Exposure and Risk Assessment {for} Dichloroethanes 1,1-dichloroethane, 1,2-dichloroethane {microform}


              United States
              Environmental Protection
              Agency
              Office of Water          April 1982
              Regulations and Standards (WH-553) EPA-440/4-85-009
              Washington DC 20460
Water
<> EPA
An Exposure
and Risk Assessment
for

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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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S0273-101
REPORT DOCUMENTATION i. REPORT NO 2.
PAGE EPA-440/4-85-009
4. TIM* and Subtitle
An Exposure and Risk Assessment for Dichloroethanes
1,1-Dichloro ethane 1,2-Dichloroethane
7. Authors) Perwak, J.; Byrne, M. ; Goyer, M. ; Lyman, W. ; Nelken, L.;
Scow, K. ; Wood, M. (ADL) Moss, K. (Acurex Corporation)
9. Performing Organization Name and Address
Arthur D. Little, Inc. Acurex Corporation
20 Acorn Park 485 Clyde Avenue
Cambridge, MA 02140 Mt. View, CA 94042
112. Sponsoring Organization Nam* and Address
Monitoring and Data Support Division
Office of Water Regulations and Standards
U.S. Environmental Protection Agency
Washington, D.C. 20460
3. Recipient* s Accession No.
5. Report oat* Final Revision
April 1982
6.
8. Performing Organization Rept. No.
10. Projcet/Task/Work Unit No.
11. Contrsct(C) or Grant(G) No.
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AN EXPOSURE AND RISK ASSESSMENT

DICHLOROETHANES

1,1-Dichloroethane
1,2-Dichloroethane
EPA-440/4-35-009
April 1981
(Revised April 1982)
by

Joanne Perwak
Melanie Byrne, Muriel Goyer,
Warren Lytnan, Leslie Nelken,
Kate Scow, and Melba Wood
Arthur D. Little, Inc.
U.S. EPA Contract No. 68-01-5949
Kenneth Moss
Acurex Corporation

U.S. EPA Contract No. 68-01-6017

Charles Delos
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
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
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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 cf 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. J.t 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
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TABLE OF CONTENTS
LIST OF FIGURES v

LIST OF TABLES vi

1.0 TECHNICAL SUMMARY 1-1

1.1 Risk Considerations 1-1
1.1.1 Human — 1,2-Dichloroethane 1-1
1.1.2 Human — 1,1-Dichloroethane 1-1
1.1.3 Biota 1-2
1.2 Materials Balance 1-2
1.3 Fate and Distribution in the Environment 1-3

2.0 INTRODUCTION 2-1

3.0 MATERIALS BALANCE 3-1

3.1 Introduction 3-1
3.2 Manufacture of 1,2-Dichloroethane 3-1
3.3 Manufacture of 1,1-Dichloroethane 3-9
3.4 Uses of 1,2-Dichloroethane 3-9
3.5 Use and Environmental Release of 1,1-Dichloroethane 3-10
3.6 Municipal Disposal of 1,1- and 1,2-Dichloroethane 3-10
4.0 FATE AND DISTRIBUTION OF DICHLOROETHANE IN THE 4-1
ENVIRONMENT

4.1 Introduction 4-1
4.2 Distribution of Dichloroethanes in the Environment 4-1
4.2.1 Waters and Sediment 4-1
4.2.2 Air 4-5
4.2.3 Soil 4-5
4.2.4 Biota 4-8
4.3 Environmental Pathways and Fate 4-8
4.3.1 Physicochemical Properties 4-8
4.3.2 Major Environmental Pathways 4-8
4.3.2.1 Behavior in Air 4-14
4.3.2.2 Behavior in Water 4-15
4.3.2.3 Behavior in Soils and Sediments 4-22
4.3.3 Fate of Dichloroethanes Discharged from 4-25
Major Sources
4.3.3.1 Air Emissions from Major Petrochemical 4-25
Plants
4.3.3.2 Air Emissions from 1,2-Dichloroethane 4-28
in Automobile Gasoline
ii
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TABLE OF CONTENTS (Continued)
4.3.3.3 Water Discharges from Petrochemical
Plants
4.3.3.4 Land Discharges from Petrochemical
Plants
4.3.3.5 Fate of 1,2-Dichloroethane Discharged
to Sanitary Sewers
4.4. Summary
5.0 EFFECTS AND EXPOSURE 5-1

5.1 Human Toxicity 5-1
5.1.1 1,2-Dichloroethane 5-1
5.1.1.1 Metabolism and Bioaccumulation 5-1
5.1.1.2 Human and Animal Studies 5-3
5.1.1.3 Overview 5-11
5.1.2 1,1-Dichloroethane 5-13
5.1.2.1 Introduction 5-13
5.1.2.2 Metabolism 5-13
5.1.2.3 Human and Animal Studies 5-14
5.1.2.4 Overview 5-15
5.2 Human Exposure 5-15
5.2.1 Introduction 5-15
5.2.2 Ingestion 5-15
5.2.2.1 Drinking Water 5-15
5.2.2.2 Food 5-22
5.2.3 Inhalation 5-24
5.2.3.1 Occupational 5~24
5.2.3.2 Ambient Air 5-24
5.2.3.3 Indoor Air 5-25
5.2.3.4 Near Sources 5-25
5.2.4 Dermal Exposure 5-27
5.2.5 Exposures Resulting From 1,2-Dichloroethane 5-27
as a Contaminant in Other Products
5.2.6 Overview 5-30
6.0 EFFECTS AND EXPOSURE ~ AQUATIC BIOTA 6-1

6.1 Effects on Biota 6-1
6.1.1 Introduction 6-1
6.1.2 Freshwater Organisms 6-1
6.1.3 Marine Organisms 6-1
6.1.4 Factors Affecting Toxicity of Dichloroethanes 6-2
6.1.5 Conclusions 6-2
6.2 Exposure of Biota 6-3
6.2.1 Introduction 6-3
iii
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TABLE OF CONTENTS (Continued)
6.2.2 Monitoring Data
6.2.3 Ingestion
6.2.4 Fish Kills
6.2.5 Conclusions
6-3
6-4
6-4
6-4
7.0 RISK CONSIDERATIONS
7.1 Introduction
7.2 Humans
7.2.1
7.2.2
7.2.3
7.3 Biota
Health Effects
Exposure
Human Risk Evaluation
7.2.3.1 Carcinogenic!ty
7.2.3.2 Risk to Exposed Populations
7-1

7-1
7-1
7-1
7-2
7-7
7-7
7-13
7-14
APPENDIX A Manufacture of 1,2-Dichloroethane
APPENDIX B Manufacture of 1,1-Dichloroethane
APPENDIX C Uses of 1,2-Dichloroethane
APPENDIX D Municipal Disposal of 1,1- and 1,2-
Dichloroethane
A-l
B-l
C-l
D-l
IV
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LIST OF FIGURES

Figure
No. Page

3-1 1,2-Dichloroethane Materials Balance Flow Sheet 3-2

3-2 1,1-Dichloroethane Materials Balance Flow Sheet 3-3

4-1 Major Pathways of Dichloroethanes in the Environment 4-13

4-2 Percent Volatilization of 1,1-Dichloroethane as a
Function of Distance Downstream From Source 4-24

A-l Locations of 1,2-Dichloroethane Facilities A-3

A-2 C~ Chlorinated Hydrocarbon Manufacture A-6

A-3 Manufacture of 1,2-Dichloroethane Via Direct
Chlorination A-10

A-4 Manufacture of 1,2-Dichloroethane Via Oxy-
chlorination A-ll

A-5 The Balanced Process for Vinyl Chloride Manufacture A-16

C-l Flow Diagram for 1,1,1-Trichloroethane from Vinyl
Chloride C-4

C-2 Ethylenediamine Manufacture C-7

C-3 Flow Diagram for Perchloroethylene and Trichloro-
ethylene by Chlorination C-ll

C-4 Flow Diagram for Perchloroethylene and Trichloro-
ethylene by Oxy-chlorination C-13

C-5 Manufacture of Vinylidene Chloride from 1,1,2-
Trichloroethane C-15
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LIST OF TABLES

Table
No. Page

3-1 Production of 1,2-Dichloroethane and Related C2
Products, by Facilities and Locations 3-4

3-2 Materials Balance of 1,2-Dichloroethane in 1978 3-6, 3-7,
3-8

3-3 Materials Balance of 1,1-Dichloroethane in 1978 3-11

4-1 Ambient Water Concentrations for Dichloroethanes " 4-2

4-2 Concentration of 1,2-Dichloroethane in Surface
Waters From Industrial Areas 4-3, 4-4

4-3 Concentrations of 1,1-Dichloroethane in Sediments 4-6

4-4 Concentrations of Dichloroethanes in Ambient Air
at Four Sites in the State of New Jersey, April
to November, 1978 4-6

4-5 Dichloroethane Levels in Ambient Air of Industrial
Areas 4-7

4-6 Concentrations of Dichloroethanes in Fish Tissue 4-9

4-7 Physicochemical Properties of 1,2-Dichloroethane 4-10, 4-11

4-8 Physicochemical Properties of 1,1-Dichloroethane 4-12

4-9 Tropospheric Half-Life of Dichloroethanes 4-16

4-10 Biodegradability of Dichloroethanes 4-18

4-11 Chemical Properties and Rate Constants Used as
Input to EXAMS Model 4-20

4-12 Results of EXAMS Model Runs 4-21

4-13 Volatilization t 1/2 for Dichloroethanes in
EXAMS System 4-23

4-14 1,2-Dichloroethane Residues in Plants 4-23

4-15 Meteorological Conditions Near Major Petrochemical
Plants Producing Dichloroethanes 4-26
vi
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LIST OF TABLES (Continued)

Table
No. Page

4-16 Estimated One-Hour Average Downwind Atmospheric
Concentrations of 1,2-Dichloroethane 4-29

4-17 Comparison of 1,2-Dichloroethane Monitoring and
Modeling Atmospheric Concentrations 4-30

4-18 Rough Dispersion Modeling Results for
1,2-Dichloroethane Emissions for Gasoline
Service Stations 4-31

5-1 Incidence of Primary Tumors at Specific Sites in
Male and Female Osborne-Mendel Rats Administered
1,2-Dichloroethane by Gavage 5-4

5-2 Incidence of Primary Tumors at Specific Sites in
Male and Female B6C3F1 Mice Administered
1,2-Dichloroethane by Gavage 5-5

5-3 Adverse Effects of 1,2-Dichloroethane 5-12

5-4 Adverse Effects of 1,1-Dichloroethane on Mammals 5-16

5-5 Dichloroethanes in Drinking Water — Federal Data 5-17

5-6 Occurrence of Dichloroethanes in Groundwater —
State Data 5-19

5-7 Groundwater Data Reportedly Available From State
Agencies for 1,2-Dichloroethane 5-20

5-8 Groundwater Data Reportedly Available From State
Agencies for 1,1-Dichloroethane 5-21

5-9 1,2-Dichloroethane Residues Found in Spice
Oleoresins From Three Manufacturers 5-23

5-10 Estimated Human Population Exposures to Atmospheric
1,2-Dichloroethane Emitted by Producers 5-26

5-11 Dermal Exposures to 1,2-Dichloroethane Resulting
From Spills 5-28

5-12 Concentration of 1,2-Dichloroethane as a Contaminant
in Other Compounds 5-29

5-13 Human Exposure to 1,2-Dichloroethane 5-31, 5-32
VI1
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LIST OF TABLES (Continued)

Table
No. Page

6-1 Maximum Observed Dichloroethane Concentration in
Minor U.S. River Basins (1974-1978) 6-5

7-1 Adverse Effects of 1,2-Dichloroethane 7-3

7-2 Adverse Effects of 1,1-Dichloroethane on Mammals 7-4

7-3 Estimated Human Exposure to 1,2-Dichloroethane 7-5, 7-6

7-4 Carcinogenicity of 1,2-Dichloroethane 7-9

7-5 Estimated Number of Excess Lifetime Cancers Per
1,000,000 Population Exposed to Different Levels
of 1,2-Dichloroethane Based on Four Extrapolation
Models 7-12

7-6 Estimated Ranges of Carcinogenic Risk to Humans
Due to 1,2-Dichloroethane For Various Routes of
Exposure

A-l 1,2-Dichloroethane Capacity, 1978 A-2

A-2 1,2-Dichloroethane Consumption, 1978 A-4

A-3 Production of 1,2-Dichloroethane and Related
G£ Products, by Facilities and Locations A-7

A-4 1,2-Dichloroethane Summary Materials Balance A-8

A-5 Composition of Crude 1,2-Dichloroethane A-13

A-6 Vinyl Chloride Producers, Locations, and
1978 Capacity A-14

A-7 Composition of Oxy-chlorination Wastewater A-19

A-8 Composition of Vinyl Chloride Tars A-20

A-9 Composition of Vinyl Chloride Heavy Ends A-21

B-l Materials Balance of 1,1-Dichloroethane in 1978 B-2

C-l 1,2-Dichloroethane Materials Balance: Uses, kkg/yr C-2

C-2 Production Capacity for 1,1,1-Trichloroethane C-3
viii
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LIST OF TABLES (Continued)

Table
No. Page

C-3 Production Capacity for Ethylenediamine C-6

C-4 Trichloroethylene and Tetrachloroethylene Production C-9

C-5 Vinylidene Chloride Producers, Locations, and
Capacity C-16

C-6 EDC Emissions from Use as Lead Scavenger 1978 C-20

C-7 Minor Uses of 1,2-Dichloroethane C-22

C-8 1,2-Dichloroethane Residues, Ug/g Found in Spice
Oleoresins from Three Manufacturers C-24

C-9 Wastewater Loading of Dichloroethanes in the
Pharmaceutical Industry C-25

C-10 Pesticide Products Containing 1,2-Dichloroethane C-27, C-32

D-l Dichloroethane Materials Balance: Municipal POTWs
and Refuse (kkg/yr) D-2
ix
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ACKNOWLEDGEMENTS
The Arthur D. Little, Inc., task manager for this study was Joanne
Perwak. Major contributors to this report were Melanie Byrne (Biological
Effects), Leslie Nelken (Environmental Fate), Warren Lyman (Environmental
Fate), Kate Scow (Biological Fate), Muriel Goyer (Human Effects), and
Melba Wood (Monitoring Data). In addition, Joseph Fiksel was responsible
for the risk extrapolation and Anne Littlefield, Nina Green and Irene
Rickabaugh were responsible for editing and report production.

The materials balance for the dichloroethanes (Chapter 3.0 and
Appendices A-D) was provided by Acurex Corporation, produced under
Contract 68-01-6017 to the Monitoring and Data Support Division (MDSD),
Office of Water Regulations and Standards (OWRS), U.S. EPA. Kenneth Moss
was the task manager for Acurex Corporation. Patricia Leslie was respon-
sible for report production on behalf of Acurex Corporation.

Charles Delos, MDSD, was the project manager at EPA.
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1.0 TECHNICAL SUMMARY
The Monitoring and Data Support Division, Office of Water Regulations
and Standards, the U.S. Environmental Protection Agency, is conducting an
ongoing program to identify the sources of, and evaluate the exposure to,
129 priority pollutants. This report assesses the exposure to and risk
associated with dichloroethanes.
1.1 RISK CONSIDERATIONS

1.1.1 Human —1,2-Dichloroethane

The compound 1,2-dichloroethane has been shown to be carcinogenic in
rats and mice when administered by gavage. However, both rats and mice
exposed to equivalent doses (as gavage) via inhalation showed no increased
incidence of malignant tumors. This disparity in results remains to be
resolved; however, it may be due to a difference in strain sensitivity,
or the production of carcinogenic metabolites of 1,2-dichloroethane when
administered by gavage that would not occur upon inhalation.

The isomer has been identified as an effective bacterial inutagen,
although no teratogenic or reproductive effects have been observed in
animals as a result of inhalation exposure. Chronic effects associated
with exposure to 40-400 rng/m^ have included CNS depression, GI upset,
and kidney and liver damage.

Most persons in the U.S. ingest less than 7 ug/day 1,2-dichloroethane
in food and drinking water. Water supplies are generally found to contain
less than 1 yg/1 of this compound, and little information is available on
levels in food. If exposure is assumed at 7 yg/day to 187 million persons,
an estimated 19-1047 excess lifetime cancers could occur in the exposed
populations, depending on the risk extrapolation models used.

If one assumes that persons residing in industrialized areas receive
about 100 ug/day and that 1,2-dichloroethane is carcinogenic via the
inhalation route (the latter assumption is unsupported by data), then
this exposure could result in a maximum estimated risk of 13-80 excess
lifetime cancers/million population.

The subpopulations identified as being exposed to highly contaminated
groundwater, residing in highly industrialized areas, or residing in the
immediate vicinity of a production facility, may experience 400-1000
maximum excess lifetime cancers/million population.

The carcinogenic risks associated with major routes of exposure to
1,2-dichloroethane were estimated, using a range of risk based on several
dose-response extrapolation models. There is considerable controversy
1-1
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over the most appropriate model for performing such extrapolations.
Moreover, additional uncertainty is introduced into the risk estimates
by the choice of a particular set of laboratory data, by the conversion
techniques used to estimate human equivalent doses, and by possible
differences in susceptibility between humans and laboratory species.
Due to the use of a number of conservative assumptions in -the risk cal-
culations, the estimated risks most likely overestimate the actual risk
to humans.

1.1.2 Human — 1,1-Dichloroethane

Little is known regarding the toxicity of 1,1-dichloroethane.
Carcinogenicity tests have been inconclusive due to poor survival. No
information is available regarding mutagenicity. Fetotoxic effects have
been observed in rats upon inhalation of high levels (24,300 mg/m^).
Chronic toxic effects appear to be similar to those observed for 1,2-
dichloroethane.

Similarly, exposure to 1,1-dichloroethane is largely unquantified.
Surface water contamination appears to be relatively rare, although as
for 1,2-dichloroethane, high exposures have occurred as a result of
contaminated groundwater. Inhalation exposures may occur in urban
areas.

Due to the lack of both effects and exposure data, the risks of
1,1-dichloroethane cannot be evaluated. A potential risk certainly
exists, however, due to the high concentrations reported in groundwater
in some locations.

1.1.3 Biota

The monitoring data indicate that levels of 1,1- and 1,2-dichloro-
ethane are much lower than the reported effect levels, and are almost
always lower than 10 ug/1. Thus, although the effects and exposure data
are limited, it does not appear that aquatic organisms are at risk to
dichloroethanes.

1.2 MATERIALS BALANCE

The compound 1,2-dichloroethane is the highest volume chlorinated
organic compound manufactured in the United States. Production of
1,2-dichloroethane in 1978 was approximately 5.9 x 10° kkg, with the
production facilities located primarily in the Gulf Coast area. About
80% of 1,2-dichloroethane was used in the production of vinyl chloride
monomer; about 5% was exported, and the remaining 15% was used in the
production of 1,1,1-trichloroethane, ethylenediamine, tetrachloroethylene,
trichloroethylene, vinylidene chloride, and as a lead scavenger. Minor
uses account for less than 1% of production, including polysulfide manu-
facture; paint; coating; adhesive solvent; extraction solvent; cleaning
solvent; grain fumigant; diluent in pesticides and herbicides; and film
manufacture.
1-2
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Of the identified releases to the environment, it. is estimated that
94% goes to the atmosphere (28,000 kkg/yr). About 85% of this amount is
attributed to production facilities, including vinyl chloride production,
in the western Gulf area. An additional 2% is attributed to the produc-
tion of other chemicals, and about 3% (700 kkg) to the use of 1,2-dichloro-
ethane as a lead scavenger. While the minor uses account for a small
portion of production, releases account for about 15% of the atmospheric
releases, although these are more widely dispersed than those from produc-
tion facilities.

Releases of 1,2-dichloroethane to the aquatic environment are
thought to be low, < 1% of the total releases, or about 190 kkg. About
34% of these releases are attributed to trichloroethylene and tetra-
chloroethylene production. An additional 53% is thought to be released
from its use as a cleaning solvent. The remainder is attributed to
miscellaneous sources, although releases to water are not well quanti-
fied. Releases from production facilities appear to be less than 1 kkg,
a very small amount considering the amounts of 1,2-dichloroethane
produced.

It is estimated that the land receives about 5% of the total
releases, or about 1600 kkg. About 73% is a result of 1,2-dichloro-
ethane and vinyl chloride production. One percent is attributed to
ethyleneamine production. Again, the minor uses can account for
significant portions of releases. The use of 1,2-dichloroethane as
a cleaning solvent may result in 15% or 240 kkg of the releases to
land, while its use in pesticide formulation accounts for about 11%
of the total estimated releases to the compartment.

In contrast to 1,2-dichloroethane, commercial production of 1,1-
dichloroethane is as an unisolated intermediate during the manu-
facture of 1,1,1-trichloroethane. However, small amounts (10 kkg) are
produced and sold by specialty and laboratory chemical firms. It is
also produced inadvertently in the production of 1,2-dichloroethane.

Atmospheric releases of 1,1-dichloroethane (1200 kg) represent
about 99% of identified releases. About 52% of atmospheric releases
are attributed to the production of 1,1,1-trichloroethane, and about
35% to the production of 1,2-dichloroethane. The remainder of the
atmospheric releases is attributed to POTWs and its use as a cleaning
solvent.

The identified aquatic releases (2 kkg) represent less than 1% of
the environmental releases. The sources include solvent use, and POTWs.
Both are expected to be widely dispersed.

The only identified sources of- 1,1-dichloroethane to the land are
POTWs and solvent use, which released about 6 kkg in 1978, or about 1%
of the total environmental releases.
1-3
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1.3 FATE AND DISTRIBUTION IN THE ENVIRONMENT

The releases of dichloroethanes considered in conjunction with the
compounds' probable fate pathways are generally reflected in the moni-
toring data.

Releases to aquatic systems are low compared to environmental
releases to air or land. In addition, volatilization from surface
waters is expected to be the predominant loss mechanism. Laboratory
results suggest a half-life for volatilization of 30 minutes for 1,2-
dichloroethanes, although the use of the EXAMS model predicted a half-
life of 35 hours in river water. Similar results were obtained for
1,1-dichloroethanes. Thus it is possible that released dichloroethanes
may be carried a considerable distance downstream, although the concen-
trations may be considerably reduced due to dilution.

Where these compounds have been monitored, levels of both 1,2- and
1,1-dichloroethane in surface waters are almost always less than the
detection limit, generally 10 yg/1. However, a few high values have
been reported, with maximums of 230 yg/1 and 1900 yg/1, respectively.
These levels appear to represent temporary situations.

Large amounts of dichloroethanes, especially the 1,2-isomer, are
released to the atmosphere in the vicinity of production facilities.
Although photochemical degradation is generally thought to be the
predominant loss pathway, it is probably of less importance in the
Gulf Coast area due to the high percentage of cloudy days. Atmospheric
losses due to washout could occur in this area due to frequent and heavy
rains, although some may be re-volatilized. Thus, dichloroethanes
released in this area will generally be transported north over populated
areas.

The maximum levels observed in the vicinity of production facili-
ties range from 70-500 ug/m3 1,2-dichloroethane. Levels of 1,2-dichloro-
ethane in industrialized areas appear to range from 1-5 yg/m^, while in
urban areas, the levels appear to range from 0.04-1.4 yg/m^ as a result
of the use of this compound in leaded gasoline. In rural areas, levels
of 1,2-dichloroethane appear to be less than 0.02 yg/m^.

Large amounts of 1,2-dichloroethane are disposed on land. Volatili-
zation may be possible in some situations. Rapid movement through the
soil column has been shown in sandy soil; however, the fate of dichloro-
ethanes in soils of higher organic content has not been studied. Consi-
dering their low affinity for adsorption, however, movement is likely to
be rapid. Transport to groundwater will be facilitated by the porous
soil found in the vicinity of production facilities, as well as the
proximity to the water table, and the frequent and heavy rainfalls.
1-4
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2.0 INTRODUCTION
The Office of Water Regulations and Standards (OWRS), Monitoring
and Data Support Division, of the U.S. Environmental Protection Agency
is conducting a program to evaluate the exposure to and risk of 129
priority pollutants in the nation's environment. The risks to be
evaluated include potential harm to human beings and deleterious effects
on fish and other biota. The goal of the task under which this report
has been prepared is to integrate information on cultural and environ-
mental flows of specific priority pollutants and to estimate the risk
based on receptor exposure to these substances. The results are
intended to serve as a basis for developing suitable regulatory strategy
for reducing the risk, if such action is indicated.

This report is intended to provide a brief, but comprehensive,
summary of the production, use, distribution, fate, effects, exposure,
and potential risks of 1,1- and 1,2-dichloroethane. Waterborne routes
of exposure are stressed due to the emphasis of the OWRS on aquatic and
water-related pathways. Occupational exposure and the exposure of the
general population to atmospheric levels of dichloroethanes are only
considered in terms of the perspective they shed on the magnitude of
water-related exposure.

The major problem with attempting a risk assessment for 1,2-dichloro-
ethane is the disparity in the carcinogenicity results for ingestion and
inhalation exposures. While ingestion exposures do occur, the highest
exposures are a result of inhalation. Thus, it is difficult to evaluate
the risk resulting from these exposures in light of the carcinogenicity
data. For purposes of comparison, it was assumed that 1,2-dichloroethane
is carcinogenic via inhalation, with a similar dose-response curve to
that found for ingestion.

There are a number of problems with attempting a risk assessment for
1,1-dichloroethane. Data are limiting in all aspects, including sources,
monitoring data, exposure information, and effects data. As a result,
it was impossible to implement a quantitative risk assessment for this
compound. The exposure routes and the effects associated with 1,1-
dichloroethane have been identified to the extent possible.

It should be noted that there is some unavoidable inconsistency in
terminology in this report and references. While the full chemical names,
1,1- and 1,2-dichloroethane are generally used, occasionally references to
1,2-dichloroethane as EDC (ethylene dichloride) are made.

This report is organized as follows:

• Chapter 3.0 contains information on releases from the
production, use, and disposal of dichloroethanes,
including identification of the form and amounts released
and the point of entry into the environment.

2-1
-------
• Chapter 4.0 considers the fate of dichloroethanes leading
from the point of entry into the environment until exposure
of receptors. Reports of available data regarding concen-
trations detected in environmental media are also discussed.
Chapter 5.0 discusses the adverse effects of dichloro-
ethanes and concentrations eliciting these effects in
humans and quantifies the likely pathways and levels
of human exposure.

Chapter 6.0 considers the effects of dichloroethanes
on biota and quantifies the environmental exposure of
aquatic biota to the compounds.

Chapter 7.0 discusses risk considerations for various
subpopulations of humans and aquatic organisms using
various risk extrapolation techniques.

Appendices A, B, C, and D present the assumptions and
calculations for the estimated environmental releases
of dichloroethanes described in Chapter 3.0.
2-2
-------
3.0 MATERIALS BALANCE
3.1 INTRODUCTION

One perspective from which exposure to a compound may be evaluated
is that of a materials balance. As matter is neither created nor
destroyed in chemical transformations, the total mass of all materials
entering a system equals the total mass of all materials leaving that
system, excluding those materials retained or accumulated in the system.
From the perspective of risk analysis, a materials balance may be
performed around any individual operation which serves to identify a
specific population at risk (e.g., process air emissions creating high
worker exposure to a toxic byproduct). An environmental materials
balance, therefore, consists of a collection of materials balances, each
of which is directed to a specific source or sink within the environment.

The scope of this chapter has been limited to a review of both
published and unpublished data concerning the production, use, and dis-
posal of dichloroethanes within the United States. Available literature
has been critiqued and compiled to present an overview of major sources
of environmental release of dichloroethanes and fully annotated tables
to aid data evaluation. The environmental flows of 1,2- and 1,1-dichloro-
ethane are shown in Figures 3-1 and 3-2, respectively.

G£ chlorinated hydrocarbons (1,1-dichloroethane, 1,2-dichloroethane,
1,1,1-trichloroethane, vinyl chloride, vinylidene chloride, trichloro-
ethylene, and tetrachloroethylene) are produced as coproducts or are
produced individually by several processes within a single plant. In
order to maximize G£ chlorinated hydrocarbon production efficiency, these
processes are integrated within a single complex where the product, by-
products, and waste streams from one process are used as raw materials
for another process. The interrelationships among products manufactured
at 1,2-dichloroethane facilities are shown in Table 3-1.

3.2 MANUFACTURE OF 1,2-DICHLQROETHANE

Two distinct but related processes are used to produce 1,2-dichloro-
ethane: (1) direct chlorination in the presence of a catalyst, and
(2) oxy-chlorination in the presence of a catalyst. Within oxy-chlorina-
tion plants further distinction is made as to whether air or oxygen is
used as feedstock. For either process, both yield and selectivity are
high for 1,2-dichloroethane manufacture, ranging from a nearly qualita-
tive yield and 99% selectivity for direct chlorination to 93-97% yield
and 93-95% selectivity for oxy-chlorination processes (see Appendix A
for process descriptions). The major environmental releases of 1,2-
dichloroethane from production processes are atmospheric.

For purposes of this report, manufacture of 1,2-dichloroethane has
been treated within the context of an integrated balanced process at a
3-1
-------
Sources

Direct (Production)
Balanced „
Process 5,400,000
Direct Chlorination
380.000
Oxy-Chlorination
110,000
Indirect
Manufacture of other
Chlorinates Hydrocarbon;
Chlorination
of Water
Supplies
Uses

ManaufaetuHnq Intermediate
Environmental Releases
Vinyl Chloride
Monomer 4,800,000
1,1,1-TricMoroe thane
200,000
Ethyl enea/nines
230,000
Trichloroethylene

110,000
Tetrachloroethylene
110,000
Vinylidene Chloride
(l,l-D1chloroethane)

100,000
Dispersive Uses
Lead Scavengers
72,OOP
Paints, Coatings, Adhesives
1.300
Extraction SolventI
1.3001
Cleaning Solvent
1.000
Polysulfide Elastomers
15
Grain Fumigant
500
Diluent for Pesticides
350
Film Manufacture
150
Air
20,000
1
360
1100
63
1300
75
700
32
1,300
1,300
660
neg
500
175
8
Water
neg
neg
20
neg
29"
neg
35
neg
4
neg '
neg
100
1
neg
neg
neg
Land
830
neg
20
95
neg
2SO
neg
neg
neg
neg
neg
240
neg
neg
175
neg
Figure 3-1. l.2-D1cn1oroethane Materials Balance Flow Sheet, 1978 (kkg/yr)

a) Emissions contained within balanced process emissions.
3-2
-------
Sources
Direct:
iriydrochlorination
Tf vinylchloride
L 230,000
Indirect:
1,2-Dichloroethane
|Production
In Tori nation
of Water
supplies
POTW
Uses
Manufacturing Intermediate
Manufacturing Intermediate
1,1,1-Trichloroethane
200.000
Solvent
10 kkg
TOTAL
Environmental Releases
Air
600
500
neg
52
1159
Water
neg
neg
neg
Land
neg
neg
neg
Source: See Appendix B.
Figure 3-2. 1,1-Dichloroethane Materials Balance Flow Sheet (kkg/yr)
3-3
-------
Table 3-1. Production of 1-,2-Dichloroethane and Related C, Products,
by Facilities and Locations '
PLANT
///
?° f° sT -J
": i ^ v
-* -s* -^ V
/ / / / /
••i* « £? -? «:•
" / ^ $ *
/ / / f

Borden Chemical Co.
Geismar, LA
Continental Oil Co.
Lake Charles, LA
Diamond Shamrock Corp.
Deer Park, TX
LaPorte, TX
Dow Chemical Corp.
Freeport, TX
Oyster Creek, TX
Plaquemine, LA
• •
• •
•
• •
• •
• • • •
• •
•
• •
Dupont and Company
Wilmington, DE •

Ethyl Corporation
Baton Rouge, LA • • • •
Pasadena, TX

B.F. Goodrich Co
Calvert City, KY • •

ICI Americas, Inc.
Baton Rouge, LA • •

Monochem Inc.
Geismar, LA •

PPG Industries, Inc.
Lake Charles, LA •••• • •

Shell Chemical Co.
Deer Park, LA • •
Norco, LA • •

Stauffer Chemical Co.
Long Beach, CA • • •

Union Carbide Corp
Taft, LA • •
Texas City, TX • •

Vulcan Chemical Co.
Geismar. LA • • •
Wichita, KS •
3-4
-------
vinyl chloride monomer (VCM) manufacturing facility. Waste loads gener-
ated by the three distinct processes — direct chlorination of ethene,
oxy-chlorination of ethylene, and dehydrochlorination of 1,2-dichloro-
ethane — are typically combined at any given facility for recovery,
treatment, and disposal. Therefore, the specific number of point sources
of atmospheric, aqueous, and solid wastes at a manufacturing site is a
function of the actual plant design unit requirements. Daily loadings
may vary at each plant site with individual operating conditions and
production requirements, particularly with regard to the use of the oxy-
chlorination process. Point sources of 1,2-dichloroethane loss from VCM
manufacture via the balanced process include direct and oxy-chlorination
reactor vent streams, light ends distillation column vent, heavy ends
from the 1,2-dichloroethane recovery tower, wastewater from drying columns
and scrubbers, and fugitive emissions from storage, pumps, seals, etc.
(Catalytic 1979, EPA 1979a). In 1978, total loss of 1,2-dichloroethane
during VCM manufacture from all sources is estimated to be 20,083 kkg
(see Section A.I, Appendix A).

Assuming all VCM plants exhibit atmospheric emissions similar to
those given by Drury and Hammons (EPA 1979a) and that such streams, where
economically feasible, are chemically treated to recover the various
organic compounds present, approximately 20,000 kkg of 1,2-dichloroethane
were emitted to the atmosphere in 1978. These emissions arise largely
from vent gas streams.

Combined wastewaters which arise from 1,2-dichloroethane manufacture
— vent gas scrubbers, water produced during oxy-chlorination, and wash-
water — are treated in three ways (Catalytic 1979). Pretreatment is
common and eight plants steam strip process wastewater prior to biologi-
cal treatment. Twelve of the sixteen plants producing 1,2-dichloroethane
discharge directly to surface waters after primary and/or secondary
treatment. Of this first group, two plants incinerate a portion of the
1,2-dichloroethane waste stream, and four use primary treatment only
(neutralization and chemical treatment); of the eight plants using
secondary treatment, three use activated sludge and five have aerated
lagoons. The second group (two plants) pretreats the waste stream by
steam stripping prior to discharge to municipal treatment systems. The
remaining two plants dispose of wastes by deep well injection and direct
discharge to Publicly Owned Treatment Works (POTWs). Based on published
EPA data gathered from questionnaires to industry, and actual sampling
data (see Table A-7), between 250 kkg and 600 kkg 1,2-dichoroethane are
estimated to be present in wastewaters arising from 1,2-dichloroethane
manufacture, assuming plants operate at 80% capacity (EPA 1976, EPA
1974). After treatment, 1,2-dichloroethane concentration is reported
to range from 12 yg/1 to 75 ug/1; based on these concentrations and a total
wastewater flow of 9.5 x 108 1/yr (Catalytic 1979), 1,2-dichloroethane
discharge to surface waters is negligible (i.e., <. 1 kkg: Table 3-2).

Solid wastes (containing tars, spent catalysts, and dessicants) are
usually treated to recover organic compounds present. Wastes are subse-
quently disposed in a landfill or incinerated, recovering chlorine as
3-5
-------
Table 3-2. Materials Balance of 1,2-Dichloroethane in 1978a
CO
i
cr>
— ^~_— — ~— ^ „
Source
EXPORTS13
b
IMPORTS
PRODUCTION:
Direct Chlorination0
Oxy-chlorination
Balanced Process6
CONSUMPTIVE USES:f
1,1,1-THchloroethane^
Ethyleneamines
Trichloroethene
Tetrachl oroethene J
t,
Vinyl idene Chloride
Polysulfide Elastomers
DISPERSIVE USES
Lead Scavenger"1
Paint, Coating, Adhesive Solvent"
Extraction Solvent0
Cleaning Solvent*3
Grain Fuinigant''
Pesticide/Herbicide Carrier1"
Film Manufacture5
kkg 1,2-Dichloroethane
310,000

neg

380,000
110,000
5,400,000

200,000
230,000
110,000
110,000
100,000
15

72,000
1,300
1,300
1,000
500
350
150
Estimated Environmental Qispersion Mg
Air

1.100
1,300
20,000

1
360
63
75
neg
neg

700
1,300
1,300
660
500
175
8
Uater

neg
neg
neg

neg
20
29
35
neg
1

neg
neg
neg
100
neg
neg
neg
Land

95
280
830

neg
20
neg
neg
neg
neg

neg
neg
neg
240
neg
175
neg

FOOTNOTES NEXT PARE
-------
Table 3-2. (continued)

a) Values have been rounded to two significant figures, neg is <1 kkg.

b) U.S. Department of Commerce, 1980.

c) Air emissions: storage facilities (0.0006 kg EOC/kg EDC produced) and scrubber vent (0.0022 kg/kg). Water discharge:
scrubber waste (0.0018 kg/kg EDC produced), uncontrolled; see p. 3-5 for post-treatment concentrations, resulting in negligible
(<1 kkg) discharge shown. Doth from EPA, 1974a. Land dispersion: 0.0007 kg tar/kg EDC produced, EPA, 1974a; up to 35% EDC
in EDC tar (Jensen et al_., 1975).

d) Emission factors for all media from EPA, 1974b. Air: process vent gas (0.007 kg EDC/kg EDC produced) and distillation vent
gas (0.0045 kg EDC/kg EDC produced). Water: 0.0006 kg EDC/kg produced, (uncontrolled discharge); see p. 3-5 for post
treatment concentrations, resulting in negligible (<1 kkg) discharge shown. Land: heavy ends 0.0025 kg EDC/kg EDC produced.
Storage facilities: 0.0006 kg EDC/kg EDC produced (Included in air total).

e) Total atmospheric emissions: 0.0027 kg EDC/kg EDC consumed from distillation vent, 0.0010 kg EDC/kg from direct chlorination
and 0.0010 kg EDC/kg oxy-chlorination (EDC produced by direct and oxy-chlorination assumed equal). Total water discharge
based on 190 gpm flow rate, EDC concentration 1500 - 3600 ppm, and 80% capacity operation, EPA, 1978; EPA, 1974a, uncontrolled;
see p. 3-5 for post-treatment concentrations, resulting in negligible ( 1 kkg) discharge shown. Total land discharge tar
concentration 0.8 kg tar/kkg VCM produced, 36% EDC in tar, Lunde, 1965. Discharge of EDC by company using balanced process
based on individual company capacity as a percent of total production; totals do not add due to rounding.

f) Based on amount of product derived from 1,2-dichloroethane and reaction stoichiometry (SRI, 1979a).

g) Air: I) 0.004g EDC/kg 1,1,1-trichloroethane produced (distillation vent gas), for ethane- and vinyl chloride-based processes
controlled by combusion in incineration (EPA, 1979b). Water: Estimated as 1-10 kkg, plus 1-10 ppm EDC in
1,1,1-trichloroethane streams based on industry estimate Denison, 1980. Aquatic discharges are believed to be insignificant
based on process configuration. 1,2-Dichloroethane discharge to land is believed to be negligible based upon recycling of
solid waste streams to carbon tetrachloride/tetrachloroethylene production. See Appendix C-2.

h) EDC consumption based on total ethylenediamene production of 64 x 103 kkg (SRI, 1979a) and reaction yield of 45% (Lichenwalter
and Cour, 1969). Environmental releases based on factor of 6 kg EDC/kkg product, distributed 90:5:5. See Appendix C-3.

i) EDC residual level in TCE streams = 10-100 ppm (Dension, 1980); air: 3.1 g/kg Trichloroethylene, 85% control (EPA, 1979b).
Water: 0.42 kg H20/kg trichloroethylene, 510 pg EDC/1 (catalytic, 1979). 135,000 kkg Trichloroethylene produced in 1978
(SRI, 1979a). See Appendix C-4.

j) 1.6 x 10 kkg produced using EOC as feedstock (SRI, 1979a). Same emission factors as In note 1.
-------
Table 3-2. (concluded)
k) No EDC detected In waste streams. See Appendix C.5.
1) Based on reaction yield of 99%, solubility of 1,2-dichloroethane in water, and water use rate of 20 kkg/kkg product.
Air emissions are assumed to be controlled by vent condensers. See Appendix C.6.
in) Combined discharge from gasoline blending, filling and "breathing" of storage tanks, and refueling of automobiles.
See Appendix C.7. Releases to water and land are thought to be negligible.
n) Used as 1) solvent to dissolve binder and then coatings or paints and 2) as a solvent cement for thermoplastic
materials. All EDC is assumed to evaporate. See Appendix C.8.1.
o) Includes extraction of spices oleoresins and animal feeds. Assume solvent recovery of 95% (Lo, 1980). Permissible
residues in spices: 30 ppm, feed: 300 ppm (Federal Food, Drug and Cosmetic Act. Aquatic discharges are assumed
to be negligible. See Appendix C.8.2.
P) PVC equipment cleaning and degreasing of textiles; assume equal distribution between these uses. By analogy to
trichloroethylene use as degreasing/fabric scouring to solvent, 66% emitted to air, 24% to land and 10% to water
(EPA, 1981). See Appendix C.8.3.
q) Assume that all EDC is eventually released to the atmosphere following processing and cooking of the grain. See
Appendix C.8.4.
r) Assume 50% of EDC evaporates to the atmosphere, 50% is retained by soil initially. See Appendix C.8.5.
s) Assume use as a specialty solvent within the film Industry in quantities too small to warrant recovery. See
Appendix C.8.5.
-------
hydrogen chloride (McPherson et_ al_. 1979). The compositions of vinyl
chloride tars and heavy ends are shown in Tables A-8 and A-9. The
concentration of 1,2-dichloroethane in VCM tars is process dependent;
EPA (1975a) lists such tars as 36% 1,2-dichloroethane by weight. Esti-
mates of VCM tar production rates range from 0.8 kg/kkg (EPA 1975b) to
the exceedingly high value of 40 kg/kkg of vinyl chloride produced
(Jensen et al. 1975). Using the former emission factor (2.89x10^ kkg
VCM produced from 1,2-dichloroethane) and a 1,2-dichloroethane concen-
tration of 36% by weight, 83 kkg of 1,2-dichloroethane were discharged
as solid waste. Using the information in footnotes c and d of Table 3-2,
solid waste releases of 1,2-dichloroethane totaled 93 kkg and 280 kkg
for direct and oxychlorination, respectively. The disposition of such
wastes is unclear; indeed, this waste may be a suitable feedstock for
tetrachlorethylene/carbon tetrachloride via a chlorinolysis process
(EPA 1976). If incinerated, assuming a combustion efficiency of 99.9%,
1 kkg of 1,2-dichloroethane would be emitted.

3.3 MANUFACTURE OF 1,1-DICHLOROETHANE

In contrast to the production of 1,2-dichloroethane, commercial
production of 1,1-dichloroethane is as an unisolated intermediate step
during manufacture of 1,1,1-trichloroethane. Small amounts (<10 kkg) are
produced and sold, however, by specialty and laboratory chemical firms.
Inadvertent sources of 1,1-dichloroethane include production of 1,2-
dichloroethane via oxy-chlorination of ethylene, direct chlorination of
ethane (1,1,1-trichloroethane manufacture), direct and oxychlorination
of 1,2-dichloroethane to produce trichloroethylene/tetrachloroethylene,
and epichlorohydrin manufacture. As shown in Figure 3-2, the major
environmental releases of 1,1-dichloroethane are in the form of atmo-
spheric emissions (see Appendix B for specific production and use data).

3.4 USES OF 1,2-DICHLOROETHANE

Uses of 1,2-dichloroethane fall into two broad categories: (1)
consumptive uses (e.g., used as a chemical manufacturing intermediate),
and (2) dispersive uses, where 1,2-dichloroethane is released to the
environment as a normal consequence of product use. Dispersive uses of
1,2-dichloroethane as a solvent, fumigant, herbicide or pesticide carrier,
and lead scavenger are an important source of 1,2-dichloroethane emissions
to the atmosphere (see Appendix C). Discharges of 1,2-dichloroethane
wastes to land are somewhat more difficult to quantify; many wastes which
result from 1,2-dichloroethane production are suitable for recycle as
feedstock for carbon tetrachloride/tetrachloroethylene production. While
it is assumed that such wastes are recycled wherever possible, there is
a portion of such wastes which is nonrecyclable. The 1,2 isomer is also
used as a cleaning solvent for PVC reactors and as a textile scouring
agent. Losses during textile scouring operations are largely to the
atmosphere but reactor wastes are presumed to be collected and drummed
for land disposal. The compound used as a pesticide/herbicide carrier
is also an important source of 1,2-dichloroethane discharged to land.
3-9
-------
Indirect sources of 1,2-dichloroethane release, such as in the manufac-
ture of other chlorinated hydrocarbons or chlorination of water supplies,
do not appear to be significant (see Appendix A, Section A-7).

3.5 USE AND ENVIRONMENTAL RELEASE OF 1,1-DICHLOROETHANE

Release of 1,1-dichloroethane is largely to the atmosphere as a
result of intermediate storage of 1,1-dichloroethane and as an uninten-
tional byproduct during production of 1,2-dichloroethane. Discharges
to the aquatic environment occur from use of 1,1-dichloroethane as a
solvent. These losses result from the use of relatively small amounts
of 1,1-dichloroethane which do not warrant recovery. Releases of
1,1-dichloroethane to land are unknown. Releases of 1,1-dichloroethane
are summarized in Figure 3-2 and presented in annotated form in
Table 3-3.

3.6 MUNICIPAL DISPOSAL OF 1,1- AND 1,2-DICHLOROETHANE

Loading of both 1,1- and 1,2-dichloroethane to Publicly Owned
Treatment Works (POTWs) is dependent upon the type of industry in an
area, as well as variations in that industry's discharge. A framework
for estimating the flow of both these compounds through the nation's
POTWs is detailed in Appendix D. These data, based on a recent EPA
study (EPA 1980), suggest that 4 kkg of 1,2-dichloroethane are dis-
charged to surface waters from POTWs per year, while approximately
32 kkg are emitted to the atmosphere. Such an estimate is consistent
with the fact that 1,2-dichloroethane apparently is not concentrated
in sludge (EPA 1980; see Appendix D).

The 1,1 isomer exhibits a different distribution pattern. Based
on EPA (1980) data, approximately 1 kkg of 1,1-dichloroethane are
discharged in effluent from POTWs per year, 4 kkg are disposed on land
as sludge, and 52 kkg are emitted to the atmosphere (see Appendix D).
3-10

Arthur D Little, Inc
-------
Table 3-3. Materials Balance of 1,1-Dichloroethane In 1978a
Source
kkg of 1.1-Dlchloroethane
Estimated Environmental Releases, kkg
Air
Water
Land
CJ
I
PRODUCTION:0

HydrochlorI nation
of vinyl chloride

INADVERTENT:

1,2-Dlchloroethane manufacture via the
balanced process

1.2-Dlchloroethane manufacture via
direct chlorinatton
230.000
607

200

300
neg

neg
neg

neg
a) All values rounded to two significant figures.

b) Use as a solvent (10 kkg is assumed to be in relatively small amounts which do not warrant recover. Releases from solvent
use are allocated 66% to air, 24% to land, and 10% to water by analogy to trichloroethylene (EPA 1981).

c) Use as a solvent Is assumed to be In relatively small amounts which do not warrant recovery.

d) Based upon 5.1 x 10 kkg 1,2-dlchloroethane produced via the balanced process and an emission factor of 0.04 kg 1,1-dlchloroethane/
kkg 1,2-dlchloroethane produced (Lunde. 1965).

e) Based upon 380 x 103 kkg 1,2-dlchloroethane production via direct chlorlnatlon of ethylene and an emission factor of 0.8 kg 1,1-dlchloro-
ethane/kkg 1,2-dlchloroethane produced (Lunde. 1965).
-------
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Elkin, L.M. Chlorinated solvents. Process Economic Program Report
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Farber, H. Personal Communication. June 1980.
3-13
-------
Fishbein, L. Production, Uses and Environmental Fate of Ethylene
Bichloride and Ethylene Dibromide. Ames, B.; P. Infante; and R.
Reitz, eds. Banbury Report 5, Ethylene Bichloride: A Potential
Health Risk? Cold Spring Harbor, NY: Banbury Center; 1980.
(Unpublished Paper)

Fowler, D.L. (U.S. Department of Agriculture, Agriculture Stabili-
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Guardian Chemical Company. Personal Communication. May 1980.

Hardie, D.W. ' Vinyl chloride. (In) Kirk-Othmer Encyclopedia of
Chemical Technology. 2nd ed. New York: John Wiley and Sons;
5:171-178;1964.

Jacobs, E.S. Use and Air Quality Impact of Ethylene Bichloride and
Ethylene Bibromide Scavengers in Leaded Gasoline. Ames, B.; P.
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A Potential Health Risk? Cold Spring Harbor, NY: Banbury Center;
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Leach, H.S.; Price, J.L., inventors; Monsanto Company, assignee.
Chlorination of olefins in the presence of amides. U.S. patent
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Lichenwalter, M; Cour, T.H. Inventors, Jefferson Chemical Co., Inc.,
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1980.

Lowenheim, F.A.; Moran, M.K. Ethylene dichloride. (In) Faith, Keyes
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3-16
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4.0 FATE AND DISTRIBUTION OF DICHLOROETHANE IN THE ENVIRONMENT
4.1 INTRODUCTION

This chapter describes the levels of dichloroethanes which have
been observed in the environment. In addition, it discusses the
environmental pathways which may result in these levels. Laboratory
data, field data, and modelling were utilized in preparing this chapter.

4.2 DISTRIBUTION OF DICHLOROETHANES IN THE ENVIRONMENT

Monitoring data for concentrations of 1,1- and 1,2-dichloroethane
in the environment have been collected and analyzed for air and water;
data relating to concentrations in soil and biota do not appear to be
as readily available. This chapter presents data on 1,1- and 1,2-
dichloroethane concentrations in ambient waters, sediment, air, and
fish tissue.

4.2.1 Waters and Sediment

Shakelford and Keith (1976) identified concentrations of 1,2-
dichloroethane in surface waters distant from point sources at 1 yg/1,
with some samples at 100-fold greater concentrations.

Table 4-1 shows monitoring data for dichloroethanes, as reported
from the STORET system, 1975 to present (U.S. EPA 1980a). Most of the
data included is remarked, or less than the detection limit. Concentra-
tions of 1,1-dichloroethane range from undetected 1900 yg/1. The highest
reading, 1900 yg/1, occurred in the Upper Mississippi basin, Mississippi
River at Alton, Illinois; however, a second sampling on the same day at
the monitoring station was documented at 50 yg/1. A total of 192
observations were reported. Concentrations of 1,2-dichloroethane range
from undetected to 230 yg/1.

Effluents from four pilot tertiary wastewater treatment systems
were monitored for selected trace organic compounds in Los Angeles
County (Baird ^t _al. 1979). In general, 1,2-dichloroethane was not
detected in the various effluent types from the treatment system.
Detection of 1,2-dichloroethane occurred at 0.4 yg/1 in two of the four
advanced wastewater treatment systems.

A total of 204 water samples were collected from 14 heavily indus-
trialized river basins by researchers from the University of Illinois,
during 1975 and 1976. The 1,2 isomer x*as detected in 53 of the 204
samples (26%) using gas chromatographic and mass spectrometric tech-
niques. Concentrations ranged from 1-90 yg/1 as shown in Table 4-2
(Ewing and Chian 1979).
4-1
-------
TABLE 4-1. AMBIENT WATER CONCENTRATIONS FOR DICHLOROETHANES
Number of
Compound Observations Maximum (yg/1) Mean (yg/1)
1,2-dichloroethane

unremarked3 10 230 69.3
remarked 57 50 20.4
1,1-dichloroethane

unremarked
remarked 186 50 10.5
unremarkeda 6 1900 317.6
Unremarked data are generally positive values; remarked data are noted
to be less than a given value, generally the detection limit. The
maximum and the means are included to show the detection limits for
most analyses.

Source: U.S. EPA(1980a).
4-2
-------
TABLE 4-2. CONCENTRATION OF 1,2-DICHLOROETHANE IN
SURFACE WATERS FROM INDUSTRIAL AREAS
Site
Nearest Town
Concentration (yg/1)
Chicago Area and Illinois River Basin
Chicago Sanitary and
Ship Canal
North Side Sewage
Treatment Plant
North Side Sewage
Treatment Plant
Calumet River
Calumet-Sag Channel
Des Plaines River
Illinois River
Illinois River
Illinois River
Delaware
Delaware
Delaware
De1 aware
Delaware
Delaware
Delaware
Delaware
Delaware
Delaware
River
River
River
River
River
River
River
River
River
River
Raritan Bay
Raritan Bay
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Newark Bay
Hudson River
Hudson River
Hudson River
Hudson River
Hudson River
Hudson River
Hudson River
Lockport, IL

Lincolnwood, IL

Lincolnwood, IL
Chicago, IL
Blue Island, IL
Elwood, IL
Dresden, IL
Utica, IL
Hennepin, IL

Delaware River Basin

Woodland Beach, DE
Port Penn, DE
Pigeon Point, DE
Marcus Hook, PA
Paulsboro, NJ
Philadelphia, PA
Philadelphia, PA
Bridesburg, PA
Pigeon Point, DE
Torresdale, PA

Hudson River Basin

Tottenville, NY
Perth Amboy, NJ
Perth Amboy, NJ
Sewaren, NJ
Chrome, NJ
Graselli, NJ
Port Elizabeth, NJ
Newark, NJ
Bayonne, NJ
Rosebank, NJ
Sandy Hook, NJ
Beacon, NY
Poughkeepsie, NY
Poughkeepsie, NY
Glenmont, NY
1
6
1
1
2
1
1
2
1
12
15
9
15
11
90
8
4
10
9
8
9
9
8
1
3
2
2
2
1
2
2
5
4-3
-------
TABLE 4-2. CONCENTRATION OF 1,2-DICHLOROETHANE IN
SURFACE WATERS FROM INDUSTRIAL AREAS (Continued)
Site

Passaic River
Hackensack River
Hudson River
Hudson River
Nearest Town

Newark, NJ
Jersey City, NJ
Fort Lee, NJ
Fort Lee, NJ
Concentration (yg/1)
Mississippi River Basin, Louisiana and Texas
Houston Ship Channel
Houston Ship Channel
Houston Ship Channel
Mississippi River
Mississippi River
Mississippi River
Mississippi River
Mississippi River
Mississippi River
Mississippi River
Ohio River
Tennessee River
Kanawha River
Morgan Point, TX
Lynchburg, TX
Deer Park, TX
Venice, LA
Port Sulphur, LA
Luling, LA
Lutcher, LA
New Orleans, LA
New Orleans, LA
Plaquemine, LA

Ohio River Basin

Joppa, IL
Paducah, KY
Winfield, WV
Fields Brooks
Lake Superior
Great Lakes and Tennessee River Basin

Ashtabula, OH
Beaver Bay, WI
1
1
2
1
2
1
2
1
1
1
2
3
1
4
1
Source: Ewing and Chian (1979).
4-4
-------
Monitoring of dichloroethanes in sediment has been recorded in
STORE! for 1,1-dichloroethane only (U.S. EPA 1980a). The summary maxi-
mum and mean concentrations are shown in Table 4-3.

4.2.2 Air

Recent investigations of 1,2-dichloroethane in air which were
conducted near production and user facilities in Calvert City, Kentucky;
Lake Charles, Louisiana; and New Orleans, Louisiana indicate that ambient
concentrations are a function of the production rate, extent of emission
control, and meteorological and topographical features (PEDCo Environ-
mental, Inc. 1980). The highest concentration recorded in Calvert City
was 70 yg/m3. In New Orleans a concentration of 170 yg/m3 near the
production facility was reported, but a 10 yg/m3 concentration was
reported at other sites in the city. In Lake Charles concentrations
ranged from 200 to 500 yg/m3 at several sites.

In a study of 19 halocarbons in the atmosphere of rural Northwest
United States, 1,1- and 1,2-dichloroethane were noted as being absent
at a detection limit of 0.02 yg/m3 (Grimsrud and Rasmussen 1975).

Jacobs (1979) reported ambient air concentrations of 1,2-dichloro-
ethane (measured by the U.S. EPA) in heavily trafficked areas near gasoline
service stations in three cities. Phoenix, Arizona had a concentration
of 0.032 yg/m3 with 36,000 vehicles per day, Los Angeles, California
had 0.052 yg/m3 with 53,000 vehicles per day, and Seattle, Washington
had 0.04 yg/m3 with 32,000 vehicles per day. Singh et_ al. (1980)
reported somewhat higher levels of 1,2-dichloroethane in urban areas
of 0.2-6 yg/m3 as a range of averages for four cities; Houston, Texas;
St. Louis, Missouri; Denver, Colorado; and Riverside, California. As
expected, the highest levels were found in Houston, Texas. Average
levels of 0.24-0.26 yg/m3 1,1-dichloroethane were also reported for
these locations.

Table 4-4 displays ambient air concentrations of 1,2-dichloroethane
monitored at four locations in New Jersey. The subset of quantifiable
samples is shown along with the total samples. The mean concentrations
range from 0.48-2.64 yg/m3 for all samples and from 1.6-6.0 yg/m3 for
quantifiable samples (Bozzelli and Kebbekus 1979).

Pellizzari and coworkers (1979) have sampled four highly industrial
areas for halogenated organic compounds. The 1,2 isomer was commonly
found in these samples, and the 1,1 isomer was less frequently found.
Table 4-5 summarizes the results of this work. It can be seen that the
dichloroethane concentrations were highly variable, with 139 yg/m3
and 0.55 yg/m3 the respective maxima. These authors also sampled base-
ments of houses in the old Love Canal area. No 1,1-dichloroethane was
detected, and 1,2-dichloroethane was detected in 2 of 10 samples at
0.100 and 0.127 ug/m3.

4.2.3 Soil

No monitoring data are readily available for concentrations of
dichloroethanes in soils.

4-5
-------
TABLE 4-3. CONCENTRATIONS OF 1,1-DICHLOROETHANE
IN SEDIMENTS
Number of
River Basin Observations Maximum Mean
(yg/m5)

Lower Mississippi 1 ND ND

Western Gulf 14 ND ND

Pacific Northwest 20 55

ND = not detected

Source: U.S. EPA (1980a).
TABLE 4-4. CONCENTRATIONS OF 1,2-DICHLOROETHANE IN AMBIENT
AIR AT FOUR SITES IN THE STATE OF NEW JERSEY,
APRIL TO NOVEMBER, 1978
All Samples Quantifiable Samples
Location
Rutherford

Newark

Piscataway-Middlesex

Somerset County

*Trace amounts added in as lower limit of detection (0.04

Source: Bozzelli and Kebbekus (1979).
Number

150
110
18
30
Mean* Maximum
(yg/m^)
1.9 25.5
2.7 64.8
0.49 4.0
1.9 15.8
Number

55
49
5
13
Mean
(yg/mj)
5.3
6.1
1.6
4.5
4-6
-------
TABLE 4-5. DICHLOROETHANE LEVELS IN AMBIENT
AIR OF INDUSTRIAL AREAS
1,1-Dichloroethane Concentration 1,2-Dichloroethane Concentration
City No. Detected/No. Sampled Range (pg/m^) No. Detected/No. Sampled Range

Niagara Falls, NY

Rahway/Woodbridge,
Boundbrook, and
Passaic, NJ

Baton Rouge, LA

Houston, TX

aNot detected.
l)Trace .
Source: Pellizzari et al. (1979).
0/9
10/66
12/43
1/30
( NDa
T-0. 34 2
T-0 . 500
0.555
2/8
75/93
36/43
22/30
Tb
T-0. 139
0.009-0.010
T-0. 066
-------
4.2.4 Biota

Basically no data are readily available relating to residues of
dichloroethanes in the marine environment or in other biota, although
absorption by fish and oysters has been noted (Fishbein 1980).

Monitoring of fish tissue for dichloroethanes, as reported by the
STORE! system from 47 stations, includes entries for four basins
(U.S. EPA 1980a). The documentation is shown in Table 4—6.

4.3 ENVIRONMENTAL PATHWAYS AND FATE

4.3.1 Physicochemical Properties

The 1,2 isomer (C2H4C12) is a saturated aliphatic hydrocarbon of
the following structure:

H H
I 1
C1-C-C-C1
1 I
H H

The 1,1 isomer has the following structure:

Cl H
I I
H-C -C-H
I I
Cl H

Physicochemical properties of 1,1- and 1,2-dichloroethane are listed in
Tables 4-7 and 4-8.

4.3.2 Major Environmental Pathways

Figure 4-1 provides a schematic overview of the major environmental
pathways (transport and degradation) of 1,1- and 1,2-dichloroethane.
The major emission sources (see Chapter 3.0 for details) may be grouped
as follows:

• Point-source atmospheric emissions (e.g., manufacturing
sites, heavy-end incineration, and gas stations)

• Area-source atmospheric emissions (e.g., chemical dump
sites, automobiles, wastewater treatment impoundments
[lagoons, aeration basins, etc.]» fumigants, paint coat-
ings, and adhesives)

• Area-source discharges to land (sites used for disposal
of heavy ends and EDC-tar sludges from manufacturing
operations)

4-8
-------
TABLE 4-6. CONCENTRATIONS OF DICHLOROETHANES IN FISH TISSUE
Concentration
Basins

Lower Mississippi

Western Gulf

Pacific Northwest

Alaska

Total

ND = not detected

Source: U.S. EPA (1980a),
Number of
Observations
2
3
37
6
48
(mg/kg-wet weight)
Mean of
Maximum Minimum all Values
ND
ND
20
0.05
20
ND
ND
0.05
0.05
ND
ND
ND
0.7
0.05
0.5
Standard
Deviation
-
-
3.3
-
2.9
-------
TABLE 4-7. PHYSICOCHEMICAL PROPERTIES OF 1,2-DICHLOROETHANE
Property

Molecular weight 98.96

Density at 20°C, g/1 1.2351

Melting point, °C -35.36

Soiling point, °C 82.4

Index of refraction at 20°C 1.4448

Vapor pressure, torr
At -44.5°C 1
At -13.6°C 10
At 10.0°C 40
At 29.4°C 100
At 64.0°C 400
At 82.4°C 760

Solubility in water, mg/1
At 20°C 8690
At 30°C 9200

Octanol/H20 partition coefficient 1.48

Biochemical oxygen demand (5 days,
10 days), % 0

Theoretical oxygen demand, mg/mg 0.97

Measured chemical oxygen demand, mg/mg 1.025

Vapor density (air = 1) 3.42

Flash point, closed cup, °C 13

Ignition temperature, °C 413

Explosive limit, % by volume in air
Lowe r 6.2
Upper 15.9

Latent heat of fusion, cal/g 21.12

Critical temperature, °C 288
Value
4-10
-------
TABLE 4-7. PHYSICOCHEMICAL PROPERTIES OF 1,2-DICHLOROETHANE (Continued)

Property Value

Critical pressure, atm 53

Critical density, g/cm^ 0.44

Adsorption coefficient (Koc) 17

Conversion factors at 25°C and 760 torr 1 mg/1 = 1 g/m-^ = 247 ppm
1 ppm =4.05 mg/m^ =4.05 ug/1

CAS Reg. #107-06-2

NIOSH Reg. #K005250

Source: Drury and Hammons (1979).
4-11
-------
TABLE 4-8. PHYSICOCHEMICAL PROPERTIES OF 1,1-DICHLOROETHANE

Property Value

Molecular weight 98.96

Density at 20°C, g/1 1.1747

Melting point, °C -96.7

Boiling point, °C 57.3

Vapor pressure, kPA
10°C 15.37
20°C 24.28
30°C 36.96

Solubility at 20°C, g
Dichloroethane in 100 g H20 0.55
H20 in 100 g dichloroethane 0.097

Latent heat of vaporization at 20°C, J/g 280.3

Critical temperature, °C 261.5

Critical pressure, MPa 5.06

Flash point, closed cup, °C -12.0

Source: Archer (1979).
4-12
-------
I
H-
U)
Transport from
Distant Sources
(background concentration
< 0.02 ug/m3)
Area-Source
Atmospheric
Emissions
(from dumps,
sewers, etc.)
Photochemical Degradation
(t,, > 9 days with constant
sunlight)
Volatilization
1/2 hr for well-mixed
surface water; EXAMS — 35 hr for
rivers; 9 days for lakes)
Point-
Source
Atmospheri
Emissions
(~93% of total)
Note: Surface water discharges to large water body not shown for clarity, but should be considered an important pathway.

Source: Arthur D. Little, Inc.
FIGURE 4-1 MAJOR PATHWAYS OF DICHLOROET.HANES IN THE ENVIRONMENT
-------
• Point-source discharges to sewers and surface waters
(waste solvent from scrubbing gases and water solutions
discharged from production facilities).

With one exception, the nature of the waste stream from each type
of source is not likely to be very important with regard to the subse-
quent transport and fate of the compound. The emissions that go directly
to air or surface waters usually do not contain any other compounds that
will materially affect transport and fate. The one exception is
waste sludges from the manufacturer. These wastes will differ signifi-
cantly in their dichloroethane content, in the nature of the other wastes
present, and in the actual manner of disposal. All of these factors may
alter the time it takes for the dichloroethane to escape (via volatiliza-
tion or leaching) from the sludge into other environmental compartments
(air, soil, groundwater), and may alter the relative amounts that escape
to other compartments, but will not influence the major degradation
pathways.

When finally released to the environment, dichloroethane follows a
few important transport and degradation pathways (see Figure 4-1).
Since the atmospheric lifetime is on the order of nine days, long dis-
tance aerial transport (hundreds to thousands of kilometers) is possible;
photochemical degradation during sunlight periods is the only significant
atmospheric degradation pathway. Minor amounts of dichloroethane may be
removed from the atmosphere by wet and dry fallout. Dichloroethane in
well-mixed surface waters will volatilize fairly rapidly (half-life
^0.5 hr) into the atmosphere, although EXAMS predicts a volatilization
half-life of 35 hours in river water (U.S. EPA 1980b) (see Section 4.3.2.2).
Photochemical degradation provides a minor loss pathway and hydrolysis and
biodegradation are negligible. The compound can be transported in soils
to groundwaters and to sediments and in these compartments it will have a
relatively long residence time, perhaps on the order of several years or
decades, unless the turnover or mixing time in the compartment is shorter.
Chemical, photochemical, and biological degradation play no part in these
compartments. The following sections provide a more detailed discussion
of the transport and fate in each major environmental compartment.
4.3.2.1 Behavior in Air

Once dichloroethane is in the atmosphere, aerial transport plays a
major role in its distribution and leads to its distribution throughout
the environment, at least on a regional basis. The compound is, however,
subject to relatively rapid chemical or photochemical degradation so
that it does not continually accumulate in the atmosphere and does not,
itself, reach the upper stratosphere^- (ozone layer) in sufficient
concentrations to affect the ozone concentration (Drury and Hammons
1979, Fishbein 1980).
This may not hold true for some of the degradation products, mono-
chloroacetyl chloride, formyl chloride, and chloroacetic acid.

4-14
-------
Tropospheric attack on dichloroethane may be by oxygen atoms,
hydroxyl free radicals, or ozone molecules; principal reaction products
from tropospheric degradation (Table 4-9) would include monochloroacetyl
chloride, chloroacetic acid, formyl chloride, phosgene, chlorine, hydro-
gen chloride, and other chemical species. Rates of reaction, or associ-
ated half-lives, for a number of these reactions (under laboratory
conditions) are shown in Table 4-9. These data indicate that a wide
range of tropospheric half-lives, from minutes to years, have been
estimated.

It is possible that a fraction of dichloroethane in the atmosphere
may be associated with water droplets and dust particles, especially
organic particles. The compound's solubility and high vapor pressure
suggest this route is possible. From the atmosphere, dichloroethanes
could enter the hydrosphere by direct transfer (dry impact), washout by
rain, or dry fallout of particles with adsorbed dichloroethane. Processes
are discussed in more detail in Section 4.3.3.1.

4.3.2.2 Behavior in Water

Chemical Processes

Dichloroethane undergoes hydrolysis very slowly in the presence of
water. Most 1,2-dihalogen alkanes are resistant to hydrolysis, and the
half-life of 1,2-dichloroethane in water at pH 7 has been estimated to
be 50,000 years (Drury and Hammons 1979). The 1,1-isomer may hydrolyze
faster (1,1,1-trichloroethane has a half-life of 6 months), but this
mechanism is not expected to be the dominant fate pathway.

Oxidation by alkoxy radicals in water may contribute somewhat to
the degradation of 1,2-dichloroethane. However, because of the small
concentration of these radicals in water, the rate will be slow. Drury
and Hammons (1979) estimated that the half-life of the 1,2 isomer from
oxidation by R0£ radicals in water would exceed six months. Versar, Inc.
(1979) reports that oxidation of other low molecular-weight chlorinated
hydrocarbons proceeds at a rate such that the half-life is 6-18 months.
In any event, oxidation will not be the dominating degradation route for
1,1- and 1,2-dichloroethane.

The main process for the removal of dichloroethanes from shallow
surface waters is volatilization (Dilling ^t aj. 1975). Laboratory
experiments have measured the rates of evaporation from a stirred beaker
(250-ml beaker, 1 mg/1 of the compound in 200 ml water, solution depth
6.5 cm, still air, 25°C, stirred at 200 rpm) yielding a half-life for
volatilization of 29 minutes for the 1,2-isomer and 22 minutes for the
1,1-isomer (Dilling ^_t al_. 1975). Other low molecular-weight chlorinated
hydrocarbons, upon exposure to intermittent stirring every 5 minutes,
vaporized at a rate such that the half-life exceeded 90 minutes. A
vaporization experiment of compounds analogous to 1,2-dichloroethane in
a simulated sea water noted a decrease in the rate of volatilization by
about 10% (Dilling _et _al. 1975).
4-15
-------
TABLE 4-9. TROPOSPHERIC HALF-LIFE OF DICHLOROETHANES
Half-Life

3-4 months

9 days

0.75-1.3 years

1.7 minutes3

5.4 minutes'3

1.5 months to
get [l/e]a
Route of Degradation

Light

HO radical (estimated)

HO radical

and uv light

and uv light
HO radical
Reference

Drury and Hammons (1979)

Fishbein (1980)

Spence and Hanst (1978)

Versar, Inc. (1979)
al,1-dichloroethane
M,2-dichloroethane
4-16
-------
The evaporation rates far analogues of dichloroethanes were
measured under conditions more nearly like those found in the environ-
ment. Addition of various substances (clay, limestone, sand, salt, peat
moss, and kerosene) to the water had relatively little effect on the
evaporation rate. However, an increase in the wind speed across the top
of the beaker from 0 ± 0.2 mph to 2.2 ± 0.1 mph caused a significant
increase in the evaporation rate; after 20 minutes, the solute evapora-
tion was about 17% greater with the higher wind (Billing et al. 1975).

Biological Processes

Microbial biodegradation of 1,2-dichloroethane has been observed,
although usually at relatively low rates. Table 4-10 presents the results
of several laboratory tests measuring the biological degradation of the
compound.. All of the quantitative microbial tests are of a very simple
type (e.g., BODs, static flask), and are not very conducive to degrada-
tion compared to other tests using shake flasks or chemostats. There-
fore, increased rates of degradation are possible under better conditions.
However, these simple tests show either no degradation or slow rates (18%
in 10 days) in non-acclimated populations and higher rates (62% in 1 week)
in acclimated populations.

The only biodegradation test available on 1,1-dichloroethane, a
static flask study (Tabak_et a^. 1980), reported a loss rate about 10%
more rapid than for 1,2-dichloroethane. Part of the loss, however, was
attributed to volatilization; 19% volatilized in 10 days (compared to 4%
loss for 1,2-dichloroethane).

Two factors may contribute to a low environmental biodegradability
of dichloroethanes: their high volatility and the fact that .they are
not naturally occurring. Their short residence time in water makes the
likelihood of adequate time for microbial adaptation unlikely. In loca-
tions of continual discharge, acclimation may take place, although,
according to the limited data available on biodegradation, volatilization
may account for most of the dichloroethane loss.

It has been suggested that microorganisms may take part in the
second of a two-step biodegradation process involving 1,2-dichloroethane
(McConnell _e_t _al. 1975). The first step would involve higher organisms
metabolizing the compound to chlorinated acetic acids (e.g., monochloro-
acetic acid and 2-chloroethanol) which in turn are susceptible to micro-
bial utilization. Whether or not fish and other higher aquatic species
are capable of this first step has not been investigated, so the environ-
mental significance of this relationship remains to be substantiated.

Fish and shellfish have a low propensity for bioaccumulation of
1,2-dichloroethane. The only laboratory study investigating this subject
in fish and oysters found rapid uptake of -^C-labelled 1,2-dichloroethane
and depuration on removal to clean water (Pearson and McConnell 1975).
The U.S. EPA (1978) reported a steady-state bioconcentration factor
of 2 using bluegills.
4-17
-------
TABLE 4-10. BIODEGRADABILITY OF DICHLOROETHANES
Type of Test
Static culture flask
with acclimated
activated sludge
population

BOD2Q with non-
acclimated freshwater
population from
wastewater

BOD2Q with non-
acclimated sea water
population in salt
water

BOD 20
Bioaccumulation study
(with 14C) with fish
and oysters, then
transferred to clean
water
Result

1,2-Dichloroethane

Slow to moderate degra
dation following
acclimation, 62% de-
graded in 7 days

0% degraded in 5 days,
18% degraded in 10
days
7% degraded in 15 days,
15% degraded in 20 days
0% degraded
Some in vivo metabolism
of the compound by fish
and oysters indicated
by an unaccountable loss
from the tissue
Reference
Tabak e_t al. (1980),
Price et al. (1974)
Price et al. (1974)
Pearson and McConnell
(1975)

Pearson and McConnell
(1975)
Static culture flask
with acclimated
activated sludge
population
1,1-Dichloroethane

76% lost in 7 days (19%
lost to volatilization
in 10 days)
Tabak et al. (1980)
4-18
-------
In a monitoring survey of aliphatic hydrocarbon concentrations in
marine biota (at several tropic levels) in a polluted industrial region
of England, Pearson and McConnell (1975) found no dichloroethanes.

Observations of the low accumulation levels of dichloroethanes are
supported by the estimation method for bioaccumulation used by Neely and
coworkers (1974). Both dichloroethanes have low log octanol/water parti-
tion coefficients (^ 1.48), indicating a low affinity for biotic tissue
(Versar, Inc. 1980).

EXAMS Model Results

The EXAMS model, AETOX 1 (U.S. EPA 1980b), was implemented to examine
the potential fate of 1,1- and 1,2-dichloroethane in aquatic environments.
Three prototype systems were tested for each compound: eutrophic lake,
river, and turbid river.

The data used as input is presented in Table 4-11. More processes
influence 1,1,-dichloroethane levels than the 1,2 isomer. Additionally,
1,1-dichloroethene is less soluble, has a higher Henry's law coefficient,
and has a faster rate of volatilization.

A loading rate of 0.1 kg/hr was used for the model. This was esti-
mated for 1,2-dichloroethane, but for lack of other data was also applied
to 1,1-dichloroethane. The effluent is intended to represent a dichloro-
ethane production facility.

Some of the results of the model are presented in Table 4-12.
There was relatively little difference between the compounds in terms
of concentrations in the water column (on the order of 10~2 mg/1 in the
lake and 10"^ mg/1 in the rivers) and the ratio of percent volatilized
to percent transported out from the system. In the lake, more than 93%
of the load was lost to volatilization. In both rivers, the dominant
loss mechanism (> 98%) was physical transport out of the system (a 1-km
long river stretch).

In terms of accumulation in both biota (not included on table) and
sediment, 1,1-dichloroethane had a slightly higher tendency for uptake
than the 1,2 isomer, although the difference was small. Concentrations
in plankton ranged from 0.06 ug/g to 0.65 ug/g in the lake and were
approximately one order of magnitude smaller in the river systems.
Sediment concentrations were on the order of 10"3-10""5 mg/kg in all
systems.

The estimated self-purification time, when the discharge was
assumed to stop and following the establishment of equilibrium condi-
tions, was 56 and 64 hours for 1,1- and 1,2-dichloroethane, respectively,
in the eutrophic lake. In the river, the times were 9 and 6 hours,
respectively; in the turbid river, the times were slightly less, 6 and
5 hours, respectively.
4-19
-------
TABLE 4-11. CHEMICAL PROPERTIES AND RATE CONSTANTS
USED AS INPUT TO EXAMS MODEL
Property

Molecular weight, g/mole

Solubility, mg/1

Liquid-phase transport
resistance, unitless ratio

Henry's law coefficient, atnrm^/mole

Vapor pressure, torr

Partition coefficients,

Ug/g
1,1-Dichloroethane

98.96

5500
Biomass /water,
/
Sediment/water,
Octanol/water,

mg/1

Chemical oxidation, mole/1/hr

Hydrolysis rate, mole/1/hr
1,2-Dichloroethane

98.98

8690
-4
0.58
4.26xlO~3
180
10.4
34.7
63.0
1
1.15xlO~7
0.58
9.14x10
61
5
16.6
30
1
0
Source: SRI (1980).
4-20
-------
TABLE 4-12. RESULTS OF EXAMS MODKL RUNS
Prototype Maximum Concentration
System^ Water (ing/l) Sediment (ing/kg)
__ ____ _ ____ Percent Transformed, _______________ _.
Chemical or Physical Sal f-purlf lent Ion
Biological Degradation yol_a U_li zatjlon ,I_ra!l*>l>0-l"t 'I'tmu (lirK __
1/2 (hrj
Kutrophic lake 1.3 x 10
6.5 x JO
-4
J . l-l)lchloroethane

O.I
96
56
206
River*
9.9 x 10
,-5
8.8 x 10
,-5
0
98
Turbid liver 9.9 x 10 5
7.1 x 10
,-5
0
98
Knlro|>liLc lake 1.3 x 10
Klvor
Turbid rlvi-r 9.9 x 10
9.9 x 10~5

,-5
6.5 x 10
4.9 x 10"
-2
4.9 x 10
,-4
.11 IrPJj^i' "roetliane

2 '

0
4

98
226
27"
All dara simulated by the EXAMS model (see text).

Loading " O.I kg/lir for botli compounds.

Kstlmate for removal of i>75Z of tlie toxicant accumulated In sytjtem. Estimated from the
results of the half-lives for tlie toxicant In bottom sediment and water column!;, with
overall cleansing time weighted according to the toxicant's Initial distribution.

All river systems are 3/kui In length so that physical transport out of the modelled
system IK dominant loss process.
In a Kill-kin length of river.
Source: U.S. KPA (I'JDOti).
-------
The ecosystem half-lives for loss of dichloroethane from volatiliza-
tion are presented in Table 4-13. According to EXAMS, the half-lives
for volatilization for both compounds are six times greater in the
eutrophic lake than in the river systems. Comparison with total-system
half-lives (not specific to any one process) listed in Table 4-12 shows
how similar the two numbers are, thus illustrating the importance of
volatilization in determining dichloroethane persistence.

Since most of the dichloroethane discharged to river environments
was transported out before transformation was significant and due to the
likelihood of actual release to rivers, the EXAMS model was implemented
to examine losses in a longer river reach. The purpose was to determine
at what distance downstream from a point source, a significant amount of
the chemical would have volatilized.

Figure 4-2 shows a plot of percent loss of 1,1-dichloroethane due
to volatilization over some distance downstream from the initial point of
release to a river system. At approximately 200 km downstream, most of the
release (under equilibrium conditions) was lost through volatilization to
the atmosphere. Ninety percent was lost by approximately 900 km downstream.
Therefore, even though volatilization is a significant transfer process
from water to air, the dichloroethane discharges may travel a signifi-
cant distance downstream (in this case in a river with a flow rate
2.4 x 10^ m^/day) before they are reduced to negligible levels. Since
there was relatively little difference in the rate of volatilization
between the two isomers (see Table 4-12), it is assumed that these
results are fairly representative of 1,2-dichloroethane as well as
1,1-dichloroethane.

4.3.2.3 Behavior in Soils and Sediments

The movement of dichloroethanes through soils or sediments has not
been extensively studied, although movement would clearly be possible
as a result of leaching (transport in solution) and/or volatilization
(transport in the vapor phase in unsaturated soils). Billing and co-
workers (1975) showed that little adsorption onto clay, limestone, sand,
and peat occurred for low molecular-weight chlorinated hydrocarbons.
Sansone and coworkers (1979) passed 1,2-dichloroethane vapor through a
column of activated carbon and found that about 0.6 g of the com-
pound was adsorbed per gram of carbon. It may be presumed that, when
water is present, a partitioning exists between the two phases, which
may or may not be at equilibrium (octanol/water partition coefficient =
1.48). Chemical degradation would occur very slowly, and the compound
would be expected to persist in deep soils and groundwaters.

There is little information available on the biodegradation of
dichloroethane in soil. The results of simple non-soil biodegradation
tests (see Section 4.3.2.2) indicate a low susceptibility to microbial
attack and a prerequisite period of acclimation by populations before
utilization. Due to the apparent short residence time of dichloroethane
in soil surfaces because of high volatility, a propensity for leaching, and
4-22
-------
TABLE 4-13. VOLATILIZATION t 1/2 FOR DICHLOROETHANES
IN EXAMS SYSTEM
Rivers (300-km reach)

Eutrophic Lake
1,1-Dichloroethane 1,2-Dichloroethane

35 hours

9 days 10 days
Source: U.S. EPA (1980b)
TABLE 4-14. 1,2-DICHLOROETHANE RESIDUES IN PLANTS
Crop

Beet roots

Beet leaves

Corn

Grasses
Accumulated Level of
1,2-Dichloroethane (mg/kg-wet weight)

0.83-10.41

0.83-4.17

11.66-43.75

1.25-64.54
Source: Khramova and Zhirnov (1973).
4-23
-------
I
NJ
100
80
-o
0)
N
tt 60
o
40
20
I
_J
1000
10 100
km downstream (log)
Source: Arthur D. Little, Inc., based on U.S. EPA (1980 b).
FIGURE 4-2 PERCENT VOLATILIZATION OF 1,1 DICHLOROETHANE AS A FUNCTION
OF DISTANCE DOWNSTREAM FROM SOURCE
1
10,000
-------
low adsorption, the compound will most likely not persist long enough
in one place to support acclimation. Soil regions where persistence
may occur do not support significant biodegradation due to anaerobosis
and small population sizes

Wilson and coworkers (1980) studied the transport of 1,2-dichloro-
ethane in sandy soil with low organic-matter content. No degradation
was observed, and movement through the soil column was rapid, with
37-61% found in the column effluent. About 72-74% of the amount added
was reported to have volatilized, although this was thought to be over-
estimated since more than 100% of the compound applied was recovered.
The authors concluded that 1,2-dichloroethane moved readily through
sandy soil.

In addition to volatilization and leaching, dichloroethanes may be
bioaccumulated from soil. Only one study was available concerning
accumulated levels of 1,2-dichloroethane in plants. As shown in
Table 4-14, Khramova and Zhirnov (1973) found high residues (up to
65 mg/kg) in crop plants irrigated with industrial effluent water con-
taining the compound (in addition to other chlorinated compounds).
Following cessation of irrigation, the beet roots took 20 days to elimi-
nate all of the compound, while the beet leaves and other plants took
10-12 days. .The slow elimination rate in roots suggested a potential
human exposure route through similar crops exposed to contaminated water.

4.3.3 Fate of Dichloroethanes Discharged from Major Sources

4.3.3.1 Air Emissions from Major Petrochemical Plants

Emissions estimates for dichloroethanes (primarily 1,2-dichloro-
ethane) indicate (see Chapter 3.0):

• About 96% ("o 28,000 kkg/yr) of total U.S. emissions go
directly to the air.

• About 80% of these direct air emissions are from large
petrochemical plants in the Gulf Coast area of Texas
and Louisiana. An additional 8% are from large petro-
chemical plants in Kentucky, California, and Puerto Rico.

• Altogether there are about 20 plant sites involved in the
production of 1,2-dichloroethane (i.e., petrochemical plants),
16 of which are in Texas and Louisiana.

These facts underscore the need to examine the fate of dichloroethanes
discharged to the air in the Gulf Coast area. The fate of the compounds
is linked to the meteorological conditions in these areas as well as to
the compound's properties.

Some basic data on the meteorological conditions in the areas where
these petrochemical plants are located are given in Table 4-15. These
data show that the Gulf Coast climate is:

4-25
-------
TABLE 4-15. METEOROLOGICAL CONDITIONS NKAK MA.10K PETROCHEMICAL HANTS PKOtlUCINU UICIILOUOETIIANES"
-P-
I
Local-1 oil
veston„ TX
lltlUUton, TX
Luke Charlus. LA
11,11 on Rouge, LA
New Orleans, LA
I'vaiiiivllle, TNd
Lung Uuiich, CA
Santa Isabel. PRe
Avg.
Air
69.8
68.9
68.3
67.4
68.3
56.0
63.3
76.7
Yearly
Precipitation
- 42.2
48.2
55.5
54.0
56.8
41.9
10.2
32.6
Relative
Humidity
72-83
61-91
63-90
59-88
63-88
59-81
53-78
62-82
Avg.
Wind
Speed
11.0
/.4
8.8
8.0
8.4
8.3
6.4
6.4
Prevail Ing
Wind
Direct Ion'1
NA°
SSE
s
SE
NA
SSU
WNW
SE
Days with
Precipitation
of 0.01 In.
or More
96
107
95
106
113
115
29
99
Number of
Cloudy or
Partly Cloudy
NA
269
270
266
254
264
213
260
of
SuushiiK
64
W
NA
NA
59
62
NA
NA
Data art! yearly averages covering tlie period from 1941 to 1970.
Direction from which the wind blows.
NA = Not: Available
Surrogate for petrochemical sties In Kentucky.
Hase period is 1921 to 1950.
Source: Gale Research Company (1978).
-------
• Warm (average air temperatures 68°F [20°C])

• Humid (relative humidity 60-90%)

• Frequently cloudy (cloudy or partly cloudy on about
75% of the days; about 60% of the possible sunshine is
received)

• Rainy (annual precipitation is in the range of 42-57 in./yr
[ a, 110-140 cm/yr]; measurable rain falls on about 100
days each year [i.e., it rains, on average, once every
3-4 days])

• Not extremely windy (average wind speeds are 7-11 mi/hr
[12-18 km/hr], and the winds are usually from the south)

The above data indicate three basic impacts on the fate of dichloro-
ethanes released to the air by the Gulf Coast petrochemical plants.
First, the chemicals will (on most days) be transported to the north
over land and populated areas. Emissions from one particular day could
reach the populated areas of the Midwest and Northeast within 4-5 days,
although atmospheric mixing, washout, and photodegradation will have
lowered the concentrations significantly.

Second, atmospheric losses due to washout by rain could be a trans-
port* pathway. The frequent and heavy rains in the area, in combination
with the appreciable solubility of the compounds (^9000 mg/1 for 1,2-
dichloroethane and 'v-SOOO mg/1 for 1,1-dichloroethane) , will favor
removal. However, a significant fraction of the compound may reenter
the atmosphere within a few hours after a rainfall. In areas where
the rain is quickly absorbed by soils, transport of dichloroethanes
to groundwaters will be possible.

Third, the primary degradation pathway, reaction with photochemi-
cally produced hydroxyl radicals, will be of little importance for
newly released dichloroethanes. In part, this is due to the high per-
centage of cloudy (or partly cloudy) days which will tend to reduce the
concentration of hydroxyl radicals beneath the cloud cover. (The
concentration of these radicals falls to essentially zero in darkness.)
However, even with full sunlit days, one would not expect significant
losses of newly released dichloroethanes during their initial passage
over the North American continent. If the atmospheric half-live, due
to reaction with hydroxyl radicals, was as short as 9 days, less than
10% of the material released in the Gulf Coast area would have been
degraded within the time required for these emissions to reach the
Midwest and Northeast portions of the United States.

Suta (1979) utilized dispersion modeling to estimate concentrations
of 1,2-dichloroethane in air in the vicinity of producers of the compound
as well as producers that use 1,2-dichloroethane as a feedstock.
4-27
-------
Table 4-16 summarizes the one-hour average downwind atmospheric concen-
trations estimated using rough-cut Gaussian-plume techniques. As shown
in Table 4-17, the average annual modeling results obtained agreed
fairly well with the monitoring data collected for three sites by
PEDCo Environmental, Inc. (1980).

4.3.3.2 Air Emissions from 1,2-Dichloroethane in Automobile Gasoline

Suta (1979) has considered the fate of 1,2-dichloroethane in gaso-
line by analogy to dispersion modeling done for benzene, and several
different scenarios:

• concentrations at service stations,

• concentrations in the vicinity of service stations, and

• general urban concentrations resulting from this source.

This same author utilized monitoring data for benzene in the breathing
zone for persons filling their tanks and evaporation rates for 1,2-
dichloroethane and benzene to estimate the concentration of 1,2-dichloro-
ethane. Based on limited data, a. range of 1-16 yg/m3 was calculated.

Suta (1979) also utilized dispersion modeling for benzene in the
vicinity of gas stations to estimate 1,2-dichloroethane concentrations.
Table 4-18 summarizes the results obtained. There are no monitoring
data with which to compare these results.

Dispersion modeling for benzene was also used to estimate concen-
trations in urban areas due to evaporation of 1,2-dichloroethane from
automobiles. The results showed annual average 1,2-dichloroethane
concentrations of 0.04-0.12 yg/m^ from this source. Monitoring data
in heavily trafficked areas in three cities, as described in Section
4.2.2, showed levels of 0.03-0.05 yg/m3, not inconsistent with the
modeling results (Suta 1979).

4.3.3.3 Water Discharges from Petrochemical Plants

Although the aquatic releases of dichloroethanes are thought to be low
(see Chapter 3.0) , they occur in a relatively concentrated area. These
discharges presumably go from the facilities' wastewater treatment
plants to nearly surface waters (rivers, estuaries, bays), all of which
discharge into the Gulf of Mexico.

It is expected that the majority of the dichloroethanes in these
discharges would volatilize (and thus add to the regional atmospheric
burden) in a relatively short time (hours to days). These compounds
have a relatively low tendency to adsorb on suspended sediments
and thus transport to, and accumulation in, the bottom sediments
4-28
-------
TABLE 4-16. ESTIMATED ONE-HOUR AVERAGE DOWNWIND ATMOSPHERIC
CONCENTRATIONS OF l,2-DICHLOROETHANEa
Emitter with Emitter with
Downwind Point Source , 0.0625-km2 0.01-km2
Distance (km) Emitter (ug/m ) Area (ug/m^)C Area
°-30 3400 4000 10,000
0-45 4800 3400 7700
0-60 4400 2900 5700
0-75 3700 2500 4300
1-00 2700 2000 2900
1-25 2100 1600 2200
1-60 1500 1200 1600
2.50 800 720 810
4.00 410 380 410
6.00 230 220 220
9.00 120 120 120
14.00 66 64 66
20.00 39 39 39
Assumes an emission rate of 100 g/sec for each source, neutral ("D")
stability atmospheric conditions with a wind speed of 4 ra/sec.

Single stack 25 m high.

Effective emission height of 10 m.

Note: Modeling data provided by P. Youngblood (U.S. EPA 1978).

Source: Suta (1979).
4-29
-------
TABLE 4-17. COMPARISON OF 1,2-DICHLOROETHANE MONITORING
AND MODELING ATMOSPHERIC CONCENTRATIONS
Monitoring Average Concentrations3

Distance
(km)
0.7-1.0
1.1-1.5
1.6-2.0
2.1-3.0
3.1-4.0
4.1-5.0
5.1-6.0
14.0

Calvert
Cityb
8.1
c
4.0
8.5
3.6
c
c
c
(Hj
Lake
Charlesb
149
24.3
28.3
4.4
c
c
c
c
?/m-0
New
Orleans
25.5
5.7
6.5
2.8
1.2
c
3.6
2.4

3-Location
Average
60.7
15.0
12.5
5.3
2.4
c
3.6
2.4
3-Location
Modeling
Averagea
55.0
36.9
26.3
17.4
8.5
6.5
4.9
1.6
fl
Data are the average 24-hr concentrations over 10-13 days for
monitoring and estimated annual averages for modeling.
The 1,2-dichloroethane emissions have been estimated as 72.9 g/sec
for The B.F. Goodrich Co., Calvert City, KY; 70.2 g/sec for CONOCO,
Inc., Lake Charles, LA; and 119.5 g/sec for Shell Oil Company,
New Orleans, LA.
Q
Indicates that no monitoring data were collected.
Source: Suta (1979).
4-30
-------
TABLE 4-18.
ROUGH DISPERSION MODELING RESULTS FOR
1,2-DICHLOROETHANE EMISSIONS FOR GASOLINE
SERVICE STATIONS3
Distance (m) 8-hr Worst Case (ug/rn-^)^ Annual Average (ug/m-^)c
50
100
150
200
300
49
24
12
8
4
4.0
2.0
1.2
0.8
4.0
aAssumes a 1,2-dichloroethane emission of 0.01 g/sec during operation.
^Assumes continuous operation from 8 AM to 4 PM 6 days per week.
cAssumes continuous operation 24 hours per day, 7 days per week.

Note: Modified from Youngblood (1977) by adjusting the evaporation
rate of benzene for 1,2-dichloroethane.
Source: Suta (1979).
4-31
-------
will be minimal. Little or no chemical, photochemical, or biological
degradation can be expected during the brief residence in the surface
waters.

4.3.3.4 Land Discharges from Petrochemical Plants

Approximately 900 kkg/yr of dichloroethanes are discharged to land
and about 50% of this derives from the petrochemical plants in the Gulf
Coast area. Three processes can be expected to play an important role
in the fate of this material: volatilization, transport to groundwaters,
and biodegradation (especially where the wastes are landfarmed). The
relative importance of these pathways cannot be assessed without site-
specific information, monitoring data, and/or chemical modeling.

Volatilization will certainly be important for all wastes placed on
the surface of the land and the volatilized fraction will then add to
the regional atmospheric burden. Volatilization from soils is enhanced
by increasing soil moisture, increasing chemical vapor pressure (^100
torr for 1,2-dichloroethane at 29.4°CX and low adsorption tendencies.
All of these factors favor volatilization for the dichloroethanes.

Transport to groundwaters will be facilitated by high soil porosi-
ties (common in the Gulf Coast area), the proximity to the groundwater
table (most of the plant sites are only 2-10 meters above mean sea
level), the small adsorption coefficients associated with these com-
pounds, and the frequent (and heavy) rainfalls.

Biodegradation may be important in top soils with significant
microbe populations, and in landfarming areas (i.e., sites where petro-
chemical wastes are spread on the land for purposes of biodegradation).
In the latter case, acclimated microbes are likely to be present. Tests
conducted by Tabak and coworkers (1980) (discussed in Section 4.3.2.2
above) indicate that dichloroethanes may undergo biodegradation (by
sewage organisms) after a period of adaption.

4.3.3.5 Fate of 1,2-Dichloroethane Discharged to Sanitary Sewers

The wastewaters generated by the manufacture of 1,2-dichloroethane
are treated in three ways (see Chapter 3.0). Twelve of 16 plants
discharge to surface waters after primary or secondary treatment.
Primary treatment consists of neutralization and chemical treatment,
and secondary treatment involves activated sludge ponds and aerated
lagoons. Eight of the plants steam-strip the wastewater prior to treat-
ment. Two of the plants discharge directly to POTWs. Other POTWs in
the United States may receive small amounts of 1,2-dichloroethane from
miscellaneous sources.

However, a large portion of the 1,2-dichloroethane may never
reach the POTW. Thomas (1980) reported that the overall mass trans-
fer coefficient (KL) for the 1,2 isomer was 17.1 cm/hr, very close
to the value reported for chloroform, 18.2 cm/hr. In the sewer system
4-32
-------
and in treatment one can expect 75-95% loss of 1,2-dichloroethane due
to volatilization.

Both 1,1- and 1,2-dichloroethane may be biodegraded in activated
sludges after a period of adaption by the microbes. Tabak and coworkers
(1980) found that the 1,1 and 1,2 isomers were biodegraded following
acclimation by sewage organisms in a static culture flask biodegradation
study. The results are discussed in greater detail in Section 4.3.2.2
under Biological Processes. No information was available on the biologi-
cal degradation of either compound in POTWs.

The tendency for 1,2-dichloroethane to adsorb to sewage sludges is
low. The adsorption coefficients (Koc) for 1,1- and 1,2-dichloroethane
are 35 and 17, respectively (SRI 1980). A Koc value of.50 determined
for a carbamate pesticide resulted in less than 2% being removed in the
sludge for a hypothetical treatment plant. One may assume even less of
the dichloroethanes will be associated with the sludge.

Burns and Roe (1979), in their investigation of 20 POTWs, found
undetectable levels of both 1,1- and 1,2-dichloroethane in the final
effluents. Detection limits ranged from 1-5 ug/1. Levins and coworkers
(1979) found similar results in their investigations of 4 POTWs.

4.4 SUMMARY

Concentrations of 1,2-dichloroethane in surface waters range up to
230 yg/1, although almost all are below the detection limit of 10 yg/1.
The 1,1 isomer was reported at levels up to 1900 ug/1, again with most
levels less than 10 yg/1.

The background level of 1,2-dichloroethane in air appears to be
less than 0.02 yg/m^. Levels in heavily industrialized areas appear to
be in the range of 1-5 yg/m . Maximum concentrations of 1,2-dichloro-
ethane in the vicinity of production facilities range from 70-500 yg/m .

Dichloroethanes have an atmospheric lifetime on the order of 9 days,
allowing long-distance aerial transport. Photochemical degradation
during sunlight periods is the only significant degradation pathway.

Dichloroethanes in well-mixed surface waters will volatilize fairly
rapidly. Modeling results suggest that they can be carried a
considerable distance downstream, although concentrations may be consi-
derably reduced due to dilution. Other chemical and biological processes
do not appear to influence the ultimate fate of these compounds.

Little information is available on the fate of dichloroethanes in
soil, although volatilization is certainly likely. Rapid movement
through the soil column has been shown in sandy soil; however, the fate
of dichloroethanes in soils of higher organic content has not been
studied. Considering their low affinity for adsorption, however, move-
ment is likely to be rapid.
4-33
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With respect to specific types of releases, dichloroethanes released
by the Gulf Coast petrochemical plants will generally be transported north
over populated areas. Atmospheric losses due to washout could occur in
this area due to the frequent and heavy rains, although subsequent vola-
tilization is likely to occur. Photochemical degradation will be of less
importance due to the high percentage of cloudy days in the area.

Land-disposed dichloroethanes from petrochemical facilities will be
subject to volatilization. Transport to groundwater will be facilitated
by the porous soil found in the area, the proximity to the water table,
and the frequent and heavy rainfalls.
4-34
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Othmer Encyclopedia of Chemical Technology, 3rd Edition. Vol. 5. New
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Baird, R.; Selna, M.; Raskins, J.; Chappelle, D. Analysis of selected
trace organics in advanced wastewater treatment systems. Waier Res.
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Bozzelli, J.W.; Kebbekus, B.B. Analysis of selected volatile organic
substances in ambient air. Trenton, NJ: New Jersey Department of
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Burns and Roe, Inc. Preliminary data for POTW studies. Washington, DC:
Effluent Guidelines Division, U.S. Environmental Protection Agency; 1979.

Dilling, W.L.; Tefertiller, N.B.; Kallos, G.J. Evaporation rates and
reactivities of methylene chloride, chloroform, 1,1,1-trichloroethane,
trichloroethylene, tetrachloroethylene, and other chlorinated compounds
in dilute aqueous solutions. Environ. Sci. Technol. 9(9):833-839; 1975.

Drury, J.S.; Hammons, A.S. Investigations of selected environmental
pollutants: 1,2-dichloroethane. Washington, DC: Office of Toxic
Substances, U.S. Environmental Protection Agency; 1979.

Ewing, B.B.; Chian, E.K. Monitoring to detect previously unrecognized
pollutants in surface waters. Report No. EPA 560/6-77-015a. Washington,
DC: Office of Toxic Substances, U.S. Environmental Protection Agency;
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Fishbein, L. Production, uses, and environmental fate of ethylene
dichloride and ethylene dibromide. Ames, B.; Infante, P.; Reitz, R.
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227-238; 1980.

Gale Research Company. Climate of the states. Vols. 1 & 2. Detroit,
MI: Book Tower; 1978.

Grimsrud, E.P.; Rasmussen, R.A. Survey and analysis of halocarbons in
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Jacobs, E.S. Use and air quality impact of ethylene dichloride and
ethylene dibromide scavengers in leaded gasoline. Conference on ethylene
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Khramova, S.I.; Zhirnov, B.F. The dynamics of the contents of chloro-
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Levins, P.; Adams, J.; Brenner, P.; Coons, S.; Thrun, K. ; Harris, G. ;
Wechsler, A. Sources of toxic pollutants found in influents to sewage
treatment plan-ts. VI. Integrated interpretation. Part I. Contract
No. 68-01-3857. Washington,-DC: U.S. Environmental Protection Agency;
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McConnell, G.; Ferguson, D.M. ; Pearson, C.R. Chlorinated hydrocarbons
and the environment. Endeavor 34(121):13-18; 1975.

Neely, W.B.; Branson, D.R.; Blau, G.E. Partition coefficient to measure
bioconcentration potential of organic chemicals in fish. Environ. Sci.
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Pearson, C.R.; McConnell, G. Chlorinated C^ and C2 hydrocarbons in the
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PEDCo Environmental, Inc. Monitoring of ambient levels of EDC near
production and user facilities. Research Triangle Park, NC: Office of
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Pellizzari, E.D.; Erickson, M.C.; Zweidinger, R.A. Formulation of a
preliminary assessment of halogenated organic compounds in man and
environmental media. Washington, DC: U.S. Environmental Protection
Agency; 1979. Available from: NTIS, Springfield, VA; PB 80 112170.

Price, K.S.; Waggy, G.T.; Conway, R.A. Brine shrimp bioassay and sea-
water BOD of petrochemicals. J. Water Pollut. Control Fed. 46(1):63-77;
1974.

Sansone, E.B.; Tewari, Y.B.; Jonas, L.A. Prediction of removal of vapors
from air by adsorption on activated carbon. Environ. Sci. Technol.
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Shakleford, W.M.; Keith, L.H. Frequency of organic compounds identified
in water. Report No. EPA 600/4-76-062. Athens, GA: Environmental
Research Laboratory, U.S. Environmental Protection Agency; 1976.

Singh, H.B.; Salas, L.J.; Smith, A.; Stiles, R.; and Shigeishi, H.
Atmospheric measurements of selected hazardous organic chemicals.
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Spence, J.W.; Hanst, P.L. Oxidation of chlorinated ethanes. J. Air
Pollut. Control Assoc. 28(3):250-253; 1978.

Stanford Research Institute (SRI). Estimates of physical-chemical
properties of organic priority pollutants. Preliminary draft. Washington,
DC: Monitoring and Data Support Division, U.S. Environmental Protection
Agency; 1980.

Suta, S.B. Assessment of human exposures to atmospheric ethylene
dichloride. Research Triangle Park, NC: Office of Air Quality Planning
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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.

Thomas, R.G. Volatilization from water. DAND 171-78-C-8073. Monthly
Progress Report No. 18. Fort Dietrich, MD: U.S. Army Medical Research
and Development Command; 1980.

U.S. Environmental Protection Agency (U.S. EPA). Chlorinated ethanes.
Ambient water quality criteria. Washington, DC: Office of Water Plan-
ning and Standards, U.S. Environmental Protection Agency; 1978.

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.

U.S. Environmental Protection Agency (U.S. EPA). STORET. Washington,
DC: Monitoring and Data Support Division, U.S. Environmental Protection
Agency; 1980a.

Versar, Inc. 1,1-Dichloroethane: statement of probable fate.
Callahan, M.A.; Slimak, M.W.; Gabel, N.W.; May, I.P.; Fowler, C.F.;
Freed, J.R.; Jennings, P.; Durfee, R.L.; Whitmore, F.C.; Maestri, B. ;
Mabey, W.R.; Holt, B.R.; Gould, C. Water-related environmental fate
of 129 priority pollutants. I. Report No. EPA-440/4-79-029a.
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Versar, Inc. Non-aquatic fate of 1,1-dichloroethane. Contract No.
68-01-3852. Springfield, VA; 1980.

Wilson, J.T.; Enfield, C.G.; Dunlap, W.J.; Cosby, R.L.; Foster, D.A.;
Baskin, L.B. Transport and fate of selected organic pollutants in a
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U.S. Environmental Protection Agency; 1980.

Youngblood, P.L. Use of dispersion calculations in determining popula-
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U.S. Environmental Protection Agency; 1977.
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5.0 EFFECTS AND EXPOSURE — HUMANS
5.1 HUMAN TOXICITY

5.1.1 1,2-Dichloroethane

5.1-1.1 Metabolism and Bioaccumulation

The 1,2 isomer is readily absorbed by inhalation or ingestion
and somewhat less so by dermal exposure. Mammalian metabolism of
1,2-dichloroethane is not well understood. Little human data are
available, but most mammals, and probably man, are believed to rapidly
transform 1,2-dichloroethane to 2-chloroethanol and chloroacetic acid
(ORNL 1979).

Yllner (1971) injected female albino mice intraperitoneally with
50-170 mg/kg l^C 1,2-dichloroethane in 10% olive oil and followed the
elimination of radioactivity for 3 days. Greater than 90% of the
radioactivity was excreted within 24 hours of injection, with the pat-
tern of excretion dependent on dose. Some 10-42% of the dose was
expired unchanged, 12-15% was expired as carbon dioxide, 51-73% was
excreted in urine, 0-0.6% in feces, and 0.6-13% remained in the carcass.
The urine contained three major metabolites: chloroacetic acid (6-23%),
S-carboxymethylcysteine (44-46%, free; 0.5-5% conjugated), and thiodi-
acetic acid (33-34%).

Spreafico and coworkers (1980) studied the distribution and persis-
tence of 1,2-dichloroethane administered to Sprague-Dawley rats over a
range of dosages and concentrations by the intravenous, oral, and
inhalatory routes. Intravenous injection of 1, 5, or 25 mg/kg
1,2-dichloroethane resulted in rapid, biphasic disappearance from blood
by 30, 60, and 120 minutes post-dosing, respectively. The steepness of
the second or beta phase decreased with an increase in dose, indicating
a dose-dependence for disappearance from blood and suggesting that elimi-
nation of the compound may be a saturable process. Data for the brain,
kidney, and spleen were essentially superimposable on those for the
1,2-dichloroethane blood levels.

Oral administration of 25, 50, or 150 mg/kg of 1,2-dichloroethane
resulted in rapid absorption. Major tissue accumulation occurred in the
liver, with peak concentrations reached within 10 minutes of administra-
tion. Disappearance from the liver was rapid following a biphasic,
biexponential curve the second component of which was practically equivalent
to the disappearance curve of the compound from the general circulation.
The level of the compound in the lung appeared to be in equilibrium with
that in the blood, although levels were at all times lower, presumably
due to expiration of the compound. Accumulation in adipose tissue was
slower, with peak levels reached 45-60 minutes post-dosing. These
levels were approximately 5 times higher at the 50 and 150 mg/kg doses
5-1
-------
than those in blood. Disappearance from adipose tissue was monophasic
and essentially equivalent in rate to that of blood. The curve relating
peak blood levels and dose administered appeared linear up to 50 mg/kg,
with a perceptible decrease in steepness thereafter, possibly indicating
a relative saturation in gastrointestinal absorption at doses of 100-
150 mg/kg. Peak blood levels for the 25, 50, and 150 mg/kg doses were
13.3, 31.9, and 66.8 yg/ml, respectively. No significant differences .
in kinetic parameters were observed between male and female rats or
between single and 10-daily administration of 50 mg/kg 1,2-dichloro-
ethane (Spreafico _et _al. 1980).

By the inhalation route, steady-state concentrations in the body
were reached relatively slowly (2-3 hours), depending on the level of
the 1,2 isomer in the atmosphere. A clear dose-dependence of the
compound in tissue was seen. Differences on the order of 20-30 times
in blood, liver, lung, and adipose tissue existed between exposures to
200 and 1000 mg/m3 1,2-dichloroethane (e.g., the half-lives for blood
in the beta phase were 12 and 22 minutes, respectively, for the above
two exposures). The highest absolute levels of the compound were found
in adipose tissue, with concentrations 8-9 times greater than those in
blood.

Thus, Spreafico and coworkers (1980) found that the elimination
curves and relative tissue distribution for oral, intravenous, and
inhalation exposure of rats were similar. In all three situations,
the highest quantities of 1,2-dichloroethane were seen in adipose
tissue, with the lowest area under the curves noted for the lung, most
probably because of its rapid respiratory excretion. Dose also appeared
to influence kinetic parameters.

In another study, Reitz and coworkers (1980) examined the pharma-
cokinetics of 1,2-dichloroethane in Osborne-Mendel rats following
inhalation of 600 mg/m^ for 6 hours. Steady-state levels of 8-9 ug
1,2-dichloroethane/ml blood were reached in 2-3 hours and remained
constant until termination of exposure, whereupon blood levels fell
rapidly. Elimination appeared to be biphasic, with an initial phase
having a half-life of 6 minutes and the slower, beta phase, a half-life
of 35 minutes. Elimination was virtually completed after 18 hours.
Approximately 98% of the dose was excreted as metabolites and 1.8% as
unchanged 1,2-dichloroethane. Of the metabolite fraction, 84% was
eliminated as one of two unidentified metabolites in urine and 7% was
expired as C02.

A separate oral balance study with rats given 150 mg 1,2-dichloro-
ethane/kg body weight in corn oil produced many similarities except
that peak blood levels of the compound were much higher after oral
administration than after inhalation exposure (70 vs. 9 ug/ml). After
oral administration, 29% of the dose was eliminated unchanged and 71%
as metabolites (^60% in urine, 1.5% in feces, 5% as C02, 3% left in
the carcass) (Reitz et al. 1980).
5-2
-------
In two recent publications, the enzymatic conversion of 1,2-dichloro-
ethane to ethylene by GSH (glutathione)-dependent rat liver enzymes has
been demonstrated (Anders and Livesey 1980; Livesey and Anders 1979).
The enzymes catalyzing the formation of ethylene from the compound are
predominantly found in the cytosolic fraction of hepatic tissue and are
highly dependent on the presence of reduced GSH. This in vitro metabolism
of the 1,2 isomer to ethylene was inhibited only by those reagents that
react with sulfhydryl groups or that are substrates for GSH S-transferases.

Urosova (1953) reported the accumulation and excretion of 1,2-
dichloroethane in the milk of nursing mothers occupationally exposed by
inhalation and dermal contact. Exposure to a.63 mg/m^ for an unspecified
duration resulted in initial concentrations of 58 mg/m^ in expired air
and 0.58 mg/100 ml in milk; by 18 hours post-exposure, concentrations
had dropped to 8-16 mg/m^ and 0.2-0.6 mg/100 ml, respectively.

In summation, most mammalian species, and presumably man, metabolize
1,2-dichloroethane to 2-chloroethanol and chloroacetic acid. Elimination
in rats is biphasic and appears to be dose-dependent, suggesting elimina-
tion may be a saturable process. Relative tissue distributions following
oral, intravenous, and inhalation exposures are similar except for a
markedly higher peak blood value after oral administration in contrast
to that noted following inhalation exposure. Regardless of the route of
exposure, the highest quantities of the compound are found in adipose
tissue. Excretion occurs primarily in urine and expired breath.

5.1.1.2 Human and Animal Studies

Carcinogenicity

Administration of technical grade 1,2-dichloroethane (47 and 95
mg/kg/day, time-weighted average) by gavage to Osborne-Mendel rats for
78 weeks produced elevated incidences of squamous-cell carcinoma of the
forestomach, hemangiosarcomas and subcutaneous fibromas in males, and
mammary adenocarcinomas in females (see Table 5-1). A concurrent study
with B6C3F1 mice given technical grade 1,2-dichloroethane (males: 97 or
195 mg/kg/day; females: 149 or 299 mg/kg/day, time-weighted averages)
by gavage for 78 weeks also resulted in positive carcinogenic effects,
inducing mammary adenocarcinomas and endometrial tumors in females and
alveolar/bronchiolar adenomas in mice of both sexes (see Table 5-2)
(NCI 1978a).

Negative results, however, were noted in Sprague-Dawley rats and
Swiss mice exposed to concentrations up to 600 mg/m^ 1,2-dichloroethane
(99.8% pure) by inhalation for 78 weeks (Maltoni et ai. 1980). These
authors exposed groups of 90 animals of each sex for each species to
concentrations of 1000, 200, 40, or 20 mg/nr of the compound, 7 hours
per day, 5 days per week for 78 weeks. A sham control group received
filtered air according to the same treatment regimen and an additional
control group remained untreated. The 1000-mg/m-^ concentration was
5-3
-------
TABLE 5-1. INCIDENCE OF PRIMARY TUMORS AT SPECIFIC SITES IN MALE AND FEMALE
OSBORNE-MENDEL RATS ADMINISTERED 1,2-DICHLOROETHANE BY GAVAGE
Tumor
Cn
I
-p-
Squamous-cell
carcinoma of the
forestomach

llemangiosarcoma of
the circulatory
system
Sex Vehicle Controls

Male 0/20 (0%)

Male 0/20 (0%)
Subcutaneous fibromas Male

Mammary adenocarcinoma Female
0/20 (0%)

0/20 (0%)
Low Dose (47 mg/kg/day) High Dose (95 mg/kg_/_day)

3/50 (6%)
9/50 (18%)
P = 0.039
5/50 (10%)

1/50 (2%)
9/50 (18%)
p - 0.039

7/50 (14%)
6/50 (12%)

18/50 (36%)
p = 0.002
Source: NCI (1978a).
-------
TABLE 5-2. INCIDENCE OF PRIMARY TUMORS AT SPECIFIC SITES IN MALE AND FEMALE
B6C3F1 MICE ADMINISTERED 1,2-DICHLOROETHANE BY GAVAGE
Tumor
Ui
i
Alveolar/Bronchiolar Female
adenoma

Male
Mamma ry
adenocarcinoma

Endometrial
stromal polyps
or sarcomas
Sex Vehicle Controls

1/20 (5%)

0/20 (0%)

Female 0/20 (0%)

Female 0/20 (0%)
Low Dose (97 mg/kg/day) High Dose (195 mg/kg/day)

7/50 (14%)
1/47 (2%)
9/50 (18%)
P=0.039

5/49 (10%)
15/48 (31%)
p = 0.016

15/48 (31%)
p = 0.003

7/48 (15%)

5/47 (11%)
Source: NCI (1978a).
-------
dropped to 600 mg/rn^ after a few weeks because of severe toxic effects.
All animals were allowed to live beyond treatment until spontaneous
death occurred. No relevant differences between the types or incidences
of tumors were seen for the various treatment groups of Swiss mice. In
Sprague-Dawley rats, an increase of nonmalignant mammary fibroadenomas
and fibromas which was not correlated with dose was seen in females.

The apparent contradiction of results between the National Cancer
Institute (1978a) study and that of Maltoni ert al. 0-980) could be due
to a number of factors including different samples of the compound (and
hence purity), different routes of exposure, and/or different animal
strains.

The purity issue concerns the use of a 99.8% pure sample of 1,2-
dichloroethane in the inhalation work of Maltoni et al. (1980), in
contrast to the technical grade sample noted in the NCI (1978a) study.
Although the NCI report states that the test sample used was greater
than 90% 1,2-dichloroethane, the NCI Chemical Repository indicated a
purity of greater than 99.9% for the test sample utilized in the NCI
study (Hooper _et _§!. 1980). Retesting of a 7-year-old stock sample
indicated a purity between 98.5% and 99.8% with a minor chloroform
impurity (0.02%) plus 14 other trace contaminants (Hooper et^ _§_!. 1980).
Therefore, purity of the administered compound does not appear to be
a factor.

Differences in response, at least in the rat, also do not appear
to be associated with variations in the pharmacokinetics or tissue
distribution of 1,2-dichloroethane due to exposure route (Reitz et al.
1980; Spreafico et_ al. 1980). The effective doses delivered to tissue
would be similar whether the compound was administered by gavage or by
inhalation except for a transient high concentration in the liver due
to the first-pass effect of gavage exposure (Hooper et al. 1980).
Furthermore, it has been calculated (based on average daily lifetime
doses and 100% absorption) that the two highest doses in the inhalation
study were comparable on a mg/kg/day basis to those resulting in positive
carcinogenic effect in the gavage study (Hooper et_ al. 1980). By the
calculations of Hooper _e_t _al. (1980), the top rat inhalation groups
received an average of 48 and 16 mg/kg/day of the 1,2 isomer for their
lifespan compared to average doses of 48 and 24 mg/kg/day for rats
given the compound by gavage. Another consideration with respect to
different routes of exposure is the possibility that the gavage route
might result in the production of carcinogenic metabolites of 1,2-
dichloroethane by gut flora that would not occur in the lung following
inhalation of the compound (Hooper _et al. 1980). Toxicity data, however,
indicate that similar doses of 1,2-dichloroethane by these two routes
produce similar toxic effects (see Section 5.1.1.2 Other Toxic Mani-
festations) .

Sensitivity of test species to carcinogenic induction by chlori-
nated hydrocarbons may also play a role in the contradictory findings
of the NCI (1978a) and Maltoni and coworkers (1980). A report by
Banerjee and Van Duuren (1979) noted that the in vitro binding of
5-6
-------
1,2-dichloroethane to hepatic microsomal protein from B6C3F1 mice was
6-8 times greater than the corresponding binding for Osborne-Mendel
rats. In addition, the covalent binding of the 1,2 isomer to salmon
sperm DNA was 5 times greater in the presence of microsomes from male
B6C3F1 mice than in the presence of microsomes from male Osborne-Mendel
rats. The compound was bound 2.5 times greater to DNA in the presence
of microsomes from female mice than from female rats. Furthermore, the
binding of the compound to proteins was not significant when denatured
microsomes were used, suggesting metabolic activation is required for
the compound to covalently bind to macromolecules.

In other related studies, Van Duuren and coworkers (1979) reported
the induction of 26 benign lung tumors (p < 0.0005) and 3 tumors of the
forestomach (2 squamous-cell carcinomas and 1 papilloma) in 30 Ha:ICR
Swiss mice by repeated application of 1,2-dichloroethane (126 mg in
acetone/mouse 3 times per week) to the dorsal skin for a lifetime.
The sample used was reported to show "no marked impurities" by NMR
analysis. A separate assay for skin tumor initiation in a two-stage
carcinogenesis assay using Swiss mice and phorbol myristate acetate as
the promoter was considered negative by Van Duuren and his associates
(1979).

Employing a mouse pulmonary tumor induction technique, Theiss and
coworkers (1977) were unable to produce a significant number of tumors
in strain A mice following thrice weekly intraperitoneal injections of
20, 40, or 100 mg/kg 1,2-dichloroethane (98.96% pure) for 8 weeks. All
mice were killed at 24 weeks. However, the negative results in this
short-term, whole-animal assay are of limited value and are insufficient
evidence that the 1,2 isomer is not carcinogenic.

In summation, there is an apparent contradiction in carcinogenicity
findings with 1,2-dichloroethane in rodents. Elevated incidences of
squamous-cell carcinoma of the forestomach, hemangiosarcoma, and mammary
adenocarcinoma have been observed in Osborne-Mendel rats given 47 or
95 mg 1,2-dichloroethane/kg/day by gavage for 78 weeks. In contrast.
Sprague-Dawley rats exposed by inhalation to concentrations of up to
600 mg/m^, 7 hours per day for 78 weeks exhibited no increased incidence
of malignant tumors; an increase of nonmalignant mammary fibroadenomas
and fibromas which was not correlated with dose was seen in females, but
this increase appeared to be related to decreased group survival rates.
Similar contradictory findings have been reported for B6C3F1 mice given
149 (female)-195 (male) mg/kg/day of the compound by gavage and Swiss mice
exposed to 600 mg/m^ by inhalation. No relevant differences in type or
incidence of tumors were seen in Swiss mice exposed to 1,2-dichloroethane
by inhalation, while gavage administration produced alveolar/bronchiolar
adenomas, mammary adenocarcinomas, and endometrial tumors in B6C3F1 mice.
Several possible explanations for the disparity of results have been
explored, but the issue remains open.
5-7
-------
In the absence of adequate data to resolve this perplexing contra-
diction in carcinogenicity tests, the prudent course of action would be
to regard 1,2-dichloroethane as a carcinogenic risk to man. Extrapola-
tion of the lowest reported effect level (47 mg/kg/day in rats) gives
an equivalent level of 3.3 g/70 kilo man/day.

Adverse Reproductive Effects

No major malformations were seen in pregnant Sprague-Dawley rats
exposed 7 hours per day on days 6-15 of gestation to 400 mg/rn^ 1,2-
dichloroethane. Marked maternal toxicity occurred in a second group of
rats exposed to 1200 mg/m^ under identical conditions; 63% (10/16) of
the dams died at this exposure concentration and implantation sites (all
of which were resorbed) were found in only one rat (Rao jejt _al. 1980).
A second experiment conducted with New Zealand albino rabbits exposed
for the same duration and to the same concentration on days 6-18 of
gestation resulted in the death of 16% (3/19) of the dams at the 1200
mg/m3 level and 19% (4/21) of the dams at the 400 mg/m3 level. Neither
exposure, however, appeared to affect the incidence of pregnancy, mean
litter size, incidence of resorptions, or fetal body measurements. A
single fetus in the lower dose group exhibited external malformation,
but these appeared to be unrelated to treatment (Rao et al. 1980).

A single-generation two-litter reproduction study with Sprague-
Dawley rats exposed to 0, 100, 300, or 600 mg/rn3 1,2-dichloroethane,
6 hours per day, 5 days per week prior to breeding, then 6 hours per
day, 7 days per week through gestation and weaning also produced no
significant treatment-related effects (Rao et_ _al. 1980).

A report in the Russian literature indicates that female rats
exposed by inhalation to 57 mg/m3 1,2-dichloroethane, 4 hours per day,
6 days per week for 6 months prior to breeding and then throughout
gestation had a reduced number of live births, a reduced litter size,
and reduced fetal pup weights, but that no tissue or skeletal anomalies
were evident (Vozovaya 1974). The Russians, therefore, report some
fetotoxicity at 57 mg/m3 1,2-dichloroethane, while Rao and coworkers
saw no effects at 600 mg/nH. However, determination of exposure levels
and monitoring techniques utilized behind the Iron Curtain have histori-
cally been difficult to verify.

Mutagenicity

Mutagenicity studies with 1,2-dichloroethane suggest that the
compound is a weak direct mutagen which, in the presence of an activa-
tion system, is converted to a more effective mutagenic species.

Exposure of Drosophila to the 1,2 isomer has been shown to result
in heritable mutations. Using the sex-linked recessive assay, increased
mutations were observed in Drosophila exposed to the compound at 4.9 g/1
(King _et _al. 1979, Shakarnis 1969, Rapoport 1960). The somatic mutation
assay also produced a mutation frequency of 7.21% in larvae exposed to
5-8
-------
0.5% 1,2-dichloroethane in their food supply compared to an incidence
of 0.045% for untreated controls (Nylander et al_. 1978). *

The production of mutagenic bile by male CBA mice injected intra-
peritoneally with 89 mg 1,2-dichloroethane/kg body weight has been
demonstrated in Salmonella typhimurium (Rannug and Beije 1979). Similar
findings were reported by Jenssen and coworkers (1979) who tested the
compound on Chinese hamster V79 cells with perfused rat liver as the
metabolizing system. The bile produced, following addition of the
compound, was strongly mutagenic, while no effect was noted with the
perfusate. The 1,2 isomer is believed to be activated through conjuga-
tion with glutathione, which is then excreted in bile. Rannug and
Ramel (1978) have reported enhancement of the mutagenic effects of the
compound in Salmonella typhimurium in the presence of glutathione
S-transferases and glutathione.

Negative results were reported in the micronucleus assay using
bone marrow cells from mice injected twice, 24 hours apart, with 396 mg
1,2-dichloroethane/kg intraperitoneally (King et_ aJL. 1979). Negative
findings were also noted in a host-mediated assay with Escherichia coli
in mice injected intraperitoneally with 198 mg 1,2-dichloroethane/kg
(King ^t al. 1979) and in a rec-assay, a bacterial mutagenesis assay,
using Bacillus subtilis (Kanada and Uyeta 1978).

Point mutations have been observed in the bacterium Salmonella
typhimurium subsequent to exposure to the compound; base pair mutations
were induced in strains TA-100, TA-1530 (McCann et_ al^. 1975; Kanada and
Uyeta 1978; Rannug and Beije 1979; Rannug and Ramel 1978), and frame-
shift mutations were seen in the TA-98 strain (Kanada and Uyeta 1978).
Enhanced mutagenic activity was noted in these studies upon addition of
a liver microsomal activation system. Negative results have also been
reported for these strains (King j^t _§_!. 1979), but one study suggested
that differences in the chemical employed to induce enzymes in liver
homogenate as well as different strains of rat used for liver activation
may influence the mutagenic response (Fabricant and Chalmers 1980).

Other Toxic Manifestations

The 1,2 isomer is moderately toxic following acute exposure, with
similar effects for all routes of entry. Acute effects in man are
principally associated with CNS depression, GI upset, and injury in the
liver, kidneys, lungs, and adrenals (Irish 1963). Hyperemia and
hemorrhagic lesions are seen throughout the body in cases of acute
poisoning and have been attributed to a reduction in the level of blood
clotting factors and thrombocytopenia (Martin _e_t £l. 1969). Death is
usually attributed to respiratory and circulatory failure (NIOSH 1976).
Ingestion of 15 ml of 1,2-dichloroethane was lethal to a 14-year-old boy
within 5 days of exposure. Clinical features included hypoglycemia and
hypercalcemia. Major findings at autopsy were florid liver necrosis,
renal tubular necrosis, and focal adrenal degeneration and necrosis
(Yodaiken and Babcock 1973). However, the survival of a 25-year-old
5-9
-------
male, who drank 50 ml of the compound with suicidal intent, was reported.
He was discharged from the hospital 87 days post-exposure with small
cirrhotic areas in the liver (Prezdziak and Bakula 1975). Case histories
of fatal and non-fatal poisoning are reported in some detail in the
NIOSH (1976) report.

Similar effects are reported for laboratory animals following acute
oral exposure to 1,2-dichloroethane. Oral 1>V$Q values of 700 and 860
rag/kg have been reported for rats (McCollister _et _al. 1956) and rabbits
(RTECS 1980), respectively. In a two-year feeding study with rats fed
a mash fumigated with 1,2-dichloroethane, only a slight increase in
liver fat was observed in rats receiving mash with 500 ± 40 mg 1,2-
dichloroethane/kg diet; no effect was noted in rats at a lower, 250 ±
30 mg/kg diet exposure level. Mash was stored for 7-10 days with a 57,
loss of residue with actual consumption estimated to be 60-70% of the
original residue level. No significant differences in growth, feed
consumption, or reproductive activity were noted in either group
(Alumot _et _al. 1976).

No adverse effects were observed in two men exposed by inhalation
to 4800 mg/m^ 1,2-dichloroethane for two minutes (Sayers ^t jil. 1930).
Chronic exposures are generally occupational in nature and are linked
to neurological disorders, kidney and liver dysfunction, irritation of
mucous membranes, abdominal pain, nausea, and anorexia (Byers 1943,
Delplace _e_t _al. 1962, Watrous 1947). The concentrations and exposure
times associated with the onset of chronic symptoms in humans are
difficult to deduce from the literature, but 8-hour exposures to
40-400 mg/m for a duration of from a few weeks to a few months appear
to be characteristic of most cases. Reports of occupational exposures
that were without effect have not been found in the literature (NIOSH
1976).

Cardiac and nervous system effects were reported in 100 factory
workers exposed to a maximum concentration of 1,2-dichloroethane of
100 mg/rn^ for durations of 6 months to 5 years. No changes in blood
or internal organ functions were noted (Rosenbaum 1947). Kozik (1957)
reported effects on liver and bile ducts in Russian aircraft workers
chronically exposed to the compound such that peak exposures exceeded
160 mg/m-3 with a time weighted average of about 90 mg/m^ per work shift.

The use of 1,2-dichloroethane as a fumigant has resulted in many
episodes of human poisoning (NIOSH 1976). Reported cases, however,
frequently involve combined exposure with other chemicals and thus make
evaluation of effects due to the 1,2 isomer alone difficult to assess.
Khubutiya (1964) noted the presence of hyperchromic erythrocytes without
megaloblasts and moderate to high figures for sedimentation rate,
apparently induced by the increase in blood globulin, in workers exposed
to 1,2-dichloroethane (concentrations not given). Leukopenia was also
observed. Cases of moderate and marked monocytosis were frequent and
platelets were reduced. Turk cells (mononuclear cells with morphologic
characteristics of both an at3/pical lymphocyte and a plasma cell) were
5-10
-------
present in the peripheral blood of 19% of the workers; total study
population size was not stated.

Another study examined 118 Polish agricultural workers using 1,2-
dichloroethane as a fumigant. Skin absorption resulting from spillage
on clothing, shoes, skin, etc. appeared to be as significant a contribu-
tor to exposure as inhalation. Environmental air sampling in the field
suggested exposure levels of 16 mg/m3, but more controlled air sampling
in a simulated laboratory setting indicated concentrations in air of
about 60 mg/m3, reaching 240 mg/m3 during pouring operations. About
90% of the workers reported symptoms, including conjunctival congestion
(69% of all workers), weakness (46%), reddening of the pharynx (42%),
bronchial symptoms (35%), metallic taste in the mouth (34%), headache
(33%), dermatographism (31%), nausea (26%), cough (25%), liver pain
(25%), burning sensation of the conjuctiva (20%), tachycardia (18%), and
dyspnea after effort (18%). The compound was also stated to be excreted
in urine, but the amounts excreted reportedly did not correlate with the
appearance of clinical symptoms (Brzozowski jit. a±. 1954).

In laboratory animals, an LC5g value of 4000 mg/m3/4-houir was docu-
mented for rats (Carpenter et_ _al. 1949). LCLo values of 5000, 6000, and
12,000 mg/m^ 1,2-dichloroethane have been reported for a 2-hour exposure
to mice and 7-hour exposure to guinea pigs and rabbits, respectively
(RTECS 1980).

Chronic inhalation exposures to 400-1600 mg/m^ 1,2-dichloroethane
for 5-32 weeks were toxic to the liver at 800 mg/m3 and above for
several species (Spencer _et al. 1951, Hofmann et al. 1971). Increased
liver weights were reported for guinea pigs exposed to 400 mg/m3 for 32
weeks (Spencer _e_t _al. 1951).

Speafico and coworkers (1980) reported that exposure of Sprague-
Dawley rats in inhalatory concentrations of 1,2-dichloroethane up to
600 mg/m3 for up to 18 months, 7 hours/day, 5 days/week did not appear
to be associated with marked toxicity, as indicated by a series of
standard clinical chemistry parameters. A second group of rats exposed
to 200 or 600 mg/m3 for 12 months beginning at 14 months of age, however,
showed functional signs suggesting effects on the liver and kidney.

Brief dermal contact with 1,2-dichloroethane seldom produces serious
systemic poisoning, but repeated or prolonged contact can result in
defatting of skin and dry, chapped skin (ORNL 1979).
5.1.1.3 Overview

Exposure to 1,2-dichloroethane adversely affects the circulatory,
respiratory, and nervous systems as well as the liver and kidney. Most
mammalian species, and presumably man, metabolize the compound to
2-chloroethanol and chloroacetic acid, with excretion primarily via
the urine and expired air. A summary of irreversible adverse effects
associated with 1,2-dichloroethane is presented in Table 5-3.

5-11
-------
TABLE 5-3. ADVERSE EFFECTS OF 1,2-DICHLOROETHANE
Ul
I
A(lY §£§ *L Effect

Carcinogenesis
Species
Heritable
Mutation
Teratogenesis
Neurologi cal
disorders
Lethality
(ingestion)
Rat (Osborne-Mendel)

Mouse (B6C3F1)

Rat (Sprague-Dawley)
Mouse (Swiss)
Drosophila (sex-linked
recessive)
DrosophiJ a (soma tic
mutation)
Rat (Sprague-Dawley)
Human

Human

Rat
Lowest Reported Effect Level

47 rag/kg/day technical grade
by gavage, 5 days/week for
78 weeks
149 mg/kg/day technical grade
by gavage, 5 days/week for
78 weeks
No Apparent Effect Level
4.9 g/1

0.5% in diet
100 mg/ra , 8 hours/day,
5 days/week for 6 months-
5 years
LDL0 15 ml

IJ>50 700 mg/kg
600 mg/m3, 99.8% pure
99.8% pure, 7 hours/day,
5 days/week for 78 weeks
400 mg/m , 7 hours/day,
days 6—15 of gestation
difficult to deduce from
literature
-------
Elevated incidences of squamous-cell carcinoma of the forestomach,
hemangiosarcoma, and mammary adenocarcinoma have been observed in
Osborne-Mendel rats given 47 or 95 mg 1,2-dichloroethane/kg/day by
gavage for 78 weeks. In contrast, Sprague-Dawley rats exposed by inha-
lation to concentrations up to 600 mg/m^ for 7 hr/day for 78 weeks
exhibited no increased incidence of malignant tumors. Similar contra-
dictory findings have been noted with mice. Gavage administration of
149-195 mg/kg/day 1,2-dichloroethane to B6C3F1 mice resulted in alveolar/
bronchiolar adenomas, mammary adenocarcinomas, and endometrial tumors,
while exposure to 600 mg/m^ 1,2-dichloroethane by inhalation was without
carcinogenic effect in Swiss mice. This disparity in results remains to
be resolved, but a prudent course of action would suggest considering
1,2-dichloroethane to be a carcinogen.

Reproduction studies with the compound are negative but heritable
mutations in Drosophila and point mutations in Salmonella were produced.

Human ingestion of 15 ml of 1,2-dichloroethane was lethal, but
survival following ingestion of 50 ml has been documented. Inhalation
is the more typical route of human exposure, with exposures of 40-400
mg/m^ for a few weeks to a few months generally associated with chronic
symptomology (e.g., CNA depression, GI upset, and kidney and liver
damage).

5.1.2 1,1-Dichloroethane

5.1.2.1 Introduction

There is scant information published on 1,1-dichloroethane.
Formerly it was used as an anesthetic but this was discontinued because
of marked excitation of the heart (Browning 1965). Based on the avail-
able data, there appear to be no marked differences in the toxicity of
1,1-dichloroethane and 1,2-dichloroethane, with the 1,1 isomer being
somewhat less toxic.

5.1.2.2 Metabolism

Little is known about the metabolism of 1,1-dichloroethane except
that following application to the shaved abdominal skin of rabbits
prevented from inhaling the solvent, no definite metabolites could be
detected in the exhaled air (Browning 1965).

Nakajima and Sato (1979) recently demonstrated enhanced activity
of liver microsomal enzymes to metabolize 1,1-dichloroethane in vitro
following a one-day food deprivation of male and female Wistar rats
(i.e., metabolic rates were 2.9 and 3.3 times respective control levels).
A sex difference was observed in the metabolic rate, with male rats
(both fed and one-day fasted) metabolizing at a somewhat faster rate
than females; the extent of this difference decreased when food depriva-
tion was extended to 3 days. Fasting, however, did not produce a
significant increase in the microsomal protein or cytochrome P-450
content, and a marked loss of liver weight occurred.

5-13
-------
5.1.2.3 Human and Animal Studies

Carcinogenicity

Initial test results for the NCI bioassay with groups of 50 male
and 50 female Osborne-Mendel rats and B6C3F1 mice administered technical
grade 1,1-dichloroethane (99% pure) by gavage for 78 weeks were incon-
clusive. Test animals were administered 1,1-dichloroethane in corn oil
by gavage, 5 days per week for 78 weeks at time-weighted average dosages
of 764 and 382 mg/kg/day for male rats, 950 and 475 mg/kg/day for female
rats, 2885 and 1442 mg/kg/day for male mice, and 3331 and 1665 mg/kg/day
for female mice. For each species, 20 control animals of each sex were
administered the corn oil vehicle according to the same schedule. Survi-
val was poor in all rat groups and several mouse groups (e.g. 5, 4, and
8% of the male rats given 0, 382, and 764 mg/kg/day, respectively, were
alive at study termination). The high early mortality appeared to be
related to a high incidence of pneumonia; pneumonia was observed in 80%
of the rats in this bioassay. The high early mortality complicates
interpretation of this study in that the number of rats of both sexes
and male mice surviving long enough to be at risk from late-developing
tumors was low. Dose-related marginal increases in mammary adenocarci-
nomas and in hemangiosarcomas among female rats (475 and 950 mg/kg/day)
and a significant increase in the incidence of endometrial stromal
polyps (benign endometrial neoplasms) in high-dose female mice compared
to controls (9% vs. 0% in controls) are indicative of possible carcino-
genic potential of 1,1-dichloroethane, but under the conditions of this
bioassay, no conclusive evidence for the carcinogenicity of 1,1-dichloro-
ethane was established (NCI 1978b).

Fetotoxicity

Schwetz and coworkers (1974) found 1,1-dichloroethane to be feto-
toxic in Sprague-Dawley rats exposed to 24,300 mg/m-* reagent-grade
ls1-dichloroethane 7 hr/day on days 6-15 of gestation. A significant
increase in the incidence of retarded fetal development, characterized
as delayed ossification of sternebrae, was seen at 24,300 mg/m^ (42% vs.
11% in controls), but not in rats similarly exposed to 15,390 mg/m^.
There were no effects on the incidence of fetal resorptions, fetal body
measurements, or the incidence of gross or soft tissue anomalies. No
signs of toxicity were observed in the dams at either concentration.

Mutagenicity

No mutagenicity data on 1,1-dichloroethane have been found.

Other Toxic Manifestations

Adverse effects in laboratory animals associated with exposure to
1,1-dichloroethane include central nervous systems depression expressed
as abnormal weakness, intoxication, restlessness, irregular respiration,
muscle incoordination, and unconsciousness. Damage to the liver and/or
5-14
-------
kidney has been demonstrated in various animal species following expo-
sure to 1,1-dichloroethane (Parker ^t _al. 1979). An LD5Q value of
725 mg/kg was recorded for the rat by the oral route (RTECS 1980) and
minimal lethal concentrations of 64,800 mg/m3 and 70,000 mg/m3 have
been reported for rats and mice, respectively (Smyth 1956, Lazarew 1929).

In man, toxic chemical hepatitis and/or kidney injury, pulmonary
irritation, and damage to the hematopoetic system are associated with
inhalation of 1,1-dichloroethane. Repeated or prolonged skin exposure
can defat the skin and cause dermatitis (Parker jet _al. 1979).

5.1.2.4 Overview

Although data are sparse, available effect levels for mammalian
species are summarized in Table 5-4. Initial carcinogenicity studies
in rodents exposed to 1,1-dichloroethane by gavage for 78 weeks were
inconclusive due to poor survival. However, the compound's structural
similarity to 1,2-dichloroethane and the dose-related marginal increases
in some tumor types observed in the NCI bioassay are indicative of
possible carcinogenic potential. The 1,1 isomer is currently being
reevaluated by the National Cancer Institute. Until the results from
this second bioassay are available, 1,1-dichloroethane should be consi-
dered a suspect carcinogen. In view of the relative paucity of data in
other areas, such as the teratogenicity, mutagenicity, and long-term
oral toxicity of 1,1-dichloroethane, estimates of the effects of chronic
oral exposure at low levels cannot be made with any confidence.

5.2 HUMAN EXPOSURE

5.2.1 Introduction

This section considers the exposure of humans to 1,2-dichloroethane
and 1,1-dichloroethane. Since the 1,2 isomer is the largest volume
synthetic organic chemical manufactured in the United States, a large
potential for exposure exists. The 1,1 isomer, on the other hand, is
produced in very limited quantities, thus suggesting limited exposures.
However, monitoring data for both of these chemicals is extremely limited,
making exposure estimation difficult. The following sections will consider
exposure through ingestion, inhalation, and dermal absorption for various
subpopulations.

5.2.2 Ingestion

5.2.2.1 Drinking Water

The 1,2 isomer has been found in drinking water. The National
Organics Reconnaissance Survey found it in 14% of the raw water supplies
sampled and 32.5% of finished water samples; the highest concentration
observed was 6 ug/1 (U.S. EPA 1975). More recently, data from national
surveys of drinking water have been summarized (Coniglio _et_ _a_l. 1980).
These data are shown in Table 5-5 and suggest that dichloroethanes
5-15
-------
TABLE 5-4. ADVERSE EFFECTS OF 1,1-DICHLOROETHANE ON MAMMALS
Ul
t
Adverse F.ffert
Carcinogenesis
Species

Rat
Mouse
Fetotoxicity
(delayed ossification)

Mutagenesis
Chronic Oral
Toxicity

Lethality
(ingestion)
Rat
Rat
Lowest Reported Effect Level

No conclusive evidence is
currently available, but some
dose-related marginal increases
in some tumor types noted for
both rats and mice in a gavage
study complicated by poor
survival.

24300 rng/m3, 7 hours/day,
days 6-15 of gestation
No data available
No data available
LD5Q 700 mg/kg
No Apparent Effect Level
15,390 mg/m , 7 hours/day,
days 6-15 of gestation
-------
TABLE 5-5. DICHLOROETHANES IN DRINKING WATER — FEDERAL DATA
No. Cities % Positive
Water Source Sampled Samples Mean*Qig/l)_ Median*'^ug/1) Range* (ug/1)
Raw Finished Raw Finished Raw Finished Raw Finished Raw Finished
Surface 105
1,1-Dichloroethane
103 1.9
2.9 0.1
0.2 0.1
0.2 0.1-0.1 0.2-0.2
Ground
13
13 23.1 23.1 0.7
0.3 0.8
0.2 0.4-0.9 0.2-0.5
Surface 105
1,2-Dichloroethane
133 9.5 4.5 1.46 2.14 0.55 1.8 0.1-45 0.8-4.8
Ground
13
25 7.1
4.0 0.2
0.2
0.2
0.2
*0f positive results
""Of all results.
Source: Coniglio et al. (1980).
-------
are detected infrequently in surface water and at low levels,
generally less than 1 yg/1. However, a few samples showed higher
levels of the 1,2 isomer in finished surface water, up to 4.8 yg/1.

Data from Federally sponsored surveys of groundwater are sparse.
Coniglio and coworkers (1980) also summarized data collected by the
states regarding contamination of groundwater supplies. These results
are shown in Table 5-6. These data suggest that dichloroethanes are
commonly found in groundwater supplies; however, the results are not
representative, since state sampling is commonly done where contamina-
tion is suspected. The presence of 1,1-dichloroethane in 18% of the
wells tested is somewhat surprising since its production is so limited.
The high maximum concentration of 11,300 yg/1 suggests a local contami-
nation incident. Tables 5-7 and 5-8 summarize the data available by
state, suggesting a widespread problem, although it may be very local-
ized within each state. Unfortunately, no data are available for
groundwater supplies in the Gulf states, where most of the production
facilities are found (see Chapter 3.0).

The number of persons exposed to dichloroethane may be estimated
by assuming that the percent of water supplies where dichloroethanes
were detected equals the percent of the population exposed. This can
only represent a rough approximation since there is wide variation in
the size of water supplies, and it is not likely that the monitoring
data for dichloroethanes is a representative sample by size of the
water supply. However, for comparison purposes, it was estimated that
about 5 million persons are exposed to detectable levels of the 1,2
isomer as a result of surface water contamination, with an average
concentration of about 2 yg/1, or an exposure of about 4 yg/day (assuming
a consumption of 2 I/day). About 3 million persons may be exposed to
detectable levels of 1,1-dichloroethane in drinking water from surface
water supplies. Mean levels are 0.2 yg/1, resulting in a mean exposure
for these persons of 0.4 yg/day. These estimates assumed that 117
million persons utilize surface water supplies (Temple, Barker and
Sloane, Inc. 1977).

Similar estimates could be made for groundwater, assuming that
75 million persons utilize groundwater supplies (Temple, Barker and
Sloane, Inc. 1977). Thus, 5 million persons could be exposed to
detectable levels of the 1,2 isomer, and 13.5 million persons to
detectable levels of the 1,1 isomer. However, there are numerous
problems with making these estimations. The number of groundwater
samples taken in Federal surveys is too small to be considered repre-
sentative. The sample size from state surveys is larger, but is biased
toward the detection of contaminated supplies, as is shown in some cases
in Table 5-7 and 5-8. Thus, the population estimates are probably over-
estimated. It is also difficult to determine the levels of exposure.
According to Table 5-5, mean levels in groundwater are 0.2 and 0.3 yg/1
for the 1,2 isomer and 1,1 isomer, respectively, based upon limited
sampling. These levels represent typical exposures of 0.4 and 0.6 yg/day.
However, maximum values of 400 and 11,330 yg/1 suggest maximum exposures of
' 5-18
-------
TABLE 5-6. OCCURRENCE OF DICHLOROETHANES IN GROUNDWATER ™ STATE DATA
Compound
% Positive

No. States Tested No. Wells Tested Samples
Maximum
, 1-dichloroethane
9
785
18
(Mg/D
11,330
1,2-dichloroethane
12
1212
400
I
M
vo
Source: Coniglio et al. (1980).
-------
TABLE 5-7. GROUNDWATER DATA REPORTEDLY AVAILABLE FROM
STATE AGENCIES FOR l,2-DICHLOROETHANEa
No. Wells Tested % Positiveb

Alabama 80 3

Delaware 15 73

Florida 329 15

Kentucky 22 0

Maine 89 0

Massachusetts 163 3

New Jersey 411 2

North Carolina 44 7

South Carolina 4 25

South Dakota 1 0

Tennessee 50 8

Washington 4 0

a26 states have not tested for this compound.

These data represent a compilation and no information is available
on methods or detection limits.

Source: Coniglio et al. (1980).
5-20
-------
TABLE 5-8. GROUNDWATER DATA REPORTEDLY AVAILABLE FROM
STATE AGENCIES FOR l,l-DICHLOROETHANEa
No. Wells Tested % Positive*3

Alabama 80 8

Florida 329 36

Kentucky - 22 0

Maine 89 0

Massachusetts 163 1

North Carolina 44 14

South Carolina 4 0

Tennessee 50 26

Washington 4 0

a29 states have not tested for this compound.

These data represent a compilation and no information is available
on methods or detection limits.

Source: Coniglio e_t _al. (1980).
i-21
-------
800 and 23,000 yg/day may occur in some locations. It is unknown how
prevalent such exposures are.
•

5.2.2.2 Food

Numerous uses of 1,2-dichloroethane may result in contamination
of food, such as its use as a pesticide, grain fumigant, solvent to
clean grain mill machinery, solvent to extract oleoresins, and adhesive
coating for food packaging (Gold 1980). However, data on residues of
the compound in food are sparse.

Numerous formulations of the 1,2 isomer are registered for use as
fumigants as is shown in Table C-10 (see Appendix C); however, there is
some controversy as to whether residues are found in the crop after
storage. They have been exempted from a tolerance requirement when used
as a post-harvest fumigant on barley, corn, oats, popcorn, rice, rye,
wheat, and sorghum due to a lack of detection of the compound in baked
products (Gold 1980, Jacobson 1979). Although levels of 20-50 mg/kg have
been found in fumigated soybeans and wheat (Wit 1969, Storey et. _al. 1972).
residues in baked products have not been reported.

Berck (1974), on the other hand, was not able to remove or analyze
1,2-dichloroethane in wheat treated with Dowfume EB-5 (contains the
1,2 isomer, ethylene dibromide, and carbon tetrachloride). However,
no 1,2-dichloroethane was detected in cereal. It appears likely that
any 192-dichloroethane remaining in the milled product would be lost
through volatilization or degradation in baking. Support for this
hypothesis exists in the fact that ethylene dibromide was found in
wheat but not in baked bread.

Although, the 1,2 isomer is exempted from a tolerance, the World
Health Organization (WHO) established suggested guidelines for residue
limits of 50 mg/kg in raw cereal, 10 mg/kg in milled cereal products,
and 0.1 mg/kg in bread and other cooked cereal products (Anonymous 1975).

Jacobson (1979) reports that, in addition to its use as a fumigant,
the 1,2 isomer may be used by homeowners in northern California for
fruits and vegetables. This author points out that crops like straw-
berries and cabbage can be eaten raw within 1 day of harvest. The
extent of use of the compound is unknown, as is the resultant residue.

The 1,2 isomer is also used as a solvent to extract oleoresins
from spices. Page and Kennedy (1975) examined oleoresins for the
compound and found some evidence of contamination (see Table 5-9);
however, consumption of these products would be extremely low. For
example, assuming a pepper consumption of 0.4 g/day (USDA 1978), an
individual could consume about 5 yg/day of 1,2-dichloroethane from
pepper alone. A person consuming large amounts of these spices could
be ingesting larger amounts of the compound.
5-22
-------
TABLE 5-9. 1,2-DICHLOROETHANE RESIDUES FOUND IN SPICE
OLEORESINS FROM THREE MANUFACTURERS
Concentration
Spice Oleoresin

Black Pepper

Celery

Cinnamon

Clove

Mace

Marj oram

Paprika

Rosemary

Sage

Thyme

Turmeric
(yg/g)
Manufacturer
A j$
9
2
3
23
4
6
J 9
3
6
13
6
^
12
3

2
Source: Page and Kennedy (1975)
5-23
-------
In addition to these direct routes of contamination, Urosova (1953)
found the 1,2 isomer in mother's milk. The women had been occupationally
exposed to levels of 63 mg/m^. Their milk was found to contain 0.54-
0.64 mg/100 ml immediately after exposure. Exposure was thought to be
dermal, since gas masks were used. Eighteen hours after exposure, the
milk contained 0.2-0.6 mg/100 ml. However, maximum concentrations
allowed are currently 8 mg/m^ in the United States over a 15-minute
sampling period (NIOSH 1978). Thus, assuming a linear relationship,
milk of a woman exposed to the maximum of 8 mg/m^ could contain 0.07 mg
1,2-dichloroethane/lOO ml. Assuming a consumption of 1.5 I/day, an
infant could consume about 1 mg/day in milk from a woman exposed at
these levels.

Although low concentrations of 1,2-dichloroethane have been observed
in water, it has not been detected in marine aquatic organisms. The U.S.
EPA (1980), however, calculated a weighted average bioconcentration factor
of 1.2 for the compound. Assuming an average water concentration of 1 yg/1,
considering the data reported in Chapter 4.0, a concentration in fish of
about 1.2 lug/kg might be expected. Assuming an average consumption of
11 g/day (USDA 1980), an intake of 0.13 ug/day in fish can be estimated.

Thus, intake of 1,2-dichloroethane in food is not well documented.
It appears to come, however, from various sources as a result of its
uses. No information is available on levels of 1,1-dichloroethane in
food. It is expected, however, that human exposure to this compound
would be considerably less than to the 1,2 isomer.

5.2.3 Inhalation

5.2.3.1 Occupational

NIOSH (1978) estimates that about 2 million workers are exposed to
1,2-dichloroethane in about 150,000 work places. Occupational exposure
to 1,1-dichloroethane is much less extensive. Parker and coworkers
(1979), in a NIOSH bulletin, estimated that about 5000 workers are
exposed to 1,1-dichloroethane. While the level of occupational exposure
will not be a consideration of this report, it is important to note that
a large number of workers are exposed in numerous occupational settings.

NIOSH (1978) has recently lowered the standard for the 1,2 isomer
to 4 mg/m3 as a time-weighted average for up to a 10-hour workshift and
a 40-hour week. Assuming a respiratory flow of 1.2 m^/hr during the
working day (ICRP 1975), an exposure of 48 mg would result from a 10-hour
exposure. NIOSH also recommends a ceiling concentration of 8 mg/m^ over
a 15-minute sampling period. There are presently no standards for
1,1-dichloroethane.

5.2.3.2 Ambient Air

Limited data are available on concentrations of dichloroethanes in air
(see Chapter 4.0). Neither isomer has apparently been detected in rural
5-24
-------
areas, at a detection limit of 0.02 ug/m . Thus, a maximum exposure in
these locations would be 0.4 ug/day. The population size for rural areas
is estimated to be 55 million (U.S. Department of Commerce 1980). Recent
data show average levels of 1.6-6.0 yg/m 1,2-dichloroethane in industrial
areas of New Jersey where it was detected. Of the 308 samples taken,
quantifiable levels of the 1,2 isomer (at 0.04 ug/m ) were found in 40%
of the samples. The maximum value reported was 64 ug/m in Newark (Boz-
zelli and Kebbekus 1979). These levels would result in exposures of
32-130 ug/day and 1300 ug/day for average and maximum conditions.
3
Suta (1979) has estimated that concentrations of 0.04-0.12 ug/m of
1,2-dichloroethane might be found in urban areas and in the vicinity of
gas stations. This is not inconsistent with the data described above,
although higher levels of up to 1.4 ug/m have been reported in urban
areas (see Chapter 4.0). Suta also estimates that 14 million persons are
exposed to these concentrations. This population could inhale 0.8-28
Ug/day of the 1,2 isomer, assuming a respiratory flow of 20 m^/day for
adults. Presumably the other 152 million persons residing in urban areas
(U.S. Department of Commerce 1980) receive exposures of less than 0.8
Ug/day. In one study, average levels of 0.24-0.26 ug/nr were reported
for 1,1-dichloroethane in urban areas, resulting in exposures of about
5 ug/day.

5.2.3.3 Indoor Air

Limited information suggests that levels in air indoors may be
similar to levels in air outdoors. Pellizzari and coworkers (1979)
sampled basements of houses in the old Love Canal area in New York.
No 1,1-dichloroethane was reported. The 1,2 isomer was detected in
2/10 samples at 0.10 and 0.13 ug/m^. Traces were measured in ambient
air. Harris (1972) found levels of 11 ug of 1,2-dichloroethane/m3 in
the controlled airspace of a grounded spacecraft.

5.2.3.4 Near Sources

As discussed in Chapter 4.0, high levels of 1,2-dichloroethane
have been observed in the vicinity of production facilities. Suta (1979)
utilized dispersion modeling and information on the living patterns of
populations near production facilities to estimate that 12.5 million
people are exposed to average annual concentrations of 1,2-dichloro-
ethane of 0.04-40 ug/m3. Table 5-10 illustrates the distribution of
exposures. Suta also estimated that another 2.3 million persons are
exposed to 0.04-4 ug/m3 as a result of emissions of the 1,2 isomer
from plants that use it as a feedstock. However, this would appear to
be double counting for the most part, since most of these plants also
produce the compound. The concentrations shown in Table 5-10 would be
slightly higher due to the use of the compound as a feedstock. For the
most part, however, the emissions are due to the production (see
Chapter 3.0).

Inhalation exposures may also occur in the vicinity of gasoline
stations. However, exposures of this nature would be of very short
duration. For example, Suta (1979) estimated that about 30 million
Americans are exposed to 1,2-dichloroethane while filling their tanks
5-25
-------
TABLE 5-10. ESTIMATED HUMAN POPULATION EXPOSURES TO ATMOSPHERIC
1,2-DICHLOROETHANE EMITTED BY PRODUCERS
Number of People
Annual Average Atmospheric Concentration Average Exposure Exposed
(yg/m3) (ug/day)

40 800 1700

24-40 480-800 3300

12-24 240-480 28,000

4-12 80-240 280,000

2.4-4.0 48-80 400,000

1.2-2.4 24-48 1,500,000

0.40-1.2 8-24 4,300,000

0.24-0.40 4.8-8 l,900,000b

0.12-0.24 2.4-4.8 3,500,000b

0.04-0.12 0.8-2,4 550,000b

Total 12,500,000
Assumes inhalation of 20 m /day.
b
These are underestimates because the dispersion modeling
results were not extrapolated beyond 30 km from each
1,2-dichloroethane production facility.
Source: Suta (1979).
5-26
-------
in self-service stations. He estimates this large subpopulation is
exposed to 6 yg/m for 2.2 hr/yr; however, this seems too low. It has
been assumed for this report that a person fills his gasoline tank an
average of once a week, spending 10 minutes per visit. Thus, an expo-
sure duration of about 9 hr/yr can be estimated, or 0.02 hr/day.
Assuming a respiratory flow of 1.2 m-Vhr, this is a time-weighted expo-
sure of 0.1 yg/day.

In the case of a gasoline spill, air concentrations could be much
higher. McDennott and Killiany (1978) and Jacobs (1979) both calculated
the equilibrium vapor concentration of the 1,2 isomer in unleaded gaso-
line to be about 800 yg/m . This would, however, be an acute episode
of perhaps 1-8 hours, thus resulting in an exposure of 960-7680 yg
1,2-dichloroethane, assuming a respiratory flow of 1.2 m /hr.

Homeowners applying 1,2-dichloroethane as a pesticide would also
be subject to inhalation exposure. The information regarding the nature
and extent of this use does not allow the estimation of exposure.

5.2.4 Dermal Exposure

Numerous uses of 1,2-dichlbroethane could result in dermal exposure,
especially its use in gasoline, as a fumigant, and as a cleaning solvent.
Gasoline contains about 0.95 g of the compound/gallon of gas, or about
250 mg/1. Only one solvent containing 1,2-dichloroethane (at 50 mg/1)
is available for consumer use (Gold 1980). Pesticides may contain 70%
or 700,000 mg/1 of the compound. In order to estimate exposure to these
products, it was assumed that a spill occurred on 5% of the body's
surface area or about 800 cm . This is about equal to the surface area
of both hands. The duration of exposure was assumed to be 2 minutes,
and the permeability constant for 1,2-dichloroethane was assumed to be
0.01 cm/hr, which is intermediate between butanol and chloroform, and
about equal to that for ethyl ether. Table 5-11 shows the dermal expo-
sures that were calculated, ranging from 0.01-185 mg as acute exposures.

These scenarios illustrate the relative magnitude of exposure. In
addition, inhalation exposures would result from such incidents.

Dermal exposure to 1,1-dichloroethane is unknown, but is expected
to be small, since the compound is not used in any products available to
the consumer.

5.2.5 Exposures Resulting From 1,2-Dichloroethane as a Contaminant
in Other Products

Table 5-12 summarizes the concentration of 1,2-dichloroethane in
other products (see Chapter 3.0). Dermal and inhalation exposures may
occur as a result of the use of these products.
5-27
-------
TABLE 5-11. DERMAL EXPOSURES TO 1,2-DICHLOROETHANE
RESULTING FROM SPILLS-
Concentration in
Product Product (mg/1) Exposure (mg)

Pesticide 700,000 185

Solvent 50 0.01

Gasoline 250 0.07

Source: See Chapter 3.0.
5-28
-------
TABLE 5-12. CONCENTRATION OF 1,2-DICHLOROETHANE
AS A CONTAMINANT IN OTHER COMPOUNDS
Final Product Concentration
(mg/kg)

VCM 10

1,1,1-trichloroethane 1-10

Ethyleneamines 1-10

Trichloroethylene < 1

Tetrachloroethylene < 1

Vinylidene chloride 1

Source: See Chapter 3.0.
5-29
-------
5.2,6 Overview

The general population is largely exposed to 1,2-dichloroethane in
drinking water from surface supplies (^4 yg/day) and food (^6 yg/day).
Inhalation may be an important route of exposure in some urban areas due
to the use of this compound in leaded gasoline (^0.8-28 yg/day). Inhala-
tion would be the predominant route of exposure for persons living in
highly industrial areas due to the common use of this compound as a
solvent (^32-120 yg/day). Persons living in the vicinity of production
facilities can receive 0.8-800 yg/day through inhalation, depending
upon their distance from the plant.

However, local situations may occur which reverse these trends.
For example, local contamination of drinking water, especially ground-
water, may occur resulting in exposures of up to 800 yg/day via this
route. In addition, maximum inhalation exposures of 1300 yg/day may
occur in industrial areas. A potential exposure route which warrants
more investigation is the suggestion that nursing infants of occupa-
tionally exposed mothers may receive up to 1000 yg/day in breast milk.

In addition to these chronic exposures, acute exposures may occur as
a result of gasoline, solvent, and pesticide spills. An 8-hour exposure
to a gasoline spill could result in an exposure of about 8000 yg. A two-
minute dermal exposure could result in an exposure of 70 yg for gasoline,
70 yg for a commercial solvent, and 185,000 yg for a pesticide. The
latter is due to the high levels of the 1,2 isomer in pesticide formula-
tions. Table 5-13 summarizes the estimates of human exposure to 1,2-
dichloroethane.

Exposure to 1,1-dichloroethane is largely unknown. It appears that
an important route of exposure is drinking water; typical exposures of
0.4-0.6 yg/day are found. While contamination of surface waters does
not appear to be very common, contamination of groundwater appears
relatively frequently. Even in the Federally collected data, this
compound was found in 23% of the groundwater supplies, and this sampling
is probably not severely biased toward contaminated sites. In the state-
collected data, 18% of the groundwater supplies tested contained
1,1-dichloroethane, although this sampling is more likely to be biased.
Thus, it appears that exposure to 1,1-dichloroethane in drinking water
is relatively common. In addition, maximum levels have resulted in
exposures of up to 23,000 yg/day. Exposure via inhalation, at levels of
about 5 yg/day, have been reported in urban areas.
5-30
-------
TABLE 5-13. HUMAN EXPOSURE TO 1,2-DICHLOROETHANE
General Population
Route
Ingestion
Drinking water
Surface

Ground

Food
Pepper
Fish

Inhalation
Rural areas
Urban areas

Industrial areas
Near production facilities
Persons using self-service
gas stations
ibpopulation Size

5 million
112 million
5 million
70 million
large
may be large
large
14 million
152 million
may be large
300,000
6.2 million
6 million*
Assumptions
2 pg/1, 2 I/day
<1 pg/1, 2 I/day
0.3 ug/1, 2 I/day
<0.2 pg/1, 2 I/day
0.4 g pepper/day, 12 pg/g
1 pg/1 in water, BCF of 1.2
11 g fish/day
<0.02 pg/m3, 20 m3 air/day
0.04-1.4 ug/m3, 20 m3
<0.04 ug/m3, 20 m3
1.6-6.0 iJg/m3, 20 m3 air/day
4-40 pg/m3, 20 m/3 day
0.4-4 |jg/m3, 20 m3/ day
0.04-0.4 pg/m3, 20 m3/day
Exposure
(pg/day)
4
<2
0.6
<0.4
5
0.13
<0.4
0.8-28
<0.8
32-120
80-800
8-80
0.8-8
30 million
6 pg/m , 0.02 hr/day
0.1
-------
TABLE 5-13. HUMAN EXPOSURE TO 1,2-DICHLOROETHANE (Continued)
Isolated Subpopulations
Route
Ingestion
Drinking water
Surface
Ground
Food
Breast-fed infants

Inhalation
Occupational
Industrial
Acute Exposures
Inhalation
gasoline spill
Dermal
gasoline spill
Assumptions
maximum level of 4.8 yg/1, 2 I/day
maximum level of 400 ug/1, 2 I/day
Exposure
9.6 j.ig/day
800 US/day
mother's occupational exposure at
4 mg/m3, 0.07 tng/100 oil milk, 1.5 1 milk/day 1000 ug/day
4 mg/m3, 10-hour exposure, 1.2 m3 air/hour 48,000 ug/day
maximum level of 64 ug/m3/day, 20 m3/day 1300 ug/day
800 pg/m , 1-8 hour exposure, 1.2 m3/hour

2
spill to 800 cm j permeability constant
of 0.01 cm/hour, duration of 2 minutes,
concentration of 250 mg/1 in gasoline
960-7680 ug
70 ug
solvent spill
spill to 800 cm , permeability constant
of 0.01 cm/hour, duration of 2 minutes,
concentration of 50 mg/1 in solvent
10 pg
pesticide spill
spill to 800 cm2, permeability constant
of 0.01 cm/hour, duration of 2 minutes,
concentration of 700,000 mg/1 in product
185,000 ug
Underestimated
Source: See text.
5-32
-------
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Smyth, H.F., Jr.; Cummings, D.E. Memorial Lecture. Am. Ind. Hyg.
Assoc. Quart. 17:129; 1956. (As cited by Irish 1963)

Spencer, H.C.; Rowe, V.K.; Adams, E.M.; McCollister, D.D.; Irish, D.D.
Vapor toxicity of ethylene dichloride determined by experiments on
laboratory animals. Arch. Ind. Hyg. Occup. Med. 4:482-493; 1951. (As
cited by NIOSH 1976)

Spreafico, F.; Zuccato, E. ; Marcucci, F.; Sironi, M.; Paglialunga, S-;
Madonna, M. ; Mussini, M. Pharmacokinetics of ethylene dichloride in
rats treated by different routes and its long-term inhalatory toxicity.
In Ethylene dichloride: a potential health risk? Banbury Rep. 5:107-
135; 1980.

Storey,C.L. ; Kirk, L.D.; Mustakas, G.C. Fate of EDC-CC14 (ethylene
chloride-carbon tetrachloride (75:25) during milling and oil extraction
of soybeans. J. Econ. Entomol. 65:1126; 1972. (As cited by Berck 1974)

Suta, B.E. Assessment of human exposures to atmospheric ethylene
dichloride. Research Triangle Park, NC: Office of Air Quality Planning
and Standards, U.S. Environmental Protection Agency; 1979.
5-37
-------
Temple, Barker and Sloane, Inc. Survey of operating and financial
characteristics of community water systems. Washington, DC: Office
of Water Supply, U.S. Environmental Protection Agency; 1977.

Theiss, J.D.; Stoner, G.D.; Shimkin, M.B.; Weisburger, E.K. Test for
carcinogenicity of organic contaminants of United States drinking waters
by pulmonary tumor response in strain A mice. Cancer Res. 37(8)Pt. 1:
2717-2720; 1977.

Urusova, T.P. About a possibility of dichloroethane absorption into
milk of nursing women when contacted under industrial conditions. Gig.
Sanit. 18(3):36-37; 1953. (As cited by NIOSH 1976)

U.S. Department of Agriculture (USDA). Food and nutrient intakes of
individuals in 1 day in the United States, Spring 1977. Nationwide
Food Consumption Survey 1977-78. Preliminary Report No. 2. Washington,
DC: U.S. Department of Agriculture, Science and Education Administration;
1980.

U.S. Department of Commerce. Statistical abstract of the United States.
Washington, D.C., Bureau of the Census, 1980.

U.S. Environmental Protection Agency (U.S. EPA). Ambient water quality
criteria. Criterion document — trichloroethylene. Washington, DC:
Criteria and Standards Division, Office of Water Planning and Standards;
1979. Available from NITS, Springfield, VA: PB 292 445.

U.S. Environmental Protection Agency (U.S. EPA). Ambient water quality
criteria for chlorinated ethanes. Report No. EPA 440/5-80-029.
Washington, DC: Office of Water Regulations and Standards, U.S.
Environmental Protection Agency; 1980.
U.S. Environmental Protection Agency (U.S. EPA). Monitoring of ambient
levels of EDC near production and user facilities. Research Triangle
Park, NC: Environmental Monitoring and Support Laboratory, U.S.
Environmental Protection Agency; 1975.

Van Durren, B.L.; Goldschmidt, B.M.; Loewengart, G.; Smith, A.C.;
Melchionne, S.; Seldman, I.; Roth, D. Carcinogenicity of halogenated
olefinic and aliphatic hydrocarbons in mice. J. Natl. Cancer Inst.
63(6):1433-1439; 1979.

Vozovaya, M.A. Development of offspring of two generations obtained
from females subjected to the action of dichloroethane. Gig. Sanit.
7:25-28; 1974. Abst.

Watrous, R.M. Health hazards of the pharmaceutical industry. Br. J.
Ind. Med. 4:111-125; 1947. (As cited by IARC 1979)
5-38
-------
Wit, S.L.; Besemer, F.H.; Das, H.A.; Goedkoop, W.; Loojes, F.E.;
Meppelink, E.R. Results of an investigation on the regression of three
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Institute of Public Health, Bilthoven, Netherlands; 1969. (As cited by
Gold 1980)

Yllner, S. Metabolism of l,2-dichloroethane-14C in the mouse. Acta
Pharmacol. Toxicol. 30:257-265; 1971. (As cited by NIOSH 1976)

Yodaiken, R.E.; Babcock, J.R. 1,2-dichloroethane poisoning. Arch.
Environ. Health 26(5):281-284; 1973.
5-39
-------
-------
6.0 EFFECTS AND EXPOSURE -- AQUATIC BIOTA
6.1 EFFECTS ON BIOTA

6.1.1 Introduction

This section provides information about the levels of 1,1- and
1,2-dichloroethane exposure at which the normal physiologic processes
and behavior of aquatic organisms are disrupted, as indicated by labora-
tory and field studies. The data base on the toxicity of these compounds
is very limited, tests having been conducted for only a few species. The
1,2 isomer is a liquid and is sufficiently water soluble to be of poten-
tial concern as a water pollutant (U.S. EPA 1980a). Most of the studies
conducted on marine freshwater organisms were static toxicity tests,
which would most closely approximate the occasional and short-term occur-
rence of higher concentrations of 1,2-dichloroethane found in aquatic
systems. No toxicity data were available for 1,1-dichloroethane specifi-
cally.

6.1.2 Freshwater Organisms

Two freshwater organisms, bluegill (Lepomis macrochirus) and Daphnia
were tested for their sensitivity to 1,2-dichloroethanes. In static bio-
assays, the 96-hr 1650* values for these organisms were 550 mg/1 and
218 mg/1, respectively (Dawson et al. 1977). Bioassays were also
conducted under the same conditions using several other chlorinated
ethanes. In general, the less chlorinated compounds were more toxic to
Daphnia than to bluegill. Other studies on rainbow trout indicate an
LC5Q of greater than 100 mg/1 in 13°C water of pH 7.1 and 40 mg/1 hard-
ness (Drury and Hammons 1979). The uptake of C02 was reduced by 50% in
the alga Phaeodactylum tricomutam in a concentration of 340 mg/1
(Pearson and McConnell 1975). No data were found on chronic or sublethal
effects for freshwater organisms.

Chlorinated ethanes do not strongly bioaccumulate and the bioconcen-
tration factor for 1,2-dichloroethane in bluegill was approximately 2
(U.S. EPA 1980a).

6.1.3 Marine Organisms

As was found for freshwater organisms, very little data exist
regarding acute effects on marine biota; chronic effects data include
only one study on reproduction of polychaetes. Pearson and McConnell
(1975) studied the marine flatfish Limnada limnada and determined the
LC5Q to be 115 mg/1 for 1,2-dichloroethane. Marine invertebrate toxicity
values were found to be 2 mg/1 for the mysid shrimp Mysidopsis
bahia and greater than 433 'mg/1 for the alga Skeletonema costatum
(U.S. EPA 1978).

*
LC5Q is the concentration that is lethal to 50% of the test organisms.
6-1
-------
Static tests using 1,2-dichloroethane were conducted on the poly-
chaete Ophryotrocha and the shrimp, Crangdon crangdon. In 300 mg/1
1,2-dichloroethane all shrimp in the tests were killed within 7 hours.
After 24 hours the LC^Q value was approximately 170 mg/1. Mortality
decreased after 1-2 days, probably due to loss through volatilization.
In shock experiments with the 1,2 isomer, in which the polychaetes were
suddenly introduced into the test solution, all animals in concentrations
of greater than 800 mg/1 1,2-dichloroethane were killed within 24 hours;
in 400 mg/1, half of the test population was dead after the same time.
During the following 8 days of the experiment, only 10% more of the
animals died. In concurrent tests, wherein the concentration of the
compound was successively increased, all animals in concentrations of
less than 800 mg/1 survived for at least 8 days. In 1000 mg/1, 75% of
the test population was dead within 4 days (Rosenberg ^t J^> 1975).

Sublethal effects of 1,2-dichloroethane on reproductivity of the
marine polychaete Ophryotrocha labronica were also investigated. Eggs
laid in concentrations of 50, 100, and 200 mg/1 1,2-dichloroethane
showed hatching of 100%. In 400 mg/1 hatching success decreased to
approximately 10%, although the number of egg masses initially laid was
not reduced. In 600 mg/1 the average number of eggs per egg mass and
the number of egg masses were reduced compared to those at lower concen-
trations of 1,2-dichloroethane. In shock experiments with 800 and
400 mg/1, almost the entire test population of adult Q_. labronica was
killed within one day (Rosenberg _et aJL. 1975).

6.1.4 Factors Affecting Toxicity of Dichloroethanes

No information was found in the literature concerning the effects
of salinity, temperature, or other water quality factors on the toxicity
of dichloroethanes.

6.1.5 Conclusions

According to the literature surveyed, the lowest concentration at
which adverse effects of 1,2-dichloroethane have been detected in aquatic
biota is 2.0 mg/1, which caused mortality in the mysid shrimp Mysidopsis
bahia, a marine organism. Freshwater acute toxicity data were extremely
limited and no chronic data were available. The range of toxic levels for
the few freshwater species tested was approximately 200-550 mg/1.

The effects of 1,2-dichloroethane on marine organisms have been
studied somewhat more extensively. The most sensitive organisms were
the shrimp Crangdon crangdon, LC5Q 170 mg/1, and the flatfish Limnada
limnada, LCjg 115 mg/1. Acute toxicity levels for other marine species.
including algae, polychaetes, and brine shrimp, were in the 300-500 mg/1
range. Reproductivity in the polychaete Ophryotrocha labronica was
affected in concentrations of greater than 200 mg/1.

The EPA has not set water quality criteria for aquatic life due to
the lack of data (U.S. EPA 1980a).
6-2
-------
• 1.0 ug/1-2 mg/1

• 2.0-100 mg/1

• 100-300 mg/1
• 300-550 mg/1
In summary, although data are extremely limited, general concentra-
tion ranges can be suggested at which certain effects are seen in the
laboratory. These ranges are not rigidly defined, and may overlap as a
result of differences among species or environmental variables.

• 1.0 ug/1 This represents the detection limit for
1,2-dichloroethane generally reported in
monitoring studies. No adverse effects
have been observed at this level.

No adverse effects have been observed
in this range.

Concentrations in this range have been
found toxic to mysid shrimp, a marine
species.

Concentrations of the 1,2 isomer acutely
toxic to marine flatfish, Daphnia, marine
shrimp, and several arthropods. No
chronic data available for this range.

Sublethal effects on reproductive
viability in polychaetes reported for
this range. Acute toxic effects on
bluegill, marine algae Skeletonema
costatum, adult Qphryotorcha, and brine
shrimp Artemia; reduced oxygen uptake
in freshwater algae.

6.2 EXPOSURE OF BIOTA

6.2.1 Introduction

Releases of dichloroethanes to the environment are primarily to the
air during primary production or end-product manufacture. Large amounts
of dichloroethanes are disposed of on land, usually by burial in land-
fills, and small amounts are discharged directly to water. Chapter 3.0
of this report addresses the sources and amounts of discharges of
dichloroethanes to aqueous systems per year in the United States. The
1,2 isomer is a volatile compound with a half-life in river water of
about 35 hours (see Chapter 4.0). Although washout of dichloroethanes
may occur, it is not expected to be a dominant pathway to aquatic
systems.

6.2.2 Monitoring Data

Overall, monitoring data for the dichloroethanes is quite limited;
but there is some nationwide data from several sources.
6-3
-------
During 1975 and 1976, 204 water samples were collected by the
University of Illinois from 14 heavily industrialized U.S. river basins.
The detection limit for dichloroethanes in these tests was 1 ug/1 or
greater. The 1,2 isomer was detected in 53 of the 204 samples, and most
of these concentrations were near 1 ug/1. The Delaware River in general
had higher concentrations, and one sample near Bridesburg, Pennsylvania
was 90 ug/1 (see Table 4-2).

Water quality monitoring data retrieved from STORET yield samples
from 12 of the 18 EPA STORET major river basins in the continental
United States (U.S. EPA 1980b). Dichloroethanes are not a frequently
measured parameter, thus the data base is very limited. Very little
monitoring data were available from the Texas and Louisiana Gulf coasts
where there is a heavy concentration of dichloroethane production.

Of the 280 samples of dichloroethanes reported, nearly all the values
were below the detection limit, generally 10 yg/1. There were several
scattered incidences of value from 20-50 yg/1. Concentrations of greater
than 50 yg/1 were found in nine samples from five major river basins,
including the areas of the Northeast and Southeast, and in the Ohio Upper
Mississippi and Upper Missouri Rivers. In order to further examine the
high concentrations, data were retrieved from the sampling stations within
these five major river basins. Table 6-1 shows the location and source of
these high dichloroethane concentrations.

6.2.3 Ingestion

No specific studies were found that addressed the uptake by or
effects on aquatic organisms of dichloroethanes via ingestion.

6.2.4 Fish Kills

No data were found in the literature concerning any fish kills
related to dichloroethanes in aquatic environments.

6.2.5 Conclusions

Given the shortage of monitoring data for dichloroethanes, it is
difficult to estimate exposure levels of dichloroethanes in aquatic
systems. Based on the available data, however, it would appear that
where these compounds are detected, they are almost always found in low
concentrations, generally lower than those levels which have been deter-
mined toxic to aquatic biota in laboratory studies, as discussed in
Section 6.1. The infrequent higher concentrations may have occurred as
a result of an accidental spill or some non-routine input from a specific
plant to the environment. In cases where measurements were taken the
same day or a few days later, concentrations had decreased. Given the
short self-purification time of dichloroethanes in river water of 6-9
hours, as predicted by EXAMS (U.S. EPA 1980c), these concentrations
probably did not persist for long. Overall, the concentrations to which
aquatic biota are exposed on a nationwide basis are in the low ug/1
range.
6-4
-------
TABLE 6-1. MAXIMUM OBSERVED DICHLOROETHANE CONCENTRATIONS
IN U.S. RIVER BASINS (1974-1978)
River Basin
Wall Kill River
(Middle Hudson River)
Concentration
Sampling Station/Area Isomer ug/1

Ames Rubber Corp. 1,1 110.0
Hamburg, NJ
St. John's River Basin
SCM Corp. 1,1
Jacksonville, FL
200.0
Ohio River
The B.F. Goodrich Co. 1,2
Louisville, KY
1100.0
Upper Mississippi River
Mississippi River 1,2
Alton, IL 1,1
210.0; 98.0
1900.0
Lower Missouri River
Blue River near
Missouri River
confluence
1,2 60.0; 230.0
Source: U.S. EPA (1980b).
6-5
-------
REFERENCES

Dawson, G.W.; Jennings, A.L.; Drozdowski, D.; Rider, E. The acute
toxicity of 47 industrial chemicals to fresh and salt water fishes.
J. Hazardous Mater. 1(4):303-318; 1977. (As cited in U.S. EPA 1980a)

Drury, J.S.; Haramons, A.S. Investigations of selected environmental
pollutants: 1,2-dichloroethane. Washington, DC: Office of Toxic
Substances, U.S. Environmental Protection Agency; 1979.

Pearson, C.R. ; McConnell, G. Chlorinated C]_ and G£ hydrocarbons in the
marine environment. Proc. R. Soc. Lond. B. 189:305-322; 1975.

Rosenberg, R.; Grahn, 0.; Johansson, L. Toxic effects of aliphatic
chlorinated by-products from vinyl chloride production of marine
animals. Water Res. 9:607-612; 1975.

U.S. Environmental Protection Agency (U.S. EPA). Ambient water quality
criteria for chlorinated ethanes. Washington, DC: Office of Water
Regulations and Standards, U.S. Environmental Protection Agency; 1980a.

U.S. Environmental Protection Agency (U.S. EPA). In depth studies on
health and environmental impacts of selected water pollutants.
Washington, DC: U.S. Environmental Protection Agency; 1978. (As cited
in U.S. EPA 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; 1980c.

U.S. Environmental Protection Agency (U.S. EPA). STORET. Washington,
DC: Monitoring and Support Division, U.S. Environmental Protection
Agency; 1980b.
6-6
-------
7.0 RISK CONSIDERATIONS
7.1 INTRODUCTION

This chapter will consider the integration of effects and exposure
or risk to humans and other biota. This will be done as quantitatively
as possible in view of available data. However, in many cases, due to
the number and type of assumptions made, the results obtained must be
qualified. The scenarios which involve a great deal of uncertainty will
be noted.

7.2 HUMANS

7.2.1 Health Effects

The compound 1,2-dichloroethane has been shown to be carcinogenic
in rats and mice when administered by gavage. Squamous-cell carcinoma
of the forestomach, hemangiosarcoma, and mammary adenocarcinoma have
been noted in rats; alveolar/bronchiolar adenomas, mammary adenocarcino-
mas, and endometrial tumors have been observed in mice. In addition,
lifetime dermal exposure of mice to 1,2-dichloroethane produced an
elevated incidence of benign lung tumors. However, both rats and mice
exposed to 1,2-dichloroethane via inhalation showed no increased inci-
dence of malignant tumors.

Several possible explanations of these differences in results were
proposed in Chapter 5.0 and will only be mentioned here briefly. The
conflicting results do not appear to be explained by differences in
purity of the administered compound or phannacokinetics. There may be
a difference in strain sensitivity in the different tests. Another
possibility is that the gavage route might result in the production of
carcinogenic metabolites of 1,2-dichloroethane in the gut that would not
occur upon inhalation. In essence, however, this disparity of results
remains to be resolved.

Studies with 1,2-dichloroethane suggest that it is an effective
mutagen in the presence of a metabolic activation system, such as is
found in vivo. In general, no teratogenic or reproductive effects have
been noted as a result of inhalation of 1,2-dichloroethane. One Russian
study reported fetotoxic effects, but similar exposure of the same species
at concentrations of five times that used in the Russian study induced no
significant treatment-related effects.

Human ingestion of 15 ml 1,2-dichloroethane has been lethal, although
ingestion of 50 ml has been survived. Exposures to 40-400 mg/m^ via
inhalation for at least a few weeks have been associated with such effects
as CNS depression, GI upset, and kidney and liver damage.
7-1
-------
Little is known regarding the toxicity of 1,1-dichloroethane.
Carcinogenicity tests (gavage) have been inconclusive due to poor
survival. No information is available regarding inutagenic activity.
Fetotoxic effects have been observed in rats upon inhalation of high
levels of 1,1-dichloroethane (24,300 mg/rn^) during gestation. However,
no effects were noted in rats similarly exposed to 15,390 mg/m .
Chronic toxic effects appear to be similar to these observed for
1,2-dichloroethane.

The effects discussed above, as well as in Chapter 5.0 are sum-
marized with their corresponding effect levels in Tables 7-1 and 7 2.

7.2.2 Exposure

Section 5.2 discusses the potential for human exposure to dichloro-
ethanes. These results are summarized in Table 7-3- The discussion in
Section 5.1 noted no major differences in the pharmacokinetics or tissue
distribution of 1,2-dichloroethane due to exposure route. The 1,2 isomer
has been indicated as a carcinogen via ingestion, but results have been
negative for inhalation exposures. Therefore, these exposure routes
will be differentiated in the following discussion. In addition, it
should be noted that 100% absorption has been assumed.

As can be seen in the table, ingestion exposure to 1,2-dichloro-
ethane of the general population is around 7 yg/day, resulting primarily
from ingestion of contaminated surface waters, and from residues in
spices. It has been estimated that about 5 million persons are exposed
to detectable levels of 1,2-dichloroethane in surface water. Persons
utilizing groundwater supplies could receive a lower exposure, on the
order of 6 yg/day. The contribution from inhalation in rural areas is
probably very low. However, in urban areas (involving up to 14 million
persons) inhalation exposures may contribute up to 28 yg/day. The
exposure to 1,2-dichloroethane of persons living in highly industrial
areas and near production facilities would be dominated by inhalation,
with a maximum exposure of about 800 yg/day.

Certain other subpopulations, however, also receive high exposures.
Of particular concern are the high levels reported in groundwater,
resulting in exposures up to 800 yg/day. The source of these reported
exposures is unknown, but may be due to land disposal of solvent wastes
or other wastes containing 1,2-dichloroethane. The data are too limited
to determine the prevalence of these exposures, but considering the wide-
spread use of 1,2-dichloroethane, these incidents may not be uncommon.

Since 1,2-dichloroethane is apparently transferred into mother's
milk, breast-fed infants may also receive a high exposure to the compound
if their mothers are exposed to high levels of this compound.

In addition, persons may occasionally be exposed to higher levels ct"
the 1,2 isomer in industrial areas. The maximum estimated exposure is
1300 yg/day; however, this may not represent a chronic exposure.
7-2
-------
TABLE 7-1. ADVERSE EFFECTS OF 1,2-DICHLOROETHANE
i
UJ
Adverse Effect
Carcinogenesis
Species
Heritable
Mutation
Teratogenesis
Neurological
disorders
Lethality
(ingestion)
Rat (Osborne-Mendel)

Mouse (B6C3F1)

Rat (Sprague-Dawley)
Mouse (Swiss)
Drosophila (sex-linked
recessive)

Drosophila (somatic
mutation)

Rat (Sprague-Dawley)
Human

Human

Rat
Lowest Reported Effect Level

47 mg/kg/day technical grade
by gavage, 5 days/week for
78 weeks

149 mg/kg/day technical grade
by gavage, 5 days/week for
78 weeks
No Apparent Effect Level
4.9 g/1

0.5% in diet
100 mg/ra , 8 hours/day,
5 days/week for 6 months
5 years

LDL0 15 ml

LD 700 mg/kg
600 mg/m , 99.8% pure
99.8% pure, 7 hours/day,
5 days/week for 78 weeks
400 mg/m , 7 hours/day,
days 6-15 of gestation

difficult to deduce from
literature
Source: Data taken from Section 5.1.1 of this report.
-------
TABLE 7-2. ADVERSE EFFECTS OF 1,1-DICHLOROETHANE ON MAMMALS
Adverse Effect
Carcinogenesis
Fetotoxicity
(delayed ossification)

Mutagenesis
Chronic oral
toxiclty
Lethality
(ingestion)
Species

Rat
Mouse
Rat
Rat
Lowest Reported Effect Level No Appa ren t Effect Le ve 1

No conclusive evidence is —
currently available, but some
dose-related marginal increases
in some tumor types noted for
both rats and mice in a gavage
study complicated by poor
survival.
24,300 rng/m , 7 hours/day,
days 6-15 of gestation
No data available
No data available
LD5Q 700 mg/kg
15,390 mg/m , 7 hours/day,
days 6-15 of gestation
Source: Data taken from Section 5.1.2 of this report.
-------
TABLE 7-3. ESTIMATED HUMAN EXPOSURE. TO 1,2-DICHLOROETHANE
General Population
Route
Ingestion
Drinking water
surface
Food
ground
I
pepper
fish
Inhalation
Rural areas
Urban areas (levels resulting
from gasoline use)
Industrial areas
In the vicinity of production
facilities
Subpopulation Size
M.12 million
•\, 5 million
unknown3
^70 million
large
may be large
55 million
14 million
152 million
may be large
300,000
6.2 million
6 million13
Exposure
(yg/day)
<2
4
0.6
<0.4
5
0.13
< 0.4
0.8-28
<0.8
32-120
80-800
8-80
0.8-8
Persons using self-service
gas stations
30 million
0.1
-------
TABLE 7-3. ESTIMATED HUMAN EXPOSURE TO 1,2-DICHLOROETHANE (Continued)
Isolated Subpopulations
Route
Ingestion
Drinking water
surface
ground - maximum
Food
breast-fed infants - maximum from
occupationally exposed mothers
Inhalation
occupational
industrial - maximum
Acute Exposures
Inhalation
gasoline spill
Dermal
gasoline spill
solvent spill
pesticide spill
Exposure
(ug/day)
9.6
800
1000

48,000
1300
960-7680 ug

70 yg
10 ug
185,000
A number of 5 million was discussed in Section 5.2. However, due
to the considerable uncertainty associated with this estimate, it
was not included in this table to be associated with risk.
This population is probably underestimated.
Source: See Section 5.2, as well as Table 5-13 for sources
of information as well as derivation of estimates.
7-6
-------
Spills of products containing 1,2-dichloroethane can result in
dermal and inhalation exposure, although these exposures are not of a
chronic nature. Of particular concern is the use of 1,2-dichloro-
ethane as a pesticide, which may contain 700,000 mg/1 active ingredient.

The major sources of uncertainty in the exposure estimates presented
in Table 7-3 are:

• Lack of adequate monitoring data for groundwater
resulting in an inability to estimate the size of the
population exposed as well as the levels.

• Limited data available on residues of 1,2-dichloroethanes
in spices and other foods.

• No information available on levels in breast milk from
exposed mothers, aside from cases of extremely high
occupational exposures.

• Lack of monitoring data to validate air concentration
models in urban areas. Monitoring of industrial areas
has been very limited, aside from production facilities.

Exposures to 1,1-dichloroethane are largely unquantified. Drinking
water exposure may be in the range of 0.4-0.6 pg/day. Surface water
contamination is relatively rare, but presence in groundwaters appears
to be more common. Maximum levels have resulted in exposures of up to
23,000 yg/day. Inhalation exposures of 1,1-dichloroethane are signifi-
cantly lower than the 1,2 isotner, or about 5 ug/day in urban areas.

7.2.3 Human Risk Evaluation

7.2.3.1 Carcinogenicity

Ambient Water Quality Criteria - Human Health

The Environmental Protection Agency has established an ambient
x^ater concentration for the maximum protection of human health from the
potential carcinogenic effects of 1,2-dichloroethane exposure through
ingestion of water and contaminated aquatic organisms (U.S. EPA 1980).
The water quality criterion is based on the induction of hemangiosar-
comas in male Osborne-Mendel rats given a time-weighted average dose of
47 mg/kg/day technical grade 1,2-dichloroethane by gavage for a period
of 78 weeks (NCI 1978). The concentration of 1,2-dichloroethane in water
calculated to keep any additional lifetime cancer risk below 10~^ is
0.94 yg/1 (U.S. EPA 1980).

No human health criterion has been set for 1,1-dichloroethane due to
lack of human effects data.
7-7
-------
Risk Extrapolation

The data selected for extrapolation are the NCI data which demon-
strated increased alveolar/bronchial adenomas in male mice and increased
mammary adenocarcinomas in female rats (NCI 1978). These data are listed
in Table 7-4. Other types of carcinomas were observed in both species,
such as hemangiosarcoma (upon which the EPA calculated human risk [U.S.
EPA 1980]), but the implied dose-response relationships were not as
severe. It must be noted that interpretation of these results for human
risk assessment is subject to a number of important qualifications and
assumptions:

• Although positive carcinogenic findings exist, there
have been contradictory negative findings in tests
with the same species using different routes of exposure.
No adequate explanation has been found for these dispar-
ate results, as discussed above.

• Assuming that the positive findings indeed provide a
basis for extrapolation to humans, the estimation of
equivalent human doses involves considerable uncertainty.

• Due to inadequate understanding of the mechanisms of
carcinogenesis, there is no scientific basis for selecting
among several alternate dose-response models which yield
widely differing results.

In order to deal with the large uncertainties inherent in extra-
polation to humans, a conservative approach has been taken in the conver-
sion to equivalent human doses, and three commonly used dose-response
models have been applied to establish a range of potential human risk.
A discussion of these models may be found in a report by Arthur D.
Little, Inc. (1980).

Calculation of Human Equivalent Doses

The experimental results in Table 7-4 for both mice and rats show
three animal groups: the vehicle controls (zero dose), the low-dose
group, and the high-dose group. In both species the low-dose results
were not statistically significant, so that the high-dose results alone
were used for extrapolation to humans. The first step in this extra-
polation was to calculate the equivalent human dose rate corresponding
to the experimental treatment. The approach recommended by the EPA-
was followed, which accounts for the duration of exposure relative to
the animal lifespan and normalizes the dose rate according to body
surface area (U.S. EPA 1979). This approach is conservative, in that
it results in a lower equivalent human dose than would be obtained from
simple multiplication of animal dose rate (mg/kg/day) by human body
weight. Whether surface area or body weight is a more appropriate
normalization factor is still open to debate. The former method yields
a dose rate about 6 times lower for rats, and about 14 times lower for
-------
Female rats
TABLE 7-4. CARCINOGENICITY OF 1,2-DICtlLOROETHANE
Species
Tested

Male mice

Average
Body
Weight
(kg)
0.025

Time-Weighted
Average Dose
(mg/kg/day)
195

Observed
Response
(%)
15/48 (31%)

Observed
Effects

alveolar/
bronchial
adenomas
Duration of
Exposure
(week)
78

Animal
Lifespan
(week)
90

0.32
97
0
1/47 (2%)
(vehicle controls)0/20
95
47
0
18/50 (36%)
1/50 (2%)
(vehicle controls)0/20
mammary
adenot-
cinomas
78
110
Source: NCI (1978).
-------
mice. Thus, the choice of method introduces an uncertainty of roughly
an order of magnitude into the risk estimates.

The actual calculation of equivalent human dose was performed as
follows, assuming an average human weight of 70 kg:
1

„ , m i v • i j v /animal weighty „ p\v/duration of exposure^
Human dose = 70 kg X animal dose X [r r-£— Xl-rlXl : :—r-r^ c
/ ,, \ , ,, ,, N I human weight / \7/ \animal lifespan '
(mg/day) (mg/kg/day) \ 5 / \ / \ ^

The correction factor for body surface area is the cube root of the
ratio of animal to human weight, as shown by the EPA (1979). A correction
factor of 5/7 was also included since the animals were treated only on five
days per week. As a result, we conclude that:

• the dose of 195 mg/kg/day which produced a 31% effect in
male mice is equivalent to a human dose of approximately
600 mg/day

• the dose of 95 mg/kg/day which produced a 36% effect in
female rats is equivalent to a human dose of approximately
560 mg/day

These results are roughly the same, with slightly greater potency implied
by the rat experiment. Therefore, only the rat data were used in subsequent
risk estimation. Using a linear extrapolation, the daily dose corresponding
to a human per capita risk of 10~" is about L5 yg/day.

Three separate extrapolations were performed using the female rat data
(L.e., 36% response at a human equivalent of 560 mg/day). The "one-hit"
extrapolation is performed by simply assuming a constant increase in proba-
bility of tumor induction for each increment of dose. This leads to a
gradually rising dose-response curve which is nearly linear at sufficiently
low doses. The log-probit model assumes that carcinogenic doses are log-
normally distributed, resulting in an S-shaped dose-response curve with a
threshold-like effect. These two models, generally speaking, tend to bound
the range of risk estimates that could be obtained from other dose-response
models. The one-hit model is conservative, in that it probably over-esti-
mates the true response at low doses, whereas the log-probit model usually
results in much lower risk estimates for typical human exposure levels.

For the one-hit extrapolation, the rat data were used to solve for the
coefficient B in the following equation:
7-10
-------
T> T. r i -B (dose)
Prob. of response = 1 -e

0.36-1 -e -B <560>

B - - -~ In (1-0.36)
- 8 x 10~4

The human per capita risk at low dose levels may then be found simply by
multiplying the coefficient B by the dose in mg/day.

Prob. of response ~ B (dose)

The expected incidence of cancer in a given population may then be found
by multiplying the probability of response times the size of the population.

For the log-probit extrapolation, the rat data were used to solve for
the "probit" intercept A in the following equation:
Prob. of response = $ /A + login (dose)J
where $ is the cumulative normal distribution function.

This equation makes the usual assumption that the log-probit dose-response
curve has unit slope with respect to the log-dose (Arthur D. Little, Inc.
1980). Thus:
0.36 = 4 /A + log (560))
Using tables of the standard normal distribution we find that A is approxi
mately equal to -3.2. This value may then be used to find the probability
of a response at various dose levels from the above equation.

The multi-stage model, described by Arthur D. Little, Inc. (1980),
was also applied to the combined rat and mouse data. The multi-stage
model generally gives dose-response estimates intermediate to the one-hit
and log-probit models. The multi-stage model assumes that:
D v * i (~[ax2 + bx + c])
Prob. of response = l-ev L '
where x is the dose, and the parameters a,b, and c are estimated from the
data. A maximum likelihood method was used for this estimation, aided by
a computer program which performed a heuristic search for the best fit.
The parameter b dominates for small doses, and a dominates for large doses.

In Table 7-5 the risk estimates obtained from these models are
summarized. The estimated number of cancers per million exposed population
is shown for daily exposures ranging from 1 yg to 1 mg. The gap between
the estimates is large in the low-dose region; only at doses above 10 ug/
day does the log-probit dose/response curve begin to rise more steeply.
7-11
-------
TABLE 7-5. ESTIMATED NUMBER OF EXCESS LIFETIME CANCERS
PER 1,000,000 POPULATION EXPOSED TO DIFFERENT
1,2 DICHLOROETHANE LEVELS BASED ON FOUR
EXTRAPOLATION MODELS
Extrapolation Method
Number of Excess Lifetime Cancers
Per Million Population at Exposure Level3
1 yg/day 10 yg/day 100 yg/day 1000 yg/day
One-hit extrapolation
0.8
80
800
Log-probit extrapolation negligible
0.1
13
690
Multi-stage model
0.5
50
500
0.5
50
500
Estimated excess lifetime cancers (per million exposed population) are
based on several different dose-response extrapolation models. The
lifetime excess incidence of cancer represents the increase in probabil-
ity of cancer over the normal background incidence, assuming that an
individual is continuously exposed to 1,2-dichloroethane at the indicated
daily intake over their lifetime. There is considerable variation in
the estimated risk due to uncertainty introduced by the use of laboratory
rodent data, by the conversion to equivalent human dosage, and by the
application of hypothetical dose-response curves. In view of several
conservative assumptions that were utilized, it is likely that these pre-
dictions overestimate the actual risk to humans.

Carcinogen Assessment Group (see U.S. EPA 1980).
Source: Arthur D. Little, Inc., estimates.
7-12
-------
The dose corresponding to a per capita risk of 10 is about 100 yg/day
according to the log-probit model, which is about eight times greater
than the level obtained from the linear model. The multi-stage model
predicts a risk intermediate between these two levels in the range of
1 ug/day to 100 yg/day. Thus, there is a substantial range of uncertain-
ty concerning the actual carcinogenic effects of 1,2-dichloroethane. The
minimal response of rats and mice at the lower experimental doses (see
Table 7-4) suggests that the true dose-response curve falls well below
the linear estimate. However, present scientific methods do not permit a
more accurate or definitive assessment of human risk.

7.2.3.2 Risk to Exposed Populations

The relative carcinogenic risks associated with major routes of ex-
posure to 1,2-dichloroethane are shown in Table 7-6, using a range of
risk based on three dose-response extrapolation models. There is consi-
derable controversy over the most appropriate model for performing such
extrapolations. Moreover, additional uncertainty is introduced into the
risk estimates by the choice of a particular set of laboratory data, by
the conversion technigues used to estimate human equivalent doses, and
by possibly differences in susceptibility between humans and laboratory
species. Due to the use of a number of conservative assumptions in the
risk calculations, the results shown in Table 7-6 most likely overestim-
ate the actual risk to humans.

For most persons, ingestion exposures are less than 7 yg/day (Table
7-6). This exposure could result in a range of <0.1-5.6 excess lifetime
cancers per million persons exposed, depending on the extrapolation model
used. Assuming, a population size of 187 million (see Table 7-3), an
estimated <19-1047 excess lifetime cancers could occur in the exposed
population. It should be noted, however, that this population is exposed
to drinking water containing largely undetectable levels of 1,2-dichloro-
ethane. In addition, little is known regarding levels of this compound
in food. The exposure shown in Table 7-6 is based on an estimated consump-
tion of pepper containing 1,2-dichloroethane. It is unknown how prevalent
such contamination is, and if the concentration reported is representative
of levels in pepper in the United States.

A smaller subpopulation is exposed to detectable levels of 1,2-di-
chloroethane in surface waters and may receive about 4 yg/day. In addi-
tion, a very small subpopulation may be exposed to about 800 yg/day re-
sulting from the consumption of contaminated groundwater. The estimated
range of carcinogenic risk is 400-600 excess lieftime cancers per million
exposed at this level. While the population size cannot be quantified,
it is expected to be small.

Inhalation exposures typical of rural and urban areas are generally
lower than ingestion expsoures as is shown in Table 7-6, although, as
discussed above, little information is available.
7-13
-------
TABLE 7-6. ESTIMATED RANGES OF CARCINOGENIC RISK
TO HUMANS DUE TO 1,2-DICHLOROETHANE
FOR VARIOUS ROUTES OF EXPOSURE
Route
Estimated
Average Lifetime
Exposure (ug/day)
No. Excess
Estimated Lifetime Cancers
(per million exposed)

<2
-5

One hit
1.6
4
Multi-
Log Stage/
Probit CAG
< 0.1 1
< 0.1 3
Drinking water

Food

Inhalation

rural <0.4 ' 0.3 <0.1 0.2
urban <0.8 0.6 <0.1 0.4
industrial 32-120 30-100 1-20 20-60
in the vicintiy of
production facilities 0.8-80 0.6-60 <0.1-10 0.4-40

Isolated subpopulations

groundwater (maximum) 800 600 500 400
inhalation in industrial 1300 1000 1000 700
area

3Data taken from Table 7-3.

Estimated excess lifetime cancers are given based on three different
dose-response extrapolation models. The lifetime excess incidence of
cancer represents the increase over the normal background incidence
assuming that an individual is continuously exposed to 1,2-dichloro-
ethane at the indicated daily intake over their lifetime. There is
considerable variation in the estimated risk due to uncertainty
introduced by the use of laboratory rodent data, by the conversion
to equivalent human dosage, and by the application of hypothetical
dose-response curves. In view of several conservative assumptions
that were utilized (see Section 7.2.3.1), it is likely that these
predictions overestimate the actual risk to humans.
7-14
-------
If one assumes chat persons residing in highly industrialized areas
receive about 100 yg/day, and if 1,2-dichloroethane is assumed to be
carcinogenic via the inhalation route (two major assumptions of which the
latter is unsupported by experimental data), this exposure would corres-
pond to a predicted risk of 13-80 excess lifetime cancers/million popula-
tion. This population is expected to be some subset of the 14 million
persons identified as exposed to 1,2-dichloroethane in urban areas at levels
greater than 0.8 ug/day as a result of its use in leaded gasoline. Only a
small part of the exposure (and therefore the risk) to this population is
attributable to waterborne routes.

The small subpopulations residing in highly industrialized areas,
exposed at maximum reported levels, would be at a higher risk; an estimated
700-1000 excess lifetime cancers per million population. Approximately
300,000 persons have been identified as residing close enough to production
facilities to receive up to 800 ug/day.

Again, all of these estimates are based upon the various extrapola-
tion models used and their inherent uncertainties, as well as the uncer-
tainties described above in the exposure assumptions.

The risks to 1,1-dichloroethane cannot be evaluated due to the lack
of both effects and exposure data. However, it is clear that a potential
risk exists due to high concentrations reported in groundwater in some lo-
cations.

7.3 BIOTA

The lowest concentration at which adverse effects of 1,2-dichloro-
ethane have been observed in aquatic biota is 2000 yg/1, which caused
mortality in the mysid shrimp. Freshwater acute toxicity data were
limited, but the range of toxic levels for the few species tested was
about 200,000-555,000 ug/1- No chronic data were available. No toxicity
data at all were available for 1,1-dichloroethane. EPA has not set water
quality criteria for aquatic life for either of these two compounds,
because of the very limited data.

The monitoring data indicate that levels are much lower than the
reported effect levels, almost always lower than the detection limit of
10 yg/1. Thus, the limited data suggest that aquatic organisms are not
at risk to dichloroethanes.
7-15
-------
REFERENCES

Arthur D. Little, Inc. Integrated exposure risk assessment methodology.
Contract 68-01-3857. Washington, DC: Monitoring and Data Support
Division, U.S. Environmental Protection Agency; 1980.

National Cancer Institute (NCI). Bioassay of 1,2-dichloroethane for
possible carcinogenicity. Tech. Report NCI-CG-TR-44. Washington, DC:
National Cancer Institute; 1978.

U.S. Environmental Protection Agency (U.S. EPA). Guidelines and method-
ology used in the preparation of health effect assessment chapter of the
consent decree water criteria documents. Federal Register 44(52):
15641; 1979.
7-16
-------
APPENDIX A

MANUFACTURE OF 1,2-DICHLOROETHANE

A.I INTRODUCTION

1,2-Dichloroethane (commonly known as ethylene dichloride or EDC)
is the highest volume chlorinated organic compound currently
manufactured in the United States. First synthesized in 1795 by Dutch
chemists (Hardie, 1964), it is now produced by the direct chlorination
or oxy-chlorination of ethylene. Nearly 80% of all 1,2-dichloroethane
produced is used for vinyl chloride manufacture; accordingly, demand
is inextricably tied to vinyl chloride production. Other uses of
1,2-dichloroethane are as a chemical intermediate in the manufacture
of methyl chloroform, tetrachloroethylene, vinyl idene chloride,
trichloroethylene, ethyleneamines, and as an additive in tetraethyl-
lead and antiknock mixtures. Additional applications, totaling <1% of
1,2-dichloroethane production, include use as a solvent or fumigant.
Production of 1,2-dichloroethane was approximately 5.9 x
kkg according to U.S. International Trade Commission (USITC, 1979)
records. U.S. manufacturers, their capacities, and locations are
shown in Table A-l and Figure A-l, respectively. In recent years,
1,2-dichloroethane production has reflected trends in vinyl chloride
production rates. Small declines occurred during the years of 1971,
1974, and 1975 (as a result of recession and feedstock shortages), but
overall 1,2-dichloroethane production has had a clear upward growth
trend since shortly after World War II. During the 1960s, ethylene
became much less expensive than acetylene as a feedstock. Accord-
ingly. the balanced process displaced the classical, more costly,
process for vinyl chloride production from acetylene and significantly
increased 1,2-dichloroethane demand. Market growth projections
through 1981 are expected to average about 4 to 5 %, (Chemical
Marketing Reporter, 1977), corresponding to production of approxi-
mately 6.1 million metric tons in 1981. As a result of expansion of
available production facilities, annual nameplate capacity will be 8.2
million metric tons by the second half of 1980 (SRI, 1979a); past
production rates have been estimated as between 60 to 80% of capacity
(EPA, 1979a; SRI, 1979b).

The 1978 consumption pattern for 1,2-dichloroethane is shown in
Table A-2. Vinyl chloride production is anticipated to rise 3% in the
coming year, despite a general business slowdown in 1980 (CaEN, 1979).
While a general decline in trichloroethylene production is expected as
a result of environmental controls, 1,2-dichloroethane demand will be
met by the substitute solvents, 1,1,1-trichloroethane and tetrachloro-
ethylene. Overall growth in chlorinated hydrocarbon solvent markets
is likely to be small, however. With the market for leaded gas
forecast to disappear by about 1990 for passenger cars, a general
decline is anticipated in the use of 1,2-dichloroethane as a
A-l
-------
Table A-l. 1,2-Dichloroethane Capacity, 1978
Plant Capacity (103kkg)
Borden Chemical Co.
Geismar, LA 225

Continental Oil Co.
Lake Charles, LA 524

Diamond Shamrock Corp.
Deer Park, TX 145
LaPorte, TX • 720

Dow Chemical Corp.
Freeport, TX 726
Oyster Creek, TX 499
Plaquemine, LA 952

Ethyl Corporation
Baton Rouge, LA 317
Pasadena, TX 118

B.F. Goodrich Co.
Calvert City, KY 154

ICI Americas, Inc.
Baton Rouge, LA 315

PPG Industries, Inc.
Lake Charles, LA t 544

Shell Chemical Co.
Deer Park, TX 544
Norco, LA 544

Stauffer Chemical Co.
Long Beach, CA 154

Union Carbide Corp.
Taft, LA 68
Texas City, TX 68

Vulcan Chemical Co.
Geismer, LA 140
Source: SRI, 1979a

A-2
-------
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(ID
(12)
(13)
(14)
(15)
(16)
(17)
(18)
ICI Americas, Inc., Baton Rouge, LA
Borden Chemical Co., Geismar, LA
Conoco Chemicals, Lake Charles, LA
Diamond Shamrock Corp., Deer Park, TX
Dow Chemical Co., Freeport, TX
Co., Oyster Creek, TX
Co., Plaquemine, LA
Baton Rouge, LA
Houston, TX
Co., Calvert City, KY
Dow Chemical
Dow Chemical
Ethyl Corp.,
Ethyl Corp.,
B.F. Goodrich
PPG Industries
PPG Industries
Shell Chemical
Shell Chemical
Inc., Lake Charles, LA
Inc., Guayanilla, P.R.
Co., Deer Park, TX
Co., Norco, LA
Stauffer Chemical Co., Long Beach, CA
Union Carbide Corp., Taft, LA
Union Carbide Corp., Texas City, TX
Vulcan Materials Co., Geismar, LA
Figure A-l, Locations of 1,2-Dichloroethane Facilities
A-3
-------
Table A-2. 1,2-Dichloroethane Consumption, 1978
Market Consumption

Volume, 10 kkg %

Major'Uses:b

Vinyl Chloride monomer 4,800 81
1,1,1-Trichloroethane 200 3
Ethylenediamine 230 4
Tetrachloroethylene 110 2
Trichloroethylene 110 2
Vinylidene Chloride 100 2
Lead Scavenger 72 1

Minor Uses: 5
Paint, coating or adhesive solvent
Extraction solvents
Cleaning solvents
Grain Fumigant
Polysulfide manufacture
Diluent in pesticides and herbicides
Film manufacture
Exports
Imports
TOTAL
1.3
1.3
1
0.5
0.4
0.2
310
neg
5,900

100
Source: EPA, 1978b.

a) Numbers may not add due to rounding.

b) See text for derivation of consumption figures.
A-4
-------
lead scavenger in gasoline (Jacobs, 1979). Annual growth rates
forecast for the remaining 1,2-dichloroethane end uses are as follows:
tetrachloroethylene, 6%; ethyleneamines, 7%; and vinylidene chloride,
7%. Export markets are expected to remain constant (SRI, 1979a).

Chloroethanes are produced commercially via two distinct but
related processes: direct chlorination of ethylene in the presence
of a catalyst or oxy-chlorination of ethene, also in the presence of'
a catalyst. Within oxy-chlorination plants, further distinction is
made as to whether air or oxygen is used as a feedstock. For either
process, both yield and selectivity are high for 1,2-dichloroethane
manufacture, ranging from a nearly quantitative yield and 99%
selectivity for direct chlorination to 93-97% yield and 93-95%
selectivity for oxy-chlorination processes. Though both processes
are independent, the balanced process combines both direct and oxy-
chlorination processes to produce 1,2-dichloroethane, which is then
pyrolyzed to produce vinyl chloride. Only five U.S. plants produce
EDC by other means: Ethyl Corporation (Pasadena, TX); Borden Chemical
Co.; and Union Carbide Corporation (two plants) have a combined annual
capacity of 5 x 105 kkg EDC via direct chlorination; Vulcan
Materials Company (Geismer, LA) has an annual capacity of
1.4 x 10^ kkg EDC via oxy-chlorination (see Table A-l).

Most chloroethane manufacturing facilities produce more than
just 1,2-dichloroethane and vinyl chloride. Each of the remaining
chlorinated ethanes/ethylenes is, in fact, manufactured using the same
basic feedstocks ~ chlorine, ethylene, and hydrogen chloride; and
each, to a greater or lesser degree, is a by-product of 1,2-dichloro-
ethane manufacture, whether intended or not. Therefore, a modern,
fully integrated VCM facility might reasonably produce, in addition to
vinyl chloride and 1,2-dichloroethane, ethyl chloride;
1,1-dichloroethane, 1,1,1- and 1,1,2-trichloroethane, 1,1,1,2- and
1,1,2,2-tetrachloroethane, 1,1-dichloroethylene, tetrachloroethylene,
and trichloroethylene. The relationship between these processes is
shown in Figure A-2. The combination of products from individual
plants is shown in Table A-3. Discharges from 1,2-dichloroethane
manufacture are listed in Table A-4.

A.2 DIRECT CHLORINATION

Production of 1,2-dichloroethane via direct chlorination of
ethane is generally carried out in the liquid phase, using
1,2-dichloroethane as a solvent at temperatures ranging from 40 to
120°C and pressures of 1 to 3 atmospheres. Iron(III) chloride is
normally used as a catalyst for direct chlorination processes, but in
theory, any Friedel Crafts catalyst might be used.
A-5
-------
en

1
IICI
-1

CI^CUjjCl

WASTE
INCIN-
R1IATJON

Hydrogen
Chloride
Ethyl Chloride
Aid
Tetracliloi oelhylenc
Chlorine
Figure A-2. C« Chlorinated Hydrocarbon Manufacture
-------
Table A-3. Production of 1,2-Dichloroethane and Related C. Products,
by Facilities and Locations
„ „ /• „ 4
/ / * / , * ? ^ ^
Borden Chemical Co.
Geismar, LA • •

Continental Oil Co.
Lake Charles, LA • •

Diamond Shamrock Corp.
Deer Park, TX • • •
LaPorte, TX • •

Dow Chemical Corp.
Freeport, TX •••••••
Oyster Creek, TX • • •
Plaquemine, LA • • • • •

Dupont and Company
Wilmington, OE •

Ethyl Corporation
Baton Rouge, LA • • • •
Pasadena, TX

B.F. Goodrich Co
Calvert City, KY • •

ICI Americas, Inc.
Baton Rouge, LA • •

Monochem Inc.
Geismar, LA •

PPG Industries, Inc.
Lake Charles, LA • • • • • •

Shell Chemical Co.
Deer Park, LA • •
Norco, LA • •

Stauffer Chemical Co.
Long Beach, CA • • •

Union Carbide Corp
Taft, LA • •
Texas City, TX • •

Vulcan Chemical Co.
Geismar, LA • • •
Wichita. KS •
__
-------
Table A-4. 1,2-Dlchloroethane Summary Materials Balance
re-
I
oo
Process
Direct
Chlorlnatlon

o*y- d
Chlorlnatlon
Balanced
Process

Producer
Borden Chemical Co.
Ethyl Corp.
Union Carbide Corp.
Vulcan Materials Co.
(Totals)
Continental Oil Co.
Diamond Shamrock Corp.
Dow Chemical Corp.
Ethyl Corp.
B. F, Goodrich Co.
id Americas. Inc.
PPG Industries Inc.
Shell Chemical Co.
Stauffer Chemical Co.
Location
Gelsmar. LA
Pasadena, TX
Taft, LA
Texas City, LA
Geisnar, LA

Lake Charles, LA
Deer Park. TX
LaPorte. TX
Freeport, TX
Oyster Creek. TX
Plaquenlne. LA
Baton Rouge, LA
Calvert City. KY .
Baton Rouge, LA
Lake Charles, LA
Deer Park. TX
Norco. LA
Carson. CA
Capacity
(lO'Jkkg)a
2.3
1.2
0.7
0.7
1.4
65
5.2
1.5
7.2
7.3
5.0
9.5
3.2
4.5
3.2
5.4
6.3
5.4
1.5
Production
(kk9)»>
180.000
90.000
55.000
55.000
110,000
5.400,000
430.000
120.000
600.000
600.000
420.000
790,000
270.000
370,000
270.000
540,000
520.000
450.000
120.000
Estimated Environmental Dispersion (kkql
Air Water land
500
270
150
150
1.300
20,000
1 ,600
460
2,200
2,200
1,500
2.900
980
1.400
980
1.700
1.900
1.700
460
44
23
14
cneg 14
280
83C
66
19
92
93
64
120
41
.neg 57
41
69
80
69
19
a) Values have been rounded to two significant figures, neg. Is <1 kkg.

b) Production is 791 of capacity, EPA, 1978a; USITC, 19/9; SRI, 19796.

c) Air emissions: storage facilities (0.0006 kg EDC/kg EOC produced) and scrubber vent (0.0022 kg/kg). Water discharge:
scrubber waste (0.0018 kg/EOC produced) uncontrolled (see p.3-5 for controlled releases). Both from EPA. 1974a. Land
dispersion: 0.0007 kg tar/kg EOC produced. EPA. 1974a; up to 351 EDC In EOC tar (Jensen et a_l_.. 1975).
d) Emission factors for all media from EPA, 19?4b. Air: process vent gas (0.007 kq EDCAg EOC produced) and distillation
vent gas (0.0045 kg EDC/kg EDC produced) Water: 0.0006 kg £DC/kg EDC produced (uncontrolled discharge, see p.3-5
for controlled releases). Land: heavy ends 0.0025 kg EOC/kg EOC produced. Storage facilities: 0.0006 kg EDC/kg
EOC produced.

e) Total atmospheric emissions: 0.0027 kg EDC/kg EDC consumed from distillation vent. 0.0010 kg EDC/kg from direct
chlorlnation and 0.0010 kg EDC/kg oxy-chlcrinatlon. Total water discharge based on 190 gpm flow rate, EOC concentration
1500 - 3600 ppm. and eOX capacity operation (uncontrolled, see p.3-5 for controlled releases), EPA, 1978; EPA, 1974a.
Told! land discharge tar concentration 0.8 kg tar/Hi) VCM produced, 36J EDC in tar, Lunde. 1965. Discharge of EDC
by company using balanced process based on individual company capacity as a percent of total production; totals do
not adil due to rounding.

Source: EPA, I978
-------
Approximately equimolar amounts of chlorine (containing a small
amount of oxygen, either added as air or present as an impurity) and
•ethylene are fed to the reactor through separate distributors as
depicted in Figure A-3. The reactor in essence, is an empty tower in
which liquid 1,2-dichloroethane, chlorine, and ethylene flow
concurrently upward. Both gas streams dissolve and react in the
liquid phase; further, the rate of reaction is mass transfer
controlled and related to the superficial inlet velocity of the
feedstreams (Balasubramanian, _e_t _§_]_., 1966). The reaction is
catalyzed by continuous addition of iron(III) chloride ^-600 ppm)
dissolved in a portion of the 1,2-dichloroethane feedstream. The
reaction is exothermic ^45 kcal/mole) and heat is removed by passing
a large portion of the product stream through a heat exchanger (not
shown).

Species emitted from the reaction vessel vent include: oxygen,
nitrogen, ethylene (sufficient to keep the mixture out of the
explosive range), methyl chloride, ethyl chloride, 1,2-dichloroethane,
and other low boiling reaction products. 1,2-Dichloroethane is
recovered by refrigeration and the noncondensible gases are vented.

The product stream is withdrawn from the top of the reactor and,
with the exception of dissolved catalyst, is of sufficient purity for
vinyl chloride production. Iron(III) chloride can be removed in a
number of ways, including adsorption (e.g., activated carbon),
washing, or by distillation (including operating the reactor at the
boiling point of 1,2-dichloroethane and taking the product overhead).

A.3 OXY-CHLORINATION

Oxy-chlorination of ethylene is conducted at elevated tempera-
tures (225-325°C) and pressures (1 to 15 atmospheres) in the presence
of a supported copper(II) catalyst. Like direct chlorination, both
liquid and vapor phase oxy-chlorination processes are known.
Commercial processes, however, are carried out exclusively in the
vapor phase. The process shown in Figure A-4 incorporates features
from several patents and is not representative of any single plant.

Approximately stoichiometric amounts of ethene and hydrogen
chloride are mixed and fed as one stream to the reactor. Preheated,
purified air (or oxygen) is fed as a separate stream to the reactor.
Although the theoretical amount of hydrogen chloride and oxygen
required are 2 moles and one-half mole per mole of ethene,
respectively, both are commonly used in excess (#10%) to favor
1,2-dichloroethane formation.

Both fixed bed and fluidized bed reactors are used commercially,
although temperature control of the former is more difficult and
A-9
-------
o
C12

C2H4
VENT
LIGHT
ENDS

rt
o
H
0
w
rt

1
•

RECYCLE

f
I
P
"N
»-)
O
O

i — TPnPl

n
D
O
O

k. J

^
HEAVY
ENDS
^1,2-DICHLORO-
ETHANE
Figure A-3. Manufacture of 1,2-Dichloroethane Via Direct Chlorination
-------
VENT

(TO ETHYLENE RECOVERY)
»L HC1
C2H4
AIR
NaOH
A
(aq)
V
WASTE
WATER
LIGHT ENDS
-»• 1,2-DICHLORO-
ETHANE
V
HEAVY
ENDS
Figure A-4. Manufacture of 1,2-Dichloroethane Via Oxy-Chlorination
-------
requires graded catalyst packing (Vulcan, 1965). Fixed bed
oxy-chlorinations, are normally run with excess ethylene (relative to
HC1). Excess ethylene is recovered in subsequent reaction steps by .
direct chlorination (Severino, 1977), although if oxygen is used
rather than air, excess ethene may be directly recycled. Fluidized
bed reactors offer good temperature control by virtue of effective
heat transfer between catalyst particles and by use of internal
cooling surfaces (Antwerp _e_t aj_., 1970). Catalyst attrition and
carry-over may present certain operating problems; catalyst makeup
however, in fluidized bed systems is relatively easy.

Both reactor systems control reaction temperature (225°-325°C)
by low pressure steam generation. The product gases are quenched,
and scrubbed with dilute caustic (Z6% NaOH). After separation, crude
1,2-dichloroethane is purified by distillation in several stages in
which water and other low boiling components as well as high boiling
components (b.p. >85°C) are removed. This product stream is typically
of 99.5% purity. The composition of crude 1,2-dichloroethane from
direct chlorination and oxy-chlorination is shown in Table A-5.

The oxy-chlorination process discharges larger amounts of
1,2-dichloroethane than the direct process. For oxy-chlorination
these include: emissions vented from the scrubbing column and product
storage tanks; wastewater from scrubbing of the vented gases and
caustic washing of crude EDC; and solid waste in the form of tars
produced in the heavy ends column (see Figures A-4 and A-5; and Table
A-4). 1,2-Dichloroethane discharge from direct chlorination is much
less than from oxy-chlorination and occurs largely from the reactor
vent and product storage tanks.

A.4 THE BALANCED PROCESS: VINYL CHLORIDE MANUFACTURE

Virtually all vinyl chloride capacity in the United States is
based upon dehydrochlorination of 1,2-dichloroethane (SRI, 1979b);
pyrolysis, however, yields co-product hydrogen chloride on an
equimolar basis. Hydrogen chloride, in turn, serves as a chlorine
source for oxy-chlorination of ethane. By using both processes --
direct chlorination and oxy-chlorination -- vinyl chloride is produced
from two commodity chemicals, ethylene and chlorine, without producing
by-product hydrogen chloride. These processes in combination are
known as the "balanced" process and provide about 92% of the vinyl
chloride manufactured in the United States. Vinyl chloride monomer
producers, their location, and their respective capacities are listed
in Table A-6.

Current yields of dehydrochlorination of 1,2-dichloroethane are
on the order of 50% to 60% with selectivities to vinyl chloride of 96%
to 99% (McPherson _et a_l_., 1979). Based on the current yield of
1,2-dichloroethane pyrolysis with equimolar production of hydrogen
A-12
-------
Table A-5. Composition of Crude 1,2-Dichloroethane
CO
Component
Reactor Effluent, Mole
Direct Chlorination
a ,b
Oxy-Chlorination
Ethene
Vinyl Chloride
Ethyl Chloride
Vinyl idene Chloride
Trans-dichloroethene
Cis-dichloroethene
Chloroform
1,2-Dichloroethane
1 , 1 , 1-Tri chl oroacetal dehyde
1 , 1 ,2-Trichloroethane
1,1-Dichloroethane
Methyl Chloride
0.427
-
0.342
-
Or\ i ~7
.017
-
99.123
-
0.039
0.009
0.043
0.535
0.10
2.322
0.029
0.021
0.047
0.011
96.031
0.533
0.463
-
-
Adapted from Lunde, 1967. A selectivity to 1,2-dichloroethane of 99.7% and 95%
conversion of ethene has been assumed.
Teach and Price (1967) report chlorobenzene and bis (2-chloroethyl ether).
cAdapted from Vulcan, 1965. Fixed bed oxy-chlorination: 230-290°C, 4.6 atm,
13.2wt%CuCl2 on alumina; 14 and 6 mole % excess oxygen and hydrogen chloride
respectively.
-------
Table A-6. Vinyl Chloride Producers, Locations, and 1978 Capacity
Producer
Location
Capacity (xlO5 kkg)
Borden
Continental Oil
Diamond Shamrock Corporation
Dow Chemical Corporation

Ethyl Corporation
B.F. Goodrich Company
ICI Americas
Monochem Incorporated
PPG Industries Incorporated
Shell Chemical Company

Stauffer Chemical Company
Total
Geismar, LA
Lake Charles, LA
LaPorte, TX
Freeport, TX
Oyster Creek, TX
Plaquemine, LA
Baton Rouge, LA
Calvert City, KY
Baton Rouge, LA
Geismar, LA
Lake Charles, LA
Deer Park, TX
Norco, LA
Carson, CA
1.4
3.2
4.5
0.91
3.2
5.7
1.5
4.5
1.4
1.4a
1.8
3.8
3,2
0.79
37.3b
Source: SRI, 1979b.
I*Acetylene feedstock. fi
b!978 Production: 3.1 x 10° kkg (USITC, 1979), 83% of capacity.
-------
chloride (and allowing for losses), capacities of oxy-chlorination and
direct chlorination processes are approximately equal. Based on a
reaction yield of 96% and 1978 vinyl chloride production of 3.15 x
10° kkg (92% of which was based upon 1,2-dichloroethane), 4.8 x
10~ kkg of 1,2-dichloroethane were consumed to produce 2.85 x
106 kkg of vinyl chloride in 1978 (SRI, 1979a; USITC, 1980). This
1,2-dichloroethane figure is at variance with production reported by
USITC. This difference is attributed to ambiguity in the manner in
which production is defined by the USITC. In particular, captive
production (that portion of a product used as a chemical intermediate)
is not always adequately reflected in the numbers reported to the
USITC by a manufacturer, thus distorting production rates released by
the USITC.

A typical flow diagram for vinyl chloride monomer manufacture via
the balanced process is shown in Figure A-5. Crude 1,2-dichloroethane
from the oxy-chlorination process is washed with dilute caustic to
remove hydrogen chloride and chlorinated by-products (notably chloral)
and dried. "Crude" 1,2-dichloroethane from direct chlorination may be
combined with this stream and purified for pyrolysis; alternatively
1,2-dichloroethane from direct chlorination may be of sufficient
purity for pyrolysis without further purification. After dehydro-
chlorination, the reactor effluent is quenched with 1,2-dichloroethane
and separated by fractional distillation in a series of columns.
Hydrogen chloride is recycled to the oxy-chlorination reactor while
recovered 1,2-dichloroethane is returned to the 1,2-dichloroethane
purification system.

A.5 TREATMENT OF PROCESS WASTES

Vinyl chloride monomer is used to manufacture polyvinyl chloride
resins, homopolymers, and copolymers. Emissions of EDC from use of
VCM are apparently small. PPG Industries, for example, estimates a
1,2-dichloroethane concentration of/vlO ppm in final product VCM
(Denison, 1980). Assuming this concentration to be representative of
all VCM manufacturers, 30 kkg of 1,2-dichloroethane are estimated to
be present and, therefore, potentially lost to the environment from
VCM use in 1978.

A new method for VCM manufacture, the "TRANSCAT" process, may
reduce process discharges from VCM manufacture significantly.
Developed by the Lummus Company and tested on a large pilot plant
scale, but not currently in commercial use, the method uses ethane and
chlorine or HC1 as starting materials (McPherson, et _§_]_., 1979). A
notable advantage of this method of VCM manufacture is the reduction
of organic gaseous emissions. Vent streams are said to include only
C02, N2, Oo, and H20 vapor (EPA, 1979a). If this process proves to be
commercialfy effective, 1,2-dichloroethane emissions from VCM
manufacture could be drastically reduced.
A-15
-------
I
*-*
en
HC1

AIR
C2!V
Cl,
NaOH
REACTOR
OXYCHLORINATION
(aq)
WASHER
DIRECT CHLORINATION
REACTOR
WASTE-
WATER
Z
2
D
>1
O
O
LIGHT
ENDS
O
O
V
HEAVY

ENDS
t/j
•-• w
O
H
^<
OP:
X <
Hi
Ul
o
o
1,2-DICHLOROETHANE

RECYCLE
VINYL
CHLORIDE
Figure A-5. The Balanced Process for Vinyl Chloride Manufacture
-------
A.6 1,2-DICHLOROETHANE FROM ETHYLENE'OXIDE MANUFACTURE

A small portion (CXO-2% in 1978) of 1,2-dichloroethane production
results from recovery as a by-product during ethylene oxide manu-
facture via the chlorohydrin process. Once a significant source of
1 ,2-dichloroethane, the chlorohydrin process.has been superceded by
direct oxidation processes. In 1978 the chlorohydrin process was used
by the DOW Freeport plant and accounted for approximately 3% of
ethylene oxide production; this process has reportedly been
discontinued. The principal process waste stream is a lime slurry
fc£500 1/kkg of product). Based on 1978 ethylene oxide production
via the chlorohydrin process (£68,000 kkg) and 1,2-dichloroethane
process emission factors both air emissions and water discharges of
1 ,2-dichloroethane are negligible (i.e., <1 kkg).

A.7 INADVERTENT SOURCES OF 1,2-DICHLOROETHANE RELEASES

In general, any man-made activity in which a chemical is
released to the environment is an inadvertent (unintentional) source
of that chemical. A particularly important class of inadvertent
sources is found within the chemical industry. Chemical species do
not react via a single reaction pathway; depending on the nature of
the reactive intermediate there are a variety of pathways which lead
to a series of reaction products. Often, and certainly the case for
reactions of industrial significance, one pathway may be greatly
favored over all others, but never to total exclusion. Thus, by
appropriate process design and proper control of reaction conditions,
manufacturers maximize product yield while minimizing waste
production. At its simplest, then, manufacture of a chemical product
necessarily consists of three steps: (1) combination of reactants
under suitable conditions to yield the desired product; (2) separation
of the product from the reaction matrix (e.g., by-products,
coproducts, reaction solvents); and (3) final purification of the
product. These waste products, thus, constitute additional sources
of a chemical or chemicals to the environment. Such sources of a
chemical are not limited to those of chemical manufacturing processes
however; disinfection of drinking water or wastewaters by
chlorination, for example, is a potentially important inadvertent
source of chlorinated organic hydrocarbons.

Because 1,2-dichloroethane is used primarily as a manufacturing
intermediate for other G£ chlorinated hydrocarbons, discussion of
inadvertent sources of emissions from manufacture of other chemicals
is deferred to Appendix C (Uses of 1,2-Dichloroethane).

The chlorination of drinking waste and wastewater (see Appendix
D, Municipal Disposal of Dichloroethane) has come under scrutiny
recently, largely due to the discovery that chlorination of residual
organic matter in such waters may lead to the formation of chlorinated
degradation products. Contamination of municipal drinking waters has

A-17
-------
been Investigated in three recent studies: (National Organic
Monitoring Survey (EPA, 1977b); (2) National Organics Reconnaissance
Survey for Halogenated Organics (Symons _et_ al., 1975); (3) and a local
survey conducted by the state of CaliforniaTPhillippe, 1980).

The National Organic Monitoring Survey examined 113 community
water supplies, representing all types of sources' and treatment
process, in three phases during a twelve month period. 1,2-Dichloro-
ethane is detected neither in high concentration nor frequently (see
Table C-9). Moreover, the source of 1,2-dichloroethane is not readily
apparent though the data suggest that chlorination is not a signifi-
cant source of 1,2-dichloroethane found in these waters. This result
is supported by the similarity of 1,2-dichloroethane concentrations of
Phase III samples collected with (quenched) or without (terminal) a
chlorine reducing agent. A similar conclusion is derived from the
National Organic Reconnaissance Survey. In approximately one-third of
the cases where 1,2-dichloroethane was present in finished waters, it
was also present in the raw water. For the cases where 1,2-dichloro-
ethane was found in finished water but not in raw water, it was
suggested as attributable to artifacts caused by the varying limits of
detection of the analysis, rather than formation during chlorination
(Symons et a]_., 1975).

Finally, the California Regional Water Quality Control Board has
detected 1,2-dichloroethane (up to 52 ppm) in well water on the
property of Aerojet General Rocket Plant in Sacramento. Investi-
gators have presumed this contamination to be linked solely to
leaching from solvent disposal sites on the facility's property,
rather than introduced by chlorination treatment.

On the basis of these studies it is assumed that chlorination of
drinking water contributes negligible amounts of 1,2-dichloroethane to
the environment. Disposal per se (e.g., POTWs and Urban Refuse) will
be discussed in Appendix D.
A-18
-------
Table A-7. Composition of Oxy-Chlorination Wastewater

Component
HC1
Chloral
1 ,2-Dichloroethane
Ethanol
Acetaldehyde
Monochl oroacetal dehyde
Concentration
1.49 -
14100 -
1500 -
290 -
0 -
0 -
5.78%wta
16900 ppm
3360 ppm
520 ppm
TOO ppm
300 ppm

Source: EPA, 1976
3Determined by titration.
A-19
-------
Table A-8. Composition of Vinyl Chloride Tars
Species % Weight

Trichloroethene CL2
Tetrachloroethene 0.2
1,1,1-Trichloroethane 0.4
1,2-Dichloroethane 36
1,2-Dichlorobutane + Unknown Butadiene 0,3
Dichlorobutenes 1,8
Chlorobenzene ' 0=7
1,1,2-Trichloroethane + 1,1,1,2-Tetrachloroethane 15
1,2-Dichlorohezane 0.6
2-Chloroethanol + 1,4-Dichlorobutane 0.7
Pentachloroethane 0.6
Hexachloroethane 0.6
1,2,3-Trichlorobutane 1
1,2,3-Trichloropropane 0.8
1,1,2,2-Tetrachloroethane 5
bis(2-Chloroethyl) ether 3
1,2,4-Trichlorobutane 5
C4-C6-C1X 14
Unspecified Aromatics 2
Unknown 2
Freon-Soluble Material 4
Freon-Insoluble Material 6
Water 0.1
TOO

Source: EPA, 1975-
A-20
-------
Table A-9. Composition of Vinyl Chloride Heavy Ends
Species % Weight
1-Chlorobutane 0.3
Tetrachloroethene 0.9
1,1,1-Trichloroethane 0.8
1,2-Dichloroethane 15
1,2-Dichlorobutane 0.7
Dichlorobutenes 5
Chlorobenzene 2
1,1,2-Trichloroethane + 1,1,1,2-Tetrachloroethane 58
1,2-Dichlorohexane ' 1
2-Chloroethanol + 1,4-Dichlorobutane 0.6
Pentachloroethane 0.5
Hexachloroethane 0.4
l,2,3^Trichlorobutane 0.9
1,2,3-Trichloropropane 0.8
1,1,2,2-Trichloroethane 5
bis(2-Chloroethyl) ether 1
1,2,4-Trichlorobutane 1
C4-C6-C1x 4
Water 0.1
Unknown 2

100

Source: EPA, 1975.

A-21
-------
-------
APPENDIX B

MANUFACTURE OF 1,1-DICHLOROETHANE
B.I INTRODUCTION
Once used as an anaesthetic and as a solvent, 1,1-dichloroethane
occurs largely as an unisolated intermediate during the production of
1,1,1-trichloroethane. Since 1,1-dichloroethane has been identified as
a carcinogen by the National Institute of Health, increased industrial
use (other than intermediate uses) is not expected. Specialty chemical
companies, however, do distribute small amounts of 1,1-dichloroethane
for use as a solvent or as a chemical intermediate. A spokesperson for
Aldrich Chemical Company estimated that 400-500 kg were sold annually
(Aldrich Chemical Company, 1980); Guardian Chemical Corporation indicated
that sales figures were proprietary information but annual sales were
"small kilo quantities" (Guardian Chemical Corporation, 1980). On the
basis of these data, industry sales probably amount to <10 kkg.

Although not usually isolated as a consumer product, 1,1-di-
chloroethane can be manufactured by several processes: addition of
HC1 to vinyl chloride in the presence of aluminum chloride, ferric
chloride, or zinc oxide catalysts:

H2C=CHC1 + HC1—^H3CCHC12

or addition of HC1 to acetylene in the presence of a mercuric-ferric
chloride catalyst:

HCSH + 2HC1 ^>H3CCHC12-

The vinyl chloride process, followed by chlorination of 1,1-dichloro-
ethane is used to produce approximately 95% of the 1,1,1-trichloro-
ethane in the U.S. (SRI, 1979b). (Capacity, locations and
manufacturing methods, of U.S. 1,1,1-trichloroethane producers are
discussed in Appendix C). Based on reaction stoichiometry, reaction
yield (c^95%), and that portion of 1,1 ,1-trichloroethane produced via
the vinyl chloride process (90-95%), 2.2 - 2.3 x 105 kkg of
1 ,1-dichloroethane were produced as an intermediate for captive use in
1 ,1,1-trichloroethane production in 1978 (Denison, 1980).

Releases of 1,1-dichloroethane from this process as listed in
Table B-l are chiefly atmospheric and originate from the distillation
vents (EPA, 1979b). Assuming 2.2 kg of 1,1-dichloroethane are emitted
per kkg of 1,1 ,1-trichloroethane produced (Elkin, 1969), an estimated
600 kkg of 1,1-dichloroethane were emitted to the atmosphere in 1978.
B-l
-------
Table B-l. Materials Balance of 1,1-Dichloroethane in 1978a
CO

Source
PRODUCTION6'0
Hydroch lor (nation
of vinyl chloride
INADVERTENT
1,2-Olchloroethane manufacture via the
balanced process
1,2-Oichloroethane manufacture via e
direct chlorination
kkg of 1,1-Dichloroethane Estimated Environmental
Air Mater

230,000 607 1

200 neg
300 neg
Releases, kkg
Land

neg
neg
a) All values rounded to two significant figures.

b) The bulk of 1,1-dichloroethane production is as an unisolated intermediate; approximately 10 kkg are produced and sold for solvent application
by specialty chemical manufacturing firms.

c) Use as a solvent is assumed to be relatively small amounts which do not warrant recovery. Releases from solvent use are
distributed 66% to air, 24% to land, and 10% to water by analogy to trichloroethylene (EPA, 1981).
d) Based upon 5. 1 x 10 kkg 1,2-dichloroethane produced via the balanced process and an emission factor of 0.04 kg 1,1-dichloroethane/
kkg 1,2-dichloroethane produced (Lunde, 1965).

e) Based upon 380 x 1CI3 kkg 1,2-dichloroethane production via direct chlorination of ethylene and an emission factor of 0.8 kg 1.1-dlchloro-
ethane/kkg 1,2-dichloroethane produced (Lunde. 1965).
-------
No specific data concerning the occurrence of 1,1-dichloroethane
in solid waste residue from 1,1,1-trichloroethane manufacture are
available. The total VOC emissions from these residues, however, are
1 kg per kkg of product; release of 1,1-dichloroethane from solid
waste disposal is therefore expected to be small (EPA, 1979b).

1,1-Dichloroethane has also been detected in waste gas streams
from production of 1,2-dichloroethane by oxy-chlorination (Lunde,
1965). Total discharges of 1,1-dichloroethane from this source are
approximately 200 kkg annually. 1,1-Dichloroethane has not been
detected in the wastewater from 1,2-dichloroethane manufacture.
Discharge of 1,1-dichloroethane during manufacture of other
chlorinated hydrocarbons is probable, but specific data are lacking.
Based on reaction chemistry only, 1,1-dichloroethane formation as a
by-product is favored in manufacturing processes where free radical
chlorination is predominant or at least significant. Processes in
which 1,1-dichloroethane formation is probable but unverified
include: 1,1,1-trichloroethane (ethane-based process),
trichloroethylene, tetrachloroethylene, and epichlorohydrin (ally!
chloride) manufacture.
B-3
-------
-------
APPENDIX C

USES OF 1,2-DICHLOROETHANE
C.I INTRODUCTION
This material balance has arbitrarily treated the manufacture of
vinyl chloride monomer (VCM) within the context of EDC production (see
Appendix A), rather than as an EDC use per se. The following
descriptions and discussions of the remaining industrial use
categories for 1,2-dichloroethane are divided into two subgroups:
manufacturing intermediates (e.g., for tri- and tetrachloroethylene,
ethyleneamines, polysulfide elastomers) or dispersive end uses (e.g.,
fumigant, solvent). The consumption pattern for EDC is shown in Table
C-l.

C.2 1,1,1-TRICHLOROETHANE

Approximately 4% or 2 x 10^ kkg of 1,2-dichloroethane
produced in 1978 was used as a feedstock for 1,1,1-trichloroethane
(methyl chloroform) manufacture (SRI, 1979a). The predominant use of
1,1,1-trichloroethane is as a metal-cleaning solvent; additional
applications are as a vapor pressure depressant in aerosol formula-
tions, and as a solvent in adhesive, coating, and drain cleaner
formulations. Though once suggested as a replacement for trichloro-
ethylene, 1,1,1-trichloroethane demand has remained relatively
constant from 1976 to 1979. In the short term, domestic demand is
forecast to decline 10% to 20% in 1980. Production should remain
relatively constant over the long term (Mannsville Chemical Products,
1979). The producers of 1,1,1-trichloroethane, along with geographi-
cal locations and production capacities and processes, are listed in
Table C-2. 1,1,1-Trichloroethane production totalled 290 x 103
kkg in 1978 (USTIC, 1979).

A simplified flow diagram for production of 1,1,1-trichloroethane
is shown in Figure C-l. 1,1,1-Trichloroethane is produced chiefly by
hydrochlorination of vinyl chloride (obtained from EDC) to
1,1-dichloroethane, which is then thermally or photochemically
chlorinated:
CH2=CHC1 + HC1;^> CH3CHC12 -^»CH3CC13 + HC1

Since 1979, when PPG Industries placed its vinylidene-based process
on standby and opened a new vinyl chloride-based operation (Dehn,
1979), nearly all of the 1,1,1-trichloroethane producers in the U.S.
have been using the latter process. The one exception is the Geismer,
Louisiana plant of Vulcan Materials Company, which manufactures
1,1,1-trichloroethane by noncatalytic chlorination of ethane.

In 1978, approximately 1 kkg of 1,2-dichloroethane (1,100 kg from
the vinyl chloride process and 60 kg from the ethane process) was
emitted to the atmosphere, largely from process distillation vents..

C-l
-------
Table C-I. 1,2-Diehloroethane Materials lalance: Uses, kkg/yr*
Use Category
Hanufacturino Intermediate6
1.1,1-Trlcliloroe thane
Ethyleneaf»1nesc
Trichloroetnene"
Tetracftloroethene'
*
l,2-01cnloroetnene
Lead scavenger3
Hlnor uses
Paints, coatings, adhesive*
Eitraction solvent
Cleaning solvent^
Polysulflde elastaners*
grain fumigant
Pesticide carrier1"
Film manufacture" -
Exports"
Imoorts °
Toul
1.2 Olchloroethane Input
(kkg)

200.000
230.000
110.000
110,000
100 000
72.000

1.300
1.300
1.300
IS
500
ISO
ISO
310.000
n«g
1.140.000
Estlnited Envlr
Air

1
360
53
75
700

1.300
1.300
tea
n«g
500
17S
8

5142
onmenta'
Hater

neg
20
29
35
n«9

IK?
n«1
100
1
"•»
"•«
neg

185
Oisoersion (kfcq)
Land

we?
20
«9
«9
i»9

M«
«t«
240
neg
"*»
175
n«9

4U
») Bisec on Mount of product o>ri»e« fn» l.2-d1ehloroetmn« ind ruction sto»cn1o«etr> ($«1, 1979«). floures «•» not Md due
to rounding.

b) Air: 1) 0.004g EOC/kg 1,1.1-tricMoroetnine Brodueed (disti)Ution y«nt jit}, for ethine- ind vin»l chloride-lnsec
processes controlled DJ incinerition (EP». 1979S). 1-10 ppm EDC in 1.1.1-trichloroetnine strews used on industry
estixtes (Oenison. 1980! Aqumc discntrges ire Believed to be in»ijnific«nt Msed on process confiour.tion.
1.2-«icnloroetn»ne discnjrge to Und is believed td be neglijtble Used upon recycling of solid -»ue strums to cirbon
tetrtcnloride/tetrtcnloroethane production.

c) Input b»M on 64 » JO3 kkg etnylenedlwiine (EDA) produced (»1. 1979b) «M reaction yield of 451 (Lichemulter ind
UOur. 1969 }.

d) EDC residual level in TCE strews • 10-100 ppo (Denison, 1980); lir: 3.1 g/k9 Trichloroethylene. 361 control (EPA, 1979).
r:7 "2 TrlcnIorotthJ'l«n«' 51° »» £DC'" (Catalytic. 1979). Production • 136,000 ktg Tncnloroetn.len.
e) Air: 3.1 9/ko Tetracnloroethyene. 85t control (EPA. 1979). Kater: 0.42 kg M,0/k9 Tetracnloroetnylene. 510 u« EUC/1
(Catalytic, 1979). Production • 161.000 ktj Tetracnloroetnjlene (»i , I979«f.

f) No EDC detected 1n «stt strums, see te«.

9) Cowiined discharge fro» gasoline blending, filling and 'breathing' of storage tanks, and refueling of autonomies; see teit.

*' All^EDC is assuMd l° d1*50J'" O'nd*r in<1 W'" Co
-------
Table C-2. Production Capacity for 1,1,1-Trichloroethane
Facility Location Capacity (xlO kkg) Process
Dow Chemical Corporation Freeport, TX
Plaquemine, LA
PPG Industries, Inc. Lake Charles, LA
Vulcan Materials Co. Geismer, LA

204
136
159 b
29C
528

vinyl chloride
vinyl chloride
vinyl chloride
ethane
.

a!978 production: 290 x 103 kkg, 55% of capacity.

b ?
Does not include 79 x 10J kkg/yr plant (vinylidene chloride) on standby.

GEthane process.

Capacity reportedly increased to 86-91 x 103 kkg/yr in October, 1979 (Cogswell, 1979)
-------
VlklVL.
1.1,1- I
TCJCHLOR.O-
(j LO^OIU^^

^^'
I

Figure C-l. Flow Diagram for 1,1,1-Trichloroethane from Vinyl Chloride (EPA, 1979b)
-------
These estimates are derived from 1,2-dichloroethane emissions factors
calculated by the manufacturers; it was further assumed that emissions
were 98% controlled by combustion in an existing incinerator (EPA,
1979b). Approximately 640 kkg of 1,2-dichloroethane are estimated to
be produced during 1,1,1-trichloroethane manufacture via the vinyl
chloride process. Again, this estimate is based upon emission factors
derived from process patents rather than actual sampling data. Thus,
disposition of such wastes is uncertain but, based upon the process
configuration shown in Figure C-l, are assumed to be recycled to
tetrachloroethene/carbon tetrachloride manufacture. Thus, 1,2-di-
chloroethane discharges to land from 1,1,1-trichloroethane manufacture
are assumed to be negligible.

Published estimates of aquatic discharges of 1,2-dichloroethane
during production are unavailable but, based upon process chemistry
are believed to be small (<1 kkg). 1,1,1-Trichloroethane streams are
estimated to contain 1-10 ppm of EDC, based on estimated 1,2-dichloro-
ethane concentration in feedstock streams (Denison, 1980). Thus,
between 0.3 to 3 kkg may be released during use of
1,1,1-trichloroethane.

C.3 ETHYLENEAMINES

The production of ethyleneamines accounts for approximately
230 x 103 kkg (4%) of the annual EDC consumption (EPA, 1977). In
1978, 64 x 103 kkg of ethylenediamine (EDA) were produced at the
facilities and locations listed in Table C-3 (SRI, 1979b). Ethylene-
diamine is typically produced in conjunction with additional poly-
amines such as diethylenetriamine, triethylenetetramine, tetraethy-
lenepentamine, pentaethylene hexamine, and aminoethylpipera- zine.
U.S. ethylenediamine capacity is estimated to be approximately 50% of
total polyamine capacity. Ethyleneamines are used for a variety of
purposes, including carbamate fungicides, chelating agents, wet-
strength resins, and fuel/ lubricating oil additives.

Reaction of aqueous ammonia with 1,2-dichloroethane is the major
commercial manufacturing route used in the U.S. for the entire family
of polyamines, including ethylenediamine (EDA), and higher homologs,
such as diethylenetriamine (DETA), pentaethylenehexamine (PEHA) and
aminoethylpiperazine (AEP):

C1CH2CH2C1 + 2NH3-^NH2CH2CH2NH2 + 2HC1 + other ethyl eneamines

A minor production variation uses anhydrous rather than aqueous
ammonia; similar yields of polyamines are obtained. A simplified
production scheme is shown in Figure C-2. The NH3:l,2-dichloro-
ethane ratio and reaction conditions control the distribution of
amines produced: 15:1 mole ratio of NHo dichoroethane, tempera-
ture and pressure of 100°C and 4.82 MPa(47.6 atm) respectively results
C-5
-------
Table C-3. Production Capacity for Ethylenedlamine
FACILITY CAPACITY,103 kkga PRODUCTION, 103kkgb

Dow Chemical Corp.
Freeport, TX 27 20

Union Carbide Corp.
Taft, LA
Texas City, TX
TOTAL
32
27
86
24
20
64

Source: SRI,1979b.

a Capacities are for ethylenediamine; it is assumed that ethylenediamine
production is~50% of polyamine production( ethylenediamine, diethylene-
triamine, triethylenetetraamine, tetraethylenepentamine, pentaethylene-
hexamine, and aminoethylpiperazine ).

Based on 74% capacity.
C-6
-------
C1CH2CH2C1
o
I
NH
3(aq)
,

/*
^
Y

REACTOR COLUMN

Pol
C
N*>H
-------
in a product distribution of 45% EDA, 49% higher amines and 6% residue
(Lichenwalter and Cour, 1969). At higher Nh^rEDC ratios, higher
temperatures, and higher pressures, yields of ethylenediamine are
increased to approximately 90% (Blears and Simpson, 1966). Vinyl
chloride may form in significant amounts under these conditions;
subsequent polymerization may cause equipment blockage and thus limit
the utility of this process. The amines are produced as hydrochloride
salts which are then neutralized with sodium hydroxide to yield the
free amines. A portion of the amine product is lost when the salt is
separated from the product amines, but losses are minimized by
recrystallization of the processs salt and subsequent recovery of the
amines (Steele, 1975).

Reactor pressure vents, dehydration columns and distillation
columns, as well as wastewater streams from neutralization and drying
operations, are probable sources of unreacted 1,2-dichloroethane
discharges. Data concerning process discharges are unavailable
however; accordingly, 1,2-dichloroethane emissions, based on analogy
to the 1,2-dichloroethane manufacturing process, are estimated to be
approximately 6 kg/kkg of product or 400 kkg annually. Also based on
this analogy, 360 kkg (90%) are assumed to be emitted to the atmos-
phere, 20 kkg (5%) to be discharged to surface waters, and 20 kkg (5%)
to be discharged as solid wastes. Estimating 1,2-dichloroethane
concentrations in the ethylenediamine product stream to range from
1 ppm to 10 ppm, negligible amounts (0.07 to 0.70 kkg) of
1,2-dichloroethane are released annually from use of EDA.

C.4 TRICHLOROETHYLENE AND TETRACHLOROETHYLENE

Trichloroethylene is produced either separately or as a
co-product with tetrachloroethylene by either chlorination or
oxy-chlorination of 1,2-dichloroethane or other Co chlorinated
hydrocarbons (including waste streams). All of the 135,000 kkg of
trichloroethylene were produced in the United States in 1978 from
1 ,2-dichloroethane-based processes, accounting for approximately 2% of
total 1,2-dichloroethane production (SRI, 1979a,b; see Table C-l).
Prior to 1978, 8% of U.S. trichloroethylene production was via an
acetylene-based process, since abandoned due to the increasing cost of
the feedstock (SRI, 1979b). The principal uses of trichloroethylene
include metal degreasing and use as a chain transfer agent in
polyvinyl chloride production. Many minor solvent applications in
food, textiles and medicine have been discontinued subsequent to
findings by the National Cancer Institute which suggest that
trichloroethylene may cause cancer in humans (NIOSH, 1975).

The major industrial use of tetrachloroethylene is in dry
cleaning and textile processing; other uses include metal cleaning
(degreasing) and as a chemical intermediate. Table C-4 lists
producers, processes and capacities for tri- and tetrachloroethylene
production.

C-8
-------
Table C-4. Trichloroethylene and Tetrachloroethylene Production
Facility
Trichloroethylene Production
Process
Capacity, 10 kky
Tetrachloroethylene Production

Process Capacity, 10 kkg
Diamond Shamrock Corp
Deer Park, TX
Dow Chemical Corp
Free Port. TX
Pittsburg. CA

Plaquemfne, LA
DuPont and Co., Inc.
Corpus Christ!. TX
Ethyl Corp.
Baton Rouge, IA
PPG Industries, Inc.
Lake Charles.
Stauffer Chemical Co.
Louisville, KY
Vulcan Materials Co.
Geismar, LA
Wichita, KS
Direct Clilorination
of 1,2,-dichloroethane
Direct Chlorlnatlon
of 1.2-dichloroethane
Oxy-chlortnation of
1,2-dlchloroethane
68
20
91
Direct Chlorlnatlon 75
of 1,2-dichloroethane
Direct Chlorination
of 1.2-dichloroethane 68

Chlorinolysis of hydro-
carbon feedstocks 18

Chlorinolysis of hydro-
carbon feedstocks 54
Chlorinolysis of hyrdo-
carbon stocks 73
Direct Chlorination
of 1,2-dichloreothane 23
Oxy-ch1 orination of
1,2-dichloroethane 91
Clilorinolysis of
heavy-ends 32
Chlorinolysis of
1,2-dichloroethane
and chlorinated 68

Chlorinolysis of
1,2-dichloroethane
and chlorianted 23
TOTAL
179
b25
Source: SRI. 1979b
-------
Total production of tetrachloroethylene in 1978 was 330,000 kkg
(USITC, 1979), approximately 49% of which was produced from
1 ,2-dichloroethane (SRI, 1979a). Assuming a reaction yield of 90%
(SRI, 1979a), 108,000 kkg EDC (approximately 2% of EDC production)
were consumed via tetrachloroethene production in 1978.

C.4.1 Direct Chlorination

The reaction for direct chlorination of 1 ,2-dichloroethane to
tri-and tetrachloroethylene is:

2 C1CH2CH2C1 + 5C1 - ^^ C12C=CHC1 + C12C=CC12+7HC1

The chlorination is carried out at temperatures between 400 to 450°C,
at approximately atmospheric pressure, and without the use of a
catalyst. Other chlorinated C2 hydrocarbons or recycled
chlorinated hydrocarbon by-products may be used as feedstocks.
By-product hydrogen chloride is typically used in other processes.

Figure C-3 represents a simplified process for manufacture of
tri-and tetrachloroethylene via direct chlorination of 1 ,2-dichloro-
ethane. 1,2-Dichloroethane and chlorine are first vaporized and fed
to the reactor. Hydrogen chloride is separated from the reaction
mixture and recovered as a by-product. The chlorinated hydrocarbon
mixture is neutralized with a sodium hydroxide solution.

The crude product is dried and separated by distillation into
two crude streams. Crude trichloroethylene is distilled and the light
ends taken overhead. The bottom stream which contains trichloro-
ethylene and heavy chlorinated hydrocarbons are distilled in the
finishing column. Trichloroethylene is taken overhead and sent to
storage; the heavy by-products are combined with the light ends from
the trichloroethylene column and recycled. The crude tetrachloro-
ethylene is separated in the tetrachloroethylene column; purified
tetrachloroethylene goes overhead to storage and the bottoms go to the
heavies column. The heavy by-products are fractionated and are
recycled. The bottom product (largely tars) is incinerated.

C.4.2 Qxy-Chlorination

Tri- and tetrachloroethylene may also be produced by oxy-
chlorination of 1,2-dichloroethane:
2C1CH2CH2C1 + 202 - 3^C12C=CC12+ 4C12C=CHC1 + 8H20

The reaction is carried out at an approximate temperature and
pressure of 425°C and one atmosphere respectively. Other chlorinated
hydrocarbons may be used as feedstocks; indeed, most organic by-
products may be recycled to the process. The process is relatively
C-10
-------
TC>
REACT oa
two
CMi.OC.lUE.
o
I
D'CHLC^lDE
\ZATiOM
AMD
DTHVLEUC
v j j>~£iT e v v AT e a.
To -j-^e
COL-UN^KJ
CMI.O?.! MATED
Jl
T
LOAOVMC,
TRlCHv.C--OE.TH.MJE.
FlKJ\S»^\M<:^
COt-UMW
HEAVY
EKJOS
COLUMN
T
Figure C-3. Flow Diagram for Perchloroethylene and Trlchloroethylene by Chlorlnation
-------
flexible and production of either tri- or tetrachloroethylene may be
increased at the expense of the other.

Figure C-4 represents a simplified process for tri- and tetra-
chloroethylene manufacture via oxy-chlorination of 1,2-dichloroethane.
Hydrogen chloride, oxygen, and 1,2-dichloroethane are vaporized and
fed to a fluidized bed reactor. The crude product is cooled, sepa-
rated from by-product water and noncondensed phases (e.g., carbon
dioxide, hydrogen chloride, nitrogen, and small amounts of chlorinated
hydrocarbons) and are scrubbed with water to make by-product hydro-
ch-loric acid. The remaining inert gases are purged.

The crude product is dried by azeotropic distillation and
separated into two product streams in the tetrachloroethylene/tri-
chloroethylene column. Crude trichloroethylene is further fractiona-
ted. Low boiling impurities (light ends) are recycled to the reactor.
Trichloroethylene is neutralized with ammonia, dried, and sent to
storage. Crude tetrachloroethylene from the tetrachloroethylene
column is also further fractionated. Tetrachloroethylene and low
boiling by-products are taken overhead. High boiling impurities are
fractionated into two streams: by-products suitable for recycle, and
tars which are unsuitable for recycle. Crude tetrachloroethene (which
contains low boiling impurities) is distilled once again. Low boiling
impurities are recycled to the process. Tetrachloroethylene is then
neutralized with ammonia, dried, and sent to storage.

C.4.3 Process Discharges

Few data are available regarding process discharges of 1,2-di-
chloroethane during trichloroethylene/tetrachloroethylene production.
Major point sources of atmospheric emissions of 1,2-dichloroethane are
the neutralization and drying vent and feedstock storage tanks.
Assuming an emission factor of 3.1 kg of 1,2-dichloroethane/ kkg
product and a control level of 85%, 138 kkg of 1,2-dichloroethane were
emitted from neutralization and drying vents during trichloroethylene/
tetrachloroethylene production (EPA, 1979b). Feedstock storage
emission data are unavailable. Trichloroethylene and
tetrachloroethylene are produced in the same plant as
1,2-dichloroethane, however, and it is assumed that a portion of
1,2-dichloroethane product storage tanks may serve as feedstock
storage tanks for tri- and tetrachloroethylene production. If
separate tanks are in fact required for 1,2-dichloroethane feedstock
storage, approximately 130 kkg would be emitted based on an emission
factor of 0.6 kg/kkg product and 1978 consumption of
1,2-dichloroethane for trichloroethylene/tetrachloroethylene
production. 1,2-Dichloroethane may also be emitted from reactor and
distillation vents, but no specific data are available.
C-12
-------
n
i
Figure C-4. Flow Diagram for Perchloroethylene and Trichloroethylene

by Oxy-chlorlnation (EPA, 1979b)
-------
Neutralization is the predominant method of treatment of
trichloroethylene/tetrachloroethylene process wastes. Of the ton
plants producing trichloroethylene/tetrachloroethylene, seven
discharge to surface waters. Assuming tota.1 wastewater production of
0.42 kkg HgO/kkg product, total trichlcroethylene/tetrachloroethy-
lene production via 1,2-dichloroethane processes of 300,000 kkg, and
an average 1,2-dichloroethane concentration of 510 H-g/1, approximately
64 kkg of 1,2-dichloroethane were discharged to surface waters
(Catalytic, 1979). This value is calculated on the basis of raw waste
load. Neither neutralization nor biological treatment are likely to
degrade 1,2-dichloroethane. Aerated lagoons, of course, do lower
aquatic discharges at the expense of air emissions. Data regarding
solid waste releases are unavailable. Based on the physical proper-
ties of 1,2-dichloroethane and the fact that solid wastes are largely
incinerated or recycled as chlorinolysis process feedstocks, emissions
or discharges of 1,2-dichloroethane are presumed to be negligible.

Emissions of 1,2-dichloroethane from use of trichloroethylene
and tetrachloroethylene are small. PPG Industries estimate 1,2-di-
chloroethane concentration in tetrachloroethylene to be <1 ppm
(Denison, 1980). Taking this estimate as being valid for
trichloroethylene and tetrachloroethylene, less than 0.3 kkg of
1,2-dichloroethane was emitted to the environment (primarily the
atmosphere) from use of both products.

C.5 VINYLIDENE CHLORIDE

Vinylidene Chloride monomer (VDM), once used to produce
1,1,1-trichloroethane, is manufactured by dehydrochlorination of
1,1,2-trichloroethane, manufactured in turn by chlorination of vinyl
chloride. Dehydrochlorination is carried out at a temperature
of approximately 100'C; reaction yields are reported to range from 80
to 90%. A simplified flow diagrom of vinylidene chloride manufacture
is shown in Figure C-5.

The major use today of vinylidene chloride is the manufacture of
copolymers (e.g., Saran®). Vinylidene chloride has been produced by
direct chlorination of ethane or ethylene as a coproduct of 1,2-di-
chloroethane (Neufield jet_ _al_., 1977); however, Dow Chemical Co. and
PPG Industries, Inc., the only U.S. producers, currently utilize the
dehydrochlorination method (EPA, 1979). Table C-5 lists the locations
and capacities of vinylidene chloride manufacturers; in 1978 pro-
duction totaled 81,000 kkg (EPA, 1979b). Assuming a reaction yield of
approximately 80% (EPA 1979), 102 x 103 kkg or 2% of the total
1,2-dichloroethane production was consumed in manufacture of
vinylidene chloride.
C-14
-------
1.1,2--
TRICHLOROETHANE
N2
r>
tn
NaOH —
( 5-10%)
o
I-—4

K-H
o: or
n:
O
o
o: D:
Q
LU
c*;
o
LO
AA
C3
>- _J
Q£ O
Q <_>
a.
a
< o
: o
U-STEAM
To Wastewater
Treatment
3: s:
(/> ID
M —I
z o
V—X
J/INYLIDENE
CHLORIDE
Figure C-5. Manufacture of Vlnylidene Chloride from 1,1,2-Trlchloroethane (EPA, 19795)
-------
Table C-5. Vinylidene Chloride Producers, Locations, and Capacity
o
Producer Location Estimated Capacity (xlO kkg)

PPG Industries, Inc. Lake Charles, LA 79

Dow Chemical Co. Plaquemine, LA 44
Freeport, TX

TOTAL 123

Source: EPA, 1979b

31978 production: 81 x 103 kkg (EPA, 1979), 66% of capacity
-------
Specific data concerning 1,2-dichloroethane loss from vinylidene
chloride manufacture were not found; however, it is estimated that
such discharges are negligible. The starting material for vinylidene
chloride production, 1,1,2-trichloroethane (made from EDC), usually
contains 0.1% EDC (Farber, 1980). EDC was reportedly not detected in
distillation vent gas streams or in wastewater streams from vinylidene
chloride manufacture (EPA, 1979; EPA, 1977).

Losses of 1,2-dichloroethane from use of vinylidene chloride
appear to be minor. PPG Industries limits (as a product specifica-
tion) 1,2-dichloroethane concentration to *-l ppm in vinylidene
chloride monomer (Denison, 1980). Assuming this specification to be
representative of all manufacturers, and that all vinylidene chloride
is produced from 1,2-dichloroethane (SRI, 1979a) , 0.1 kkg
1,2-dichloroethane was available for release to the environment from
vinylidene chloride use in 1978.

C.6 POLYSULFIDE RESINS

Polysulfide rubbers are produced as high performance polymers
where solvent resistence is important. Manufactured at a single site
by the Thiokol Corporation, Chemical Division (Moss Point, MS), only
two polysulfide rubbers - Type A® and FA® - are based on 1,2-dichloro-
ethane systems. Type A®, the first of the polysulfide rubbers to be
produced, is based on the reaction product of 1,2-dichloroethane and
sodium tetrasulfide:
C1CH2CH2C1 + Na2 S4_>.-fCH2 CH2 -S-S-S-S^ + 2NaCl
Further research in polymeric polysulfide compositions resulted in an
improved polymer, FA® based on use of dichlorodiethyl formal and
1,2-dichloroethane:
C1CH2CH2C1 + CH2(OCH2CH2C1)2 +

CH2 -S-S-CH2CH2OCH2OCH2CH -S-
Solid polymers are manufactured in the aqueous phase in the form of
small particles in the presence of wetting and dispersing agents. The
dispersed product is washed free of soluble salts and coagulated with
acid yielding high molecular weight elastomers.

Thiokol Type A® is used principally as a sulfur modifier. Sulfur,
used as a mortar for acid pickling plants, water sewers, and oil
pipes, is brittle and can crack upon impact or from thermal
expansion/contraction. From 2% to 5% Thiokol Type A® dissolved in
molten sulfur, prevents crystallization of sulfur at ambient
temperatures [i.e., an amorphous state is maintained as opposed to the
normal crystalline state, (Panek, 1973)].
C-17
-------
A major use of polysulfide rubber FA® is in the manufacture of
rollers employed for lacquering cans, roller and grain coating of
paint on metal, and for the application of quick drying inks for
printing. A second important application is in hose liners, again
because of solvent resistance. Hoses lined with FA are widely used
for paints, paint thinners, lacquers, and aromatic hydrocarbons.
Putties formulated with FA polysulfide rubbers as base material find
diverse sealing applications.

In 1978, approximately thirty-six metric tons of polysulfide
rubber Type FA® were produced; two metric tons of Type A were
produced (Shultheis, 1980). Based on reaction stoichiometry and
assuming that 1,2-dichloroethane is the limiting reactant, 15 kkg of
1,2-dichloroethane were used in polysulfide rubber manufacture. Of
these fifteen metric tons, 99 percent is assumed to incorporated into
the product, and less than 1 kkg are discharged as process (largely
aquatic) and fugitive emissions. Assuming process water use to be
approximately 20 kkg/kkg product and a 1,2-dichloroethane concentra-
tion of 9000 ppm (the solubility limit), 0.7 kkg of 1,2-dichloro-
ethane is contained in process wastewaters. Air emissions are assumed
to be controlled by use of vent condensers;using an using an emission
factor of 10 kg/kkg, 0.02 kkg of 1,2-dichloroethane are emitted to the
atmosphere annually.

C.7 LEAD SCAVENGERS

1,2-Dichloroethane, together with ethylene dibromide (EDB) is
added to the tetraethyllead/tetramethyllead (TEL/TML) antiknock
mixtures to scavenge lead compounds (e.g., PbO) which are formed and
deposited on engine components during combustion. Lead oxides are
removed (on the deposit surface, rather than in the gas phase) by
reaction of hydrogen chloride and bromide formed during combustion of
1,2-dichloroethane and 1,2-dibromoethane as shown below. The lead
halides so formed are volatile and are emitted to the atmosphere in
the automotive exhaust.

PbO + 2HBr ^ PbBr2 + H20
PbO + 2HC1 *• PbClo + H20
PbO + HBr + HC1 *• PbBrCl + H20
PbBr2 + nPbO *• PbBr2 nPbO
PbCl2 + nPbO *• PbCl2 nPbO

A typical "Motor Mix" contains 1 mole of 1,2-dichloroethane and 0.5
mole of 1,2-dibromoethane per mole of lead. Use of lead scavengers
has steadily declined since 1973 as a result of decreased leaded
gasoline consumption. In 1978, 72,000 kkg of 1,2-dichloroethane were
used as lead scavengers; 1970 usage totalled 103,000 kkg (Jacobs,
1979). This trend will continue as new cars requiring unleaded gas
replace older vehicles using leaded fuel. The market for leaded gas
C-18
-------
for passenger cars, 2.8 x 101 1 in 1978 (Monthly Energy Review 1980),
has been forecast to disappear about 1990, although some trucks will
requ-ire leaded gas beyond this date.

Of the 72,000 kkg of 1,2-dichloroethane used as lead scavenger in
1978, approximately 700 kkg were emitted to the atmosphere from blending
of gasoline, fueling of cars, evaporation from storage tanks, and filling
of storage tanks. Estimated emissions from these sources are summarized
in Table C-6.

Atmospheric emissions of 1,2-dichloroethane are assumed to occur
both prior to and after combustion of gasoline. Though 1,2-dichloro-
ethane was not detected (analytical) detection limit: 150 ppb) in a
sampling of automotive exhaust from two vehicles operating on leaded
gasoline containing 0.95 g 1,2-dichloroethane per gallon of gas
(Jacobs, 1980), the detection limit corresponds to a combustion
efficiency of only 97-98%. If on the other hand, combustion of
1,2-dichloroethane is comparable to that of ethylene dibromide
(from 5 to 20 ppb of EDB were detected in the same analysis), decom-
position of 1,2-dichloroethane may be as great as 99.3 to 99.8% of the
amount originally present. Using the latter data, 1,2-dichloroethane
emissions would range from 140 kkg to 500 kkg. Assuming a conservative
combustion efficiency of 99.33$, approximately 500 kkg of 1,2-dichloro-
ethane were emitted in automotive exhaust.

Blending of gasoline additives is usually a closed system
operation involving little personnel contact. 1,2-Dichloroethane
concentration in a gasoline blending plant ranged from 0.003-0.18 ppm
as a 8-hour time-weighted average. Estimated emission of EDC from
blending of gasoline totaled 35 kkg, based on an assumed emission
factor of 0.5 kg/kkg EDC in gasoline blended.

An estimated 120 kkg of 1,2-dichloroethane were emitted to the
atmsophere in 1978 by refueling of automobiles, assuming no emission
control on gasoline pump nozzles. Total volatile organic emissions
could be reduced by as much as 95% if control mechanisms such as
hooded nozzles and pressurized pump delivery systems were utilized
(Simeroth, 1980).

Emissions of 1,2-dichloroethane from filling of storage tanks and
evaporation from storage tanks are atmospheric; an estimated 40 kkg of
1,2-dichloroethane were lost via these pathways in 1978. This esti-
mate includes both underground and above ground storage and filling
discharges with no emission control equipment.

C.8 MINOR USES

Minor uses of 1,2-dichloroethane, though comprising only a small
percentage of total output - 0.1% - totalled approximately 5000 kkg in
1978. These uses include: production of paints, coatings and
C-19
-------
Table C-6. EDC Emissions from Use as Lead Scavenger 1978
Source Estimated Atmospheric EDC Emissions
(kkg)

Blending of gasoline 35

Refueling of automobiles 120
Filling of gasoline storage tanks
40
c
Evaporation from gasoline storage tanks

Combustion of gasoline 500

Source: Acurex estimates.

aLoss of 0.05% from blending operations is assumed.
72,000 kkg EDC used in gasoline.

4.5 g hydrocarbons emitted/gal gas dispersed (simmeroth, 1980).
Assume that EDC emissions are proportional to hydrocarbon
(0.16% by weight). Gasoline has a specific gravity of 0.73
(Jacobs, 1980).
cAssume above ground storage and filling loss 14 kg gasoline/3785 1
gasoline (Simeroth, 1980), 5700 facilities, 15,000 I/day through-
put (EPA, 1977). EDC emissions proportional to gasoline loss
(0.95 g EDC/gas. gas).
A combustion efficiency of 99.3% is assumed.
C-20
-------
adhesives; extraction solvent; cleaning solvent; grain fumigant;
diluent for pesticides/herbicides; and as a specialty solvent used
during manufacture of color film. The primary source of information
covering minor applications is a 1978 EPA report (EPA, 1978a). These
data were based on a review of the literature and information acquired
from direct contacts with 1,2-dichloroethane manufacturers
such as Dow Chemical Corp.; PPG Industries, Inc.; Ethyl Corp.;
Diamond Shamrock Corp., etc. (Sittenfield, 1980; EPA, 1978a).
Minor uses of 1,2-dichloroethane are delineated in Table C-7.

C.8.1 Paints. Coatings and Adhesives

Approximately 1,300 kkg of 1,2-dichloroethane are reported to be
used in paints, coatings and adhesives, accounting for about 25% of
all minor uses (EPA, 1978a; SRI, 1979a). Experts within the paint
industry, however, were unable to provide names of specific formula-
tions containing 1,2-dichloroethane but indicated that 1,2-dichloro-
ethane is a low volume specialty solvent used principally in fast
drying paints. Possible applications include traffic paints, printing
ink and swimming pool resistant coatings (Palmer, 1980). The solvent,
which dissolves the binder and thins the product to brushing, rolling
or spraying consistency, is lost by evaporation and does not remain in
the cured film, (Drisko, 1980). 1,2-Dichloroethane either alone or
with methylene chloride or acrylic polymers, finds some use (parti-
cularly in the auto industry) as a solvent cement for thermoplastic
materials, e.g., polymethyl methacrylate or polycarbonate (Shields,
1976). In addition, 1,2-dichloroethane in combination with phenolic
compounds is reported to be an effective solvent for epoxy resins
(Vazirani, 1980).

Emissions from this category occur both in formulation of the
components and as a normal consequence of use. It is assumed
that all of the 1,2-dichloroethane used, 1,300 kkg, is eventually
volatilized.

C.8.2 Extraction Solvents

The amount of 1,2-dichloroethane consumed for use as an
extraction solvent is reported to be from 1,000-1,250 kkg (20%-25% of
the minor uses) in 1978 (EPA, 1978a; SRI, 1979a). This includes
extraction of oils from oil-bearing seeds, oleoresins from spices,
vitamins from fishliver oils, nicotine from tobacco, as well as
applications in processing of animal fats and Pharmaceuticals.
Industry experts, though indicating that 1,2-dichloroethane is a
common extraction solvent within these industries, were unable to
provide specific consumption data (Burns, 1980); one spice extraction
company contacted indicated recent discontinuance of 1,2-dichloro-
ethane solvent usage (Bower, 1980).
C-21
-------
Table C-7. Minor Uses of l,2-Dichloroethane£
Use Area
Consumption
Environmental Releases
~Mr Eanci Water
Paints, Coatings and Adhesives
Extraction Solvent
Oils from oil seeds
Processing animal fats
Pharmaceutical industry
Cleaning Solvent
PVC reactors
Textile cleaning
1300
1300
1000
Source: EPA, 1978a; Sittenfield, 1980.
a) Values do not add due to rounding
1300
130C
neg
neg
660 240
neg
neg
100
Grain Fumigant
Polysulfide Manufacture
Miscellaneous
Film manufacture
Diluent for pesticides
TOTAL
500
15
500
150
350
5000
500
neg

8
175

neg
neg

neg
175

neg
neg

C-22
-------
Two types of products appear to be extracted with 1,2-dichloro-
ethane — spice oleoresins and oilseed cake. Oleoresins offer a
superior product in terms of product uniformity and potency (5 to 20
times more potent) than the corresponding crude spices from which they
are derived and are commonly shipped in bulk to specific customers.
Certain spices (e.g., paprika, tumeric) moreover, are extracted not
for their flavor but for their color. Oleoresins are extracted by
percolating a volatile solvent, for example dichloromethane or
1,2-dichloroethane, through a ground spice; the solvent is removed by
distillation and recovered for reuse, leaving the oleoresin. The
extracted spice residue may be used as an animal feed supplement.
Only three companies in the United States are known to produce
oleoresins in 1980; apparently none use 1,2-dichloroethane as a
solvent. Oleoresin production data are unavailable at this time; an
unknown but substantial portion of oleoresins however:, are, imported.

Vegetable oils are produced by crushing oil-bearing seeds and
recovering the resulting oil. The crushed seeds however, contain
substantial amounts of oil which is recovered by solvent (largely
hexane) extraction. As with oleoresin production, solvents are
removed by distillation and recovered for reuse. The extracted seed
cake is used as an animal feed supplement.

In 1961, permissible residues of 1,2-dichloroethane in spice
oleoresins intended for human consumption were limited to 30 ppm or
less by the Federal Food, Drug and Cosmetic Act (26 FR 2403, 1961).
Residues of 1,2-dichloroethane ranging from 3 ppm to 23 ppm have been
detected in a variety of spice oleoresins [(e.g., black pepper,
cinnamon, ginger and paprika, (Page and Kennedy, 1975; see Table
C-8)]. The annual U.S. production of spices is approximately 2.2 x
105 kkg (Census Bureau, 1979); if all spices were extracted, 1 to
5 kkg of 1,2-dichloroethane might be contained in these products. In
1967, also under the same Act, the concentration of 1,2-dichloroethane
animal feeds was limited to 300 ppm (32 FR2942, 1967). It is assumed
that oilseed-meals is the principal feed component which could be
extracted with 1,2-dichloroethane. Approximately 20 x 10° kkg of
oilseed-meals were used as animal feeds in 1978 (US Department of
Agriculture, 1980). No data are available as to the percentage of
products extracted with 1,2-dichloroethane but, based upon limited
discussions with industry and government experts, usage is uncommon.

Ninety-five to 99% of 1,2-dichloroethane used is recovered by
use of vent condensers and carbon recovery systems; <5 ppm is
estimated to be present in vent gas, effluents (see Table C-9) or
residues (Lo, 1980; Page and Kennedy,1975). Thus, consumption of
1,000 to 1,250 kkg of 1,2-dichloroethane listed for this category may
represent in fact, process loss, assuming zero market growth. This in
turn, implies a total 1,2-dichloroethane solvent inventory (assuming
C-23
-------
Table C-8. 1,2-Dichloroethane Residues, ug/g Found in Spice
Oleoresins from Three Manufacturers
Spice Oleoresin
Black Pepper
Celery
Cinnamon
Clove
Mace
Marjoram
Paprika
Rosemary
Sage
Thyme
Turmeric
1,2-DICHLOROETHANE CONCENTRATION, ug/g
Manufacture
ABC
9 12
2 3
3
23
4
6
3 9
3
6
13
6 2
Source: Page and Kennedy, 1975.
C-24
-------
Table C-9. Wastewater Loading of Dlchloroethanes in the Pharmaceutical Industry
Plant If

o
i
ro
Ul

12015
12022
12028
12036
12038
1 20'j8
12044
12066
12097
12108
12119
12132
12161
12204
12210
12231
12236
12256
12257
12311
12342
12411
12420
12439
12447
12462
12999
Total
How (10 I/day) Concentrations (pg/1)
1,1-Dichloroethane 1,2-Dichloroethane
Influent Effluent Influent Effluent
Effluent Loading (kg/yr)
1,1-Dichloroethane 1,2-Dichloroethane
0.30
4.9
0.30
4.6
3. a
27.5
0.49
0.99
0.30
0.53
0.19
3.8 5
3.8
0.76
0.038
1.9
3.2
110
1.9
0.61
4.0 N/Ab
1.3
0.64
0.038
5.7 54
1.1
1.7

19
11,000
17
_
3.000
10-30/3,500-14,00
_
<10 <10
_
< 10
_
12
-
28
.
_
68-560
.
<10 <10
15
j
H/A_
_
_
14.000
_
UNKC

500
-
_
65
22-44
_
<10 <2.7
.
<1 .4
_
.
.
.
-
.
69-560
.
<10 *5. 1
_
-
1.1
_
_
.
.
20
<10

600

67
160-330

<2.7

50-260

< 5. 1

9.2
920-1300
Source: EPA, Effluent Guidelines Division, 1980.

a) Based on a 270 day operating year
u) Not applicable, i.e., no waste treatment plant
c) Unknown
-------
97% solvent recovery) of approximately 40,000 kkg, a value not
inconsistent with spice production and oil extraction.
C.8.3 Cleaning Solvents

Approximately 1,000 kkg of 1,2-dichloroethane is used as cleaning
solvents, primarily to clean polyvinyl chloride production equipment
and as a degreaser/spotting agent in the textile manufacturing
industry (EPA 1978a; SRI, 1979b). The quantities consumed in each use
are unavailable however, usage therefore has assumed to be apportioned
equally between these uses.

Use within the textile industry is reported to be within a closed
system and only small amounts are discharged on a continuous basis.
The disposition of spent solvents is unknown, but solvents are
presumed to be recovered. It is arbitrarily assumed that all
1,2-dichloroethane used for cleaning purposes is eventually emitted to
the atmosphere since PVC reactor cleaning wastes are presumed to be
drummed prior to disposal. These wastes are presumed to be landfilled
or ocean dumped rather than incinerated.

C.8.4 Grain Fumigants

Approximately 500 kkg of 1,2-dichloroethane were used for grain
fumigation in 1978 (EPA, 1978a; SRI, 1979a). Grain fumigation in
general is expected to increase due to the recent Soviet grain
embargo, resulting in storage of an additional 20 million bushels of
grain (Fowler, 1980). Fumigants are defined as gaseous pesticides.
They must remain in the gas or vapor state and in sufficient
concentration to be lethal to the target pest species. In the case of
1,2-dichloroethane, toxic vapors are generated from a liquid and
usually used as part of multi-component fumigant mixtures for the
control of insect and fungal infestations in stored grain (see Table
C-10). The sorption and persistence of 1,2-dichloroethane depends on
the grain type, exposure conditions and degree of subsequent
ventilation. It is assumed that all fumigant vapors not retained by
the grain are lost to the atmosphere. Although some investigators
have reported high (up to 84%) retention of EDC residues in fumigated
grains (Berck, 1965; Wit_et_a_[., 1969, as cited in Fishbein, 1980)
most feel that subsequent to processing, preparation and cooking,
negligible levels of 1,2-dichloroethane remain in the final product.
Thus, 99.9+% of the 1,2-dichloroethane used for grain fumigation, or
500 kkg, should ultimately be discharged to the atmosphere. However,
animals which consume grain directly, such as chickens and cattle,
C-26
-------
Table C-10. Pesticide Products Containing l,2-DicMoroethanee
Active ingredients
Pesticide product name
Component
Concentration
Product
toxicity
rating^
Products containing one active ingredient

Destruxol Borer-Sol
Ferti-Lome Tree Borer Killer
Hacienda Borer Solution
Navlet's Borer Solution
Staffel's Boraway
1,2-Dichloroethane
1,2-Dichloroethane
1,2-Dichloroethane
1,2-Dichloroethane
1,2-Dichloroethane
50.0
50.0
50.0
50.0
50.0
Products containing two active ingredients
Best 4 Servis Brand 75-25
Standard Fumigant

Big F "LGF" Liquid Gas
Fumigant
Brayton Flour Equipment
Fumigant for Bakeries

Brayton 75-25 Grain
Fumigant
Bug Devil Fumigant

Cardinalfume

Cheafonn Brand Bore-Kill

Cooke Kill-Bore

De-Pester Fumigant No. 1

Diamond 75-25 Grain Funigant

Diveevil

Dowfume 75

Excelcide Excelfuine

Fume-Q-Death Gas No. 3

Fumisol

Gas-0-Cide
1,2-Dichloroethane
Carbon tetrachloride

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dichloroe thane
Carbon tetrachloride
1,2-Dichloroethane
Carbon tetrachloride
1,2-Dichloroethane
Carbon tetrachloride
1,2-Dichloroethane
Carbon tetrachloride

1,2-Dichloroethane
Propylene dichloride

1,2-Dichloroethane
Lindane

1,'2-Dichloroethane
Carbon tetrachloride
1,2-Dichloroethane
Carbon tetrachloride
1,2-Dichloroe thane
Carbon tetrachloride
1,2-Dichloroethane
Carbon cetrachloride
1,2-Dichloroethane
Carbon tetrachloride
1,2-Dichloroethane
Carbon tetrachloride
1,2-Dichloroethane
Carbon tetrachloride
1,2-Dichloroethane
Carbon tetrachloride
70.3
29.7

75.0
25.0
70.2
29.8
70.2
29.8

70.3
29.7

70.2
29.8

35.0
15.0

50.0
1.0

70.2
29.8
70.2
29.8
70.0
30.0

70.0
30.0
70.0
30.0
70.0
30.0

70.3
29.7
70.3
29.7
3

1
C-27
-------
Table C-10. (Continued)
Pesticide product name
Grain Fumigant
Hill's Hilcofurae 75
Hydrochlor Fumigant
Hydrochlor GF Liquid Gas
Fumigant
Infuco Fumigant 75
J-Fume 75
Koppersol
Maxkill 75-25
Pearson's Fuaigrain P-75
Riverdale Furaigant
Selig's Selcofuae
Spray-Trol Brand
Insecticide Fuai-Trol
Standard 75-25 Fuaigant
Stephenson Chemicals Stored
Grain Fuzsigant
Vulcan Formula 72 Grain
Fumigant
Westofume Fumigant
Zep-0-Fune Grain Mill
Fumigant
Products
Brayton EB-5 Grain Fumigant
Crest 15 Grain Funigant
Active ingredients
Product
_ . toxicity
„ .. Concentration . v
Component ,„. rating^
1,2-Dichloroe thane
Carbon tetrachloride
1 , 2-Dichloroe thane
Carbon tetrachloride
1 , 2-Dichloroethane
Carbon tetrachloride
1 , 2-Dichloroe thane
Carbon tetrachloride
1 , 2-Dichloroethane
Carbon tetrachloride
1 , 2-Dichloroethane
Carbon tetrachloride
1 , 2-Dichloroethane
Copper oleate
1 , 2-Dichloroethane
Carbon tetrachloride
1 , 2-Dichloroethane
Carbon tetrachloride
1, 2-Dichloroethane
Carbon tetrachloride
1 , 2-Dichloroethane
Carbon tetrachloride
1 , 2-Dichloroethane
Carbon tetrachloride
1 , 2-Dichloroethane
Carbon tetrachloride
1 , 2-Dichloroethane
Carbon tetrachloride
1 , 2-Dichloroethane
Carbon tetrachloride
1,2-Dichloroe thane
Carbon tetrachloride
1 , 2-Dichloroethane
Carbon tetrachloride
75.0 1
25.0
70.2 2
29.8
70.0 1
30.0
75.0 1
25.0
70.0 1
30.0
70.0 1
30.0
3.0 3
11.0
70.2 1
29.8
67.5 1
32.5
70.3 2
29.7
25.0 1
75.0
70.2 1
29.8
70.3 2
29.7
70.2 1
29.8
70.2 2
29.8
70.2 1
29.8
70.2 1
29.8
containing three active ingredients
1, 2-Dichloroethane
Carbon tetrachloride
1 , 2-Dibr oraoe thane
1 , 2-Dichloroethane
Carbon tetrachloride
1 , 2-Dibromoethane
29.2 1
63.6
7.2
19.6 2
57.0
20.4
C-28
-------
Table C-10. (Continued)
Pesticide product name
Active ingredient
Component
Concentration
. (2)
Product
toxicity
rating-^
De-Pester Weevil Kill
Dowfume EB-5 Effective Grain
Fumigant

Dowfume EB-15 Inhibited
Dowfume E3-59
Farrarite Mushroom Spray
FC-7 Grain Fumigant
(FC-13) Mill Machinery
Fumigant

FC-13 Mill Machinery
Fuaigant

Formula 635 (FC-2) Grain
Fumigant

Grainfume MB
Infuco 50-50 Spot Fumigant
J-Fume-20
Leittle Spotfume 60
Max Spot Kill Machinery
Fumigant

Okay Mole and Gopher
Fumigant
1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibromoethane
1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibrorcoethane

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibroraoethane
1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibroaoethane

1,2-Dichloroe thane
Malathion
Petroleum distillate

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibromoethane

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibroraoe thane

1,2-Dichloroet hane
Carbon tetrachloride
1,2-Dib romoe thane

1,2-Dichloroe thane
Carbon tetrachloride
1,2-Dibromoethane

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibromoe thane

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibromo e thane

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibromoethane

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibroooethane

1,2-Dichloroethane
Carbon tetrachloride
Paradichlorobenzene.
29.2
63.6
7.2

20.0
64.0
7.0

20.0
57.0
20.0

9.0
32.0
59.0

75.0
22.5
2.5

64.7
27.4
7.9

19.6
59.9
20.5
19,
59.
20,
29.2
63.6
7.2

29.2
63.6
7.2
26.84
11.40
61.76

20.0
57.0
20.0

8.5
31.5
60.0

20.0
57.0
20.0

30.0
50.0
20.0
C-29
-------
Table C-10. (Continued)
Pesticide produce narr.e
Parson Lechogas Furaigant

Solig's Grain Fumigant
No. 15

Spot Furaigant

T-H Vault Funigant

Tri-X Garment Fumigant

Vulcan Formula 635 (FC-2)
Grain Fur.i§anc

Waco-50

Active ingredient

Conponent Concentration
1 , 2-Dichloroethana
Carbon tetrachloride
1, 2-Dibronoethane
1 , 2-Dichloroethane
Carbon tetrachloride
1,2-Dibroraoe thane
1 , 2-Dichloroe thane
Carbon tetrachloride
1 , 2-Dibronoethane
1, 2-Dichloroethane
Carbon tetrachloride
1 , 2-Dibrocioe thane
1, 2-Dichloroethane
Carbon tetrachloride
1 , 2-Dibronoethane
1 , 2-Dichloroe thane
Carbon tetrachloride
1, 2-Dibronoethane
1 , 2-Dichloroethane
Carbon tetrachloride
1 , 2-Dibronoethane
73.5
24.5
2.0
19.6
57.0
20.4
19.6
59.9
20.5
29.2
63.6
7.2
30.0
65.0
5.0
29.2
63.6
7.2
9.0
32.0
59.0
Product
eoxicitv
rating
1
.

Products containing four active ingredients
Agway Serafc^e
Coop New Activate Weevil
Killer Fu=.i-a.-t
De-Pester Grain Conditioner
and Weevil Killer
Dowfume F
Dyna Fune
(FC-4) SX Grain Storage
Fumigant
1,2-Dichloroe thane
Carbon disulfide
Carbon tetrachloride
•1,2-Dibronoe thane

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dihrotnoethane
Sulfur dioxide

1,2-Dichloroethane
Carbon tetrachloride
1,2-DibroriOe thane
Sulfur dioxide

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibror.oe thane
Sulfur dioxide

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibrd~oe thaue
Sulfur dioxide

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibroraoe thane
Sulfur dioxide
10.0
10.0
76.5
3.5
66.0
27.0
5.0
2.0

64.6
27.4
5.0
3.0

65.0
27.0
5.0
"KC;

12.0
83.8
1.2
3.0

64.6
27.4
5.0
3.0
C-30
-------
Table C-10. (Continued)
Pesticide product name
Active iiigi eu j.cuta
_ Concentration
Component ,., .
(.'•)
Product
toxicicy
racing-
Fcrnula MU-39'
Iso-Furr.e
Max Kill Spot-59 Fumigant
for Mills and Milling
Machinery

Patterson's Weevil Killer
Pioneer Brand Grain Fumigant
Selig's Grain Storage
Fumigant
Serfume
Sure Death Brand Mi11fume
No. 2
T&C Fruit and Vegetable
Insecticide and Miticide2
T-H Grain Fureigant No. 7
Weevil Killer and Grain
Conditioner

914 Weevil Killer and Grain
Conditioner
1,2-Dichloroechane
Malathion
Petroleum distillate
Xylene

1,2-Dichloroe thane
Carbon tetrachloride
1,2-Dibrorr.oe thane
Sulfur dioxide

1,2-Dichloroethane
Carbon disulfide
Carbon tetrachloride
1,2-Dibromoethane

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibromoethane
Sulfur dioxide

1,2-Dichloroethane
Carbon disulfide
Carbon tetrachloride
1,2-Dibromoethane

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibromoe thane
Sulfur dioxide

1,2-Dichloroethane
Aromatic petroleum
derivative solvent
Methyl azinphos
Petroleum distillate

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibromoethane
Sulfur dioxide

1,2-Dichloroethane
Carbon tetrachloride
1,2-Dibromoethane
Sulfur dioxide
10.00
23.75
50.00
15.00

11.4
80.6
5.0
3.0

10.0
1.5
29.5
59.0
64.
27,
5.
63.1
26.9
7.1
2.9
66.0
27.0
5.0
2.0
64.6
27.4
5.0
3.0
10.0
10.0
76.5
3.5
3.0
28.0

28.0
5.0
28.0
63.1
26.9
7.1
2.9
63.1
26.9
7.1
2.9
C-31
-------
Table C-10. (Concluded)
Active ingredient
Pesticide product nane
Component
Concentration
U)
Product
toxicity
rating^
Products containing five active ingredients
Cooke Bug Shot Lawn Special
Spray Concentrate^
49'er Gold Strike Bonanza
Plant
Old Scratch Concentrated
Rotenone-Malathion
Sirotta's Sircofuzae Liquid
Funigating Gas
1,2-Dichloroethane 20.0
Cyclohexanone 4,0
Lindane 4.0
Petroleum distillate 24.0
Toxaphene 40.0
1,2-Dichloroethane 10.25
Copper oleate 15.25
Cube resins other
than rotenone 2.00
Pyrethrins 0.50
Rotenone 1.00
1,2-Dichloroethane 11.75
Cube resins other
than rotenone 3.75
Malathion 42.00
Pine oil 40.00
Rotenone 2.50
1,2-Dichloroethane 1.0
Carbon tetrachloride 96.0
Tetrachloroethylene 1.0
1,1,1-Trichloroethane 1.0
Trichloroethylene 1.0
Products containing seven active ingredients
1,2-Dichloroethane
Copper oleate
Cottonseed oil
Cube resins other
than rotenone
Ethylene glycol
Pyrethrins
Rotenone
10.25
15.25
35.25
2.00
26.50
0.50
1.00
Unless otherwise indicated, the pesticide is an insecticide or miticide
that is applied without dilution as a liquid fumigant.
^Toxicity scale is relative and is based on acute toxicity; 1 represents the
highest level of toxicity.
^pray in oil, use undiluted, not pressurized.
Concentrate or emulsifiable.
^Concentrate, solution.

Source: EPA, 137Sa.
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may be exposed to relatively high concentrations of 1,2-dichloroethane
(EPA, 1979a).

C.8.5 Miscellaneous Uses

In previous reports, 10% of minor 1,2-dichloroethane uses, 500
kkg, has been apportioned to miscellaneous applications such as color
film manufacture, as a diluent for pesticides and herbicides, and
amine carrier used in hydrometallurgical treatment of copper ores
(EPA, 1978a). 1,2-Dichloroethane, though suggested as a component of
specialized solvent formulations (i.e., amine carriers), is apparently
no longer used for this purpose (Schurtz, 1980; Sudderth, 1980).

Approximately 150 kkg of 1,2-dichloroethane are used in the film
industry, not in film manufacture per se but rather as a specialty
solvent. Since the 1,2-dichloroethane used in this application is
reported to be spread over a number of small, isolated steps in the
manufacturing process, solvent recovery is not economically feasible,
and therefore not practiced (Klanderman, 1980). A large majority of
the 1,2-dichloroethane is completely destroyed by incineration,
however, with no more than 5% (^8 kkg) emitted to the atmosphere
during use (Klanderman, 1980).

1,2-Dichloroethane is also authorized for used as a stabilizer in
soil and animal pesticide and soil fumigants (40 CFR 553-558; July 1,
1979). Use and production data for the above applications, however,
are held as proprietary data by EPA; specific information, therefore,
is unavailable at this time.
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APPENDIX D

MUNICIPAL DISPOSAL OF 1,1- AND 1,2-DICHLOROETHANE

D.I INTRODUCTION

This section deals with the ultimate disposition of 1,1- and
1,2-dichloroethane discharged to municipal waste facilities:
publicly-owned treatment works (POTWs) and urban refuse landfills or
incinerators. A summary material balance around each waste treatment
category is shown in Table D-l.

D.2 PUBLICLY-OWNED TREATMENT WORKS (POTWs)

Loading of 1,1- and 1,2-dichloroethane to POTWs is largely
dependent upon variations in industrial discharges and the type of
industry in a particular municipal area. A framework for calculating
the total 1,1- and 1,2-dichloroethane flow through the nation's POTWs
(see Table D-l) is provided by data from a recent EPA study of treat-
ment facilities (EPA, 1980); significant concentrations of dichloro-
ethanes were found, however, in only one facility. A materials
balance of dichloroethanes at treatment plants can be constructed
using a total POTW flow of approximately TO11 I/day (EPA, 1978b).
The compound 1,2-dichloroethane was detected in the influent of
3 of 20 POTWs with an overall mean of 1.05 ug/l (assumes the not
detected are zero and the trace values are the quantifiable limit)
(EPA, 1980). It is assumed for purposes of these calculations that
influent and effluent flow rates are equal, i.e., that water loss
from sludge removal and evaporation are small compared to influent
flows. Dichloroethanes do not appear to be preferentially adsorbed
by sludge. Using these assumptions, 36 metric tons (as an upper
limit) were discharged from POTWs in 1978. In the single plant
where 1,2-dichloroethane was found at a significant influent concen-
tration (11 yg/1) approximately ninety percent was emitted to the
atmosphere during treatment operations, a not surprising result
considering the volatility of 1,2-dichloroethane. Assuming this
phenomenon occurs at other POTWs, 32 kkg of 1,2-dichloroethane
would be emitted to the atmosphere per year; 4 kkg would be dis-
charged in effluent.

The average influent 1,1-dichloroethane concentration was 1.55
(it was detected in 11 of 20 POTWs). Based upon one plant where
detectable levels were found in all sampling points, a partitioning
of 8% to sludge, 1% to effluent, and 91% to air was assumed.
Thus, approximately 52 kkg would be released to air, 4 kkg in
sludge, and 1 to waters.
D-l
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Table D-l. Dichloroethane Materials Balance: Municipal POTWs and Refuse (kkg/yr)
ro
Source Input
POTW a 36 b

URBAN REFUSE
INCINERATION unknown
LANDFILL unknown
Environmental Releases
Air Land
32
rieg

unknown unknown
unknown

Water

unknown

a) Publicly Owned Treatment Works. Air: Unsubstantiated estimate. Based on a single plant survey where 90%
of the 1,2,-dichloroethane present volatilized during treatment, see text.

b) Figures calculated from EPA data (see Table D-2): based on 1011 I/day total POTW flow and median
values for; influent concentration = 1.05 yg/l.
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D.3 URBAN REFUSE

The three options for handling of urban refuse are eneray
"erv (primarily by incineration), material recovery and
.through incineration or landfill. Urban refuse can be
r ^naJntVw°.maj°!r c°mPonents: a combustible fraction (paper,
cardboard, plastics, fabrics, etc.) and a noncombustible fraction
(ferrous and nonferrous metals, glass, ceramics etc.). There are
?° ?!£* J°wever> c°'?cern;"9 dichloroethane emissions from municipal
incineration. Dichloroethanes are unlikely to be disposed of
directly as municipal wastes.
D-3
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