >960 mg/m3 was intolerable for
an unacclimated person, while 400 mg/m3 caused painful eye and nose
irritation. An odor was detectable at 90-180 mg/m3 1,4-dichlorobenzene
(Hollingsworth e£ al.1956). In a similar study, occupational exposure
to average air concentrations of 90 mg/m3 1,2-dichlorobenzene caused no
organic injury or adverse hematologic effects. Concentrations of 300 mg/m3
in the air were detectable by the average person, although no eye or nose
irritation was experienced (Hollingsworth e_t al. 1958). Irritation, but
no serious effects were noticeable at 600 mg/nrr 1,2-dichlorobenzene
(Elkins 1959).
Hollingsworth et_ al.(1956) reported no notable hazard due to skin
irritation or dermal absorption of solid 1,4-dichlorobenzene except
under extreme conditions (exact exposures were not specified). In a
similar study, liquid 1,2-dichlorobenzene applied to the skin for 15
minutes produced a burning sensation lasting for 1 hour and hyperemia
and blisters lasting up to 3 months (Hollingsworth et al. 1958).
A case of allergic purpura was reported in a 69-year old white man
24-48 hours after exposure to 1,4-dichlorobenzene crystals. Serum anti-
bodies for 1,4-dichlorobenzene were still detectable 5 months after the
exposure (Nalbandian and Pearce 1965).
A case of contact eczematoid dermatitis was reported in a 47-year old
male after chronic skin contact with a solution containing 1,2-dichloro-
benzene (Downing 1939).
Experimental Animals
Oral Exposure
Oral LD50 (lethal dose to 50% of test animals) values for the dichloro-
benzenes are generally in the 500 mg/kg range (RTECS 1978).
Acute toxic signs include hyperemia of mucous membranes, increased lacrima-
tion and salivation, excitation followed by sleepiness, ataxia, adynamia,
paraparesis, paraplegia, dyspnea, and death attributed to central
respiratory paralysis, usually within 3 days. Autopsy showed an enlarged
liver with necrosis, submucosal hemorrhage in the stomach and brain edema.
At doses of 0.2 LD;o per day, 1,2-dichlorobenzene appeared to have cumulative
toxic effects causing deaths in one-half of the animals when cumulative
doses reached LDso levels. The 1,4- isoiaer was less coxic char. 1,2-dichloro-
benzene (Varshavskaya 1967).
5-3
-------
Hepatic cirrhosis, focal necrosis and increased liver and kidney
weights were noted in rats given 376 mg/kg of either 1,2- or 1,4-dichloro-
benzene orally, 5 days/wk for 7 months. The maximum tested dose producing
no adverse effects for both isomers was 18.8 mg/kg/day administered by
the same schedule (Hollingsworth _et al. 1956, 1958). Doses of 500 mg/kg/day
administered orally to rabbits for 12 months caused central nervous system
depression, weight loss, and liver pathology, but no hematologic changes
(Hollingsworth _et al. 1956, Pike 1944). An oral dose of 1000 mg/kg
administered to rabbits 5 days/week for several months caused tremors,
weakness, nystagmus and reversible eye changes (Pike 1944).
The Russian literature (Varshavskaya 1968) reports toxic effects at
doses of 1,2-dichlorobenzene several thousand-fold lower than those reported
in other studies. Oral doses to rats of 0.01-0.1 mg/kg/day for several
months caused serum and tissue alterations, behavioral abnormalities, and
marked reduction in hemoglobin, red-cell, and leukocyte concentrations. A
maximum no-detected-effect level of 0.001 mg/kg/day was set; the reason
for the discrepancy between this figure and that of 18.8 mg/kg/day as
set by Hollingsworth et al. (1958) is not clear; exposure levels and
their determination were not adequately addressed by Varshavaskaya (1968).
Hepatic porphyria was noted in rats after daily administration by
stomach tube of 455-1000 mg/kg 1,2- or 1,4-dichlorobenzene for 5-15 days.
An initial marked increase in urinary excretion of urinary coproporphyrin
III, increased ALA synthetase (delta-amino-levulinic acid synthetase)
activity in the liver, and increased urinary excretion of ALA was
observed. In addition, urinary excretion of uroporphyrin and porpho-
bilanogen (PBG) and liver content of protoporphyrin and uroporphyrin
all increased.. Clinical observations included anorexia, weight loss,
weakness, ataxia, and severe liver damage (Rimington and Zeigler 1963).
Poland et al. (1971) reported similar induction of ALA synthetase
activity and production of hepatic porphyria in female Sherman rats after
daily administration of 900-1000 mg/kg 1,3-dichlorobenzene by gastric in-
tubation for 9 days. However, doses of 800 mg/kg/day administered to rats
by intubation for 1, 3 or 5 days produced a biphasic stimulation in the
excretion of urinary coproporphyrin III and hepatic ALA synthetase activity
(3-4-fold increase), which peaked on days 3 and 1, respectively, and de-
creased notably by day 5 (although levels were still higher than controls).
Data suggest that the decrease in ALA synthetase and urinary coproporphyrin
III after 3 days despite continued daily dosage may be the result of an
increase in the activity of liver drug-metabolizing systems stimulated by
1,3-dichlorobenzene itself and resulting in decreased serum levels of 1,3-
dichlorobenzene. The metabolite 2,4-dichlorophenol did not appear to be the
causative agent of the biphasic hepatic porphyria and increased ALA syn-
thetase activity, although these effects can be produced by this metabolite
when administered in daily doses of 800-1000 mg/kg. Livers from rats
treated with the 800-mg/kg daily doses of 1,3-dichlorobenzene were
essentially normal with minimal vacuolization and no evidence of liver
damage (Poland _et_ al. 1971) .
3 — <4
-------
Carlson (1977) found that 1, 4-dichlorobenzene at low doses for
long periods of time has a low potential for causing hepatic porphyria
Oral administration to female rats of 40, 100 or 200 mg/kg/day 1 4-
dichlorobenzene for 30, 60, 90 or 120 days caused only slight increases
in liver porphyrins (even after 120 days) and no significant increase
in urinary excretion of ALA, PBG or porphyrins. A dose-dependent
increase in the liver weight was observed at 30 and 60 days.
Inhalation Exposure
Pike (1944) noted tremors, weakness, nystagmus and reversible eve
changes in rabbits exposed via inhalation to 5250 mg/m3 1, 4-dichlorobenzene,
8 hours/day, 5 days/week for 12 weeks. In addition to the above signs,
Hollingsworth et al. (1956) reported weight loss, liver degeneration
and necrosis in rabbits, rats and guinea pigs exposed to 4,800 mg/m3
1,4-dichlorobenzene for 7 hours/day, 5 days/week, for 6-7 months. Also
rats exhibited cloudy swelling of renal tubular epithelium, and rabbits'
showed lung congestion and emphysema. A dose of 950 mg/m^ over the same
time schedule caused growth depression in guinea pigs, increased liver
weight in rats and guinea pigs and increased kidney weight, centrolobular
cloudy swelling or granular degeneration in rats. A dose of 560 tug/m3
over this time schedule caused no adverse effects in gross appearance
oehavior, growth, organ weights, hematology, urinalysis, gross or
microscopic examination of tissues or mortality of rabbits, rats, mice
guinea pigs and monkeys. (Hollingsworth et al. 1956).
Zupko and Edwards (1949) reported the same signs of marked intoxica-
tion as described above (Pike 1944) after exposure of 18 male rabbits
10 male and 10 female rats, and 9 male guinea pigs by inhalation to 100 g/m3
air of 1,4-dichlorobenzene, 20-30 minutes daily for 30 days. Complete
recovery usually ensued within one to several hours; however, some
deaths did occur, especially in the guinea pigs (only one of the
nine test animals survived beyond 20 exposures). In addition
the majority of animals of all species developed granulocytopenia after
repeated exposures. The total leucocytic and erythrocytic counts were not
greatly affected. Autopsy of dying or sacrificed animals revealed marked
and extensive damage to the kidneys; contrary to other reports, compara-
tively little damage to the liver was evident. Some damage to the lung
'
I'M ^ P^±?ed' bUt damage C° the heart was negligible (Zupko
ana towards 1949) .
Hollingsworth et al. (1958) observed nasal and ocular irritation
drowsiness, coma, massive liver necrosis, and 10% mortality in rats '
exposed to 4,800 mg/m3 1, 2-dichlorobenzene for 11-50 hours Rats
guinea pigs, mice, monkeys and rabbits exposed to 560 mg/m3 1, 2-dichloro-
benzene 7 hours/day, 5 days/week for 6-7 months showed no adverse
effects similar to animals exposed to the same dose of 1,4-dichlorobenzene
as described previously (Hollingsworth at al. 1956). cnj.orooen«.ene,
_ _Cameron and Thomas (1937) found -hac inhalation of as li-le =s n 330-
i,2-aicnlorobenzene for one-half hour caused liver necrosis in 50%* of"' "=
exposed rats. Exposure of both mice or rats to 0.005% 1, 2-dichioroben-e-e
-------
for 24 hours, of rats to 0.039% for 3-12 hours, or guinea pigs to 0.08%
for 24 hours caused liver necrosis in all test animals and some deaths.
Maximal changes were usually seen within 24-48 hours, and the extent of
the lesions was roughly proportional to the dose. The kidneys showed
inconsistent and relatively slight changes confined to the tubular
epithelium. Similar studies with 1,4-dichlorobenzene (specific data not
given) suggested that the structural position of the chlorine atoms
influenced toxicity such that 1,2-dichlorobenzene was more toxic than
1,4-dichlorobenzene (Cameron and Thomas 1937).
Exposure bv Injection
Reid e_t al. (1973) also reported greater hepatotoxicity of 1,2- and
1,3-dichlorobenzene compared with the 1,4- isomer when administered to
male Sprague-Dawley rats by intraperitoneal injection at doses of 194,
192 and 500 mg/kg, respectively; minimal necrosis and some glycogen
loss was caused by the 1,2- and 1,3-dichlorobenzene, while 1,4-dichloro-
benzene caused little to no effect. Injection of the rats with phenobarbital
(80 mg/kg) for 3 days prior to these doses of the dichlorobenzenes markedly
increased centrolobular hepatotoxicity (glycogen loss with massive or
extensive necrosis) caused by the 1,2- and 1,3-dichlorobenzene,but had
no effect on the response caused by 1,4-dichlorobenzene (Brodie et al.
1971). In a similar experiment (Reid et_ al. 1973), intraperitoneal
injection of male Sprague-Dawley rats or male C57BL/6 mice with 80 mg/kg
phenobarbital for 3 days prior to injection with 73.5 mg/kg :4C-labelled
1»2-dichlorobenzene or 1,4-dichlorobenzene caused increased binding of
1,2-dichlorobenzene in the liver and increased excretion of its urinary
metabolites, but had no effect on 1,4-dichlorobenzene metabolism and
caused a slight decrease in its binding to centrolobular hepatocytes;
the reason for this decrease in binding is not evident (Reid et al.
1973).
The increased hepatotoxicity of the 1,2- and the 1,3-dichlorobenzenes
has been attributed to the conversion of the parent compounds by hepatic
microsomal enzymes (mixed function oxidases including cytochrome P-450)
to active intermediates (epoxides or arene oxides), which product centro-
lobular necrosis through covalent linkage to the centrolobular hepatocytes.
These intermediates are alternatively converted to GSH conjugates,
dihydrodiol derivatives, or phenols by enzymes in the soluble fraction
of the liver; phenols are excreted, dihydrodiols are converted to
catechols, and GSH conjugates are converted to premercapturic acids,
which are subsequently excreted (Brodie £t_ al_. 1971, Reid _et_ al_. 1973).
Copolla et al. (1963) reported an effect on blood coagulation
(increase in thromboelastogram reaction and clotting formation times)
in guinea pigs injected intramuscularly with daily doses of 125 mg of
1,4-dichlorobenzene for 3 weeks. Totaro (1961) observed weight loss and
increased levels of serum transaminases (SCOT and SGPT), with no change
in serum aldolase in guinea pigs injected intramuscularly with the same
dose of 1,4-dichlorobenzene for 11 or 20 days.
3-0
-------
5.1.2 Metabolic Studies
Azouz et_ _al. (1955) detected no 1,4-dichlorobenzene in the feces of
rabbits after a single intragastric administration of 500 mg/kg body weight
of the compound in oil, a finding suggesting virtually complete
absorption under these conditions. Major metabolites,' 2,5-dichlorophenol
and 2,5-dichloroquinol, were excreted in the urine as glucuronides (36% of
the dose) and ethereal sulfates (27% of the dose) with peak excretion on
day 2 after administration.
Kimura _et al. (1979) found that two sulfur-containing metabolites
of 1,4-dichlorobenzene were excreted primarily in the urine of male Wistar
rats after a single oral administration (following a 16-hour fast) of
200 mg/kg or 800 mg/kg 1,4-dichlorobenzene. After administration, the
level of 1,4-dichlorobenzene was initially higher in the adipose tissue
compared with blood or other tissue and within 48 hours, was detectable
only in the adipose tissue. The concentration of the metabolite
dichlorophenyl methyl sulfoxide (M-l) was greater in the kidney than in
the blood, but lower in the liver and adipose tissue. Up to 12 hours,
the level of M-2 prevailed, maintaining an appreciable level even after
120 hours (suggesting that M-2 might arise from M-l). The rates of
urinary excretion of M-l and M-2 were very slow (0.031% and 0.122% of
dose, respectively, after 96 hours), possibly due to slow release of
the parent compound from adipose tissue stores. The rate of urinary
excretion of M-2 was initially lower than that of M-l, but increased ana
prevailed by 48 hours. Urinary excretion of both M-l and M-2 was much
less than that of the major metabolite 2,5-dichlorophenol. Fecal excre-
tion of both M-l and M-2 was very low.
A single oral dose of 500 mg/kg 1,2-dichlorobenzene administered
via stomach tube to rabbits was metabolized primarily to 3,4-dichlorophenol
(> 30% of the dose) with minor amounts of 2,3-dichlorophenol (9%),
3,4-dichlorophenylmercapturic acid (5%), and 3,4-(trace) and 4,5-dichloro-
catechol (4%). Excretion of 76% of the dose occurred via the urine as
conjugates of glucuronide (48%), ethereal sulfate (21%) or mercapturic
acid (5%).^ Peak excretion occurred on day 1 after administration (Azouz
£t_ £l. 1955). An identical experiment conducted with the 1,4- isomer
showed it to be principally metabolized to 2,5-dichlorophenol and, in
contrast to 1,2-dichlorobenzene, excreted only as the glucuronide or
ethereal sulfate conjugates. Peak excretion occurred on the second day
after dosing, possibly reflecting a slower absorption. No 1,4-dichloro-
benzene, however, was detected in feces during a 6-day period, indicating
essentially complete absorption did occur (Azouz et al. 1955).
Jacobs et al. (1974 a,b) found 1,2-dichlorobenzene accumulated in rat
tissue after administration of oral doses of 0.4-2.0 mg/kg/day (length
of experiment not stated), indicating significant absorption from the
gastrointestinal tract even at low levels of exposure. Tissue accumula-
tion was greater in the fat than in the liver, kidney, heart, or blood
(quantitative data not given).
5-7
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Following administration of a 500 mg/kg dose of 1,3-dichlorobenzene
to rabbits via stomach tube, Parke and Williams (1955) reported conversion
to the major metabolite 2,4-dichlorophenol (20% of dose) and minor
metabolites, 3,5-dichlorophenol, 2,4-dichlorophenyl-mercapturic acid, and
3,5-dichlorocatechol. Urinary excretion of conjugates of the metabolites
(accounting for 54% of the dose) peaked on day 1 after administration and
included 36% glucuronides, 7% ethereal sulfates and 11% mercapturic acid.
Studies have also indicated absorption of the dichlorobenzenes from the
human respiratory tract. Morita and Ohi (1975) reported levels of 2.3 ug/g
1,4-dichlorobenzene in the adipose tissue of 34 subjects (14 male, 20
female) and 9.5 ng/ml 1,4-dichlorobenzene in the blood of six subjects
(4 male, 2 female) residing in Tokyo, where ambient air samples contain
2-4 ugM3 1,4-dichlorobenzene. A closet treated with this chemical to
repel moths contained 315 ug/m3,while air samples in a bedroom contained
105 yg/m3. A "wardrobe" was stated to contain 1700 ug/m3 (Morita and Ohi
1975).
. Pagnotto and Walkley (1965) reported rapid respiratory absorption of
inhaled 1,4-dichlorobenzene in occupationally exposed persons. Their
observation was based upon the rapid urinary excretion of the metabolite,
2,5-dichlorophenol, soon after exposure began. Peak excretion occurred
at the end of the work shift. No data on quantitative efficiency of
absorption of 1,4-dichlorobenzene were given, although the authors suggest
that the level of 2,5-dichlorophenol in the urine at the end of the
exposure period correlated fairly well with the average air concentration
of 1,4-dichlorobenzene and may, therefore, be useful as an indicator of
exposure to the parent compound. Urinary excretion of the other major
metabolite of 1,4-dichlorobenzene in man, 2,5-dichloroquinol, was not
determined in this study.
5.1.3 Overview
5.1.3.1 Ambient Water Quality Criterion - Human Health
The U.S. Environmental Protection Agency (1980) has established an
ambient water quality criterion of 400 ug/1 for the protection of human
health from the toxic properties of dichlorobenzenes ingested through
water and contaminated aquatic organisms. This criterion is based on
the maximum chronic no-observed effect level of 13.42 mg/kg/day
(18.8 mg x 5/7) reported for rats orally administered either 1,2- or
1,4-dichlorobenzene over a period of 5 to 7 months (Hollingsworth _et_ al.
1956, 1958). Applying an uncertainty factor of 1000, the acceptable
daily intake of 1,2- or 1,4-dichlorobenzene for a 70-kg man was calculated
to be 0.94 mg/day. The similar toxicities among the dichlorobenzene
isomers support the applicability of this value to 1,3-dichlorobenzene
as well.
5-t
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5.1.3.2 Other Health Considerations
Dichlorobenzenes are rapidly absorbed via the lungs and gastrointestinal
tract, and can also be absorbed through the skin, with major target systems
being the liver, reticuloendothelial system and the central nervous system
(see Table 5-1). Liver necrosis has been reported in rats orally admin-
istered 376 mg/kg of either 1,2- or 1,4-dichlorobenzene, 5 days per week
for 7 months (i.e., 376 mg/kg x 5/7 or 268 mg/kg/day). A no-observed
effect level of 13.4 mg/kg/day was established for this species. No
chronic toxicity study with a duration greater than 7 months has been
completed. A lifetime feeding study with 1,2-dichlorobenzene conducted
with both rats and mice is nearing completion. Preliminary data suggest
(no histopathology has been done) that ingestion of up to 120 mg/kg
1,2-dichlorobenzene, 5 days per week for 18 months (i.e., 86 mg/kg/day)
is not carcinogenic in either species. With the possible exception of
this latter study, the inadequacy of available studies on the reproductive
effects, carcinogenicity, or teratogenicity have rendered the data
insufficient for a valid assessment of risk.
Little specific information is available on human toxicity associated rith
dichlorobenzene exposure. Anecdotal reports have linked chronic
inhalation exposure to various forms of anemia and liver pathology
but no quantitative intake data are available. Additional toxicological
studies are needed before a reliable estimate of risk can be estimated
for humans exposed to the dichlorobenzenes.
5.2 HUMAN EXPOSURE
5.2.1 Introduction
The results of the materials balance analysis (Chapter 3) indicate
that 52% of the total U.S. annual production (or 62% of the net domestic
supply) of dichlorobenzenes is released into the environment. The poten-
tial for exposure of human and non-human populations to these chemicals
is, therefore, significant. However, because the dichlorobenzenes are
relatively low-volume chemicals and because the sources appear to be
widely dispersed, the actual environmental concentrations to
which populations may be exposed are generally rather low. The largest
releases of the dichlorobenzenes are directly to the atmosphere; further-
more, volatilization is a major fate pathway for dichlorobenzene released
to the aquatic environment. Therefore, inhalation is expected to be the
primary exposure route for humans.
This section contains a discussion of potential human exposures,
based upon the limited amount of monitoring data available. Releases
of commercially produced (and used) dichlorofaenzenes have been tabulated
by state or geographical area when the data were available as an indica-
tion of the extent of exposures. Daily exposure levels are estimated
for a number of scenarios, using the monitoring data and average intake
rates for water and air (ICR? 1975). The data are quite limited, and
the resulting exposures are intended to be only approximations of the
range of possible exposures to dichlorobenzenes.
T-Q
-------
TABLE 5-1. ADVPR.SE EFFECTS OF DICHLOROBENZENES IN MAMMALIAN SPECIES
a
Adverse Effect
Species
Lowest Reported Effect Level
No Apparent Effect Level
Carcinogenesls
Tera logenesls
Rat
Mouse
No data available.
1,2-Dichlorobenzene:
Preliminary data suggest
86 rag/kg/day orally for
18 months.
I
i-j
o
Mutagenici ty
in vitro
Hepatic necrosis
Aspergillus
nidu lans
Rat
200 |Jg/ml solution of
either 1,2-, 1,3- or
1,4-dichlorobenzene.
268 mg/kg/day orally of
either 1,2- or 1,4-
dichlorobenzene.
13.4 mg/kg/day orally of
either 1,2- or 1,4-
dichlorobenzene.
Anemias, liver
pathology
lluiiiu ly tic anemia
Human
Human
Chronic inhalation of
1,2- or 1,4-dichlorobenzene..
No quantitative data.
Ingestioi/of 1,4-
dichlorobenzene crystals.
No quantitative data.
500-600 mg/m3 occupational
exposure to 1,2- or 1,4-
dichlorobenzene.
Data taken from Section 5.1 of this report.
-------
5.2.2 Waterborne Exposure
5.2.2.1. Geographical Distribution.
Monitoring data are too sparse to indicate where humans may be exposed
to dichlorobenzene. Tables 5-2 and 5-3 summarize the estimated releases to
the aquatic environment of 1,2- and 1,4-dichlorobenzenes, respectively.
When available, the geographic distribution of those releases across the
United States is also indicated. The tabulated information suggests that
exposure might be somewhat lower in the western U.S., but otherwise rather
uniform across the country. The available monitoring data (Section 4-4,
summarized in Table 5-4,) suggest that patterns of observed concentrations
of the dichlorobenzenes detected in aqueous environments do not corres-
pond to the available information concerning the distribution of releases.
5.2.2.2. Exposure through Ingestion
The most direct exposure route for waterborne dichlorobenzenes is
ingestion of drinking water. NOMS data for the dichlorobenzenes indicate
that the mean non-zero concentrations for 1,2-, 1,3-, and 1,4-dichloro-
benzenes were 1.5, 0.1, and 0.07 yg/1, respectively. These data are for
Phase III of the NOMS study. The frequency of observation during this
phase was 4% for 1,2-dichlorobenzene, 2% for 1,3-dichlorobenzene and 26%
for 1,4-dichlorobenezene. Table 5-5 presents the estimated exposure
levels for humans consuming 2 liters of drinking water per day. Exposures
have been computed using NOMS mean (all non-zero data), median, and
maximum concentrations in order to give a range of possible exposure
levels.
The potential for exposure to substantial amounts of dichlorobenzenes
from drinking water appears to be low. Subpopulations in the vicinity of
production or industrial use faciliites might be exposed to transitory,
higher levels due to accidental releases, but there are no data to
support a quantitative estimate of this type of exposure.
There are no data to indicate that food consumption represents a sig-
nificant route of human exposure to dichlorobenzenes. However, there
are a few observations recorded in the Water Quality Criteria Document
(U.S. EPA 1980) that are relevant. Schmidt (1971) reported a disagree-
able odor and taste in pork, which could be traced to the use in pig
stalls of an odor-control product containing 1,4-dichlorobenzene.
Following 3 days of exposure of hens to 20-38 mg/m3 1,4-dichlorobenzene,
eggs were reported to be tainted, although neither hens nor egg produc-
tion was affected (Langner and Hilliger 1971). There are insufficient
data to quantify a human risk due to ingestion of food.
The compound 1,2-dichlorobenzene is registered for use against
termites, beetles, bacteria, sliine and fungi (Ware and West 1977).
The 1,4- isomer is used for concrol of mildew, tobacco mold, bark beetles
and peach tree borers and as a fumigant to control lice, mites, and cock-
roaches (Ware and West 1977). No uses that would be expected to lead
directly to residues in human food chain crops wera identified.
5-11
-------
TABLE 5-2. VOLUME AND GEOGRAPHIC DISTRIBUTION OF AQUATIC RELEASES
OF 1,2-DICHLOROBENZENE a
Release Source Type
Location
1,2-Dichlorobenzene Production
% of Production
36
22'
14
11
11
3
1
Delaware
Michigan
West Virginia
New Jersey
Illinois
New York
California
Estimated Aquatic
Release
(kkg/year)
84
51
33
26
26
6.6
3.3
TOTAL
230
Miscellaneous Solvents
Unknown 12
Dye Synthesis; Dye Carrier
POTWs
9 New Jersey plants; 12
3 New York, 2 Delaware,
1 Massachusetts,
1 North Carolina,
1 South Carolina,
1 Michigan, 1 Illinois
Uniform 70
Table prepared from data in Section 3.0,
b Releases from imported or exported material are unknown and, therefore,
not included .
Q
Assuming releases of isomer are proportional to production volumes.
Assuming an even distribution of all three isomers (Table 3-5, foot-
note b).
-------
TABLE 5-3.. VOLUME AND GEOGRAPHIC DISTRIBUTION OF AQUATIC RELEASES OF
1,4-DICHLOROBENZENE a
Release Source Type
1,4-Dichloroben.zene Production''
% of Production
45
18
18
9
7
2
1
TOTAL
Location
Delaware
Michigan
West Virginia
New Jersey
Illinois
New York
California
Estimated Aquatic
Release
(kkg/year)
130
53
53
26
21
6.8
290
3.4
d
Space Deodorant
Moth Control
POTWs
Northeast 27%
North Central 26%
Southeast 17%
South Central 17%
Southwest 10%
Northwest 3.6%
Northeast 27%
North Central 26%
Southeast 17%
South Central 17%
Southwest 10%
Northwest 3.6%
Uniform
500
Table prepared from data in Section 3.0, unless indicated otherwise.
Releases from imported or exported material are unknown and therefore
not included.
Von Rumker (1974).
Assuming releases of isomer are proportional to production volumes .
Assuming an even distribution of all three isomers (Table 3-5, foot-
note b) .
.3-13
-------
TABLE 5-4. SUMMARY OF REPORTED AQUEOUS ENVIRONMENTAL CONCENTRATIONS OF DICHLOROBENZENE
Concentration (ug/1)
a
Ul
I
Sample
Drinking Water
b
Mean (NOMS)
Median (NOMS)
Maximum (NOMS)
Miami, Florida (NORS)
Maximum Concentration
Reported as of 1975
Ambient Surface Water
National Mean (STORET)
Maximum (STORET)
Effluent Water
National Mean^ (STORET)
Maximum (STORET)
Maximum (other)
Municipal Wastewater (Raw)
Mean
Maximum
1,2-DCB
1.5
<.005
9.1
1
1
29
4660
17
2500
1100
1,3-DCB
0.1
<.005
0.5
<3
12
400
14
2500
1100
10-33
10-33
376-440
1,4-DCB
0
<
2
1
1
14
610
9
2500
1100
.07
.005
.0
Unless Indicated, data are from Section 4.4. of this report.
l>
NOMS Mean Is average for all'positive data.
'' U.S. EPA (1978).
STOKI'T mean is average of all data, remarked and unremarked.
-------
Ul
I
TABLE 5-5. ESTIMATED HUMAN EXPOSURE TO DICHLOROBENZENES BY INGESTION OF DRINKING WATER
a
Sources
Drinking Water
-maximum observed
-mean observed
-median concentration
-water quality criterion*3
1,2-
Conc.6
(ug /I)
9.1
1.5
<.005
400
DCB
Exposure
(rag/day)
0.018
3xlO~3
<10~5
0.8
Conc,b
(MR /I)
0.1
<.005
400
1,3- DCB
Exposure
(mg/day)
— u
-------
Dichlorobenzenes may occur in plant tissues as products of lindane
degradation; dichlorobenzenes, along with other chlorinated benzenes,
were identified among a group of lindane metabolites on lettuce and
endives (Kohli eit al. 1976) and in roots of wheat plants grown from
lindane-treated seed (Balba and Saha 1974). Dichlorobenzenes have also
been measured in soils as lindane degradation products (Mathur and Saha
1977). The degree of environmental contamination from lindane use is
small and, therefore, the degradation of lindane is not expected to be
a significant source of dichlorobenzenes in food crops.
5.2.3. Airborne Exposure
5.2.3.1. Geographical Distribution
Tables 5-6 and 5-7 summarize the estimated volume of environmental
releases of 1,2- and 1,4-dichlorobenzene, respectively, to the atmos-
pheric environment, with an indication of the geographical distribution
of those releases across the United States. (These sources are discussed
in detail in Section 3.0.) Table 5-8 summarizes the reported monitoring
data on atmospheric environmental concentrations (further discussion of
ambient levels may be found in Section 4.4). As shown, the highest concen-
trations in non-occupational settings result from the dispersive uses of
1,4-dichlorobenzene as deodorizer and as moth repellant. Occupational
exposure is expected to be associated primarily with production and with
use of 1,2-dichlorobenzene as a chemical intermediate and process solvent.
5.2.3.2. Exposure through Inhalation
Since the largest environmental releases of dichlorobenzene are to
the atmosphere, and volatilization is a major removal process for dichloro-
benzenes initially released to aquatic media, inhalation is expected to
be the major exposure route for humans. Human exposure to atmospheric
concentrations of 1,2- and 1,4-dichlorobenzenes has been reviewed for
the U.S. EPA Office of Air Quality Planning and Standards (Anderson
_e_t a_l. 1980). The size of the population exposed to various atmospheric
concentration levels resulting from point and area source emissions
of 1,2- and 1,4-dichlorobenzene was estimated. These data are presented
in Table 5-9.
Average respiration rates for an active adult (16 hours) and a
sleeping adult (8 hours) are 1.2 m3/hour and 0.4 m3/hour, respectively;
the average daily rate is about 23 m3/day (ICBP 1975). Using the data
from Table 5-9 and the average respiration rates, exposure levels can
be calculated for each concentration level, and populations exposed can
be summarized as follows:
5-16
-------
TABLE 5-6. VOLUME AND GEOGRAPHIC DISTRIBUTION OF ATMOSPHERIC RELEASES
OF 1,2-DICHLOROBENZENEa
Release Source Type'
Manufacture of Toluene Diisocyanate
% of Production
31
24
32
9
4
TOTAL
Location
Texas (2 plants)
West Virginia (2 Plants)
Louisiana (3 plants)
New Jersey
Ohio
Estimated
Release
(kkg/yr)
1110
860
1150
340
150
3600
Miscellaneous Solvents
Uniform
1900
Dye Synthesis,Dye Carriers
1,2-Dichlorobenzene Production
% of Production
36
22
14
11
11
3
1
TOTAL
Minor Uses
3,4-Dichloroaniline Synthesis
POTWs
9 NJ plants; 3 NY; 160
1 MA; 1 NC; 1 SC; 1 MI; 1 IL
Delaware
Michigan
West Virginia
New Jersey
Illinois
New York
California
Uniform
2NJplants; 1 LA plant
Uniform
35
21
14
11
11
2.7
1.4
70
24
?Tafale prepared from data in Section 3.0 unless indicated otherwise.
^Releases from imported or exportad material are not included.
^.Assuming releases of isomers are proportional to its production volumes.
-Assuming an even distribution of all three isomers (Table 3-5, footnote b).
-------
TABLE 5-7. VOLUME AND GEOGRAPHIC DISTRIBUTION OF ATMOSPHERIC RELEASES OF
1,4-DICHLOROBENZENEa
Release Source Type
Location
Space Deodorant
Northeast 27%
Northcentral 26%
Southeast 17%
Southcentral 17%
Northwest 3.6%
Southwest 10%
Estimated
Release
(kkg/vr)
14000
Moth Control
9500
1,4-Dichlorobenzene Production
% of Production
45
18
18
9
7
2
1
TOTAL
POTWs
Delaware
Michigan
West Virginia
New Jersey
Illinois
New York
California
110
43
43
21
17
5.6
2.8
240a
672
Minor Uses
(pesticide synthesis, abrasives,
textiles)
prepared from data in Section 3.0, unless indicated otherwise.
^Releases from imported or exported material not included .
<*Von Rumker (1974).
^Assuming releases of isomers are proportional to its production volumes.
5Assuming an even distribution of all three isomers (Table 3-5, footnote b)
5-18
-------
TABLE 5-8. SUMMARY OF REPORTED AIRBORNE CONCENTRATIONS OF
DICHLOROBENZENESa
Exoosure Medium
Concentrations (yg/m )
1,2-DCB
1.3-DCB
1,4-DCB
Ambient Air
Air at Waste
Disposal Site
0 - .106
0-12
0 - .382
0 - 3'4
0 - .062
0-7
Ambient Air at
Industrial Location
0 - 1.3
0 - 1.2"
(1,3 or 1,4-dichlorobenzene)
1,4-Dichlorobenzene
Manufacturing Site
150-420
Air in Vicinity of
Mothball usage:
bedroom
closet
wardrobe
105
315
1700
aData presented in this Table were taken from Section 4.4 of this report,
unless indicated otherwise.
iTsomers other than 1,2-dichlorobenzene .
5-19
-------
TAULK 5-9. ESTIMATED SIZE OF U.S. POPULATION EXPOSED TO POINT AND AREA SOURCE ATMOSPHERIC-
CONCENTRATIONS OF 1,2- AND 1,A-DICHLOROBENZENE
Number of Persons Exposed
3
Concentration (M8/m )
100
50
25
10
Ul
i 5
10
O
2.5
1
0.5
0.25
O.I
0.05
1, 2-Dichlorobenzene
2
38
4,258
16,315
26,406
57,100
159,047
353,618
1,161,116
10,105,220
34,282,399
' • — • • -••- -• — •. . • 1 1 i . , .
1 ,4-Dichlorobenzene
2
8
30
125
342
505,373
9,153,477
26,986,006
61,682,673
133,639,503
_
Source: Anderson et al. (1980)
-------
EXPOSURE LEVELS (ug/day) ESTIMATED SIZE OF POPULATION EXPOSED
1,2-DCB
11
100
< 6
- 60
- 2300
ug/day ,
ug/day
ug/day
47 x
57 x
47 x
106
10*
103
1,4-DCB
195 x 105
37 x 106
507
The size of the population with occupational exposure to airborne
dichlorobenzenes in the workplace was estimated in a NIOSH survey cited
by Hull and Co. (1980). It was estimated, by projection from an industry
subsample surveyed, that a total of almost 2 million workers had "full"
(>4 hours/week) or "part" (<4 hours/week) exposure to 1,2-dichlorobenzene
and that slightly more than one-half million workers had comparable expo-
sure to 1,4-dichlorobenzene. A survey conducted by Hull and Co. for
the Synthetic Organic Chemicals Manufacturing Association, based on
contacts with all identified shippers and receivers of the chemicals,
led to an estimate that many fewer employees (<5000 total) are actually
occupationally exposed to the dichlorobenzenes. The Occupational Safety
and Health Administration has set standards for dichlorobenzene exposure:
300 mg/m3 ceiling level, for 15-minute maximum exposure; and 450 mg/m3
for an 8-hour time-weighted exposure (NIOSH 1979).
Individuals may be exposed to transitory, high levels of 1,4-dichloro-
benzene due to consumer use of mothballs. The recommended application rate
for that use is approximately 0.16 kg/m3 (1 lb/100 ft3) of enclosed
space (Von Rumker et_ al. 1974). Von Rumker states that in order for the
moth control agent to be effective the vapors must be kept at such a
level in the enclosed space that the vapors would cause eye irritation
in humans. Exposure of consumers to such levels would undoubtedly be
brief and infrequent because of the unpleasantness of the irritant effect.
There is one report (Morita and Ohi 1975) of a dichlorobenzene con-
centration of 105 ug/m3 in the general air of a bedroom, associated
with mothball usage; the concentration in the closet was 315 ug/m3 while
the vapor concentration of dichlorobenzene inside the wardrobe (where
the moth crystals were presumably located) was 1700 ug/m3 . Confirmation
of this concentration as typical of levels arising from use of some
mothballs could be significant, since the 105 ug/a3 concentration is
higher than the highest exposure level considered by Anderson et al.
(1980) as attributable to point and area ambient air sources. The latter
authors did consider mothball use as an area source of 1,4-dichlorobenzene
but did not explicitly consider the short-term, local exposures.
Table 5-10 presents the range of estimated inhalation exposures
resulting from concentration levels reported in Section 4.4 of this
report. The data are very limited and are often reported for a very
-------
TAIII.I: r.-io. i'SriMATi:n INHALATION FXPOSUKKS TO nicinx)RoiiENZENESa
l-'-.pu.iure Type (l)urationj_
Concentrat Ion Kxposure
<\.in
-i uial
0-. 11)6
0 -.002
0-.383
1
0-.009
.02
< .02
0-.062
2.7-4.2
1.5-2.4
O-.OOl
.06-.09
.01-. 05
Aii Around Industrial SiLe
(H hrs/day
(2/. lira/day)
.002-1.J
•>-0-.01ing/6
•v.0-,03
.001-1.2
.001-1.2
'"•O-.Ol i«B/B hr
'^•O-.OI pi};ft |,r
Ol
I
AII .H DispoH.il Site
(ii hrs/dny)
(24 lira/day)
< .03-34
-v.0-.12 mp,/8 hr
•>-0-.27
0- . 76
mg/8lir
l-.07 uK/8lir
-. 16
i i upal lonal Exposure
- Ml. IX 1 HIIIIH (ft IllS/lliiy)
-OSIIA 15 minute ..•llln(. (0.25 lirs/d.iy)
-OSIIA tiiuo wi-l|>li|i!d avemi-e (8 lirs/day)
4.21xinJ
2.0x10^
4.5x10
4042 Wg/a hi
90 mg/.25lr
4 120 me,/B hr
i>.', idi-nt 1.11 Kxposure
Ix'ilroom (10 hr.s/il.iy)
-i-lnKet (0.5 lirs/day)
-wardrobe (0.1 hrs/d.iy)
105
315
1 700
0.6
0.2 MR/.Mil
0.2 ui8/.llir
'' Concent ral Ion data are presented in Section 4.4 and Tali It 5-H.
'' Kst I iii.il e.s of exposure ,111' li.isi'il on >iveriij;e adult liVeatliln)', rates ol 1.2 m /hi for ac-live adult (16 Ins) and
0.4 uiVlir lot a sleeping adult (8 hrs) ( ICKI' I'J75).
-------
specific environment; therefore, this exposure assessment is not meant
to be definitive in terms of the general population. The exposure
estimates were computed by multiplying the number of active and sleeping
hours by 1.2m3/hour and 0.4 m3/hour, respectively, in order to obtain
an estimate of the total daily air intake; that intake number was then
multiplied by the concentration data to determine exposures. No cor-
rection has been made for the amount of dichlorobenzene actually
absorbed or metabolized.
5.2.4
The total volume of releases of dichlorobenzenes to the atmosphere
is more than an order of magnitude greater than the releases to the
aquatic environment. Furthermore, any dichlorobenzene. in aquatic
systems would be expected to volatilize rapidly or be partitioned into
the sediment. Therefore, the relatively low calculated exposure levels
for drinking water are not surprising. The water quality criterion for
dichlorobenzenes allows a total daily exposure of 0.8 mg/day, assuming
an intake of 2 I/day. Based on the available data, the maximum- drinking
water exposures were calculated to be 0.018 mg/day 1, 2-dichlorofaenzene
and 0.004 mg/day 1,4-dichlorobenzene. Mean and medium exposure levels
range from 10 ~*to 10 ~3 mg/day.
The exposures due to inhalation of contaminated air are expected to
be larger than exposure from ingestion of water. According to Anderson
et al. (1980) , a very small percentage of the population would be exposed
to atmospheric concentrations greater than 2.5 wg/m3 from point and area
source emissions; the exposure level corresponding to 2.5 ug/m3 is
estimated to be 0.056 mg/day based on the ICRP <1975) respiration rates.
The vast majority of the population is expected to be exposed to
dichlorobenzene concentrations less than 0.006 mg/day. Based upon other
monitoring data, exposure to dichlorobenzenes in ambient air is generally
far less than 0.1 mg/day; the exception is exposure to air at a waste
disposal site in New Jersey, where the 24-hour exposure level near the
site could be as high as 0..76 mg/day.
The more significant exposures to dichlorobenzene are in indoor
environments. One measurement of air in a 1,4-dichlorobenzene plant would
give an exposure estimate of 4042 mg/8 hours; the OSHA time-weighted
average for an 8-hour period is 4320 mg. Another source of intermittent
exposure is indoor air near a source of mothballs. Concentrations measured
in a bedroom indicated possible exposure levels of 0.6 mg/10-hour period.
-------
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-------
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1980 and IARC 1974).
Harden, R.A.; Baetjer, A.M. Apalstic anemia following exposure to para-
dichlorobenzene and naphthalene. J. Occup. Med. 20(12):820-822; 1978.
Hollingsworth, R.L.; _et al. Toxicity of o-dichlorobenzene. Studies in
animals and industrial experience. AMA Arch. Ind. Health 17:180; 1958
(as cited in U.S. EPA 1980).
Hollingsworth, R.L.; et al. Toxicity of paradichlorobenzene. Determina-
tions on experimental animals and human subjects. AMA Arch. Ind. Health
14:138; 1956 (as cited in U.S. EPA 1980).
Hull and Co. Employee exposure to chlorobenzene products. Greenwich
CT; Hull and Co.; 1980.
IARC. Monographs on the evaluation of carcinogenic risk of chemicals to
man: Some anti-thyroid and related substances nitrofurans and industrial
chemicals. 7:231-244; 1974.
Jacobs, A.; _et_ _al. Accumulations of noxious chlorinated substances from
Rhine River water in the fatty tissues of rats. Vom Wassar (German) 43:
259; 1974a (Abstract) (as cited in U.S. EPA 1980).
Jacobs, A.; _e_t _al. Accumulations of organic compounds, identified as
harmful substances in Rhine water in the fatty tissues of rats. Kern-
forschungszentrum Karlsruhe (Ber). KFK 1969 UF:1; 1974b (Abstract) (as
cited in U.S. EPA 1980).
Kimura, R.; Hayashi, T.; Sata, M.; Aimoto, T.; Murata, T. Identification
of sulphur-containing metabolites of p-dichlorobenzene and their disposi-
tion in rats. J. Phann. Dyn. 2:237-244; 1979.
-------
Kohli, J.; et £l. Contributions to ecological chemistry, CVII. Fate of
lindane- C in lettuce, endives, and soil under outdoor conditions. J.
Environ. Sci. Health Bull. 23:1976 (as cited in U.S. EPA 1980).
Langner, H.J.; Hillinger, H.G. Taste variation of the egg caused by the
deodorant p-dichlorobenzene. Analytical proof. Berlin. Muenchen
Tierairztl. 84:851, 1971 (as cited in U.S. EPA 1980).
Mathur, S.P.; Sana, J.G. Degradation of lindane-I1+C in a mineral soil
and in an organic soil. Bull. Environ. Contam. Toxicol. 17:424; 1977
(as cited in U.S. EPA 1980).
Morita, M.; Ohi, G. Para-dichlorobenzene in human tissue and atmosphere
in Tokyo metropolitan area. Environ. Pollut. 8(4): 269-274; 1975.
Nalbandian, R.M.; Pearce, J.F. Allergic purpura produced by exposure to
p-dichlorobenzene. J. Am. Med. Assoc. 194(7): 238-239; 1965.
National Academy of Sciences. Drinking water and health. Washington,
D.C.:Safe Drinking Water Committee, Advisory Center on Toxicology, As-
sembly of Life Sciences, National Research Council; 1977:pp.681-686.
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Part 1910, Subpart 7, Section 1000. OSHA Standards for Air Contamination
of Toxic and Hazardous Substances. Code of Federal Regulations; 1979.
Pagnotto, L.D.; Walkley, J.E. Urinary Dichlorophenol as an Index of
para-dichlorobenzene exposure. Am. Ind. Hyg. Assoc. J. 26(2):137-142;
1965.
Parke, D.V.; Williams, R.T. Studies in detoxification: The metabolism
of halobenzenes, (a) metadichlorobenzene, (b) further observations on the
metabolism of chlorobenzene. Biochem. Jour. 59:415; 1955 (as cited in
U.S. EPA 1980).
Perrin, M. Possible harmfulness of paradichlorobenzene used as a moth-
killer. Bull, de 1'Acad. de Med. (French) 125:302; 1941 (Translation)
(as cited in U.S. EPA 1980).
Petit, G; Champeix, J. Does an intoxication caused by paradichlorobenzene
exist? Arch des Malad. Prof, de Med. (French) 9:311; 1948 (Translation)
(as cited in U.S. EPA 1980).
Pike, M.H. Ocular pathology due to organic compounds. J. Mich. State
Med. Soc. 43:581-584; 1944 (as cited in National Academy of Sciences
1977).
Poland, A.; Goldstein, J.; Hickman, P.; Burse, V.W. A reciprocal re-
lationship between the induction of delta-aminolevulinic acid synthetase
and drug metabolism produced by m-dichlorobenzene. Biochem. Pharmacol.
20:1281-1290; 1971.
5-26
-------
Prasad, I. Mutagenic effects of the herbicide 3',4'-dichloropropionanilide
and its degradation products. Can. J. Microbiol. 16(5):369-372; 1970.
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Fairchild, E.S.; Lewis, R.J.; Tatken, R.L.; eds. Cincinnati, Ohio:U.S.
Department of Health, Education and Welfare, Public Health Service,
Center for Disease Control, National Institute for Occupational Safety
and Health; 1978.
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mechanism of hepatic necrosis induced by aromatic hydrocarbons. Pharmacol.
10:193-214; 1973.
Rimington, C.; Zeigler, C. Experimental porphyria in rats induced by
chlorinated benzenes. Biochem. Parmacol. 12:1387; 1963 (as cited in
U.S. EPA 1980).
Schmidt, G.E. Abnormal odor and taste due to p-dichlorobenzene.
Lebensmltelhyg. 22:43; 1971 (as cited in U.S.EPA 1980).
Totaro, S. Serum transaminase and aldolase activity in subacute experi-
mental intoxication with p-dichlorobenzene. Folia Med. 44:586; 1961
(Summary) (as cited in U.S. EPA 1980).
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Environmental Protection Agency; 1978.
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Office of Water Regulations and Standards, U.S. Environmental Protection
Agency; 1980.
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benzene and dichlorobenzene (ortho- and para- isomers) in relation to
the sanitary protection of water bodies. Hyg. Sanit. 33:17-23, 1968
(as cited in National Academy of Sciences 1977).
Varshavskaya, S. The hygenic standardization of mono- and dichlorobenzenes
in reservoir waters. Nauch Tr. Aspir. i Ordin. Pervgi Mosk. Med.
Institu. (Russian) 175; 1967 (Translation) (as cited in U.S. EPA 1980).
VonRumker, R.; Lawless, E.W.; Meiners, A.F. Production, distribution,
use and environmental Impact potential of selected pesticides. Washington,
D.C.: Office of Pesticide Programs, U.S. Environmental Protection Agency;
1974.
Wallgren, K. Chronic intoxications in the manufacture of moth proofing
agents consisting mainly of paradichlorobenzene. Zentralb. Albeitsmed.
Arbatschultz (Darmstadt) 3:14; 1953 (as cited in U.S. ZPA 1980).
5-27
-------
Ware, S.; West, W.L. Investigation of selected potential environmental
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Office of Toxic Substances, U.S. Environmental Protection Agency; 1977
(as cited in U.S. EPA 1980).
Waller, R.W.; Crellin, A.J. Pulmonary granulomatosis following extensive
use of paradichlorobenzene. AMA Arch. Int. Med. 91:408-413; 1953.
Zupko, A.G.; Edwards, L.D. A toxicological study of p-dichlorobenzene.
J. Am. Pharm. Assoc. 38:124-131; 1949.
5-2S
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6.0 EFFECTS AND EXPOSURE—AQUATIC BIOTA
6.1 EFFECTS ON AQUATIC BIOTA
6.1.1 Introduction
This section discusses the levels of dichlorobenzenes that have been
determined from laboratory studies to be toxic to marine and freshwater
organisms. The data base includes values for all three isomers of
dichlorobenzenes, and for representative species from both fresh- and
saltwater environments. The available toxicity data are limited to
acute effects levels for a few species of fish, invertebrates, and
phytoplankton; only one chronic effects value was found.
6.1.2 Fish and Invertebrates
Freshwater toxicity data are presented in Tables 6-1 and 6-2. The acute
toxicities reported for 1,3- and 1,4-dichlorobenzenes were similar, whereas
1,2-dichlorofaenzene was reported to be more toxic to Daphnia magna by one
order of magnitude. The lowest acute effects level was 2,400 ug/1
1,2-dichlorobenzenes for Daphnia magna. The range in freshwater values
was from 1,000 ug/1 (chronic effects on fathead minnow) to 28,100 ug/1
1,3-dichlorcbenzenes for Daphnia. No effects were detected at concentra-
tions below 1,000 ug/1.
Toxicity data for marine organisms-are presented in Table 6-3. For all
isomers,the most sensitive species was the mysid shrimp, with LC^n of 1,199-
2,850 ug/1. Dichlorobenzene was acutely toxic to marine fish in'the
range 7,300-9,660 ug/1. No acute effects on marine organisms have been
reported for concentrations below 1000 ug/1.
6.1.3 Other Organisms
The 1,2-dichlorobenzene isomer is apparently used commonly in oyster
beds to control oyster drills. It is unclear exactly what exposures affect
these organisms, but concentrations as low as 1 mg/1 are reported to
inhibit the growth of young oysters after 24 hours of exposure. This is
approximately equivalent to the acute toxicity level for mysid shrimp.
Additional data for marine organisms are presented in Table 6-4.
6.1.4 Plants
Toxir.ity data for freshwater and marine algae are presented in
Tables 6-5 and 6-6. The ranges at which effects to algae were reported
are generally higher than the acute toxicity levels for fish and inver-
tebrates: 91,609 - 179,000 ugl for freshwater species, and 44,100-59,100 ug/1
for marine ohvtoolankton.
o-o.
-------
TABLE 6-1.
Organism
ACUTE TOXICITY OF DICHLOROBENZENES FOR FRESHWATER
FISH AND INVERTEBRATES
Compound
LC50a (ug/D
Bluegill
(Lepomis macrochirus)
Cladoceran
(Daphnia magna)
Fathead Minnow
(Pimephales promelas)
( embryo-larval)
1, 2-DCB
1,2-DCB
1,3-DCB
1,4-DCB
1, 2-DCB
1,3-DCB
1,4-DCB
1,2-DCB
27,000
5,590
5,020
4,280
2,440
28,100
11,000
1,000
(chronic
value)
Reference
Dawson _et_ al. (1977)
U.S. EPA (1978)
U.S. EPA (1978)
U.S. EPA (1978)
U.S. EPA (1978)
U.S. EPA (1978)
U.S. EPA (1978)
U.S. EPA (1978)
LCso is the concentration lethal to 50% of test organisms.
TABLE 6-2. ACUTE TOXICITY OF DICHLOROBENZENES FOR THE FRESHWATER FATHEAD
MINNOW Pimephales promalas FOR DIFFERENT EXPOSURE DURATIONS
Compound
1,2-DCB
1,4-DCB
LCgo (mg/1) at time
24 hr
(77. 8-129. 9)a
35.4
48
76.
35.
hr
3
4
96 hr
57.0
33.7
upon one partial kill, the best information that the binomial test
gives is that authors are 82.7% confident that LCso lies in this interval.
Source: Curtis et al. (1978).
6-2
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TABLE 6-3. ACUTE TOXICITY OF DICHLOROBENZENE FOR MARINE FISH
AND INVERTEBRATES
Organism Compound
Tidewater Silverside 1,2-DCB
(Menidia beryllinia) 1,2-DCB
Sheepshead Minnow 1,3-DCB
(Cyprinodon variegatas) 1,4-DCB
Mysid Shrimp 1,2-DCB
(Mysidopsis bahia) 1,3-DCB
1,4-DCB
Shrimp 1,2-DCB
(Dalaemonetes pugio) 1,4-DCB
LC50
7,300
9,660
7,700
7,400
1,970
2,850
1,199
9,400
69,000
Reference
Dawson _et_ al. (1977)
U.S. EPA (1978)
U.S. EPA (1978)
U.S. EPA (1978)
U.S~.' EPA (1978)
U0S. EPA (1978)
U.S. EPA (1978)
Curtis _et al. (1978)
Curtis et al.. (1978)
5-3
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TABLE 6-4.
Organism
EFFECTS OF DICHLOROBENZENES ON ANNELIDS AND OTHER MARINE BIOTA
Test Concentration
Reference
Poiychaete worm
(Polydora websteri)
I'oiychaete worm
(Nerils sp.)
(Mam (embryo)
(Mercenaria mercenaria)
Chun (larva)
(Mercenaria mercenaria)
I'olycliaete worm
(I'olydora websteri)
PoIychaetc worm
(Nureij. sp.)
Effect
65% emergence from
3 hrs parasitized oysters
70% emergence from
3 hrs parasitized oysters
Compound Duration
1,2-DCB
1,2-DCB
1,2-DCB 48 hrs
1,2-DCB 12 days
55% emergence from
1,4-DCB 3 hrs parasitized oysters
(Mg/1)
100,000
100,000
>100,000
>100,000
100,000
100% emergence from
1,4-DCB 3 hrs parasitized oysters 100,000
Mackenzie and
Shearer (1959)
Mackenzie and
Shearer (1959)
Davis and Hindu
(1969)
Davis and Hindu,
(1969)
Mackenzie and
Shearer (1959)
Mackenzie and
Shearer (1959)
-------
TABLE 6-5. EFFECTS OF DICHLOROBENZENES ON FRESHWATER PLANTS
Organism Compound
Alga,(Selenastrum 1,2-DCB
capricornutum)
Alga, (Selenastrum 1,2-DCB
capricornutum)
Alga, (Selenastrum 1,3-DCB
capricornutum)
Alga, (Selenastrum 1,3-DCB
capricornutum)
Ai.^a, (Selenastrum 1,4-DCB
capricornutum)
Ai££, (Selenastrum 1,4-DCB
capricornutum)
Effect*1
EC50, 96-hr,
chlorophyll a_
EC50, 96-hr,
cell number
EC50, 96-hr,
chlorophyll £
EC50, 96-hr,
cell number
EC50, 96-hr,
chlorophyll a_
EC50, 96-hr,
cell number
Concentration
(ug/I)
91,600
98,000
179,000
149,000
98,100
96,700
a_
~C5Q=coiicentratiori at which the stated effect was noted.
Source: U.S. EPA (1978)
6-5
-------
TABLE 6-6. EFFECTS OF DICHLOROBENZENES ON MARINE PLANTS
Concentration
Organism
Alga, (Skeletonema
costatum)
Alga,
Alga,
Alga,
Alga,
Alga,
(Skeletonema
costatum)
(Skeletonema
costatum)
(Skeletonema
costatum)
(Skeletonema
costatum)
(Skeletonema
costatum)
Compound
1,2 -DCS
1, 2-DCB
1,3-DCB
1,3-DCB
1,4-DCB
1,4-DCB
Effect3
EC50, 96-hr,
chlorophyll a
EC , 96-hr,
cell number
EC50, 96-hr,
chlorophyll a
EC30, 96-hr,
cell "number
ECso, 96-hr,
chlorophyll a
EC50, 96-hr
cell number
(U8/D
44,200
44,100
52,800
49,600
54,800
59,100
EC5Q- concentration at which stated effect is noted.
Source: U.S. EPA (1978)
5-6
-------
6.1.5 Conclusions
The concentrations of dichlorobenzenes that have been found to be
acutely toxic to marine and freshwater organisms range over two orders
of magnitude from approximately 1000 wg/1 to 180,000 yg/1. There was
some variation among toxicity levels for the same species from different
studies; no appreciable difference in toxicity appears to exist between
fresh and saltwater organisms. Both Daphnia magna and Daleamonetes pugio
showed an increased sensitivity to the 1,2-dichlorobenzene isomer; however,
for most of the other organisms for which there were data, there does
not seem to be an appreciable difference in toxicity among the three
dichlorobenzene isomers.
6.2 EXPOSURE OF AQUATIC BIOTA
6.2.1 'Dichlorobenzene Levels in Aquatic Systems
The only dichlorobenzene isomers that are produced commercially are
the 1,2- and 1,4-isomers. Tables 5-2 and 5-3 show that the major
environmental releases to aquatic media occur in the Northeast and North
Central parts of the U.S. Uses of 1,4-dichlorobenzene as a pesticide which
could result in aquatic releases are centered in South Carolina, California,
Florida and Maine (Von Runker 1974). Some dichlorobenzene is used for
odor control in industrial wastewater treatment plants, and enters water
systems throughout the country (Ware and West 1977). Concentration data
for POTWs indicated influent levels of 10.6 yg/1; unchlorinated and
chlorinated effluent concentrations were 5.6 yg/1 and 6.3 yg/1, respectively
(Bellar et al. 1974).
The STORET (U.S. EPA 1980a) data base for dichlorobenzene is quite
limited in that 98% of the data was remarked (observations at or below
detection limits). The range of distribution of unremarked (concentrations
actually detected) ambient and effluent levels is shown in Table 4-9;
there was a total of 79 unremarked observations (57 ambient, 22 effluent)
for all three isomers. Only 7 observations were greater than 100 yg/1.
The STORET data do not reflect the fact that discharge due to industrial
activity is expected to be higher in the Northeast and North Central
areas.
The threshold for the lowest (chronic) toxic effects to aquatic
organisms exposed to dichlorobenzenes was about 1000 yg/1. The 1,2-
dichlorobenzene isomer was actually observed once in ambient waters at
a concentration above 1000 yg/1, i.e., at 4660 ug/1 in the Missouri River;
one unremarked effluent observation of that isomer above 1000 yg/1 was also
made. Table 6-7 gives a summary of the remarked and unremarked STORET
data.
5-7
-------
TABLE 6-7. SUMMARY OF STORET DATA (Remarked and Unremarked)
Maximum Mean
Concentration Concentration % Unremarked % Remarked
Compound (MB/D . (MR/1) Data
-------
The solubility of dichlorobenzene is low (145, 123 and 79 mg/1 for the
1,2, 1-3, and 1-4 isomers, respectively) and the sediment-water partition
coefficient is moderately high. These factors, in addition to relatively
high volatility, indicate that these compounds would not remain in the
water column, but rather adsorb to soils and sediments or volatilize to
the air. EXAMS (U.S. EPA 1980b) modelling data for 1,2-dichlorobenzene
bear out these observations. Based on a loading rate of 1.0 kg/hour,
which approximates the environmental release data presented in
Chapter 3.0, 75% of the 1,2-dichlorobenzene discharged to the river
(the system most likely to receive industrial, aquatic releases) would
be dissolved in water at equilibrium, with a steady state concentration
of 0.99 ug/1; 24% would be residing in the sediment. The EXAMS data also
show that the persistence of 1,2-dichlorobenzene in the river system
following cessation of the discharge would be low. Within 12 hours, 99.9%
would be removed from the water column, 23% would be removed from the sediment,
and only 24% of the compound would be remaining in the total system.
For the pond and oligotrophic lake, EXAMS data indicate that volatilization
and transport to the sediment are the major processes for removal from
the water column. However, the steady-state accumulation and the per-
sistence in these more static systems are much greater than in the river
system.
The above discussion suggests that any dichlorobenzene that is
released to aquatic media and dissolved in the water column could be expected
to be diluted, volatilized, or adsorbed into sediment. Availability to
the aquatic biota would not be very high.
It appears that low level discharges will ordinarily not persist
near the source, particularly in a river, where transport downstream
is quite important. There have, however, been three reported fish-
kills caused by dichlorobenzene. The available data from these incidents
are summarized in Table 6-8, below. In all three cases the exact concen-
tration of dichlorobenzenes was unknown, but an accidental spill of
large quantities of the compound resulted in the fishkill. Dilution
did prove to be important in all three incidents, as in no case did
serious effects last longer than one day.
6.2.2 Conclusions
Based on the limited monitoring data, it appears that the dichloro-
benzenes are found in ambient and effluent water at concentrations pre-
dominantly in the low ppb range (10 ug/1 or less). Important environmental
fate processes in turbid systems include dilution and physical transport
downstream and, to a lesser extent, volatilization; volatilization and
transport to the sediment are the predominant processes in more static
systems. There is no evidence to indicate, however, that these compounds
will persist in the sediments to any great degree; the EXAMS data show
that 15-22% of Che DC3 in the sediment (pond and lake) will be removed
within 24 days after the discharge is stopped. Any higher concentrations
that occur as a result of accidental spills, direct discharge co
streams, or off-site migration of dichlorobenzene from a (land) disposal
site would be expected co be diluted or dissipated fairly quickly and
not result in persistent or long-cerm exposure.
-------
TABLE 6-8. SUMMARY - REPORTED FISH KILLS DUE TO DlCHLOROBENZENt"- 1970 - 1980.
l>ate Location
May 1973 Tennessee
Fish
Stream Killed
Beaver Creek 536
(20% game
species)
Extent and
Duration of
Effects
4.4 ml. stream
for one day
Source
chemical plant
o\
I
o
April 1975
Parkersburg
West Va.
Worthington
Creek
41,945
(99% non-game)
one-mile of
river for
one day
DCB from nearby
chemical dump
f1ushed down
storm drain
May 1979
Sevler City,
Tenn.
Dudley Creek
360 minnows
and rainbow
trout
2 miles stream
for one day
DCB use in washing
ciby equipment
All data from EPA Monitoring and Data Support Division Files, 1980.
-------
REFERENCES
Bellar, T.A.; Lichtenberg, J.J.; Kroner, R.C.
organohalides in chlorinated drinking waters.
Assoc. 66: 703-706;1974.
The occurrence of
J. Am.Water Works
Curtis, McW.; Copeland, T.L.; Ward, C.H. Acute toxicity of 12
industrial chemicals to freshwater and saltwater organisms. Water
Research 13: 137-141;1978.
Davis, H.C.; Hindu, H. Effects of pesticides on embryonic
development of clams and oysters and on survival and growth of the
larvae. U.S. Fish Wildl. Serv. Fish. Bull. 67: 393; 1969 (As cited
in U.S. EPA 1978).
Dawson, G.W., et al. The toxicity of 47 industrial chemicals
to fresh and saltwater fishes. Jour. Hazard. Mater. 1: 303; 1977 (As
cited in U.S. EPA 1978).
MacKenzie, C.L., Jr., Shearer, L.W. Chemical control of Polydora
websteri and other annelids inhabiting oyster shells. Proc. Natl.
Shellfish. Assoc. 50: 105;1959 (As cited in U.S. EPA 1978).
U.S. Environmental Protection Agency (U.S. EPA). In-depth studies"
on health and environmental impacts of selected water pollutants. EPA
68-01-4646. Washington, DC: U.S. Environmental Protection Agency;1978a.
U.S. Environmental Protection Agency (U.S. EPA) Ambient water quality
for dichlorobenzenes. Washington, DC: U.S. Environmental Protection
Agency;1978b.
U.S. Environmental Protection Agency (U.S. EPA) 3TORET.Washington,
D.C.: Monitoring and Data Support Division, U.S. Environmental
Protection Agency;1980a«
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;1980b.
Von Rumker, R., Lawleww, E.W.; Meiners, A.F. Protection, distribution,
use and environmental impact potential of selected pesticides.
Washington, D.C.: Office of Pesticides Programs, U.S. Environmental
Protection Agnecy;1974.
-------
7.0 RISK CONSIDERATIONS
7.1 INTRODUCTION
The purpose of this chapter is to evaluate the risks to humans and
aquatic biota resulting from exposure to dichlorobenzenes in the environ-
ment. A quantitative analysis of risk is hampered by the limited data
base for predicting the health effects and levels associated with those
effects, as well as by the scarcity of monitoring data available to use
in assessing the extent of exposure to the dichlorobenzenes.
7.2 HUMANS
7.2.1. Statement of Risk
The full extent of risk to humans resulting from environmental expo-
sure to dichlorobenzene cannot -be assessed quantitatively at present, due
to the limited availability of adequate toxicological data. Dose levels
at which acute effects "upon humans or mammals have been observed are
generally far above the estimated human exposures via inhalation or inges-
tion. However, the potential chronic effects of dichlorobenzenes are still
uncertain. Although dichlorobenzenes are considered by EPA's Carcinogen
Assessment Group to be of potential concern with regard to carcinogenicity,
preliminary data from lifetime feeding studies with 1,2-dichlorobenzene
for rates and mice exposed to 120 mg/kg, 5 days/week (i.e., 86 mg/kg/day)
suggest no carcinogenic activity. Decisions regarding the oncogenic capa-
bility of 1,2-dichlorobenzene, however, should be deferred pending comple-
tion of the study. The available information about mutagenic, teratogenic,
and other toxicological effects is also not sufficient to permit a quanti-
fication of risk to humans at this time. Consequently, the risk associated
with exposure to the dichlorofaenzenes must be evaluated qualitatively,
through a comparison of estimated exposure levels with the available data
concerning observed effect levels.
Subchronic studies indicate that ingestion of 13.42 mg/kg/day is a
no-observed-effect level for rats. In setting the current water quality
criterion, the EPA applied a safety factor of 1000 to this level; extra-
polation of this value to humans results in an estimated acceptable daily
intake of 0.94 mg/day for a 70-kg man. Humans rarely appear to be exposed
to concentrations' of the dichlorobenzenes in environmental media that are
high enough to cause apparent adverse effects. Exposure for the general
population from ambient air and drinking water is usually in the range of
0.001-0.09 mg/day. Exposure from industrial contamination of ambient air
or residential use of dichlorobenzene moth repellants is expected to be
less than 1 mg/day; these levels correspond to specific subpopulations.
Each of the environmental exposure scenarios reviewed results in an expo-
sure level at, or below, the daily intake allowed by the current EPA water
quality criterion for the protection of human health. Thus, existing
health effects data, coupled with estimated levels of exposure suggest
-------
that the risk associated with exposure to dichlorobenzenes in the envi-
ronment is not unreasonable. However, much uncertainty exists with
respect to exposure and long-term health effects, and subsequent findings
could alter these conclusions.
7.2.2 Discussion
The dichlorobenzenes have been shown to be absorbed by humans, as well
as laboratory animals, via the lungs and gastrointestinal tract; absorp-
tion through the skin has also been shown. The major target systems are
the liver, reticuloendothelial system and the central nervous system. The
inadequacy of available studies on the reproductive effects, carcinogen-
icity, or teratogenicity have rendered the data insufficient for a valid
assessment of these risks. The 1,4-dichlorobenzene isomer has been
linked anecdotally with a few cases of human leukemia, but a cause and
effect relationship could not be reliably inferred from these reports.
Preliminary data from lifetime feeding studies with rats and mice given
1,2-dichlorofaenzene suggest no induction of oncogenic effects.
The doses that have been associated with adverse effects of the dichlo-
robenzenes are summarized in Table 7-1. No serious effects were noticed
in humans following inhalation exposure to 600 mg/m3 1,2-dichlorobenzene;
no organic injury or adverse hematologic effects were found in workers
exposed to 500 mg/m3 1,4-dichlorobenzene. As discussed in Section 5.1,
no-effects levels of 13.4 mg/kg/day were observed for rats ingesting either
1,2- or 1,4-dichlorobenzene for 7 months. It should also be noted that a
Russian study indicated a much lower no-effects level of 1 yg/kg/day for
1,2-dichlorobenzene; however, these data are difficult to evaluate because
exposure levels and their determination were not adequately addressed in
the published report of this work. Very few data are available on the
effects of 1,3-dichlorobenzene. However, one study reported that a dose
of 192 mg/kg 1,3-dichlorobenzene was found to be hepatotoxic in rats when
injected interperitoneally; 500 mg/kg 1,4-dichlorobenzene caused little or
no effect.
The dichlorobenzene exposure levels have been estimated for various
concentrations in atmospheric and aquatic media by assuming specific in-
take rates of air and water for a 70-kg person; these are dis-cussed in
Section 5.2 and are summarized in Table 7-2. It should be mentioned that
these estimates are based on a number of assumptions, and that there is
considerable uncertainty involved. In addition, the size of subpopulations
exposed to elevated atmospheric concentrations of dichlorofaenzenes from
industrial activities or mothball use, as well as numbers of people exposed
to any contamination in drinking waters not yet monitored, is unknown.
It is evident that exposure to indoor air concentrations (occupational
environments and air in vicinity of mothball use) is potentially much higher
than exposure to ambient concentrations of dichlorobenzenes. Based on a
duration of exposure of 10 hours, a person could be exposed co 0.6 ing/day
dichlorobenzene in a room in close proximity co wardrobe storage of moth-
balls: breathing the air inside the wardrobe could increase the exposure bv
7-2
-------
TABLE 7-1. REPORTED DOSES ASSOCIATED WITH EFFECTS OF DICHLOROBENZENES IN MAMMALS
Route/Effect
1nhaI at ion
Odor Threshold
1iiiLation-human
No organic injury or
adverse hematologic
effects-human
No serious effects-human
LCLo - rat
Level
1,2-DCB
300 mg/ra3
3
600 m g/ m
Refa
Holllngsworth e^ _al.!958
Elkins 1959
1,4-DCB
90-180 mg/ra3
3
400 mg/ni
Ref«
Hollingsworth c
Hollingsworth e
90 mg/m
3
600 mg/m
i
5000 mg/m"
for 7 hr
Hollingsworth et al.1958
Elkins 1959
Pike 1944
500 mg/m
Hollingsworth et al.1956
Oral U)Lo - human
Oral 1.1) - rat
No adverse effects
Odor threshold
Taste threshold
500 mg/kg
500 mg/kg
- rat 13.4 mg/kg/day
2 Mg/1
0.1 Mg/1
RTECS 1978
RTECS 1978
Hollingsworth eit. aJL.1956
Varshavskaya 1967
Varsliavstcwn 1967
500 mg/kg RTECS 1978
500 mg/kg RTECS 1978
13.4 mg/kg/day Hollingsworth e_t £1.1956
2 ng/1 Varshavskaya 1967
6 Mg/1 Varshavskaya 1967
References are given in Chapter 5.O..
-------
TABLE 7-2. SUMMARY OF U.S. SUBPOPULATIONS EXPOSED TO VARIOUS LEVELS OF DICHLOROBENZENES
Exposure
Kotile
1,2-Dichlorobenzene
Estimated Exposure Levels
,4-Diclilorobenzene
Population Description
In&estion of
drinking water
avg. 2.8 pg/day'
max. 18 pg/day
avg. 0.14 ug/daya
max. 4 pg/day
4-26% of general population8
certain municipalities
I nluiJation
ambient air
air near sources
Indoor air
occupational
environment
f_ 2 ug/day
10-270 pg/day
1. 90 Mg/day
10-160 pg/day
^ 1000 pg/day
in worst case
<4 g/day (8 hr)
general population
about 0.2% of population
users of mothballs
1,4-dicblorobenzene
manufacturing plant
The National Organic Monitoring Survey (NOMS; Tabl
-------
0.2 mg/6 minutes. An additional source of local, high environmental con-
centrations of dichlorobenzene may be associated with the 100% 1,4-dichloro-
benzene blocks used for odor control in toilet bowls, urinals, garbage pails
and diaper pails. However, there are no data with which to quantify a risk
estimate for this exposure route.
From the data in Section 5.2, it is apparent that a significant expo-
sure to dichlorobenzenes exists in the workplace. A maximum concentration
of 421 mg/m^ 1,4—dichlorobenzene was measured in a manufacturing plant;
this level would result in a daily exposure of 4.0 g/day assuming an 8-hour
duration of exposure. This level of exposure is within the range of expo-
sures where acute health effects have been observed (see Figure 7-1). Eye
and/or nose irritation, but no organic injury or adverse hematologic effects,
was observed in workers exposed to average air concentrations of 500 mg/m^
1,4-dichlorobenzene (Hollingsworth _e_t al. 1956) or 600 mg/m^ 1,2-dichloro-
benzene (Elkins 1959). The OSHA has set an 8-hour time-weighted average of
450 mg/m3 for dichlorobenzenes. Further discussion of the risk from occu-
pational exposure is beyond the scope of this risk assessment. The impact
of industrial activity, however, is relevant in that the ambient air concen-
trations near plants and disposal sites where dichlorobenzenes are present
are one to two orders of magnitude higher than non-industrial areas.
The exposure levels estimated from actual dichlorobenzene concentra-
tion data can be compared with the available health effects data to deter-
mine the apparent margin of safety associated with each exposure scenario.
These comparisons are presented in Tables 7-3 and 7-4 for 1,2- and 1,4-
dichlorobenzene, respectively; there are insufficient data to make the com-
parison for 1,3-dichlorobenzene. As a worst case estimate, exposure from
ingestion of 2 liters/day of ambient water has also been included.
For the general population, the probability of acute health effects
to humans subjected to various exposure levels is shown graphically in
Figure 7-1. The probability of exposure to different amounts of dichloro-
benzenes (mg/day) has also been plotted for the ingestion and inhalation
exposure routes. It appears that inhalation is the more significant route
of exposure for most of the U.S. population. Drinking water accounts for
relatively low exposures, although heavily contaminated drinking water
in some local areas could possibly result in higher exposure levels.
The curves in Figure 7-1 represent approximate exposure and effect
levels for both 1,2- and 1,4-dichlorobenzene. In reality, these levels
are slightly different for the two substances, but the diagram
sufficiently illustrates the orders-of-magnitude gap between environ-
mental exposures and the levels at which effects may occur. The
existing criteria and standards for these substances are listed in
Table 7-5. It is clear from the diagram that the ambient water quality
standard provides adequate protection against acute risks to humans via
the aquatic environment. The results of ongoing and/or future studies
of chronic effects of the dichlorobenzenes could lead to sianificant
revisions in criteria/standards and thus require a reassessment of risk.
-------
TABLE 7-3. MARGINS OF SAFETY FOR 1,2-DICHLOROBENZENE EXPOSURE SCENARIOS
Scenario
Ingestion of
Drinking Water
- Average
- Maximum
Ingestion of
Ambient Water
- Average
- Maximum
Inhalation
- Ambient Air
- Air near
industrial site
- Air near
disposal site
Typical Exposure
(mg/day)__
0.003
0.018
0.058
9.3
<.002
<.03
<-27
Lowest Reported
Effects Level
(mg/day)
> 938
>938i
>938
>9381
13,800"
13,800'
13,800
Estimated
Margin of
a
> 3.1 x 10
> 1.9 x 10
> 1.6 x 10
> 1 x 10"
> 6.9 x 10
> 4.6 x 10-
> 5.1 x 10
Margin of Safety • lowest reported effects-level * estimated exposure level.
No adverse effects (rat) reported at 13.4 mg/kg/day x 70-kg/person = 938 mg/day,
c 33
Irritation in humans reported at 600 mg/m . Assuming 23 m /day, gives
level of 13.8 g/day. No serious effects were reported at this dose.
7-5
-------
TABLE 7-4. MARGINS OF SAFETY FOR 1,4-DICHLOROBENZENE EXPOSURE SCENARIOS
Scenario
Ingestion of
Drinking Water
- Average
- Maximum
Ingestion of
Ambient Water
- Average
~ Maximum
Inhalation
- Ambient air
- Rural air
- Urban air
• - Air near
industrial site
- Air near
disposal site
- Air in
occupational
environment (max.)
- Air in bedroom
- Air in closet
- Air in wardrobe
Typical Exposure
(mg/day)
0.0001
0.004
0.028
1.22
<.001
<.05
<.09
<.03
4042 mg/8 hr
0.6 mg/10 hr
0.2 mg/0.5 hr
0.2 mg/0.1 hr
Lowest Reported
Effects Level
(mg/day)
> 938
> 938*
> 938L
> 938*
9200
9200C
9200C
9200
9200
9200C
9200°
9200C
9200C
Estimated
Margin of
Safetva
> 9.4 x 106
> 2.3 x 105
> 3.3 x 10-
> 7.7 x 102
> 9.2 x 10'
> 1.8 x 10'
> 1.0 x 10'
> 3.1 x 10'
> 5.7 x 10
2.02U
1.5 x 10*
4.6 x 10*
4.6 x 10^
Margin of Safety - lowest reported effects level * estimated exposure level.
No adverse effects (rat): 13.4 mg/kg/day x 70 kg/person * 938 mg/day.
Irritation in humans reported at 400 mg/m (9200 mg/day); no adverse
hematologic effects at 500 mg/m^.
The margin of safety shown is in reference to the lowest reported affacts
level. The acceptable daily intake allowed by the OSHA standard is
4320 mg/day (450 mg/m^ x 1.2 m-Vhr x 3 hr) . The associated margin of
safety for the maximum calculated exposure with respect to the OSHA stan-
dard is 1.1.
-------
I
CO
PROBABILITY
OF OCCURRENCE
Very High ..
High
Moderate _.
I.(JW
Very Low
Ingestion of
Drinking Water
0.001
0.01
Inhalation
Exposure
0.1
10
100
Acceptable Intake According to
Ambient Water Quality
Criterion (0.94 mg/day)
Sublethal
Acute Effect
Levels
1000
H
10,000
100,000
EXPOSURE LEVEL
(mg/day)
FK.'UKK 7-1. ACUTE EFFECT LEVELS AND DAILY HUMAN EXPOSURE FOR 1,2- AND 1,4-DICHLOROBENZENE
-------
7.3 AQUATIC BIOTA
The lowest concentrations found to be acutely toxic to aquatic biota
range from approximately 1000 ug/1 to 180,000 ug/1. There was no
appreciable difference in concentration levels found to be toxic to
fresh and saltwater organisms. Except for increased sensitivity to
1,2-dichlorobenzene reported for two aquatic organisms, there does not
seem to be an appreciable difference in toxicity among the three isomers.
Aquatic releases of the dichlorobenzenes are not very large; about
325 kkg/year (about 1.5% of the net domestic supply) 1,2-dichlorobenzene
and 850 kkg/year (about 3% of the net domestic supply) 1,4-dichlorobenzene
were estimated in the materials balance (Section 3.0). The discussion on
the environmental fate of dichlorobenzenes released to the aquatic media
(Section 4.0) suggests that any dichlorobenzene in the water column would
be expected to be diluted, volatilized or adsorbed onto sediment depending
on the conditions in the receiving waters. The EXAMS data suggest that
these compounds will not be very persistent in the water column, and
availability to the aquatic biota would be low.
Although the monitoring data for the dichlorobenzenes are limited,
the concentration levels found in ambient and effluent waters are
generally in the low ppb range. • The unremarked STORET data include only
one observation of 1,2-dichlorobenzene above 1000 ug/1 in the ambient water
and one observation in effluent waters. Ninety-two (92) percent of the
ambient unremarked data, and 68% of the effluent unremarked data are
<. 10 ug/1.
It appears that the average concentrations of dichlorobenzenes in
the aquatic environment would not pose a severe threat to aquatic biota
since very few concentrations above the threshold of effects levels
have been observed, and natural fate processes for removal of
dichlorobenzenes released to the environment would act to prevent long-
term accumulation in aquatic systems, given the present rates of release.
However, the short-term effects of direct discharges of large
quantities of dichlorobenzenes do present a risk to aquatic biota, as
is apparent in reports of fish kills attributed to a chemical plant,
chemical dump, and cleaning of municipal equipment. The fish kills
ranged in size from 360-41,945 fish and affected from 1-4.4 miles of
river. Complete data were not available, but the extent of damage is
certainly dependent upon the ambient conditions of the river system.
The EXAMS data in Section 4.3 indicate that most of the dichlorobenzene
will be removed from the river system in a short time. This is supported
by the fact that the effects of these large discharges were only
observed for one day.
7-9
-------
TABLE 7-5. CRITERIA AND STANDARDS FOR DICHLOROBENZENES
Medium
Ambient Water
Criteria/Standard
Workplace (OSHA)
U.S. EPA - Dichlorobenzenes:
<400 ug/1 for protection of human health;
ingestion of water and aquatic organisms.
<2.6 mg/1 for ingestion of aquatic organisms
only.
Soviet Union - 2 ug/1 for 1,2- and 1,4-
dichlorobenzene.
1,2-Dichlorobenzene: 300 mg/m ceiling level.
1,4-Dichlorobenzene: 450 mg/m 8-hr, time-weighted
average.
•-10
-------
APPENDIX A
-------
Table A-l. Dichlorobenzene Emission Factors
Source
o-Oichlorobenzene Production
p-Dichlorobenzene Production
o-Oichlorobenzene Uses:
3,4-Dichloroaniline Manufacture
Dye Synthesis
Pesticide Intermediate
p-Dichlorobenzene:
Pesticide Intermediate
Process
0.00232
0.00581
0.00105
0.00040
0.00040
0.00040
Emission Factor:
Storage
0.00047
0.00041
0.00015
0.00005
0.00005
0.00005
kg lost/kg produced
Fugitive
0.00076
0.00102
0.00030
0.00005
0.00005
0.00005
(used)
Total
0.00355
0.00724
0.00150
0.00050
0.00050
0.00050
Source EPA, 1980e.
-------
BENZENE-
CHLORINE-
CHLOROBENZENE
REACTOR
AIR
VENT
H2°~
SCRUBBERS
HC1
SEPARATOR
NEUTRALIZER
NaOH
-BENZENE & WATER
T
-^BENZENE & CHLOROBENZENE
-^CHLOROBENZENE
FRACTIONATING COLUMN
- WATER
POLYCHLOROBENZENES
SLUDGE
LAND
Figure A-l. Batch Production of Chlorol>enzenes and Environmental Release
Points for DicMorobenzenes (Lowenheim and Moran, 1975)
-------
A
BENZENE
DRIER
CHLORINE
REACTOR
AIR
VENT
CARBON COLUMN
(OPTIONAL)
SEPARATOR
SCRUBBER
IIC1
-^CHLOROBENZENE
FRACTIONATING
COLUMN
WATER
HEAVY TARS
LAND
Figure A-2.
Continuous Production of Chlorobenzene and Environmental Release
Points for Dichlorobenzene (Lowenheim and Moran, 1975)
-------
Table A-2. Patents Relating to Meta-Dichlorobenzene Manufacture
Patent (Country)
Date
Purpose
2,106,454 (France)
2,943,114 (U.S.)
2,920,109 (U S.)
2,866,028 (U.S )
2,819,321 (U.S.)
2,666,085 (U-S.)
1972
1960
1960
1958
1958
1954
To produce DCB with high proportion of meta by
thermal dechlorination of hexachlorocyclohoxane.
using parraffins (C£4+) as chlorine acceptors.
Composition of chlorobenzene mixture obtained is
typically 40% mono and di : 5% mono. 29% meta + para,
6% ortho (200*~^ 300 '
To produce meta-OCR by hydrogenolysis of tn-chloro-
bonzenes. Yields of 33% OCR in example, distributed
39% rneta. 25% para. Vapor state (300 - 600°C).
Yield can be increased by chlorinating ortho and
to trichlorobonzenes and recycling.
To produce meta-OCR by isomerization of para-OCR
(pure or in a mixture of OCR's) by heat under pres-
sure. Yields 90%.
To produce meta-OCR from tri-chlorobenzenes by
reduction with hydrogen. Yields based on
trj-chlorobenzenes mixture are 17.2% (ex.)
Isomerization of o, £ to m-OCR: high pressure.
120°C. 40% conversion anhydrous MCI .
Isomerization of Q_, _p to m-OCR: water is present.
-------
I
en
Table A-3. National Organic Monitoring Survey, March 1976 through January 1977
Number of Positive Analyses
Per Mean Concentration (pg/1) Median Concentration (ug/1)
Number of Analyses Positive Results Only All Resultsh
Isomer Phase* I n m I u m i n m
°-°CB 0/113 4/110 1.5 <0.005 <0.005
m-°CB 0/H3 2/110 0.10 <0.005 <0.005
P-°CB 2/111 20/113 29/110 2.0 0.14 0.07 <1 <0.005 <0.005
a) Monitoring dates: Phase I: March - April, 1976
Phase II: May - July, 1976
Phase III: November, 1976 - January, 1977.
b) These are minimum quantifiable limits
Source:EPA, 1977f.
-------
Table A-4 Ambient Levels of Oichlorobenzenes in Water*
Levels/Isomer
Comments
1.0 ug/l, o-OCS
0.5 ug/1, tn-OC8
0.5 ug/l, p-OCB
Miami, FL; ground water; CCE
d, all isomers
d, m-DCB and p-OCBb
690 ug/l, o-DC8c
33 ug/l, OC3C
30-400 ug/l, o-OC3d
34-230 ug/l, p-DC8d
4.7-2.3 ug/l, o-OC8d
9.3-3.1 ug/l, p-OC3d
0.01 ug/l, o-DC3d
0.05 u/1, p-DCBd
-------
APPENDIX B
-------
Table B-l. Frequency of Dichlorobenzene Detection
in Industrial Wastewaters
Industry #
Adhesives and Sealants
Leather Tanning
Texti le Products
Printing and Publishing
Pesticides
Pharmaceuticals
Organics and Plastic
C^Aam PTfl^^i*!^ D AUJOY* PI sn^ c
W wC QUi ClCUUrlU r UWci r I Gil L J
Iron and Steel
Foundries
Nonferrous Metals
Photographic
Inorganic Chemical
Electrical
Auto and Other Laundries
Landfill
Mechanical Products
Samples
11
81
121
109
147
95
723
84
431
54
173
25
107
35
56
7
35
1,2-
0
15
12
4
2
1
16
1
0
0
1
1
4
5
1
0
# found
1,3-
1
4
0
1
2
0
- 13
17 .__
1
2
2
1
0
0
0
0
0
1,4-
0
15
4
4
2
2
23
3
0
2
1
1
2
7
0
5
Source: EPA, 1980g
B-l
-------
Table B-2. 3,4-Dichloroaniline Producers
Producer3
Blue Spruce Co.
E.I. du Pont de Nemours & Co., Inc.
Chemicals, Dyes and Pigments Dept.
Monsanto Co.
Monsanto Industrial Chemicals Co.
Total
Location 1,2-Dichlorobenzene
Airb Water
Bound Brook, NJ 8
Deepwater, NJ 8
Luling, LA 8
24
Releases
Land
CO
r^ a) Production capacities were not available.; SRI, 1979b.
b) See Table Al for emission factors; total broken down into process (70%), storage (10%) and
fugitive (20%).
-------
Table B-3 o-Oichlorobenzene Emission from Toluene Dilsocyanate (TO!) Producers
Producer
Allied Chemical Corp.
Specialty Chemicals Div.
BASF Wyandotte Corp.
Polymers Group
Ui ethane Div.
Ouw Chemical U.S.A.
E.I. du Pout de Nemours & Co.. Inc.
Elastomer Chemicals Dept.
Mobay Chemical Corp.
Polyure thane Div.
01 in Corp.
01 in Chemicals Group
Hub iioii Chemicals
Total
Location
Hounds vi lie, UVA
Geismar, LA
Freeport, TX
Deepwater Point, NJ
Cedar Dayou, TX
New Martinsville. WV
Ashtabula, OH
Lake Charles, LA
Geismar, LA
TDI Capacity9
(103 kkg/yr)
36
45
45
32
59
45
14
45
IB
340
1 ,2-Dichlorobenzene Releases
Airb Water Land
380
480
480
340
630
400
150
480
190
3,600
a) SKI. 1979b.
b) See fdble A-l for emission factor.
-------
SOLVENT
1 \JLUtilt
CO
I
»*r
Wa-
Ac
1 IIVIJUUHC.
H2S04 UNO, AGENT rjlT «0
J o/\j "2 o DCB
1 1 1 lit
NITRATION PUkiHtAlIUN REDUCTION PHOSGENATION — DISTILLATION
JL
id
RECOVERY
TDI
I
RESIDUE
Figure B-l. Block Diagram for Toluene Diisocyanate Production
-------
CARRIER ACTIVE
INGREDIENT ,
EMULSIFIER |
1 ""* 1
I
TjL
DYEING
MACHINE
/ / X
/ /
/ /
/ /
/ /
r v
EFFLUENT
COLLECTION ^
t
AIR POLLUTION ,
CONTROL EQUIPMENT3
t
1
1
1
!
\ DRYER
N HEATSETTING
RANGE
t
Chemical and/or
biological degradation
Figure 6-2. Air and Water Pollution Control for Dye Carriers
(Wannemacher and DeMaria, 1979)
a) Probably a wet scrubber device, as the discharge is to effluent
collection,
3-5
-------
Table- B-4 Oyestuffs Utilizing 1,2-Qiehlorobenzene as < Reaction Solvent
Colour Index Name Colour Index Number Class
Direct Blue 106 51300 oxazlne
Direct Blue 108 51320 oxazlne
Direct Violet 54 51325 oxazlne
Mordant Red 27 45180 xanthene
Pigment Violet 23 51319 oxazlne
Vat Orange 9 59700 anthraqulnone
Vat Red 10 67000 anthraqulnone
Source: Society of Dyers and ColouHsts, 1971: EPA, 1977c.
a) AAP - American Aniline Products. Inc.- Paterson, MJ
ACT - American Cyanamid Co-, Bound Brook, NJ
ALC - Allied Chemical Corp. (Buffalo Color and Chemical), Paterson, NJ
ATL - Atlantic Chemical Corp., Nutley, NJ
BAY(V) - Verona Division of Baychen Corp., Union, NJ
CGY - CIBA - GEISY Corp., Ardsley, NY
CKC - Crompton and Knowles Corp., Fairhawn, NJ and Skokie. IL
CTN - Chemetron Corp., Holland, MI
DUP - E. I. du Pont de Nemours and Co., Inc., Wilmington, DE
GAP - GAF Corp., New York. NY
HST - American Hoescht Corp., Somervllle, NJ
IC1(0) - ICI America Inc., Wilmington, DE
MM - Martin-Marietta Corp.. Sodyeco, NC
NCC - Nyanza, Inc., Lawrence, MA
S(US) - Sandoz Colors and Chemicals, East Hanover. NJ
SNA - Sun Chemical Corp., Staten Island, NY
SYN - Synalloy Corp., Spartanburg, SC
TR - Toms River Chemical Corp., Toms River, NJ
Manufacturers'
CKC. CSY, ATL
ATL
no known US maker
S (US)
BAY(V), CTN, ACY.
SNA. GAF, S(US),
HST. ALC, CGY,
MM. SYN
ICI(O), AAP. ACY,
CGY, GAF, CKC.
NCC, DUP. TR
SAP. 1CI(0), AAP,
CGY, NCC, OUP
3=5
-------
Table B-5 Ambient Levels of Dlchloroberuenes In Air
Levels/Isomer
Comments
00
I
2 1 to 4.2 g/m3, p-DCB«
trace . o-DCBb
25-35C, 7QC ppm p-DCB
<1 0 pprad
<8 ng/m2-day, o-DCBe
27 ng/m2-day. o-OCBe
<53 ng/m2-day, o-DCB2
1700 gg/m3. p-DCBa
315 ng/m3, p-DCB»
105 ng/m3, p-DCBa
Tokyo Metropolitan Area
Rural California
Workplaces associated with manufacture
of p-DCB
Monochlorobenzene manufacturing plant
Catallna Island aerial fallout, high-
volume sample.
San Clemente Island, aerial fallout,
high-volume sample
Santa Barbara, aerial fallout, high-
volume sample
Wardrobe (mothballs)
Closet (mothballs)
Bedroom (mothballs)
a) Horlta and Ohl, 1975.
b) LPA, 1978b.
c) Pagnotto and Ualkley 1965..
d) SKI. 197%; no DCB Isomer specified.
e) Young et al., 1976. as cited In EPA. 1977a.
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U.S. Environmental Protection Agency
??8,T 5',Library (PL-12J)
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