United States Office of Water July 1982
Environmental Protection Regulations and Standards (WH-553) EPA-440/4-85-018
Agency Washington DC 20460
Water "
T/EPA An Exposure
and Risk Assessment
for Trichloroethanes
-------
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 riot 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.
-------
0572-10?
REPORT DOCUMENTATION »• «PORT "«• *•
PAGE EPA-440/4-85-018
4. TOe and Subtitle
An Exposure and Risk Assessment for Trichloroethanes
1,1, 1-Tr ichloroethane 1 , 1 , 2-Tr ichloroethane
7. Authors Thomas, R. ; Byrne, M. ; Gilbert, D.;
Goyer, M. ; and Wood, M.
9. Performing Organization Name and Address
Arthur D. Little, Inc.
20 Acorn Park
Cambridge, MA 02140
12. Sponsoring Organization Nam* and Address
Monitoring and Data Support Division
Office of Water Regulations and Standards
U.S. Environmental Protection Agency
Washington, D.C. 20460
3. Recipient's Acea«slon No.
5. Raport Oat* Final Revision
July 1982
6.
8. Parformmg Organization Rapt. No.
10, Project/Taak/Work Unit No.
11. Contract(C) or Grant(G) No.
(0 68-01-6160
(G)
IX Typ* of Raport & Parlod Covered
Final
14.
15. Supplamantary Notes
' Extensive Bibliographies
IS. Abatract (Limit 200 word*)
This report assesses the risk of exposure to 1,1,1-trichloroethane and 1,1,2-
trichloroethane. This study is part of a program to identify the sources of and
evaluate exposure to 129 priority pollutants. The analysis is based on available
information from government, industry, and technical publications assembled in March of
1981.
The assessment includes an identification of releases to the environment during
production, use, or disposal of the substance. In addition, the fate of trichloro-
ethanes in the environment is considered; ambient levels to which various populations
of humans and aquatic life are exposed are reported. Exposure levels are estimated
and available data on toxicity are presented and interpreted. Information concerning
all of these topics is combined in an assessment of the risks of exposure to tri-
chloroethanes for various subpopulations.
17. Document Analyai* a. Descriptor*
Exposure
Risk
Water Pollution
Air Pollution
b. Identlflers/Open-Ended T«rma
Pollutant Pathways
Risk Assessment
e. COSATI Hold/Group Q6F 06T
Effluents
Waste Disposal
Food Contamination
Toxic Diseases
Trichloroethanes
1,1,1-Trichloroethane
1,1,2-Trichloroethane
U.S Environmental Protection Agencjj
Region V, Library ^- '
230 South Dearborn Street ^
Chicago, Illinois 60604
ft. Availability Statement
Release to Public
19. Security Claaa (This Raport)
Unclassified
20. Security Ctatt (This Paga)
Unclassified
21. No. of Pagaa
180
22. Price
$17.50
See Instruction* on fl*v*r*e
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
-------
-------
AN EXPOSURE AND RISK ASSESSMENT
FOR TRICHLOROETHANES
1,1,1-Trichloroethane
1,1,2-Trichloroethane
EPA-440/4-85-018
March 1981
(Revised July 1982)
by
Richard Thomas
Melanie Byrne, Diane Gilbert
Muriel Goyer, and Melba Wood
Arthur D. Little, Inc.
U.S. EPA Contract 68-01-6160
Patricia Cruse and Stephen Wendt
Acurex Corporation
U.S. EPA Contract 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
-------
FOREWORD
Effective regulatory action for toxic chemicals requires an
understanding of the human and environmental risks associated with the
manufacture, use, and disposal of the chemical. Assessment of risk
requires a scientific judgment about the probability of harm to the
environment resulting from known or potential environmental concentra-
tions. The risk assessment process integrates health effects data
(e.g., carcinogenicity, teratogenicity) with information on exposure.
The components of exposure include an evaluation of the sources of the
chemical, exposure pathways, ambient levels, and an identification of
exposed populations including humans and aquatic life.
This assessment was performed as part of a program to determine
the environmental risks associated with current use and disposal
patterns for 65 chemicals and classes of chemicals (expanded to 129
"priority pollutants") named in the 1977 Clean Water Act. It includes
an assessment of risk for humans and aquatic life and is intended to
serve as a technical basis for developing the most appropriate and
effective strategy for mitigating these risks.
This document is a contractors1 final report. It has been
extensively reviewed by the individual contractors pnd by the EPA at
several stages of completion. Each chapter of the draft was reviewed
by members of the authoring contractor's senior technical staff (e.g.,
toxicologists, environmental scientists) who had not previously been
directly involved in the work. These individuals were selected by
management to be the technical peers of the chapter authors. The
chapters were comprehensively checked for uniformity in quality and
content by the contractor's editorial team, which also was responsible
for the production of the final report. The contractor's senior
project management subsequently reviewed the final report in its
entirety.
At EPA a senior staff member was responsible for guiding the
contractors, reviewing the manuscripts, and soliciting comments, where
appropriate, from related programs within EPA (e.g., Office of Toxic
Substances, Research and Development, Air Programs, Solid and
Hazardous Waste, etc.). A complete draft was summarized by the
assigned EPA staff member and reviewed for technical and policy
implications with the Office Director (formerly the Deputy Assistant
Administrator) of Water Regulations and Standards. Subsequent revi-
sions were included in the final report.
Michael W. Slimak, Chief
Exposure Assessment Section
Monitoring & Data Support Division (WH-553)
Office of Water Regulations and Standards
iii
-------
TABLE OF CONTENTS
LIST OF FIGURES
LIST OF TABLES x
ACKNOWLEDGMENTS xiii
EPA PROGRAM CONSIDERATIONS xv
1.0 TECHNICAL SUMMARY 1-1
2.0 INTRODUCTION 2-1
3.0 MATERIALS BALANCE 3-1
3.1 Introduction 3-1
3.2 Summary 3-1
3.3 Manufacture of 1,1,1-Trichloroethane 3-3
3.3.1 Vinyl Chloride Process 3-3
3.3.2 Environmental Releases from the Vinyl 3-5
Chloride Process
3.3.3 Chlorination of Ethane 3-5
3.3.4 Environmental Releases from the Direct 3-7
Chlorination Process
3.4 Inadvertent Sources of 1,1,1-Trichloroethane 3-7
3.4.1 Vinyl Chloride Manufacture 3-7
3.4.2 Chlorination of Water 3-10
3.5 Uses of 1,1,1-Trichloroethane 3-11
3.5.1 Degreasing Operations 3-11
3.5.2 Cold Cleaning 3-11
3.5.3 Open-top Vapor Degreasing 3-16
3.5.4 Conveyorized Vapor Degreasing 3-16
3.5.5 Fabric Scouring 3-16
3.5.6 Aerosol Formulation 3-19
3.5.7 Adhesives and Coatings 3-19
3.5.8 Small-Volume Uses of 1,1,1-Trichloroethane 3-21
3.5.9 Paints 3-21
3.5.10 Film Cleaning 3-21
3.5.11 Leather Tanning 3-21
3.5.12 Miscellaneous Small-Volume Uses 3-22
3.6 Municipal Disposal of 1,1,1-Trichloroethane 3-22
3.7 Production and Use of 1,1,2-Trichloroethane 3-23
References 3-27
-------
TABLE OF CONTENTS (Continued)
4.0 ENVIRONMENTAL DISTRIBUTION 4-1
4.1 Introduction 4_^
4.2 Monitoring Data 4_^
4.3 Environmental Fate 4-14
4.3.1 Overview 4-14
4.3.2 Aquatic Fate Processes 4-14
4.3.2.1 Hydrolysis 4-14
4.3.2.2 Sorption onto Sediments 4-16
4.3.2.3 Volatilization from Water 4-16
4.3.2.4 Biodegradation 4-17
4.3.3 Soil Transport and Volatilization 4-17
4.3.4 Atmospheric Fate Processes 4_2Q
4.4 Modeling of Environmental Distribution 4-20
4.4.1 Ambient Concentrations 4-20
4.4.2 EXAMS Model Results 4_2i
References 4-31
5.0 EFFECTS AND EXPOSURE—HUMANS 5_i
5.1 Human Toxicity c _i
5.1.1 1,1,1-Trichloroethane 5-1
5.1.1.1 Introduction 5_1
5.1.1.2 Metabolism and Bioaccumulation. 5-1
5.1.1.3 Human and Animal Studies 5-5
5.1.2 1,1,2-Trichloroethane 5.9
5.1.2.1 Introduction 5.9
5.1.2.2 Metabolism and Bioaccumulation 5-9
5.1.2.3 Human and Animal Studies 5-10
5.1.3 Overview 5-12
5.1.3.1 Ambient Water Quality Criteria - 5-12
Human Health
5.1.3.2 Other Human Effects Considerations 5-13
5.1.4 Estimates of Human Dose-Response Relationships 5-15
5.1.4.1 1,1,1-Trichloroethane 5-15
5.1.4.2 1,1,2-Trichloroethane 5-15
5.2 Human Exposure 5-22
5.2.1 Introduction 5-22
5.2.2 Exposure through Ingestion 5-22
5.2.2.1 1,1,1-Trichloroethane 5-22
5.2.2.2 1,1,2-Trichloroethane 5-23
vi
-------
TABLE OF CONTENTS (Continued)
5.2.3 Exposure through Inhalation 5-24
5.2.3.1 1,1,1-Trichloroethane 5-24
5.2.3.2 1,1,2-Trichloroethane 5-25
5.2.4 Percutaneous Exposure 5-28
5.2.4.1 1,1,1-Trichloroethane 5-28
5.2.4.2 1,1,2-Trichloroethane 5-28
5.2.5 Total Exposure Scenarios 5-29
5.2.5.1 1,1,1-Trichloroethane 5-29
5.2.5.2 1,1,2-Trichloroethane 5-29
References 5-32
6.0 EFFECTS AND EXPOSURE—NON-HUMAN BIOTA 6-1
6.1 Effects on Biota 6-1
6.1.1 Freshwater Species 6-1
6.1.2 Saltwater Species 6-1
6.1.3 Phototoxicity 6-1
6.1.4 Biological Fate 6-3
6.1.5 Conclusions 6-3
6.2 Exposure of Biota 6-3
References 6-5
7.0 RISK CONSIDERATIONS 7_!
7.1 Risks to Humans 7_1
7.1.1 1,1,1-Trichloroethane 7-1
7.1.2 1,1,2-Trichloroethane 7-1
7.2 Risk to Aquatic Biota 7-2
Appendix A Supporting Notes to Chapter 3 A-l
Appendix B Vinyl Chloride Manufacture via the Balanced Process B-l
Appendix C Solvent Recycle Calculations C-l
Appendix D Estimation of Volatilization from Water D-l
Appendix E Atmospheric Fate of Trichloroethanes E-l
vii
-------
LIST OF FIGURES
Figure
No- Page
3-1 Materials Balance: 1,1,1-Trichloroethane, 1979 3-2
3-2 Water Releases from 1,1,1-Trichloroethane Production 3-4
via Vinyl Chloride Process
3-3 Waste Releases from 1,1,1-Trichloroethane Production 3-8
via Direct Chlorination of Ethane
3-4 Geographic Distribution of Cold Cleaning Operations 3-17
3-5 Geographic Distribution of Vapor Degreasing Operations 3-17
3-6 Geographic Distribution of Fabric Scouring Operations 3-18
3-7 Geographic Distribution of the Adhesives Industries 3-20
4-1 Fraction of 1,1,1- and 1,1,2-Trichloroethane Remaining 4-18
During Biodegradation Tests
4-2 Percentage of Trichloroethane Loss due to Volatilization 4-28
as a Function of Distance from Point Source
E-l Mixing Ratio Distribution of 1,1,1-Trichloroefhane as a E-3
Function of Tropopause Height March 1976, 4V°N
Latitude
E-2 Mixing Ratio Distribution of 1,1,1-Trichloroethane as a E-3
Function of Tropopause Height, April 1977, 37°N
Latitude
E-3 Mixing Ratio Distribution of 1,1,1-Trichloroethane as a E-4
Function of Tropopause Height, July 1977, 9°N Latitude
E-4 Global Distribution of 1,1,1-Trichloroethane by Latitude E-5
in Late 1977
E-5 Latitudinal Gradient of 1,1,1-Trichloroethane Corrected E-5
to November 1978
E-6 Diurnal Variations in Atmospheric Levels of 1,1,1- E-6
Trichloroethane in New York City
E-7 Atmospheric Levels of 1,1,1-Trichloroethane in Nonurban E-6
Areas due to Transport from Urban Areas
viii
-------
LIST OF FIGURES (Continued)
Figure
No- Page
E-8 Weekly Averages from Continuous Ground Monitoring E-9
of 1,1,1-Trichloroethane Levels, June 1977 through
January 1979, 47°N Latitude
E-9 Observed NH and SH Mixing Ratios for 1,1,1-Trichloro- E-9
ethane
E-10 Atmospheric Levels of 1,1,1-Trichloroethane, 1972- E-10
1978, Northern Hemisphere
E-ll Total Ozone Losses for Various Scenarios E-10
ix
-------
LIST OF TABLES
Table
No. Page
3-1 Environmental Releases of 1,1,1-Trichloroethane 3-6
During Production by the Vinyl Chloride Process, 1979
3-2 Environmental Releases of 1,1,1-Trichloroethane 3-9
During Production by the Ethane Process, 1979
3-3 Use of 1,1,1-Trichloroethane and Estimated 3-12
Environmental Releases, 1979
3-4 Estimated Environmental Releases of 1,1,1-Trichloro- 3-14
ethane from Degreasing Operations, 1979
3-5 Production, Use, and Estimated Environmental Dispersion 3-24
of 1,1,2-Trichloroethane in 1979
4-1 Concentrations of 1,1,1-Trichloroethanes Detected in the 4-2
Atmosphere
4-2 Concentrations of Trichloroethanes Detected in- Water
4-3 Status of STORET Data for Concentrations of 1,1,1-
Trichloroethane in Ambient Water and Effluents
4-4 Distribution of Unremarked Values in STORET for 4-10
Concentrations of 1,1,1- and 1,1,2-Trichloroethane
in Ambient Water and Effluents
4-5 STORET Data Concerning Concentrations of Trichloro- 4-11
ethanes in Sediment
4-6 STORET Data Concerning Levels of Trichloroethanes 4-12
in Fish Tissue
4-7 Levels of 1,1,1-Trichloroethane Detected in Foods in 4-13
the U.K.
4-8 Physical Properties of 1,1,1-Trichloroethane arid 1,1,2- 4-15
Trichloroethane
4-9 Fate of 1,1,2-Trichloroethane Applied to a Soil Column 4-19
in the Laboratory
4-10 Input Parameters for Trichloroethanes Used in EXAMS 4-22
Analysis
-------
LIST OF TABLES (Continued)
Table
No.
Page
4-11 Flow and Depth of EXAMS Simulated Aquatic Systems 4-23
4-12 Steady State Concentrations in Various Generalized 4-24
Aquatic Systems Resulting from Continuous 1,1,1-
Trichloroethane Discharge at 1.0 kg/hr
4-13 The Fate of 1,1,1-Trichloroethane in Various 4-25
Generalized Aquatic Systems
4-14 Steady-State Concentrations in Various Generalized 4-26
Aquatic Systems Resulting from Continuous 1,1,2-
Trichloroethane Discharge at 1.0 kg/hr
4-15 The Fate of 1,1,2-Trichloroethane in Various Generalized 4-27
Aquatic Systems
4-16 Half-Lives for Trichloroethanes in Generalized Aquatic 4-30
Systems
5-1 Pulmonary Elimination of 1,1,1-Trichloroethane in Humans 5-2
5-2 Incidence of Hepatocellular Carcinoma in B6C3F1 Mice Fed 5-11
1,1,2-Trichloroethane For 76 Weeks
5-3 Conversion of Carcinogenicity Data for 1,1,2-Trichloro- 5-17
ethane into Equivalent Human Doses
5-4 Estimated Lifetime Excess Probability of Cancer in Humans 5-21
due to 1,1,2-Trichloroethane Absorption at Various Dose
Levels Based on Four Extrapolation Models
5-5 Estimated Daily Human Exposure to 1,1,1-Trichloroethane 5-26
5-6 Estimated Daily Human Exposure to 1,1,2-Trichloroethane 5-27
5-7 Total Exposure Scenarios for 1,1,1-Trichloroethane 5-30
6-1 Acute Toxicity of 1,1,1- and 1,1,2-Trichloroethane for 6-2
Freshwater Species
6-2 Acute Toxicity of 1,1,1-Trichloroethanes for Saltwater 6-2
Species
xi
-------
LIST OF TABLES (Continued)
Page
7-1 Estimated Lifetime Excess Probability of Cancer in Humans 7-3
due to Absorption of 1,1,2-Trichloroethane at Doses of
0.6 mg/day and 1.3 ug/day on the Basis of Four Extrapola-
tion Models
D-l Measured Reaeration Coefficient Ratios for High- D-6
Volatility Compounds
xii
-------
ACKNOWLEDGMENTS
The Arthur D. Little, Inc. task manager for this study was
Richard G. Thomas. Major contributors to this report were Melanie
Byrne (Biological Effects and Biota Exposure), Diane Gilbert (Human
Exposure), Muriel Goyer (Human Effects), and Melba Wood (Monitoring
Data). In addition, Kate Scow did the EXAMS analysis, Elizabeth Cole
provided substantial inputs to the human effects section, John Ostlund
estimated dose/response for 1,1,2-trichloroethane and Jane Metzger
and Nina Green edited and documented the report.
The materials balance for the trichloroethanes (Chapter 3.0) was
provided by Acurex, Inc., produced under contract 68-01-6017 to the
Monitoring and Data Support Division (MDSD), Office of Water Regulations
and Standards (OWRS), U.S. EPA. Patricia Cruse was the task manager
for Acurex, Inc.
Charles Delos, MDSD, was the project manager at EPA.
xiii
-------
EPA PROGRAM CONSIDERATIONS
1,1,1-Trichloroethane (often called methyl chloroform) is widely
used as a solvent and in related applications. Concern about this chemi-
cal stems perhaps less from its toxicity (which is relatively low) than
from its role in depleting ozone. The other isomer, 1,1,2-trichloroethane
(occasionally called vinyl trichloride) is used primarily as a feedstock.
Although it has substantial toxicity and suspected carcinogenicity, its
environmental distribution is somewhat limited.
U.S. production of 1,1,1-trichloroethane in 1979 was 322,000 MT/yr,
which represents somewhat less than half of worldwide production. About
68% of production was consumed domestically as a degreasing solvent
(mostly for metal), and thereby released mostly to the atmosphere. Recycle
and reuse was practiced to a very limited extent in this application,
resulting in total degreasing use being about 16% greater than degreasing
consumption. The remaining uses dissipate the chemical almost entirely
to the atmosphere: 7% of production as an aerosol propellant, 7% in adhe-
sives and coatings, and 7% in other solvent uses. Some 10% of production
was exported or stockpiled. The ultimate disposition of the total domes-
tic consumption is as follows: 84% to air, 10% to land, 4% to water or
sewage, and 2% destroyed by incineration. About 80% of the chemical dis-
posed of in sewers is volatilized before discharge.
U.S. production of 1,1,2-trichloroethane is estimated to be roughly
190,000 MT/yr. The exact quantity is the proprietary information of Dow
Chemical Company, the sole producer, which captively consumes most of it
as a feedstock to produce 1,1-dichloroethylene. Dow indicated that they
sell a small amount, in the "low millions of pounds" (low thousands of
metric tons), to various other industries. Although small quantities of
1,1,2-trichloroethane are also produced inadvertently during production
of other chlorinated hydrocarbons, the quantities released to the environ-
ment during both intentional and inadvertent production appear to be
negligible compared to the quantity which Dow markets to other industries.
No information is available on how these "low millions of pounds" are
consumed; however, under the worst case assumption that none of it is
destroyed through use as a feedstock, then roughly 70-90% might be
expected to be emitted to air, 10-30% disposed on land, and a few percent
discharged to water, based on disposal patterns of other chlorinated
ethanes and ethenes. Obtaining an independent estimate of environmental
releases by comparing the levels of the 1,1,1- and 1,1,2- isomers found
in urban air, then perhaps 10,000-20,000 MT/yr might be estimated to be
released to the environment.
1,1,1-Trichloroethane is one of the most frequently detected organic
priority pollutants in municipal and industrial wastewaters. The Effluent
Guidelines Division detected it at least once in nearly all industrial
categories; it was found particularly often in Mechanical Products and
Provided by Charles Delos, EPA Program Manager.
xv
-------
Paint & Ink, as well as in the Electrical, Pharmaceutical, Photographic,
and Organics & Plastics industries. 1,1,2-Trichloroethane, on the other
hand, is detected with intermediate frequency relative to other priority
pollutants; it was most often found in Mechanical Products, Paint & Ink,
and Petroleum Refining industries.
After discharge to surface water, both trichloroethanes tend to
partition toward the atmosphere. The half-life for this process often
ranges from a few hours to a few days (corresponding to a distance of
perhaps a few miles to a few dozen miles). In the lower atmosphere
1,1,1-trichloroethane is quite stable, with half-life estimates ranging
from one to several years. Consequently, the substance has the opportun-
ity to diffuse to the stratosphere where it contributes to depletion of
ozone. The half-life of 1,1,2-trichloroethane in the atmosphere is
shorter, measured in months; ozone depletion is not a concern for this
substance.
Trichloroethanes do not bind particularly tightly to soils.
Consequently, in disposing of them as a solid waste, migration from the
dump site can be expected to occur by volatilization or percolation,
unless preventive measures are practiced. In groundwater, 1,1,1-
trichloroethane might decompose (by hydrolysis) with a half-life of
perhaps 6 months or longer to hydrochloric and acetic acids. Some
dichloroethylene, which itself decomposes at about the same rate, may be
formed. 1,1,2-Trichloroethane is expected to behave similarly in
groundwater. It can be concluded that effective disposal of trichloro-
ethanes must result in containment of the substances within the site for
a time period long enough for decomposition to take place. Adsorption
to a solid phase may or may not reduce decomposition with the same effec-
tiveness that it reduces migration. If sorption were to slow both proc-
esses equally, then its overall effect would simply be to delay rather
than to prevent migration.
The toxicity of 1,1,1-trichloroethane is somewhat less than most of
the similar solvents. Animal tests have not shown it to be carcinogenic
or teratogenic; however, the results are not considered to be conclusive.
The National Cancer Institute was scheduled to complete further testing
in 1981. It has been shown to be weakly mutagenic. EPA's water quality
criterion for protection of human health is 18,400 ug/1. Acute toxicity
to aquatic life has not been found at levels below several thousand yg/1.
The toxicity of 1,1,2-trichloroethane, on the other hand, is more
substantial. Of most concern is the carcinogenicity shown in animal
tests. EPA's water quality criterion for protection of human health is
6 wg/1 (10 risk). In contrast to its toxicity to mammals, its toxicity
to aquatic life appears to be similar to the 1,1,1- isomer.
Consistent with the trichloroethanes' tendency to partition to the
atmosphere, where they are fairly stable to decomposition, most exposure
is found to result from air rather than water contamination. For 1,1,1-
trichloroethane, urban air sampling has indicated a mean concentration of
xvi
-------
3.3 ug/m . Drinking water surveys have suggested a mean concentration
in the neighborhood of 0.1 ug/1. Assuming inhalation of about 20 m /day
and ingestion of 2 I/day, the aggregate exposure to this compound is far
greater via air than via water. Although the data on food contamination
is limited and unreliable, it suggests that exposure via food may be in-
termediate between air and drinking water. Exposure through fish is very
small, however.
Exposure to the more hazardous 1,1,2- isomer is substantially less
than for 1,1,1-trichloroethane., Observed levels of 1,1,2-trichloroethane
in urban air average 0.12 yg/m . If the Cancer Assessment Group's extra-
polation from animal tests were accurate, long-term exposure to -such a
level would represent a cancer risk of slightly greater than 10 . If
representative nationwide, such a risk would represent a cancer incidence
of 3-6 cases/year. For comparison, the observed total cancer incidence
(from all causes) is over 800,000 cases/year. Aggregate exposure and
risk via drinking water is difficult to quantify because the compound is
so rarely detected in surface and groundwater.
Overall, it can be concluded from the findings that:
(1) Trichloroethanes are primarily air pollutants. Popu-
lation aggregated exposure appears to be far greater via
air than via surface and groundwater.
(2) Unless continuing tests show 1,1,1-trichloroethane to be
carcinogenic, the concentrations generally found in air,
surface water, and groundwater are not directly hazardous.
The total quantities released to the environment might
contribute to stratospheric ozone depletion, however.
(3) The levels of 1,1,2-trichloroethane observed in urban
air might contribute very slightly to cancer risks. Its
detection in surface and groundwater is, on the other
hand, rare.
(4) Current levels of trichloroethanes in ambient surface
waters are rarely expected to harm aquatic life.
xvii
-------
-------
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 the two isomers of trichloroethane: 1,1,1-trichloro-
ethane and 1,1,2-trichloroethane.
1.1 MATERIALS BALANCE
The compound 1,1,1-trichloroethane, also known as methyl chloroform,
is a high-vapor-pressure organic solvent, primarily used in degreasing
operations and as a component of other products. The chemical has become
environmentally pervasive due to fugitive emissions during production,
use, and disposal. The 1,1,2- isomer is also a high-vapor-pressure
organic solvent, but it is used mostly as a feedstock intermediate.
Environmental releases are relatively small compared with the 1,1,1- isomer,
i
1.1.1 1,1,1-Trichlorethane
Approximately 322,000 kkg of 1,1,1-trichloroethane were produced
in 1979. Production of 1,1,1-trichloroethane has remained relatively
stable since 1976, well below its 7-9% predicted growth rate. Total
environmental release of the chemical from either the vinyl chloride
or ethane production process is estimated to be 480 kkg (see Table 3.1);
81% (~390 kkg) of the total releases were discharged to POTWs. Approxi-
mately 80 kkg were emitted to air, and 9 kkg were discharged to land
in 1979.
About 220,000 kkg (68% of the total produced) were consumed by
degreasing operations. Such use results in 151,000 kkg of atmospheric
emissions; 24,000 kkg were disposed to land, and 10,000 kkg were sent
to POTWs. The remaining uses—aerosol vapor depressant, adhesives,
paints, film cleaners, and leather tanning—result almost entirely in
atmospheric emissions. Of the total 85,000 kkg consumed in such uses,
68,000 kkg (80% of the quantity used) were emitted to air. Only 420 kkg
were disposed to land and 7 kkg were sent to POTWs.
1.1.2 1,1,2-Trichloroethane
The 1,1,2- isomer is produced in the U.S. directly or in-
directly from ethylene and is also produced as a co-product in the
manufacture of other chlorinated hydrocarbons. Its chief use is as a
feedstock intermediate in the production of 1,1-dichloroethylene.
Occasionally, it is used as a solvent for chlorinated rubber manufacture.
According to the U.S. International Trade Commission, Dow Chemical
is the sole producer of 1,1,2-trichloroethane. The quantity produced is
1-1
-------
proprietary information. Approximately 180,000 kkg of 1,1,2-trichloro-
ethane is estimated to be required for 1,1-dichloroethylene production.
This estimate represents the maximum production potential and is probably
high.
Environmental releases of 1,1,2-trichloroethane from 1,1-dichloro-
ethylene manufacture are small.
Dow Chemical does sell some 1,1,2-trichloroethane as a consumer
product but the quantity sold is considered proprietary information.
A spokesperson from Dow estimated that "low millions of pounds" are
used annually in various industries. Release of 1,1,2-trichloroethane
to the environment also results from the manufacture of other chlorinated
hydrocarbons. Total environmental releases are estimated to be 5 000
kkg/yr (1979).
1.2 FATE AND DISTRIBUTION IN THE ENVIRONMENT
1.2.1 Concentrations in Environmental Media
Trichloroethanes have been detected in all environmental media,
including food and drinking water, widely throughout the United States.
Data on levels in food are extremely limited but suggest that concen-
trations for the 1,1,1- isomer are in the low yg/kg range. Limited semi-
quantitative data on levels of the 1,1,2- isomer in fish indicate very
low levels may be present in this food. No other data on levels of
l»l»2-trichloroethane in foods were available, but, given the much lower
volume of environmental releases of 1,1,2-trichloroethane, it is assumed
that most foods would contain negligible amounts, if any.
From semi-quantitative water concentration data, it has been esti-
mated that about 20% of finished water supplies may contain >1 yg/1 of
the 1,1,1- isomer and only isolated instances of >10 yg/1 exist. Data
on the concentrations of the 1,1,2- isomer in water supplies are extremely
limited and no meaningful estimates of average concentrations can be
made; however, on the basis of a much lower volume of release of this
isomer to the environment, it is thought that most drinking water supplies
have negligible amounts of the 1,1,2- isomer.
Air monitoring data for the trichloroethanes Indicate that 1,1,1-
trichloroethane is ubiquitous. Concentrations in renote areas average
about 0.5 yg/m3 and in urban areas about 3.3 yg/m3,, It is estimated
that the concentration of 1,1,2-trichloroethane in urban air is generally
about 0.12 yg/m3.
Ninety percent, or more, of sediment concentrations reported in
STORET for both chemicals are less than 10 ug/kg.
1.2.2 Environmental Fate
Because of their high vapor pressures, trichloroethanes have high
volatilization rates relative to those of many other organic chemicals,
despite the fact that their solubilities are also quite high. The
1-2
-------
primary waterborne fate pathway for these chemicals is volatilization
from surface water or soil, followed by slow photo-oxidation in the
atmosphere. For both isomers, the half-life for volatilization from
a 1-m deep stream is estimated to be 4-5 hours. Time to 90% loss is
about 12 hours. For a 10-m deep stream, the estimated half-life increases
to about 1 week and the time to 90% depletion is about 3 weeks. The
distance for 90% to volatilize is up to 1700 km downstream from the
discharge point.
When 1,1,2-trichloroethane in water solution was applied to a sandy
soil column in the laboratory, about one-half volatilized and one-half
percolated into the soil column. These results indicate that leaching
and volatilization are the important fate processes for 1,1,2-trichloro-
ethane in soil. No similar information has been found concerning 1,1,1-
trichloroethane.
In laboratory studies, 1,1,1-trichloroethane was found to have a
hydrolysis half-life of 6-7 months. In groundwater aquifers, where
other fate processes do not operate, the compound may be degraded by
this process. If behavior in the environment is similar to results of
laboratory tests, it would take 1.5-2 years to degrade 90% of the1
original amount.
Little information was found concerning the biodegradation of the
trichloroethanes. Biodegradability studies conducted in flasks in the
laboratory indicated that both compounds were degraded by yeast extract
and domestic wastewater inoculum. However, many other chlorinated sol-
vents are resistant to biodegradation, even though they exhibit some
biodegradation in wastewater treatment or laboratory studies.
The atmospheric lifetime of the 1,1,1- isomer is on the order of
6-10 years, long enough for global mixing and transport to the strato-
sphere to occur. (Stratospheric mixing and inter-hemispherical mixing
occur on a time scale on the order of a year or less.) Ozone depletion
up to 1.3% of total ozone, depending on continuing release of the chemi-
cal, may occur following Cl atom release by photodecomposition. The
1»1»2- isomer may be photolyzed more rapidly than the 1,1,1- isomer based
on results of laboratory tests, although little information concerning
1,1,2-trichloroethane was found.
1.3 RISKS TO HUMANS
1.3.1 Human Effects
1.3.1.1 1,1,1-Trichloroethane
The compound 1,1,1-trichloroethane has a fairly low toxicity via
inhalation due to rapid and almost total elimination of the compound,
unchanged, via the lungs. The small amount that is metabolized (less
than 5% of an inhaled dose) is converted by the liver to trichloroethanol
and trichloroacetic acid and excreted in urine. Urinary clearance has
1-3
-------
an approximate half-life in man of 10-12 hours for trichloroethanol
and 70-85 hours for trichloroacetic acid. Although inhalation exposure
is most common, percutaneous absorption of both liquid and vapor 1,1,1-
trichloroethane, as well as exposure via ingestion, has been demonstrated
in humans.
„ n In laboratory animals, acute LD5Q's range from 5,000 mg/kg to
12,000 mg/kg via oral administration End 75-98 g/m3 for 3-7 hours via
inhalation. Principal effects of acute exposure in laboratory animals
are depression of the central nervous system and disturbances in cardiac
function, including sensitization of the heart of epinephrine. In sub-
chronic inhalation studies, monkeys, dogs, rabbits, rats and guinea
pigs exposed to 15 g/m3, 8 hours per day, 5 days per week for 6 weeks
showed some leukopenia (reduction in the number of white blood cells)
body weight reduction and nonspecific inflammatory changes. The liver
appeared to be most susceptible to histopathological changes in guinea
pigs and mice.
No adequate carcinogenicity studies are available for the determi-
nation of carcinogenic risks associated with exposure to 1,1 1-tri-
chloroethane. In three studies, 1,1,1-trichloroethane caused no
significant increase in tumor incidence in B6C3F1 mice (4010 mg/kg/day
by gavage), Osborne-Mendel rats (1071 mg/kg/day by gavage) or Sprague-
Dawley rats (9.5 g/m3, 6 hours per day, 5 days per week for 12 months
by inhalation); however, poor survival of test animals and insufficient
duration of study rendered these data inadequate for use in an assessment
of carcinogenicity. Further data on carcinogenicity and mutagenicity
are extremely limited; weakly positive results were reported in one
strain (TA100) of Salmonella typhimurium and in one mamalian cell
transformation assay. No teratogenic effects associated with 111-
trichloroethane exposure were observed in rats or mice exposed to
4.8 g/m-5 1,1,1-trichloroethane on days 6-15 of gestation.
At low inhalation exposures of 1,1,1-trichloroethane (< 5.5 g/m3)
the primary effects in man are psychophysiologic, including~dose-related
impairment of perception and coordination and relatively little distur-
bance in body functions. At higher exposures (> 44 g/m^) functional
depression of the central nervous system leading to respiratory or
cardiac failure are noted. Acute exposures to high levels of the
compound (> 5.5 to < 44 g/nr*) by accidental contact or abuse, may
result in transient kidney and liver dysfunction. The effects of
chronic low-level exposures are not known.
1.3.1.2 1,1,2-Trichloroethang
Data concerning the toxicity, carcinogenicity,, mutagenicity or
teratogenicity of 1,1,2-trichloroethane are very limited or non-existent
particularly regarding adverse effects to man. However, based on the
evidence available, 1,1,2-trichloroethane is considered much more toxic
than the 1,1,1- isomer of trichloroethane.
1-4
-------
Absorption of 1,1,2-trichloroethane has been demonstrated in both
man and animals following inhalation exposure or dermal contact. In
laboratory animals, fairly rapid excretion of 73-87% of an absorbed dose
occurs via the urine, and 6-8% of the absorbed dose is expired unchanged.
Major urinary metabolites in mice are S-carboxymethyl cysteine, chloro-
acetic acid, and thiodiacetic acid, and minor amounts of trichloroethanol
and trichloroacetic acid.
The 1,1,2- isomer has been shown to cause central nervous system
depression in mice and damage to the liver and kidney in mice and dogs
following single intraperitoneal injections of 0.07-0.4 ml/kg. Acute
exposure in man appears to be characterized by a narcotic effect on the
central nervous system and eye and skin irritation, while possible kidney,
lung, and gastrointestinal damage may result from long-term exposure.
Data from a study on carcinogenic effects indicated that 1,1,2-
trichloroethane caused hepatocellular carcinomas and pheochromocytomas
in B6C3F1 mice of both sexes at time-weighted doses of 195 and 390 mg/kg
of body weight/day, 5 days per week, administered by gavage. Carcino-
genicity data from a similar study with Osborne-Mendel rats were
inconclusive. No adequate data regarding mutagenic or teratogenic
effects associated with 1,1,2-trichloroethane exposure have been reported.
1.3.2 Exposure of Humans
1.3.2.1 1.1.1-Trichloroethane
The chemical 1,1,1-trichloroethane is globally pervasive in air and
has been found in many samples of ground and surface drinking water.
It has been detected in foods in the United Kingdom. Except for some
limited data on levels in fish tissue, no data on concentrations in foods
in the U.S. were found. Dermal absorption appears to be of concern only
for a relatively small subpopulation that handles the chemical occupa-
tionally.
A typical daily urban exposure based on ingestion of contaminated
water and food and inhalation of urban air is estimated to be about
40 ug/day/person. An upper limit on the population potentially exposed
to these levels is about 150,000,000 people per day.
For rural dwellers, a typical exposure is five times less, 9 ug/day/
person. Some 53,000,000 people per day might be exposed at this level.
Populations living near user or manufacturing sites may have exposures
up to 2200 yg/day/person due to higher ambient air concentrations. The
size of the exposed population cannot be estimated with reasonable
accuracy.
Occupational absorption via inhalation and percutaneous routes may
range up to 11,000 mg/day/person. This level may apply to some of the
130,000 employees in degreasing operations.
1-5
-------
1.3.2.2 1,1.2-Trichloroethane
The compound 1,1,2-trichloroethane has been found in drinking water
supplies. The estimated potential intake from drinking water ranges
from negligible to <2 ug/day/person for the majority of the population,
although it is possible that a very small subpopulation may ingest up
to 600 ug/day/person. Limited air concentration data for 1,1,2-trichloro-
ethane in urban air have been utilized to estimate an average absorption
of about 1.3 ng/day/person via inhalation.
1.3.3 Risk Considerations for Humans
1.3.3.1 1,1,1-Trichloroethane
Currently available data do not indicate that this compound is
carcinogenic. No positive mammalian teratogenic or mutagenic effects
have been demonstrated. An acceptable daily intake (ADI) of 37.5 mg/day/
person has been derived. Estimated urban and rural exposures are more
than 500 to 4,000 times less than the estimated AD]:. No toxic effects
are expected from these exposures. Occupational exposures from 27 mg/day/
person to 11,000 mg/day/person have been estimated;; consequently, an
estimated 130,000 persons (involved in degreasing operations) may be
subject to adverse health effects.
1.3.3.2 1,1.2-Trichloroethane
An NCI study indicates that 1,1,2-trichloroethane is carcinogenic
in mice but not rats and thus is a suspect carcinogen in humans.
Four risk extrapolation models were applied to the dose-reponse
data obtained in animal experiments to indicate the range -in the pre-
dicted number of possible lifetime excess cases of cancer that might
result from chronic human exposure to 1,1,2-trichloroethane. The range
of estimated risks obtained for the human exposure levels of interest
is indicative of the inherent uncertainty associated with the mathematical
models currently used for risk extrapolation purposes. There is presently
no scientific concensus for selecting the most appropriate model for
extrapolating high exposure levels utilized in animal experimentation
to the much lower levels experienced by the human population. Each of
the models is formulated in such a way that the curves pass through the
origin; that is, there is some finite response at any dose greater than
zero. This concept of no threshold is scientifically debatable, but it
has been the position of some scientists and of government regulators
that thresholds to carcinogens do not exist. The no-threshold theory
tends to make the predicted risks obtained "conservative," meaning here,
to overstate the risk.
In addition to the uncertainty associated with the choice of the mathe-
matical model, there is large and unquantifiable uncertainty regarding
extrapolating from laboratory animals to humans. The guidelines
1-6
-------
-
1.4 RISKS TO AQUATIC BIOTA
1-4.1 Toxic Effects
7 me/1 for rtl i ces tested is the
1.4.2 Exposure of Aquatic Blo<-a
m^ritf'f " ^f thS C°™ionS of
basins, and near producton anfuse SL '"^ J t3ken fr°m "^ river
The highest value for 11 1-SchlorM' T 6 in the 1<3W Ug/1 ranSe'
manufacturing site was 169 u»7? ^ 5 ne detected downstream of I
manufacturing site was 169 u»
concentrations? there is fve;ianaK UPOn repOr£ed amb±ent water
and known effects levels liJ, P between a(luatic exposure levels
to occur at lL ^ than 1 0 »g/l "° ""^ " Chr°niC 6ffeCtS are
1'4'3 Risk Considerations for AT.a^ Biota
1.0
ambient concentration rein the low a' *°nitoring d^ indicate that
for the two chemicals are not exceedL ? *?**' W*ter quality "ite
the U.S. The risk to aqua?ic organist ^ am^ent °r e«l^nt waters in
negligible. organisms is, therefore, assumed to be
1-7
-------
2.0 INTRODUCTION
The Office of Water Regulations and Standards, Monitoring and
Data Support Division, the U.S. Environmental Protection Agency, is
conducting a program to evaluate the exposure to and risk of 129 priority
pollutants in the nation's environment. The risks to be evaluated include
potential harm to human beings and deleterious effects on fish and
other biota. The goal of the task under which this report has been
prepared is to integrate information on cultural ar-d environmental flows
of specific priority pollutants and estimate the ris.v based on recep-
tor 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 provides a brief, but comprehensive, summary of the
production, use, distribution, fate, effects, exposure, and potential
risks of 1,1,1-trichloroethane and 1,1,2-trichloroethane. The 1,1,1-
isomer is more commonly produced and hence detected more often in en-
vironmental media than the 1,1,2-isomer. Consequently far more informa-
tion is available concerning 1,1,1-trichloroethane and it is dealt with
in far greater detail in each chapter.
The report is organized as follows:
Chapter 3.0 presents a materials balance for the trichloroethanes
that considers quantities of the chemical consumed or produced
in various processes, the form and amount of pollutant released
to the environment, the environmental compartment initially
receiving it, and, to the degree possible, the locations and
timing of releases.
Chapter 4.0 describes the distribution of trichloroethanes in the
environment by presenting available monitoring data for various
media and by considering the physicochemical and biological fate
processes that transform or transport the chemicals.
Chapter 5.0 describes the available data concerning the toxicity
of trichloroethanes for humans and laboratory animals and quanti-
fies the likely level of human exposure via major known exposure
routes.
Chapter 6.0 considers toxicological effects on and exposure to
biota, predominantly aquatic biota.
Chapter 7.0 compares exposure conditions for humans and other
biota and with the available data on effects levels from
Chapters 5.0 and 6.0 the risks presented by various exposures
to the trichloroethanes are estimated.
2-1
-------
Appendices A-C present more detailed information supporting
materials balance estimates in Chapter 3.0. Appendix D dis-
cusses the procedure for estimating the volatilization rates of
the trichloroethanes and Appendix E discusses in detail the
atmospheric fate of the compounds.
2-2
-------
3.0 MATERIALS BALANCE
3.1 INTRODUCTION
tricho ^aPter S'fTJ" ^ environmental materials balance for 1,1,1-
trichloroethane and 1,1, 2-trichloroethane.
the to^T f n!\ither cre«ed nor destroyed in chemical transformations,
all m^-fT58, J1 materials entering a system equals the total mass of
all materials leaving that system, excluding those materials the system
accumulates or retains. From the perspective of risk analysis, a Steals
balance may be performed around any individual operation that placet a
specific population at risk (e.g., process water discharges creating
groundwater contamination). An environmental materials balance therefore
consists of a collection of materials balances, each of which is theref°re*
to a specific source and sink within the environment.
The materials balance is based on a review of both published and
" -
°c
^environmental distribution of 1,1,1-trichloroethane.
production, use and environmental release'of 1,1,2-trichloroethane"
3.2 SUMMARY
Production of 1,1,1-trichloroethane in the U.S. has remained
relatively stable since 1976, well below its 7-9% predicteHrowth rat.
and below the 12-13% growth rate exhibited between^965 and ?"
CnP fOmnnnnH T.rao •»-,.,,-,1 __ j ^_t_ _ . . «•»»«*
more hazardous trichloroethyl
the x
capacity for that year was estimated to be 4.8 x 105 kkT 907 of which
" ° k89"f
mae to e .8 x 10 kk 907 of which
"l sJo^kfof^01111611 ^ ?Chiff 1979)« In 1979° thke8U.S9?"profd:c eT
£££ SZ&^^T^^™^™
^
3-1
-------
Inadvertent Sources
Production (Ug)
Vinyl Chloride
Manufacture
("balanced process")*1
Chlorlnatlon of _
Water Supplies *
I Stockpiled I
I M40 J
Ul*
Aerosol Forw-
latlon
?2.53U
Adheslvos and
Coatings
ji^n!
I 5.790 I
IOIAI
Environmental Release (kkg)
210
neg
120
neg
22.300
22.527
S.670
306
320
16,670 negf
42.737 28.219
F!s«rs J.! Mi'srli!- Sjlsscs: !.!.! IrUfcioroithsr* !9?S
a) See tot. Section 3.3.1 for process description, lablc 3.1 for envlioiwental release AM I, at Ion.
b) See teal. Se
-------
sent to Publicly Owned Treatment Works (POTW's) (390 kkg); about 84 kkg were
emitted to the atmosphere and 9 kkg were land-disposed.
The 1,1,1- isomer is used in degreasing, aerosol formulation; manufacture
of adhesives, coatings, and paints; leather tanning, film cleaning and other
miscellaneous solvent operations. Figure 3-1 lists quantities of the com-
pound consumed by each use in 1979, as well as the resulting environmental
releases. Of the total 282,810 kkg of 1,1,1-trichloroethane released to the
environment from use of the compound, 86% (242,653 kkg) was emitted to the
atmosphere, 10% (28,210 kkg) was land-disposed, and 4% (11,947 kkg) was
sent to POTWs. Negligible amounts of 1,1,1-trichloroethane were discharged
to surface-waters.
3.3 MANUFACTURE OF 1,1,1-TRICHLOROETHANE1
The bulk of 1,1,1-trichloroethane production in the U.S. is based
upon the vinyl chloride process; only minor amounts (wlO%) are made by
the ethane process. In the vinyl chloride process, vinyl chloride reacts
with hydrogen to form 1,1-dichloroethane, which is then thermally chlorinated
to produce 1,1,1-trichloroethane. The yields, based on vinyl chloride,
range from approximately 95% to 98%. The 1,1,1- isomer is also
produced by the noncatalytic chlorination of ethane. Ethyl chloride,
vinyl chloride, vinylidene chloride, and 1,1-dichloroethane are produced
as by-products.
The largest releases of 1,1,1-trichloroethane to the environment
during its production, by both processes, are to aquatic media. Nearly
81% (356 kkg) of the total 437 kkg of 1,1,1-trichloroethane released
to the environment during production via the vinyl chloride process was
discharged to water; 74% (34 kkg) of the total 46 kkg of 1,1,1-trichloro-
ethane released from the direct chlorination process was discharged to
water. Atmospheric emissions from the vinyl chloride process totaled
7 kkg while emissions from the direct chlorination process were 10 kkg.
Land destined 1,1,1-trichloroethane wastes totaled 76 kkg, 74 kkg of which
were attributable to the vinyl chloride process; 2 kkg were released from
the direct chlorination process.
»
3.3.1 Vinyl Chloride Process
Figure 3-2 outlines a simplified process for production of 1,1,1-
trichloroethane via vinyl chloride (see Appendix A, Note 5 and Figure B-l,
Appendix B for further details). Vinyl chloride, hydrogen chloride,
FeCl^ catalyst, ammonia, chlorine and stabilizer compounds are introduced
into the system to yield 1,1,1-trichloroethane. Wastes are generated
from the following point and nonpoint sources: heavy and light end
distillation column vents; miscellaneous wastewater discharges; fugitive
emissions; spent catalyst filters; 1,1,1-trichloroethane column vents;
product storage vents and handling operations. However, 1,1,1-trichloro-
ethane is released to the environment from only the last five of the above
TJased on the process description of EPA (1979b).
3-3
-------
OJ
I
•e-
FUGITIVE STORAGE COLUMN
EMISSIONS VENT VENTS
IIC1 TO A , A
. - , 1
^ OTHER [ 1
PROCESSES | 1
: i
VINYL CHLORIDE
IIC1
FeCl-j CATALYST
AMMONIA
CHLORINE
STABILIZER
->
.
PRODUCTION AND STORAGE
RELATING TO VINYL CHLORIDE
PROCESS
FEED TO
OTHER Hf
PROCESSES - SPENT v
/ ' CATALYST *
HANDLING
f
\
\
r^.
*-*
/ M I c r r
STORAGE
VENT
t
• ;> HANDLING
I I
1»1,1-TRICIILOROETHANE onnnnrT '
,. .^T* fKUUUtl v^ TRAN'TORTATinM
STORAGE OUT OF Pl ANT
f
^
X
1 1 AMCAlIC
(1,1,2-TRICHLOROETHANE)
WASTEWATER
COLUMN SOURCES
WATER
Figure 3.2 Waste Releases from 1,1,1-TMchloroethane Production Via Vinyl Chloride Process*
"~~] :'
a) |=Air emissions;«*= water discharge; and I = land disposal.
Source: EPA, 1979a,b.
-------
sources. Estimated environmental releases of 1,1,1-trichloroethane
from this process are shown in Table 3-1; derivations of these estimates
are given in Table B-l, Appendix B.
3.3.2 Environmental Releases from the Vinyl Chloride Process
As shown in Table 3-1, nearly 81% (356 kkg) of the total quantity
of 1,1,1-trichloroethane released to the environment from its production
via the vinyl chloride process (437 kkg) was discharged to water, while
approximately 17% (74 kkg) was emitted to the atmosphere and 2% (7 kkg)
was land-disposed.
The majority (90%) of the 1,1,1-trichloroethane wastes discharged
to water was contained in effluents from refrigerated vent condensers,
which were used to control emissions from product storage and handling
(EPA 1979b) ; liquid wastes generated from both of these sources were
sent to POTWs (EPA 1979b) . The remaining 35 kkg of 1,1,1-trichloroethane
liquid wastes from the vinyl chloride process stem from the 1,1,1-trichloro-
ethane column (vent TC, Figure B-l, Appendix B) and were also discharged
to POTWs.
Approximately 74 kkg of 1,1,1-trichloroethane were emitted to the
atmosphere during its production by the vinyl chloride process (Table 3-1) .
Nearly 80% (58 kkg) of these wastes came from product storage and handling.
The remaining atmospheric emissions (Tables 3-1 and B-l, Appendix B)
were a result of 1,1,1-trichloroethane column losses (4 kkg) and fugitive
emissions (12 kkg) .
Only 7 kkg of 1,1,1-trichloroethane wastes (2% of the tota^l wastes)
were disposed to land. This waste was a semisolid spent catalyst complex
(NH4'FeCl3-NH3) composed primarily of 1,1,1-trichloroethane (EPA 1979b) .
3.3.3 Chlorination of Ethane
The compound 1,1,1-trichloroethane is also produced by direct Chlorination
of ethane; small amounts of 1,2-dichloroethane and 1,1,2-trichloroethane
are produced as by-products. To maximize 1,1,1-trichloroethane production,
ethyl chloride and 1,1-dichloroe thane are recycled to the Chlorination
reactor; vinyl chloride and vinylidene chloride are catalytically
hydrochlorinated to 1,1,-dichloroethane and 1,1,1-trichloroethane,
respectively.
HC - CHC1 + HC1
HC1 :? — > CH3CC13
3-5
-------
TABLE 3-1 ENVIRONMENTAL RELEASES OF 1,1,1-TRICHLOROETHANE DURING
PRODUCTION BY THE VINYL CHLORIDE PROCESS, 1979 (kkg)
Producer Quantity Produced Estimated Environmental Releases3
(location) (103 kkg)b Mrc Landd Watere Tocal
Dow Chemical Co. 122
(Freeport, TX)
Dow Chemical Co. 80
(Plaquemine, LA)
PPG Industries, Inc. 95
(Lake Charles, LA)
Total 297
31 3 153 187
20 2 100 122
23 2 103 128
74 7 356 437
a) Control devices and their removal efficiencies are: product storage
and handling (refrigerated vent condensers—85%); 1,1,1-trichloroethane
vent (aqueous scrubber/recycle—90%). See Appendix A for emission
factors used.
b) Quantity of 1,1,1-trichloroethane produced from vinyl chloride process
(297,000 kkg) = total quantity produced minus quantity produced by the
direct chlorination of ethane (Harris 1980; Philips 1980).
c) Product storage and handling account for >75%.
d) Waste composed of spent catalyst complex.
e) Product storage and handling account for >85%.
Source EPA (1979a,b).
3-6
-------
gnf^
2^SL.^^S-tt-^^i.JS«SJSSr-K
the process, wastes are generated from the following point and nonpoint
sources: fugitive emissions; distillation column vents; recycle and
product storage vents; spent catalyst filters; handling operations
quench column vents; and miscellaneous wastewater sources! Wastes'
f* rtn fi*-fn^T»» 7 1 1 *••../_ t_ i — ^.« _
ov«n release<* to the environment from
£-«f ^^^
lu^mL^ hafdlin* °perf lons' Table 3-2 (and Table B-2 in Appendix B)
~ this roems"!1"'6' e°Vl— tal **-« of 1,1,1-tricSoro.ttai.
3'3'4 E.n-vironmental Releases from the Direct Chlorination
(46 k£nSLtedV4^(3A kkg) °f ^ t0tal ^Ll-trichloan
dJL^ J f ^he environment during its production by the
direct Chlorination of ethane was discharged to water, 21% (10 kk
k
was
nr A ^- 5hej1'1»1-trichloroethane discharged to water during its
production via direct Chlorination was contained in effluents ?fom
stf«!!T ^ V6nt fndensers used to ^trol emissions from recycle
storage vents, product storage vents and handling (EPA 1979b) Liauid
wastes from these sources were sent to POTWs (EPA 1979b)
Approximately 10 kkg of 1,1,1-trichloroethane were emitted to the
atmosphere during its production via the direct chlorinaSHf Ithane
(Table 3-2 see Table B-2, Appendix B). All of this waste came from the
recycle storage vent, product storage vent and handling (EPA 1979b)
Only 2 kkg of 1,1,1-trichloroethane were land-disposed. This waste
was captured by the glycol pot control devices used on the 1,1,1-trichloro-
ethane column vents; see Figure B-2, Appendix B for vent location!I (SJ 1979b)
3'4 INADVERTENT SOURCES OF 1,1.1-TRlCHLOROETHANE
Certain industrial processes not directly related to '
ethane production generate 1,1.1-trlchloroethane-containlng ,
""kkg"? ^ releaS6d C° the environment ^ small quantities U.e.,
3-4'1 Vinyl Chloride Manufacture
Virtually all vinyl capacity in the United States fc95Z) is based
upon the "balanced process," which incorporates direct and oxy-chJorination
3-7
-------
FUGITIVE
EMISSIONS
STORAGE
A VENT
' I
1 I
1 1
I 1
ETHANE
CHLORINE
AMMONIA ^
FeCl3 CATALYST "^
OJ
CHLORHIATION
AND
COLUMN
VENTS
A
[ STORAGE VENT
i A
1 1
SEPARATION
°° WASTES USED AS i / HANDLING
FEEDSTOCK V
ELSEWHERE . SPENT t /
^- " CATALYST Y
"••"-.
(1,1,2-TRICIILOROETHANE) 1
I
1
1
1
1,1,1-TRICHLOROETHANE PRODUCT
k *"TD
A " STORAGE
1 STABILIZER
i
MISCELLANEOUS
WASTEWATER
/ SOURCES
(AND 1.2-DICIILOROETHANE) '^
COLUMN
WASTES
n>
HANDLING
I
l' TRANSPORTATION
OUT OF PLANT
Figure 3.3 Waste Releases from 1,1,1-Trichloroethane Production Via Direct Chlorination of Ethane
a) | = Air emissions;^ = water discharge-, and I » land disposal.
Source: EPA, 1979a,b.
-------
TABLE 3-2 ENVIRONMENTAL RELEASES OF 1,1,1-TRICHLOROETHANE DURING
PRODUCTION BY THE ETHANE PROCESS, 1979 (kkg)
Producer Quantity Produced Estimated Environmental Releases
3 a
(location) (10 kkg) Air Land Water Total
Vulcan 25 10 2 34 46
(Geismar, LA)
a) Philips (1980).
b) Controlled releases, see Appendix A and Table B-2 in Appendix B for
calculations and emission factors. Wastes emitted to air stem from
storage and handling operations and fugitive emissions; land releases
result from control device wastes; water discharges are a result of
handling and storage operations.
Source: EPA (1979b).
3-9
-------
of ethene (Catalytic 1979). A typical flow diagram, of the "balanced
process" for vinyl chloride manufacture is shown in Figure B-3 in
Appendix B. Wastes containing 1,1,1-trichloroethane are generated by
the three distinct aspects of the process: direct chlorination of ethene
oxy-chlorination of ethene and dehydrochlorination of 1,2-dichloroethane'
and are typically combined at any given facility for recovery, treat-
ment and disposal. Therefore, the specific point sources of aqueous and
solid wastes at a manufacturing site are a function of the actual engineer-
ing design and by-product production. Wastewater streams from the
direct chlorination and oxy-chlorination of ethene may include: wash-
water from vent gas scrubbers; dichloroethane washwater; drying column
wastewater; the aqueous stream from the oxy-chlorination quench area
and the aqueous stream from the light-ends distillate decanter. However,
1,1,1-trichloroethane has not been detected in wastewater from these
sources (EPA 1975a).
Vent gases from the direct-chlorination and oxy-chlorination pro-
cesses contain nitrogen, small amounts of hydrogen chloride, chlorine,
unreacted ethene, vinyl chloride, methane, ethane and carbon monoxide',
but do not contain 1,1,1-trichloroethane [see Note 7, Appendix A
(EPA 1975a, McPherson et al. 1979)].
The two sources of solid wastes from vinyl chloride monomer pro-
duction, heavy ends from the 1,2-dichloroethane purification column and
reactor tars (see Figure B-3, Appendix B for waste source locations)
both contain inadvertently-produced 1,1,1-trichloroethane. Based on
1978 quantities of vinyl chloride produced, approximately 20 to 1,140 kkg
of 1,1,1-trichloroethane were contained in heavy ends wastes generated
by the "balanced process" (see Appendix A, Note 8 for calculations).
However, it is likely that <1 kkg of the compound is released to the
environment because the heavy ends are either treated to recover organic
compounds for in-house use or incinerated with a 99,9% destruction
efficiency (McPherson et al. 1979).
Similarly, the tars generated by the "balanced process" contained
approximately 24 kkg of 1,1,1-trichloroethane (see Appendix A, note 9
for calculations). These nonrecoverable tars are either incinerated with
99.9% destruction efficiency or disposed as solid waste to a landfill
(EPA 1975a, Lunde 1965).
3.4.2 Chlorination of Water
Chlorination of municipal water supplies apparently is not an
inadvertent source of 1,1,1-trichloroethane, as post-chlorination
effluent levels of the compound are not consistently higher than those
prior to chlorination. In fact, slightly lower concentrations were
found in treated effluent waters than untreated effluent waters (EPA
1977a, EPA 1977b, Sievers et_ al. 1977).
3-10
-------
3.5 USES OF 1.1,1-TRICHLOROETHANE
Use of 1,1,1-trichloroethane, one of the least toxic chlorinated
hydrocarbons, had been expected to increase (almost 10%) in the past
ten years and replace the more hazardous trichloroethylene . However 111-
trichloroethane has captured only an estimated 25% of the vapor degreasing'
market (Mannsville Chemical Products 1979). Table 3-3 lists consumption
quantities and estimated environmental releases of 1,1,1-trichloroethane
from its use in degreasing, aerosol formulation, adhesives manufacture,
and other smaller volume uses. Use quantities are based on the 1978 use
distribution pattern and industry trends (EPA 1979a, Mannsville Chemical
Products 1979).
3.5.1 Degreasing Operations
Degreasing is the removal of oils, fats, grease and wax from metals,
glass, plastics, and textiles by an organic solvent. The 1,1,1-isomer
is particularly suitable for degreasing due to its nonflammability,
relatively low toxicity and medium solvency. The basic types of degreasing
operations and estimated environmental releases of 1,1,1-trichloroethane
from such operations are presented in Table 3-4.
Of the total 220,130 kkg of 1,1,1-trichloroethane (virgin solvent
see Appendix C) used in degreasing, 53,010 kkg were utilized in cold
cleaning, 106,280 kkg in open top vapor degreasing, 57,600 in conveyorized
degreasing and 3,260 kkg in fabric scouring. Table B-4, Appendix B,
lists various industries that employ some form of these operations.
3.5.2 Cold Cleaning
Two types of cold cleaning are performed: maintenance degreasing
used primarily in automotive and general plant cleaning, and manufacturing
cleaning, usually associated with metal working. About 137,400 facilities
employ 1,1,1-trichloroethane in cold cleaning operations (EPA 1979c) The
geographic distribution of cold cleaning operations is shown in Figure 3-4
In both maintenance and manufacturing cold cleaning, the parts to be
cleaned are sprayed, soaked or brushed with solvent. Depending upon the
specific operation, the parts are loaded and unloaded manually or mechanically
(conveyorized) into the degreaser (see Table 3-4). Environmental releases
ot 1,1,1-tnchloroethane from cold cleaning are delineated in Table 3-4
By far, most of the 1,1,1-trichloroethane lost to the environment from
cold cleaning is emitted to the atmosphere; in 1979, emissions totaled
26,440 kkg. Approximately 12,270 kkg were released to land, and 5 260
kkg were sent to POTWs. An estimated 15,770 kkg of the total 1,1,1-
trichloroethane were waste solvent load recycled (EPA 1979c).
3-11
-------
Table 3.3 Use of 1,1,1-Trich loroethane and Estimated Environmental Releases, 1979 (kkg)
Eat i rated Environmental Releases
e
greas ing (total )
-old cleaning (total)
Manufacturing
Maintenance
Open-top vapor degreasing
Conveyor i zed vapor degreasing
^onveyorized nonboiling degreastng
rabric scouring
•osol formulation
lesvies and coatings'"
ler
'aintsd
i Im cleaner
eather tanning
iscellaneous solvent use^
ortsh
ckpi led1
Tota 1
Quantity Consumed
220,130
53,010
23,310
29,700
106,280
45,530
12,070
3,260
22,530
22,530
23,170
5,790
320
390
16,670
27,030
6,440
321,830
Air
174,780
26,440
11,630
14,810
95,540
44,890
6,020
1,896
22,300
22,527
5,670
320
386
16,670
242,653
Land
27,860
12,270
4,730
7,540
51,710
2,770
2,450
660
230
neg
120
neg '
28,210
;
j ^
Wac»r . iOtal
11,940 214,580
5,260 43,970
2,030 13,390
3,230 25,580
4,160 i09,4!0
1,190 48,850
1,050 9,520
280 2,830
neg 22,530
3 22, 530
5,790
neg 320
4 390
neg 16,670
11,947 282,810
3ased on EPA emission factors and solvent waste and recovery factors. Quantity consumed for degreasing includ
only virgin solvent, environmental releases include those from recycled solvent. See Table 3.2 and Appendix C
3ased on 99? of solvent evaporating from product dispersion; the remaining 1 % is left in container and sent to
landfills (Anthony, 7980; Simmons, 1980). Negligible is defined as
-------
Table 3.3 (concluded)
e 3" «-c««»nd.t.on Package for the Adheres and Sealants Industry,
!'50n '"^r1* UnTrMted diSCharge °f '.M-trichloroethane is projected to b. 2,920 kg per year. 0,
500 kno-n adhes.ves and sealant faculti
, .
.ves and sealant faculties, only seven are direct dischargers. Therefore, the quantty of
•
r a I!; TTtT? ^^.^^ ^^^ •- -8"8,b,.. U.. «** 33?o the indirect disch r ers rov e
.reatment. The total quantity discharged is 3 kkg per year. See Appendix A, Note 10.
evaporatin9
Based on 99? lost to atmosphere, see text dollar, I960, EPA, 1979a).
f° r«Ult •^"••'y '» atTOSPher!c emissions, see text. Miscellaneous use<
traction solvent and ,ubrlc.nt in cutting oils or .eta. dri.Hng and taoping.
Harris, 1980.
Based on difference In production and sales in 1978, extrapolated to 1979, USITC, 1979.
W*t«r discharges includ* both discharges co ?OT
-------
Table 3.4 Estimated Environmental Releases of 1,I,1-Trlchloroethane from Oogreasing Operations, 1979 (kkg)
Estimated Environmental Releases
Total Virgin
Doyroaslng Quantity Solvent % Solvent Wasted (average)
Operation Consumed Used3 and Total Waste Solvent Load^
Cold cleaning:
Manufacturing 27,040 23,310 40-60(50) 13,520
Maintenance 34,450 29,700 50-75(62.5) 21,530
Open-top vapor 123,280 106,280 20-25(22.5) 27,740
degroas Ing
*f* Conveyorlzed 52,810 45,530 10-20(15) 7,920
£ vapor degrees Ing
Conveyor! zed 14,000 12,070 40-60(50) 7,000
nonhol 1 Ing
decreasing
Fabric scouring 3,780 3,260 40-60(50) 1,890
g
Total 255,360 220,130 79,600
Quantity Alrd
Recycled
6,080 11,630
(8,140-15,120)
9,690 14,810
(10,370-19,250)
12,480 95,540
(66.880-124,200)
3,560 44,890
2,030 6,020
(4,210-7,830)
850 1,890
(1,320-2,460)
34,690 174,700
Watere
Land Surface POTW Total
4,730 2,030 18,390
7,540 3,230 25,580
9,710 4,160 109,410
2,770 1,|90 48,850
2,450 1,050 9,520
660 280 2,830
27,860 11,940 214,580
a) Based on 1otal production of 321.830 kkg of 1,1,1-trlchloroothane (Harris, 1980) and a percentage use distribution pattern
similar to that of 1978 (EPA, I979b). Virgin solvenr Is that which Is entering tho system for the first time; total
quantity consumed Is virgin solvent plus that which Is recycled from previous year (see Appendix C for derivation).
b) El'A. 1979c. Waste solvent Is that which contains Impurities from degreased parts and Is distinct from vapor emissions (due
1o evaporation from the dagreaser) or from carry-out of solvent from degreased parts.
c) Uased on 45* of the total waste solvent load Iwlng reclaimed by distillation and recycled (EPA, 1977d).
-------
Table 3.4 (concluded)
d) Cased on emission of 430 g solventAg solvent consumed for maintenance and manufacturing cold cleaners, 775 g so.ventAg
so vent consumed for open-top degreasers, 850 g solventAg solvent consumed for conveyorHed vapor deceasing, 430 g
so.ventAg solvent consumed for conveyor.zed nonboll.ng degreasers. and 500 g solvent Ag solvent consumed for fabric
scourers. The range shown represents the ± 30* uncertainty of the emission factor (EPA, 1979c).
H-
or ms, ™* — ac
or In landfills) and I5J! to water (dumped In drains resulting In discharge to POTWs). Of the remaining solvent 45* Is
recycled (often d.st.Hat.on) and 5% Is Inc.nerated. generating .nslgn.f leant atnospher.c emissions.
f) Totals may not add due to rounding.
-------
3.5.3 Open-top Vapor Degreasing
In open-top vapor degreasing, a vapor zone is created by heating
the solvent; parts to be cleaned are immersed, the solvent vapor con-
denses and impurities are washed away. A solvent spray is sometimes
employed to assist in removing heavy soil (EPA 1979c). Open-top vapor
degreasers are utilized in metal working plants for manufacturing cleaning
and are also suited for degreasing of intricate electrical parts where a
high degree of cleanliness is required (EPA 1977d). Geographic distribu-
tion of open-top (and conveyorized) vapor degreasers is shown in Figure 3-5
Approximately 4,000 establishments utilize 1,1,1-trichloroethane in
open-top vapor degreasing (EPA 1979c).
Although the body of the open top vapor degreaser is extended to
minimize the escape of solvent vapors, 87% (95,540 kkg) of the total
l»l»l-trichloroethane lost to the environment from such operations is
in the form of atmospheric emissions from solvent diffusion and convection
and carry-out on cleaned parts (Table 3-4). As noted in Table 3-4,
9,710 kkg of 1,1,1-trichloroethane are disposed to land from waste
solvent disposal, 4,160 kkg are discharged to POTWs and 12,480 kkg of
the total waste solvent load are recycled.
3.5.4 Conveyorized Vapor Degreasing
Conveyorized vapor degreasing employs the same process technique
as open-top vapor degreasing except that work to be cleaned is mechanically
transported to and from the degreaser. About 600 facilities employ
l,l»l-trichloroethane in conveyorized vapor degreasing (EPA 1979c);
the geographic distribution of conveyorized (and open-top) vapor degreasers
is shown in Figure 3-5.
Carry-out of vapor and liquid solvent is usually the largest source
of solvent loss from conveyorized vapor degreasers since the units are
normally enclosed except for small areas for entry and exit of material
to be cleaned. Total atmospheric loss of 1,1,1-trichloroethane from
conveyorized vapor degreasers, as shown in Table 3-4, is 44,890 kkg;
approximately 2,770 kkg were released to land and 1,190 to POTWs.
Approximately 3,560 kkg of the total 1,1,1-trichloroethane waste solvent
load was recycled.
3.5.5 Fabric Scouring
A relatively small amount of 1,1,1-trichloroethane, 3,260 kkg,
was consumed in fabric scouring, which is essentially conveyorized cold
cleaning (see Table 3-4). The geographic distribution of fabric scouring
facilities is shown in Figure 3-6.
Fabrics are scoured prior to dying and finishing to remove waxes
and sizings accumulated during production. Material is fed into the
degreaser where it is sprayed with solvent; multilayer treatment (several
3-16
-------
! 0 to 5 000
|i':i!illj| 5.000 tc 25.000
j 25.000 to 50 000
> 50 000
FIGURE 3-4 GEOGRAPHIC DISTRIBUTION OF COLD CLEANING OPERATIONS
Source: EPA (1979c)
NUMBES Of OPERATIONS
0 to 100
100 to 500
500 to 1,000
> 1.000
FIGURE 3-5 GEOGRAPHIC DISTRIBUTION OF VAPOR DECREASING OPERATIONS'
a) Includes open-top and conveyorized degreasers
Source: EPA (1979c)
3-17
-------
0 te 50
50 to 500
i 50C to 1,000
> 1.000
FIGURE 3-6 GEOGRAPHIC DISTRIBUTION OF FABRIC SCOURING OPERATIONS
Source: EPA (1979c)
3-18
-------
layers of fabric are fed through the degreaser at once) is sometimes
performed to increase throughput (EPA 1979c). Table 3-4 gives environ-
mental losses of 1,1,1-trichloroethane from fabric scouring operations;
1,890 kkg of the total 1,1,1-trichloroethane loss occurs as atmospheric
emissions. Appoximately 660 kkg of 1,1,1-trichloroethane were land-
disposed, while 280 kkg were sent to POTWs (Table 3-4).
3.5.6 Aerosol Formulation
The quantity of 1,1,1-trichloroethane used as a solvent and vapor
depressant in aerosols is not directly reported; based on SRI (1978)
estimates of 18,000 kkg of 1,1,1-trichloroethane used and an expected
increase in use due to the ban on chlorofluorocarbon use in aerosols,
approximately 22,530 kkg of 1,1,1-trichloroethane were utilized in
aerosol formulation in 1979 (Anonymous 1977; SRI 1978,
EPA 1979a). The compound 1,1,1-trichloroethane is a strong candidate
for replacing chlorofluorocarbons due to its flammability-suppressing
nature as well as its solvency (for hair spray resins), availability,
and relatively low toxicity (Anthony 1979). The compound is found in
insecticide sprays, automotive cleaning products, household cleaners,
and personal care items (Gordon and Hillman 1979, Hile 1977).
Losses of 1,1,1-trichloroethane from manufacturing of aerosol
products occur during filling of the containers; such losses are
atmospheric and total no more than 1% of the total amount of solvent
consumed. Thus, approximately 230 kkg of 1,1,1-trichloroethane are
emitted to the atmosphere from manufacture of aerosol products
(Anthony 1980, Simmons 1980)
Approximately 22,070 kkg of 1,1,1-trichloroethane are emitted to
the atmosphere from use of aerosol products, since the solvent evaporates
as it is dispensed from the container. Only 1% (230 kkg) of the total
1,1,1-trichloroethane present remains in the "empty" container (Simmons
1980, Anthony 1980) and is assumed to be landfilled (Table 3-4).
3.5.7 Adhesives and Coatings
The adhesives and sealant industry, consisting of about 1,500
establishments, utilized 22,530 kkg of 1,1,1-trichloroethane in 1979
in the production of water- and solvent-based adhesives, especially
contact cements (EPA 1979a, EPA 1979e, Miron 1980). Geographic
distribution of the adhesive facilities is shown in Figure 3-7.
Batch blending of adhesives occurs in enclosed vessels; emissions
of 1,1,1-trichloroethane are estimated to be 1% of the total solvent
present, or 230 kkg (Miron 1980). The remaining emissions, 22,297
metric tons, are lost during preparation of adhesive material by
spraying and 1,1,1-trichloroethane evaporation from product use (see
Appendix A, Note 10).
3-19
-------
FIGURE 3-7 GEOGRAPHIC DISTRIBUTION OF THE ADHESIVES INDUSTRIES
Size of symbol ( X) proportional to number of facilities.
-.e: EPA (1979a)
-------
Aqueous discharges of 1,1,1-trichloroethane are minimal; only
8 kg of this solvent are discharged industrywide per day (EPA 1979e).
A maximum of 3 kkg of 1,1,1-trichloroethane would be discharged
industrywide, assuming a 365 day per year operation (see Table 3-4).
Of the 1,500 adhesive and sealant facilities, only seven discharge
directly to surface waters; loss of 1,1,1-trichloroethane to surface
waters appears to be negligible (EPA 1979e).
Use of 1,1,1-trichloroethane in the adhesives industry is being
phased out, perhaps due to regulations such as Los Angeles' Rule 66.
The solvent is, however, still an important component of water-based
contact cements.
3.5.8 Small Volume Uses of 1.1.1-Trichloroethane
The 1,1,1-isomer is used, to a small extent, in paints, as a film
cleaner, in leather tanning and other miscellaneous solvent applications
(see Table 3-4). Such uses result primarily in atmospheric emissions,
with less significant quantities being discharged to water. Table B-5,
Appendix B lists detection frequency of 1,1,1-trichloroethane in various
industrial wastewaters.
3.5.9 Paints
In 1979, approximately 5,790 kkg of 1,1,1-trichloroethane were
utilized as a solvent in traffic paint formulation (EPA 1979a).
Application of such paints is performed by spray equipment with no
emission control devices, therefore an estimated 98% (or 5,670 kkg) of
the solvent evaporates during product dispersion. The remaining 2% is
left in paint containers or contained in machinery cleaning residues
(120 kkg); both of these are disposed to land.
3.5.10 Film Cleaning
An estimated 320 kkg of 1,1,1-trichloroethane were used in 1979
as motion picture film cleaner; this solvent is especially suitable
for this use due to its nonflammability. Since such cleaning is a
manual operation, all of the solvent so used evaporates, resulting in
320 kkg of 1,1,1-trichloroethane being emitted to the atmosphere.
3.5.11 Leather Tanning
In 1979, approximately 390 kkg of 1,1,1-trichloroethane were used
in the tanning industry to waterproof leather. The solvent-containing
waterproofing solution is applied with a flow coater, which provides
a "falling curtain" of solution over the hide as it is moved by a
conveyor belt (Lollar 1980). Such systems are usually equipped with
a canopy exhaust system, venting fumes to the atmosphere. An estimated
99% of the total solvent present (386 kkg) is emitted to the atmosphere
as the solvent evaporates from the "falling curtain" of water proofing
3-21
-------
solution (Lcllar 1980). The remaining 4 kkg are seint to POTWs. This
estimate seems high since 1,1,1-trichloroethane was detected in waste-
waters of only 3 out of 7 leather finishing establishments in quantities
of £10 ug/1 (Lollar 1980, EPA L980b).
3.5.12 Miscellaneous Small-volume Uses_
Miscellaneous uses of 1,1,1-trichloroethane in pharmaceutical
extraction solvents, metal cutting, drilling and tapping oils, and other
non-specified solvent applications consumed an estimated 16,670 kkg in
1979. Its use as a drain and septic tank cleaner appears to have been
discontinued.
Although the FDA banned the use of 1,1,1-trichloroethane in drug
products in 1973 (Mannsville Chemical Products 1979), the compound has
been detected in wastewaters from this industry in small amounts.
Based on EPA data (see Appendix A, Note 11) <1 kkg of 1,1,1-trichloro-
ethane is sent to POTWs annually (EPA 1980c). These aqueous discharges
could stem from the use of 1,1,1-trichloroethane as an extraction
solvent or from its application in equipment cleaning.
Use of 1,1,1-trichloroethane in lubricating oils for metal cutting
and the unspecified solvent uses are assumed to result in atmospheric
emissions. Approximately 16,670 kkg of 1,1,1-trichloroethane would
be emitted to the atmosphere from miscellaneous solvent use.
In the past, 1,1,1-trichloroethane has been used as a component
of drain and septic tank cleaners. Several industrial spokespersons
reported that, to their knowledge, such use has been discontinued
(Elliot 1980, Ashland Chemical 1980). The Consumer Product Safety
Commission did not list 1,1,1-trichloroethane as a componenet of drain
or septic tank cleaners as of December 1979 (Consumer Product Safety
Commission 1980). Cleaning compounds containing 1,1,1-trichloroethane
have, for the most part, been removed from the market (Anonymous
1979), since they have extensively contaminated groundwater in areas
of Nassau County, New York.
3.6 MUNICIPAL DISPOSAL OF 1.1., 1-TRICHLOROETHANE
Loading of 1,1,1-trichloroethane to POTWs is largely dependent
upon variations in industrial discharges and the type of industry in a
particular municipality. A framework for calculating the total 1,1,1-
trichloroethane flow through the nation's POTWs is provided by data
from a recent EPA study (EPA 1980c). A materials balance of 1,1,1-
trichloroethane at the treatment plants can be constructed using a
total nationwide POTW flow of approximately 1011 I/day (EPA 1978b) and
median values of 66 pg 1,1,1-trichloroethane/l (influent) and 10.4 yg/1
(effluent) (EPA 1980c). It is assumed for purposes of these calculations
that influent and effluent flow rates are equal, i.e., water loss from
sludge removal and evaporation are small compared to influent flows
3-22
-------
(see Note 12, Appendix A). Using these data, approximately 2,410 kkg
?f« ,7* 7trl2,loroethane are C0ntained in POTW influent nationwide and
380 kkg in effluent.
Approximately 4 kkg of 1,1,1-trichloroethane were contained in
land-destined POTW sludge, based on a raw sludge concentration of
?rof yfwf ^ 1!8°C):; and 6 X 10 kkg dry Sludge Derated per year
(EPA 1979f, see Appendix A, Note 12).
POTU The TUnt !f 1«1«1-'rlchloroethan€ emitted to the atmosphere from
POTWs can be estimated by the difference in influent, effluent and raw
sludge waste loadings. Thus, 2026 kkg of 1,1,1-trichloroethane are
emitted to the atmosphere from POTWs per year (Note 12, Appendix A)
This estimate seems reasonable due to the volatility of the compound
and aeration practices and the high temperature associated with waste-
water treatment.
Some of the 1,1,1-trichloroethane entering POTWs was possibly
biodegraded, but no specific data were found.
3'7 PRODUCTION AND USE OF 1,1, 2 -TRICHLOROETHANE
The compound 1,1,2-trichloroethane is a colorless, nonflammable
liquid produced in the U.S. directly or indirectly from ethylene; it
T^M J C°pr?duCt ln,the ^nufacture of other chlorinated hydrocarbons.
Its chief use is as a feedstock intermediate in the production of
1,1-dichloroethylene. Occasionally it is used as a solvent for
chlorinated rubber manufacture (Archer 1979) .
According to the U.S. International Trade Commission, Dow Chemical
« v JcJ domestic Producer of 1,1,2-trichloroethane (USITC 1979).
(?arber Ssnf T 'H*"* ^ 5Uantit? Produced as proprietary information
reaction 1% V ! ^ Yroduction of "2,450 kkg of 1,1-dichloroethylene,
1S7 inn V ? n10^eory' 3nd an estimated 90% yield (EPA 1978), approximately
187,100 kkg of 1,1,2-trichloroethane would be required to yield the
A^^?y !? i'J-fi^oroethylene currently being produced (see Note 13,
Appendix A) This estimate represents the maximum production potential
from !iS!r*? ? 91§ ?C?T D°W Chemical P^duces 1,1-dichloroethylene
f^Tf J I J§ § ,°v J^'^ttichloroethane, depending upon economics
and feedstock availability (EPA 1978).
Environmental releases of 1,1,2-trichloroethane from 1,1-dichloro-
ethylene manufacture are small; an EPA study found no 1,1,2-trichloro-
? PI°CeSS Vent 8aS (EPA 1979b)" Volatile organic compounds
v.vw t^sions ar cne Dow facility are controlled by incineration and
refrigerated condensers with removal efficiencies of 98 and 937
respectively (see Table 3-5); Hedley et a±_ (1975) report no l,°i,2-
trichloroethane in the 1,1-dichloroethylInT separation column wastewater.
3-23
-------
Table 3.5 Production, Use, and Estimated Environmental Dispersion of 1,1,2-Trichloroethane in 1979 (kkg)
Estimated Environmental
Releases
Production Use Air Land Water
Chlorination of 1,2-dichloroetharie Production of 1,1-dichloroethylene neqb ,,nac
187,100a 187.100 9
1,2-dichloroethane purification 60d
1,1,1-trichloroethane production, vinyl chloride process nege negc riege
750
1,1,1-trichloroethane production, ethane process riege riege nege
1,640'
Miscellaneous 4,000 900 100
5,000
a) IJased on 1,1-dichloroethylerie production of 122450 kkg (EPA, 1978), 90% yield (EPA, 1978) and reaction
stoichiometry.
b) Not detected in vent gas from reactors or distillation columns (EPA, 1979b).
c) Not detected in waste water streams (nediey, et al., 1975).
d) Based on 2 kg 1,1,2-trichloroethane discharged/kkg EDC produced by direct chlorination (Medley, et al
1975). EDC production by direct chlorination 3.08 x 10^ kkg, and 1% of waste escaping incineratTonT '
e) All of that which is produced (as a by-product) is recycled within the plant (EPA, 1979b).
f) See text.
g) Order of magnitude estimate of deposition of "low millions of pounds" which Dow markets to other industries,
jCC LCAL•
-------
The dispersion of 1,1,2-trichloroethane to the environment also
results from the manufacture of other chlorinated hydrocarbons (see
Table 3-5). From manufacture of 1,2-dichloroethane by direct and oxy-
chlorination respectively, 0.039% and 0.453% (by weight) of the process
effluent is 1,1,2-trichloroethane. During purification of 1,2-dichloro-
ethane, 2 kg of 1 1,2-trichloroethane produced by'direct chlorination
(Hedley et al^ 1975). Based on 1978 production of 3.08 x 10* kke
(USITC 1979) of 1,2-dichloroethane by direct chlorination and thf above
discharge factor, about 6,000 kkg of 1,1,2-trichloroethane would be
contained in solid wastes (see Note 14, Appendix A). These wastes are
recycled as feed materials for other processes (generating no waste)
or incinerated at approximately 99% efficiency. If 1% of the total
solid waste generated escapes incineration, approximately 60 kkg of
I,1,2-trichloroethane would be emitted to the atmosphere (see Table 3-5)
During manufacture of 1,1,1-trichloroethane by the vinyl chloride
process, 2.6 kg of 1,1,2-trichloroethane would be emitted to the
atmosphere (see Table 3-5).
process
During manufacture of 1,1,1-trichloroethane by the vinyl chloride
. _-_;ss, 2.6 kg of 1,1,2-trichloroethane are produced per kke 111-
trichloroethane (Elkin 1969). Based on a production of 289, 700 'kkg of
7sn'iC f J°f°f by the Vinyl chloride Process (USTIC 1980), about
750 kkg of 1,1,2-trichloroethane would be produced; usually, these heavy
n^/fFPr^o^ * materials for other chlorocarbons within the sam7
plant (EPA 1979D). Approximately 51 kkg of 1,1,2-trichloroethane are
produced per kkg of 1,1,1-trichloroethane manufactured by the chlorina-
tion of ethane; again all of that which is produced is recycled
within the plant (EPA 1980). recycled
Dow Chemical does sell some 1,1,2-trichloroethane as a consumer
product (Dow Chemical 1980) but the quantity sold is considered pro-
prietary information. A spokesperson from Dow estimated that "low
™ "
waastbeen detected
B-6, Appendix B (Epsb) Ou of 981 ^f* "
found only 58 times at concentrations g eat r tha'n'lO
concentration was 12 ug/i, the maximum 3,400 ug/1
3-25
-------
Very small quantities of 1,1,2-trichloroethane have been found in
POTWs Across the country (EPA 1980c). Based on a nationwide POTW flow
of 10 I/day (EPA 1978b) and influent and effluent concentrations of
1.9 and 0 ug/1, respectively, approximately 69 kkg of 1,1,2-trichloro-
ethane is contained in POTW influent and zero in the effluent. The
quantity of 1,1,2-trichloroethane contained in POTW sludge can be
determined using a raw sludge concentration of 10.9 ug of 1,1,2-trichloro-
ethane^l (EPA 1980c) and the quantity of dry sludge generated per year,
6 x 10 kkg. Based on these data, and assuming that wet sludge is 95%
water by weight, approximately 1 kkg of 1,1,2-trichloroethane is con-
tained in POTW sludge each year. As ocean dumping of sludge is man-
dated to cease by 1981, and increasing stringent air quality standards
will probably curb sludge incineration, the 1 kkg of 1,1,2-trichloroethane
is assumed to be land-disposed. The amount of 1,1,2-trichloroethane
emitted to the atmosphere from POTWs can be estimated by differences
among the quantities to the compound to influent, effluent and sludge.
Thus, approximately 68 kkg of 1,1,2-trichloroethane were emitted to the
atmosphere from POTW. This seems reasonable in light of the compound's
volatility, and the high temperatures and aeration techniques required
for water treatment. Biodegradation of the compound is a possible
explanation for the difference in influent, effluent and sludge concen-
trations; however, no specific data were found.
Chlorination of municipal water supplies is known to produce
chlorinated hydrocarbons (Sievers et al. 1977); however, it appears
that such inadvertent production of 1,1,2-trichloroethane does not
occur. 1,1,2-Trichloroethane was detected (but not quantified) in the
drinking water supply in Miami, Florida (EPA 1975c), Neither the National
Organics Monitoring Survey, nor the National Organics Reconnaissance
Survey for Halogenated Organics (Symons et al. 1975) addressed 1,1,2-
trichloroethane in drinking water supplies.
3-26
-------
REFERENCES
Anonymous. Profile - 1,1,1-trichloroethane, Chemical Marketing Reporter, 1977,
Anonymous. New York seeks to curb solvents in groundwater. Chem Week
pp. 24-25; April 4, 1979.
Anthony, T. A frank look at aerosols. Chemtech 9(5): 292-3; 1979.
Anthony, T. Personal Communication, Dow Chemical, 1980.
Archer, W. Chlorocarbons - hydrocarbons (In) Kir Othmer Encyclopedia
of Chemical Technology. Vol. 5 pp. 732-3. New York, NY: John Wiley
and Sons; 1979.
Ashland Chemical. Personal Communication, 1980.
Campbell, A.; Carruthers, R.A. Production of 1,1,1-trichloroethane
British Patent 1281541, July 12, 1972. Assignee: Imperial Chemical
Industries, Ltd.
Catalytic, Draft Summary Report of BAT-308 Responses, 1979.
Consumer Product Safety Commission, Personal Communication, 1980.
Crutzen, P.J.; Isaksen, I.S.A. Impact of chlorocarbon industry on
the ozone layer. Geophys. Res. (in press).
Elkin, L.M. Chlorinated solvents. Report No. 48, Menlo Park, CA:
Stanford Research Institute (SRI); 1969.
Elliot, B. Personal Communication, Vulcan Materials, 1980.
Environmental Protection Agency. Disposal of organo-chlorine wastes
by incineration at sea. Report No. EPA 450/9-75-014; 1975a.
Environmental Protection Agency. Engineering and cost study of air
pollution control for the petrochemical industry, vinyl chloride
manufacture by the balanced process. Vol. 8 , Report No. EPA 450/3-73-
006-h, 1975b.
Environmental Protection Agency. Preliminary assessment of suspected
carcinogens in drinking water: Report to Congress. PB 250961/OTIS.
Springfield, VA; 1975c.
Environmental Protection Agency. Chlorinated compounds found in waste-
3-27
-------
Environmental Protection Agency. Multimedia levels - Methylchloroform.
Report No. EPA-560/6-77-030. Battelle Columbus Laboratories; 1977.
Environmental Protection Agency. National organics monitoring survey,
Washington, DC: Office of Water Supply; 1977b.
Environmental Protection Agency. Environmental monitoring near industrial
sites-methylchloroform. Report No. EPA-560/6-77-025. Battelle Columbus
Laboratories; 1977c.
Environmental Protection Agency. OAQPS Guidelines,, Control of Volatile
Organic Emissions From Solvent Metal Cleaning. Report No. EPA-450/2-
77-02; 1977.
Environmental Protection Agency. Air pollution assessment of vinylidene
chloride. Report No. EPA-450/3-78-075. Washington, DC: EPA; 1978.
Environmental Protection Agency. Level II materials balance: Methyl-
chloroform. Draft Report, Contract No. 68-01-5793. McLean, VA: JRB
Associates, Inc.; 1979a.
Environmental Protection Agency. Emissions control options for the
synthetic organic chemicals manufacturing industry. EPA Contract No.
68-02-2577; July 1979b.
Environmental Protection Agency. Source assessment:: Solvent evaporation-
degreasing operations. Report No. EPA-600/2-79-019f; 1979c.
Environmental Protection Agency. Investigations of selected environmental
pollutants: 1,2-Dichloroethane. Report No. EPA-560/12-78-006; 1979.
Environmental Protection Agency. Paragraph 8 recommendation package
for the adhesive and sealant industry; 1979e.
Environmental Protection Agency. Comprehensive sludge study relevant
to Section 8002 (g) of the Resource Conservation and. Recovery Act of
1976. Report No. EPA-SW-02. Washington, D.C. Office of Solid Waste; 1979f,
Environmental Protection Agency. Development document for effluent
limitations guidelines and standards for the pharmaceutical industry.
Report No. EPA-440/l-80-084a. Washington, DC. Effluent guidelines
division; 1980a.
Environmental Protection Agency. Priority pollutant frequency listing
tabulations and descriptive statistics. Washington, DC: Office of
Analytical Programs; 1980b.
Environmental Protection Agency. Fate of priority pollutants in
publicly-owned treatment works. Interim Report No. EPA 440/1-80-301.
Washington, DC; 1980c.
3-28
-------
Farber, H. Personal Communication, Dow Chemical, 1980.
Gordon, W. ; Hillman, M. Formulation data for hydrocarbon-propelled
aerosol products under CPSC jurisdiction. Battelle Columbus Division;
1979.
Grimsrud, E.P.; Rasmussen, R.A. Survey and analysis of halocarbons in
the atmosphere by gas chromatography-mass spectrometry. Atmospheric
Environment. 9: 1014-1017; 1975.
Harris, M. USITC. Personal Communication, 1980.
Hedley, W.H.; Mehta, S.M.; Moscowitz, C.M.; Reznik, R.B.; Richardson, G.A.;
Zanders, D.L. Potential pollutants from petrochemical processes.
Technomic Publications; 1975.
Hile, J.P. Trichloroethane: Status as a new drug in aerosolized drug
products intended for inhalation, Federal Register 42 (242); 1977.
Lillian, D.; Singh, H.B.; Appleby, A.; Lobban, L.; Arnts, R.; Gumpert, R.;
Haque, R.; Toomey, J.; Kazazis, J.; Antell, M.; Hansen, D.; Scott. B.
Atmospheric fates of halogenated compounds, Environ. Sci. Technol.
9(12):1042-1048.
Lillian, D.; Singh, D.; Appleby, A. Gas chromatographic analysis of
ambient halogenated compounds. J. Air Poll Control Assoc. 26(2):141-142; 1976.
Lollar, R. Personal Communication, University of Cincinnati, 1980.
Lunde, K.E., Vinyl chloride. Report No. 5 Menlo Park, CA: Stanford
Research Institute; 1965.
Miron, J. Personal Communication, Skeist Laboratory, Livingston, NJ; 1980.
National Institute for Occupational Safety and Health (NIOSH). Chloroethanes:
Review of toxicity. Current Intelligence Bulletin 27. NIOSH 78-181.
Cincinnati, OH; NIOSH: 1978.
Mannsville Chemical Products, 1979. 1,1,1-Trichloroethane chemical
product synopsis. Cortland, NY: Mannsville Chemical Products; 1979.
McConnell, J.C.; Schiff, A.I. Methyl chloroform: Impact on stratospheric
ozone. Science 199(13); 1978.
McPherson, R.W.; Starks, R.W. Fryar, G.J. Vinyl chloride monomer ...
what you should know. Hydrocarbon Processing; March 1979.
Philips, Ed., Plant Manager, Vulcan Materials Company. Personal
Communication, August 1980.
3-29
-------
Rideout, W.H.; Mitchell, J.D. Vapor phase chlorination of 1,1-dichloro-
ethane. U.S. Patent 4,192,823, March 11, 1980. Assignee: PPG Industries,
Inc., Pittsburgh, PA.
Russell, J.W.; Shadoff, L.A. The sampling and determination of halocarbons
in ambient air using concentration on porous polymer. J. Chromatog. 134:
374-384; 1977.
Sievers, R.E.; Barkely, R.M.; Eiceman, G.A.; Haack, L.P.; Shapiro, R.H.;
Walton, H.F. Generation of volatile organic compounds from nonvolatile
precursors in water by treatment with chlorine or ozone. Water Chlorination:
Environmental Health Effects, Proc. Conf. 78(2):615-24; 1977.
Simmons, R. Personal Communication, Dow Chemical, 1980.
Singh, H.B.; Salas, L.; Shigeishi, H.; Crawford, A. Urban-nonurban
relationships of halocarbons, SF , NO and other atmospheric trace
constituents. Atmospheric Environ: 819-828; 1977.
Stanford Research Institute (SRI).Chemical economics handbook, Menlo
Park, CA: SRI; 1978.
Stanford Research Institute (SRI). Chemical economics handbook.
Menlo Park, CA: SRI; 1979.
Symons, J.M.; Bellar, T.A.; Carswell, J.K.; DeMarco, J.; Kropp, K.L.;
Robeck, G.G.; Seeger, D.R.; Slocum, C.J.; Smith, B.L.; Stevens, A.A.
The national organics reconnaisance survey for halogenated organics.
J. Amer. Water Works Assoc. 67:634-646; 1975.
United States International Trade Commission (USITC). Synthetic organic
chemicals, U.S. production and sales, 1978. Washington, DC: USITC; 1979.
3-30
-------
4.0 ENVIRONMENTAL DISTRIBUTION
4.1 INTRODUCTION
This chapter contains information concerning environmental dis-
tribution and environmental fate for the trichloroethanes. The scient<-
fic literature and EPA's STORET Water Quality files were searched for
information pertaining to ambient environmental levels of the chemicals
and concentrations in foods. The environmental fate of the two chemicals
was assessed. In both cases, little information was found for 112-
trichloroethane. The 1,1,1- isomer was well characterized with
respect to both topics.
Concentrations of the chemicals in natural surface waters are gen-
erally below 10 wg/1, although, in a small number of cases, higher con-
centrations have been detected. For both trichloroethanes, the princi-
pal fate pathway is volatilization from surface water followed by slow
decomposition in the atmosphere. The 1,1,1- isomer has an atmos-
pheric lifetime of six to ten years, while 1,1,2-trichloroethane
apparently decomposes more quickly.
Section 4.2 presents monitoring data. Sections 4.3 and 4.4 discuss
aspects of environmental fate.
4.2 MONITORING DATA
Trichloroethanes are found in ambient air and water. These com-
pounds have also been detected in foods and in aquatic biota.
v ^ exhibits concentrations of 1,1,1- trichloroethane reported
in published literature for the U.S. The levels reported are generally
in the low yg/m range or less< Background levels of this isomer
pervasive on a global scale are less than 1 yg/m3 . (Correia et al.
1978, Su and Goldberg 1979). Concentrations in foreign countrTe~in
both cities and rural_areas, are generally <10 yg/m3. Average
atmospheric concentrations of 1,1,2-trichloroethane found in seven
cities were in the 40-250 ng/mj range (Singh et al. 1979, 1980). No other
data were found for the 1,1,2-isomer in air.
Table 4-2 displays concentrations reported in the literature for
drinking water (surface and groundwater supplies), ambient surface
water and wastewater. Most reported data are for the 1,1,1- isomer
Though reported values range up to 16,500 wg/1 near a production site
most levels are in the low yg/1 range. Indeed, these published values
are consistent with trichloroethane concentrations in ambient and
effluent waters reported from the STORET data base.
Ambient and effluent concentrations of 1,1,1- and 1,1,2-trichloro-
o-S3^ af6 usua11? less than or e
-------
TABLK 4-1 a. CONCENTRATIONS OF 1 , 1 ,1-TKICHI.OROETHANE DETECTED IN THE ATMOSPHERE
Sample Date
BACKGROUND
9/16- 19/74
11/24- 30/75
12/02- 12/75
March, 1976
March 10,1976
May, 19/6
November, 1976
' Hay, 1977
UKRAN AREAS
6/27- 28/74
8/78- 12/73
7/08- 10/74
7/11 - 12/74
May, 1976
August, 1978
7/17/74 1228
7/17/74 1203
Location
White Face Mountains, NY
Lower end, San Francisco Bay
Point Keyes, CA
Pullman. UA (rural)
Western Montana
Badger Pass, CA
St. Francis National Forest
Helena, AK
Point Arena, CA
New York City, 45th & Lexington
Uayonne , NJ
Delaware City Del. Rte. 448 &
Rt. 72 Int.
Baltimore, MD Fort Holabird Area
Kiverside, CA Airport, 610 m
Claremont, CA
Wilmington, Oil, 5000 ft. .above
inversion
Wilmington, OH, 1500 ft. , Inversion
layer
Concentration
Max. Min. Mean
0.71 0.17 0.37 pg/rn3
Avg. 423 ng/m3
o 34 ng/m3
Avg. 492 ng/m3
o 58 ng/m3
Mean 515 ng/m3 a 47 ni5/mj
26 samples
530 ng/ro3
Mean 533 ng/m3
Std. Dev. 52 ng/m3
£1.7 ,,g/ra3
Mean 598 ng/m3
Std. Dev. 97.7 ng/m3
Max. M_in. Mean
8.7 0.55 3.3 ng/m3
78.5 0.41 8.7 ,,g/m3
1.6 0.16 0.55 ug/m3
1.14 0.24 0.65 |ig/m3
5.9 pg/ra3
27 ,JR/m3
0.14 t'g/m3
0.35 ug/m3
Comment
Concentration varies with
urban plume passage.
75 samples
100% detection
Avg. 458 ng/m3
100% detection
CH3CC13 0-14.6 km altitude
Concentration decreases with
Intrusion into stratosphere
At tropopause height, 11.4 km
MSL
Troposphere average
12% increase over May 76 -
May 77
Background Site
12% increase over May 76 -
May 77
Rel erence
Ml Man i^t aK (1975)
Singh ^t jjl. (1977)
Cronn e£ a^. (1977)
Croiui & ll,u :it: h (1979)
Si ngli L.£ al . 1978
Bat tell i- (1977)
Singh et al. (1978)
Li 11 Ian et al . (1975)
II
>.
II
Cronn (1980)
II
Lill ian £t a_l. (1975)
••
-------
TABLE 4-la. CONCENTRATIONS OF ],1,1-TRICHLOROETHANE DETECTED TN THE ATMOSPHERE (Continued)
— •-•—-- • •- 1 .
Sample Date
1/74- 10/75
1/29/74 0800
4/6/74 1130
4/6/74 1400
4/16/74 0830
1200
1700
4/19/74 0730
3/15/75
Urban Arpfis
5/15-5/25. 1980
5/29-6/9, 1980
6/15-6/28, 1980
7/1-7/J3. 1980
5-6/79
5-6/79
7/79
MAJUNE
October, J978
1974
May 9. 1974
May 9, 1974
May 9, 1974
May 8, 1974
May 24, 1974
~ ' — • — •• » . , ,
Location
LaJolla, CA
Washington, DC
— _
Los Angeles, Chinatown, CA
Santa Monica Residential Area.CA
Orange County.CA
Chicago, Downtown Loop, I L
Chicago Airport, IL
Houston, TX
St. Louis MO
Denver, CO
Riverside, CA
Los Angeles, CA
Phoenix, AZ
Oakland, CA
Atlantic Ocean, average
Southern California
Oaborn Bank Basin, CA
Santa Cruz Basis-., CA
San Pedro, CA
Santa Barbara Basin, CA
San Diego Trough, CA
Concent rat Ion
<0.32- 5.9 pg/m3
2.7 pg/mj
1.8 ug/m3
7.0 pg/m3
2.2 Mg/m3
1.5 inj/m3
2.5 pg/m3
1.1 Mg/m3
*~ -' • . „.-—— -
1.7 pg/m*
Average Standard Deviation
B/m^
1.9 1.5
1-3 0.7
3.9 3.0
4-1 1.4
5.6 3.6
4.5 3.3
!•<> 0.9
0.4 pR/m3
l.Oi 0.3 pg/m3
0.76 pg/n.3
0.76
1.6
1.3 pg/ni3
0.76 g/,q3
Commen t
Continental U.S.
pg/day (23 in /day)
42 13
1 28 7
9? 11
-
93 18
133 45
116 39
38 I J
Marine Air
Marine Air
Marine Air, off California
Coast
Reference
Su & Goldberg (1976)
it
M
ii
ii
*i
Singh at ill. (1980)
...
1
Su and Coldbcrg (1976)
II
II
1*
II
-------
TABLE 4~la. CONCENTRATIONS OF 1,1,1-TRICHLOROETHANE DETECTED IN THE ATMOSPHERE (Continued)
Sample Date
NEAR PRODUCERS
November, 1976
December, 1976
November, 197fc
December, 1976
January, 1977
Urban Areas
May, 1980
May- June, 1980
June, 1980
June, 1980
May-June, 1980
May-June. 1980
July, 1980
Location
Dow Plant A; Freeport, TX
Vulcan Materials Co.; Gelamar, LA
Ethyl Corporation; Baton Rouge, LA
PPG Industries; Lake Charles, LA
Hoeing; Auburn, UA
TABLE 4-lb. CONCENTRE
Houston, TX
St. Lout a, MO
Denver, CO
Riverside, CA
Los Angeles, CA
Phoenix, AZ
Oakland. CA
Concentration
<1.7-64 pg/m3
£1.7-860 ug/m3
<1.7- 22 ug/m3
<1.7-47 ug/m3
2.2-5.5 ug/m3
iTIONS OF 1,1,2-TRICHLOROETII
Average Standard Deviation
ng/mj
180 130
80 30
150 60
230 120
50 30
90 60
40 20
Comment
1,1,1-Producer, distance £ 3.2
km,f (direction, distance, time)
1,1,1-Producer, distance <1 km
1 ,1,1-Producer , distance, -:.3kin
1,1,1-Product Site, distance
<4 km
User site, Distance <3 km
ANE DETECTED IN THE ATMOSPHERE
Dally Dose ug/day
Average Standard Deviation
3.1 1.8
1.9 0.4
3.4 0.6
5.0 2.1
1 0
1 1
1 0
Reference
Battelle (1977)
It
II
It
II
Singh et al . J 980
ti
it
it
Singh et al . 1979
II
II
r
-------
TABLE 4-
CONCENTRATIONS OF TRICHLOROETHANES DETECTED IN WATER
Sample Type/Date
DRINK inn WATER—
SURFACE WATER
8-78/6/79
6/12/1978
2/76-2/78
DRINKING WATER—
GROUNDWATER
,
Location
All over U.S.
Nlngiira Falls, NY
Poughkeepsle, NY
Waterford, NY
— • _____
Concentration
1,1.1- 1.1,2-
Detected In ~T7lO~ I/ 10
Hi eh Concentration 8,5 iie/K <1.0 iig/
Raw Finished
No. Samples 105 103
t Positive 12.4 21.8
Mean 0-32 pg/« 0.56 pg/t
Median 0.2 0.4
RanBe 0.1-1.2 0.1-3.3
Detected 9.92 of finished surface
water samples.
Mean of all samples » 0.12 lie/I
Max. 2,250 pg/t
1.1.1- 1.1.2-
Detected in 15/330 Not
Average of 2.2 ng/« Analyzed
Positives
Range <0 5-650 Mg/£
<0.33, l.l ug/
4 samples, all <5 |ig/t
0.1 I'g/t, ND, 6 samples <2 pg/t
Kaw Finished
No. Samples 13 23
% Positive 23.1 21.7
Mean 4-8 |ig/t 2.13 |ig/t
Median 1.1 2.1
Range 0.3-13.0 1.3-3.0
Oetecte.l in 22. 2* of finished ground
water samples.
23% of 1611 wells tested in three
states were positive.
— — _
Comment
NORS
-
NOMS
| of positive samples
CWSS Data
,1,1- Finished Drinking Water
Supplies
NOMS ,
> of positive samples
" "1
Reference
EPA (1975)
'OnJgllo £t aK (1980)
Brass (1981)
Kim and Stone (1979)
-------
TABLE 4-2. CONCKNTRATIONS OK TRICIII.OROETHANES DKTECTKD IN WATER (Continued)
Sample Type/Date
4/28/78
Location
i
Alabama
Connecticut
Florida
Idaho
Kentucky
Maine
Massachusetts
New Hampshire
New Jersey
New York
Norlh Carolina
Rhode Island
South Carolina
Tennessee
Washington
New Jersey
Nassau County, L.I., NY
All Over U.S.
Concentration
No. Wells Tested % Positive
80 10
1200 ?
329 15
9 11
22 0
89 18
163 21
6 0
All 48
372 9
44 2
88 ?
4 0
50 26
32 69
iil«lz 1.1.2-
No. Samples 394 399
K, Positive 10 66
<1.0 M8/1 376 203
1-10 |.B/» 17 141
10-1000 ng/l 1 55
>100 |ig/l - ]
yi.l- 1,1.2-
No. Tested 372 372
No. Positive 33 50
% Positive 9 13
Maximum 310 ng/l 300 ng/t
1 ,1,1- 1,1,2-
Detected In 3/106 Not
Average of 2.8 ug/H Analyzed
Positives For
Range <0.5-7 |ig/l
Comment Reference
* ~ " '— — - -
1 ,1,1-Trlchloroethane Conlgllo et al. (1980
i
i
i
n
•i
CWSS , Brass (1981)
1
-------
TABLE 4-2. CONCENTRATIONS OF TRICIII.OROETHANES DETECTED IN WATER (Continued)
Sample Type/Date
AMBIENT SURFACE
WATER
11/76- 1/77
WASTEWATER
1977
l're-1977
location
Near Production Plants
Chicago
Illinois
Pennsylvania
New York City Area
Hudson River Area
Upper & Mid-Mississippi R
Lower Mississippi River
Houston Area
OliJo River Basin
Oreat Lakes
Tennessee River Basin
Concentration
0.5-8 (3)
0.05 ng/t- 16,500 |ig/t
Concentration
No. Samples Range (Mean)
11
12
14
I
3
1
3
3
6
2
Detected 2-300 ug/t
1-2
and 4 (<2)
Not Detected
Maximum 8 |ig/t
1 Mg/l
4 Hg/e
Commen t
Sediment ND - 6.1 ug/kg
Lake Michigan, sewage plant
effluent, fllltratlon plant,
channels
Illinois River
Delaware, Schuylklll, Lehlgh
Rivers
Hudson River and Bays
Calveston Bay and Channels
6/129 Raw Waste Samples from
Textile Plants
0/129 Secondary Effluent
Samples
3/4 Sewage Treatment Plant
Effluents
2/18 Finished Waters
25/182 Ambient Samples
Reference
Battelle (1977)
Battelle (1977)
Raw] Ings and Sanflcltl
(1978)
U.S. EPA (1977)
-------
As Table 4-3 exhibits, the majority of STORE! data values for
trichloroethanes have associated remark codes: ambient data—1,1,1-
trichloroethane (85%), 1,1,2-trichloroethane (94%); effluent data —
1,1,1-trichloroethane (76%), 1,1,2-trichloroethane (97%). The remark
codes include:J — estimated value; K—actual value is known to be less
than value given; and U— material analyzed for but: not detected.
A detection limit (K remark) of 10 yg/1 appears most frequently
in association with observations from sampling in a.mbient waters — for
1,1,1-trichloroethane,34% of the time and for 1,1,2-trichloroethane,
36% of the time. Sampling in effluent waters reflects several frequently
used detection limits: 0.01, 1.0, 5 and 10 yg/1. These limits combined
account for 52% of the values recorded for 1,1,1-trichloroethane and
81% for 1,1,2-trichloroethane. Levels might therefore be less than or
equal to the reported value.
The distribution of unremarked STORET observations is presented
in Table 4-4. The majority of ambient and effluent values range between
1 yg/1 and 10 yg/1, inclusively; the exception is ambient values recorded
for 1,1,2-trichloroethane for which 60% are less than 1 yg/1.
As of October 2, 1980, 80 observations of 1,1,1-trichloroethane
in sediment and 79 observations of 1,1,2-trichloroethane were recorded
in STORET. The observations reflect regional conditions for the
South, Southwest, and West, for sampling has occurred in only ten states:
Alabama, Arizona, California, Idaho, Louisiana, Nevada, New Mexico,
Oregon, Texas, and Washington. Table 4-5 shows the ranges for unremarked
and remarked values and the number of observations within each category.
Dickson and Riley (1976) reported concentrations of trichloroethanes
(1,1,1 and 1,1,2-isomers were not distinguished) between 16 ng/g and 2 ng/g
in aquatic biota in the United Kingdom.
STORET system also contains observations in fish tissue. Sampling
has been conducted in the ambient waters of nine states: Alaska,
California, Idaho, Kansas, Louisiana, Nevada, Oregon, Texas, and
Washington. The concentration ranges of unremarked and remarked data
are presented in Table 4-6.
Only one study (McConnell e_t al. 1975) provides data concerning
1.1.1-trichloroethane in foods. The sampling was done in the United
Kingdom. No data are available concerning concentrations of the
1,1,2- isomer in food. Table 4-7 shows the concentrations of 1,1,1-
trichloroethane ranging from 1 yg/kg to 10 yg/kg. PVC used in food
storage containers was found to contain the 1,1,1-isomer, but none was
found to have contaminated cooking oils purchased in these containers
(Gilbert et al. 1978). Subsequent to the study, the manufacturer of
the bottles disclosed that 1,1,1-trichloroethane was no longer present
in food packaging grades of PVC.
4-8
-------
TABLE 4-3. STATUS OF STORET DATA FOP. CONCENTRATIONS OF
1,1,1- AND 1,1,2-TRICHLOROETHANE IN AMBIENT
WATER AND EFFLUENT
Status
Observations
Number % in Range Range in Values (ug/1)
Ambient Data:
l>l»l-trichloroethane
unremarked 54
remarked K 213
remarked U 99
366
1,1,2-trichloroethane
unremarked 20
remarked K 214
remarked U 123
357
Effluent Data:
1,1,1-trichloroethane
unremarked 126
remarked J 2
remarked K 360
remarked U 43
531
1,1,2-trichloroethane
unremarked
remarked J
remarked K
remarked U
13
2
411
43
469
24
0.3 - 1600.0
0.3K - 50.OK
O.OU - 10.OU
0.5 - 58.0
0.5K - 50.OK
O.OU - 10.OU
0.2 - 7100.0
2.0J - 7.0J
O.OK - 20.OK
O.OU - 5.0U
1.1 - 3000.0
3.0J - 6.0J
O.OK - 20.OK
O.OU - 5.0U
Source: U.S. EPA STORET Water Quality System, as of September 24, 1980,
KEY: J - estimated value; K - actual value less than value given;
U - analyzed for but not detected.
4-9
-------
TABLE 4-4. DISTRIBUTION OF UNREMARKED VALUES
IN STORET FOR CONCENTRATIONS OF
1,1,1- AND 1,1,2-TRICHLOROETHANE
IN AMBIENT WATER AND EFFLUENTS
1,1,1-Trichloroethane 1,1.2-Trichloroethane
Ambient
Effluent
Ambient
Effluent
Concentration
(Vig/l)
<1
1-10
11-100
101-500
501-1000
>1000
No.
Obs.
13
22
14
3
1
1
54
%
24
41
26
6
2
2
No.
Obs.
11
76
28
9
0
2
126
%
9
60
22
7
-
2
No.
Obs.
12
7
1
-
-
-
20
No.
% Obs.
60 0
35 6
5 2
4
0
1
13
%
^
46
15
31
—
8
Source: U.S. EPA STORET Water Quality System, as of September 24, 1980,
4-10
-------
TABLE 4-5. CONCENTRATIONS OF TRICHLOROETHANES IN
SEDIMENT REPORTED IN STORET
Compound/Status of Observation Concentration
No. Range
Observations (yg/kg)
1,1,1-trichloroethane
unremarked 15 0.1-16.6
remarked K 49 5.OK - 15000.OK
remarked U 16 O.OU - 5U
80
1,1,2-trichloroethane
unremarked 7 0.3-7.0
remarked K 56 5.OK - 580.OK
remarked U 16. O.OU - 15000.OU
79
Source: U.S. EPA STORET Water Quality System, as of September 24, 1980,
4-11
-------
TABLE 4-6. STORE! DATA CONCERNING LEVELS
OF TRICHLOROETHANES IN FISH
TISSUE
Compound/Status Observations
Concentrations
No . •
Observations
1,1, 1- trichloroethane
unremarked
remarked K
remarked U
19
47
_7_
73
Range
(ug/kg)
0.002 - 0.97
0.005K - 20. OK
O.OU
1,1, 2-Trichloroethane
unremarked
remarked K
remarked U
64
_7_
71
0.005K - 20. OK
O.OU
Source: U.S. EPA STORET Water Quality System.
4-12
-------
TABLE 4-7. LEVELS OF 1,1,1-TRICHLORETHANE
DETECTED IN FOODS IN THE UK
Concentration
Food Type (ug/kg)
Meats
English beef, steak 3
English beef, fat 6
Pig's Liver 4
Oils and Fats
Olive Oil (Spanish) 10
Cod Liver Oil 5
Castor Oil 6
Fruits and Vegetables
Potatoes (S. Wales) 4
(NW England) 1
Apples 3
Pears 2
Packet Tea 7
Fresh Bread 2
Source: McConnell et al. (1975).
4-13
-------
4.3 ENVIRONMENTAL FATE
4.3.1 Overview
The trichloroethanes have high volatilization rates relative to
many other organic chemicals due to their high vapor pressures, even
though their solubilities are high also (Table 4-8). The primary fate
pathway for these chemicals is volatilization from surface water or
soil, followed by slow photooxidation in the atmosphere. Atmospheric
lifetime due to photooxidation for 1,1,1-trichloroethane is on the
order of six to ten years, long enough for global mixing and transport
to the stratosphere to occur. (Hemispheric and stratospheric mixing
occur on a time scale on the order of a half year to a year.) Decom-
position in the stratosphere can release Cl atoms, which may cause
ozone depletion. Estimated ozone depletion due to the 1,1,1- isomer
are about 1.3% of the total ozone or less, depending on assumptions of
continuing release rates. Little information on the amospheric fate
was found of the 1,1,2-isomer although it may photooxidize more rapidly
than the 1,1,1-isomer.
The following three sections summarize aquatic fate processes, soil
transport and volatilization, and atmospheric fate processes.
4.3.2 Aquatic Fate Processes
4.3.2.1 Hydrolysis
Dilling et al. (1975) found that 1,1,1-trichloroethane in sealed
tubes had a 6.9-month half-life for hydrolysis at 25°C. Decomposition
products were acetic and hydrochloric acids, along with a minor amount
of vinylidene chloride. In aerated water in a closed system decomposition
occurred with a half-life of about 6 months in either dark or in sun-
light. This time is similar to the 6.9 months for hydrolysis.
McConnell et al. (1975) reported that the 1,1,1-isomer is subject
to dehydrochlorination at a rate dependent upon pH. Chemical half-life
in seawater is estimated to be 9 months at pH 8 and 10°C. The decom-
position product is vinylidene chloride, with a minor amount of acetic
acid arising by hydrolysis. In aqueous systems, metallic iron was
found to accelerate decomposition, but degradation products were not
known.
Dilling et al. (1975) inferred from their experiments that 1,1,1-
trichloroethane is chemically stable in water. This is probably a
reasonable assumption for surface waters particularly in contrast to the
much more rapid volatilization rate. However, for 1,,1,1-trichloroethane
in groundwater, where volatilization is not possible, hydrolysis may be
an active fate mechanism. The 6-9 month half-life for hydrolysis
indicates that about 90% of 1,1,1-trichloroethane in an aquifer would be
decomposed in about 2 years.
4-14
-------
Property
Synonyms
1,1,l-Trichloroethanea
Alpha-trichloroethane
Methyl chloroform
1,1,2-Trichloroethaneb
vinyl trichloride
Molecular formula
Formula weight
Boiling point
Melting point
Vapor density
Specific gravity
Solubility
Density of saturated air
Concentration of saturated air
Vapor pressure
Conversion factors-Air
(25C 760 mm Hg)
N10SII 1976
133.41
74.0 C (165.2 F)
(760 mm Hg)
-32.62 C (-26.7 F)
4.6 (air = 1)
1.339 at 20 C (water -
1.000 at 4 C)
4400 mg/1 water at 25 C
soluble in ethyl ether,
ethyl alcohol
1.6 (air = 1)
16.7% by volume at 25 C
62 mm Hg at 10°C
100 mm Hg at 20°C
127 mm Hg at 25°C
150 mm Hg at 30°C
240 mm Hg at 40°C
3
1 g/m = 183 ppm
3(b)
1 ppm = 5.54 mg/m
133.41
113.7°C
-35, -36.7 C
4.63 (air - 1)
1.44 at 20°C (Water = 1.00
at 4°C)
4500 mg/1 water at 20°C
136 g/m at 20°C
225 g/m at 30°C
19 mm Hg at 20°C
32 mm Hg at 30°C
40 mm Hg at 35°C
3
i
1 ppm =
3
1 mg/m =0.18 ppm
5.55 mg/m
b
Verse luioren 1977
-------
4.3.2.2 Sorption onto Sediments
No information has been found concerning the sorption of trichloro-
ethanes, although the organic carbon partition coeffficient (K ) for
the 1,1,1- isomeris reported to be 180 (Karickhoff et al. 1979*?? The
Koc for 1,1,2- isomer is estimated by the method of Chiou _et al. (1979)
to be 57. These Koc values indicate that the trichloroethanes will
sorb to a high degree onto organic matter in soils or sediments.
4.3.2.3 Volatilization from Water
Billing (1977) found that 1,1,1-trichloroethane volatilized with a
half-life of 15.3 - 28.2 minutes from a stirred (200 rpm) 250-ml beaker
holding 200 ml of a 1 ug/1 solution, 6.5 cm deep. Under similar con-
ditions Dilling et al. (1975) found a half-life of about 20 minutes for
the same isomer. 90% volatilized in 60-80 minutes. For 1,1,2-trichloro-
ethane, the half-life was 21 minutes and the time to 90% loss was
reported to be 102 minutes.
The Dow Chemical Company (Battelle 1977) has reported the following
evaporation rates from a similar experiment:
.. ,. T, ,„ minutes
Medium 1/2
Tap Water at 25 °C 22
Tap Water at 1-2°C 33
3% Salt Solution 25
Water with ^500 mg/kg peat moss 20
Water with ^500 mg/kg wet bentonite clay 20
Water with 2.2 mph wind 17
These laboratory measured rates are not directly indicative of
volatilization rates from natural water bodies. When compared with
volatilization rates found in a similar manner for other organic
chemicals, the trichloroethanes will apparently volatilize relatively
quickly. Thus, the trichloroethanes will probably volatilize rapidly
from natural water bodies when compared with the other organic chemicals.
Appendix D details estimations of volatilization rates from natural
water bodies. The half-life for 1,1,1-trichloroethane from aim deep
stream flowing at 1 m/sec with a 3 m/sec wind speed is about 4 or 5
hours. For a 10 m deep stream, the half-life increases to about 6.7 days.
Time to 90% loss is about three half-lives, or 12 hours to 20 days. For
the 1 m/sec current speed, the distance to 90% loss is 43 to 1700 km
downstream. These estimates may represent upper limits since other
conditions, such as high wind speed or turbulence in the water, would
increase the volatilization rate. Estimated volatilization rates for
1,1,2-trichloroethane are similar, but about 20% slower.
4-16
-------
A.3.2.4 Biodegradation
Tabak £t a]L_ (1980) conducted static culture flask tests to
determine the susceptability of the trichloroethanes to microbial
degradation. Wastewater microbiota and a yeast extract were used
to inoculate 5 mg/1 and 10 mg/1 solutions of the 1,1,1- and 112-
isomers. Figure 4-1 shows that 15-25% of the 1,1,1- isomer and 55-60%
of the 1,1,2-isomer remained after 21 days. Though these results may
not be totally representative of susceptability to biodegradation in
the environment, they are indicative of the potential for these com-
pounds to biodegrade in the environment and in waste treatment processes,
4.3.3 Soil Transport and Volatilization
. Wilson |t al.. (1980) studied the transport and fate of chemicals
including 1,1,2-trichloroethane applied to a sandy soil composed of
92/. sand; 5.9* silt, 2.1% clay and 0.08% organic carbon. The results
are somewhat ambiguous since more compound was recovered than was
applied. More than half of the 1,1,2-trichloroethane in a water
solution apparently volatilized, although more than one-half apparently
percolated through the 140-cm soil column (Table 4-9). None was
degraded. Soil columns were not saturated.
When Wilson et aT._ (1980) compared volatilization from the soil
column to volatilization from water, they found that volatilization
from soil was inhibited by the soil by about a factor of ten or more
(forna,502) of 1,1,2- isomerapplied to soil may
volatilize.
• A large part (>50%) may percolate through the soil column.
The chemical is minimally retarded by sandy soil.
• Volatilization from the soil column will occur at a rate ten
or more times slower than from a water column of similar depth.
4-17
-------
% Remaining from Original
Concentration
% Remaining from Original
Concentration
-O
I
M
OO
w
J>
5? Z
2 o
c ••*
o> Ol
o" 3
51- 1
\°L w
~ I
CO oi
00 r*
O ^J
~ 6.
Ol
<
5'
o>
-1
<
M
-------
TABLE 4-9. FATE OF 1,1,2-TRICHLOROETHANE APPLIED TO
A SOIL COLUMN IN THE LABORATORY
Fate (%)
Degraded or
Concentration Applied.(mg/I) Volatilized Column Effluent not Accounted for
1.000 56 ±16 65 ± 12 -21 ± 10
0.16 95+13 61 ± 5 -56 + 7
Source: Wilson et al. (1980).
4-19
-------
In soils in which a large organic matter component is present
volatilization and transport rates will probably be slower than those
described here, due to sorption onto the organic matter.
. No comparable information has been found for 1,1,2-trichloroethane.
4.3.4 Atmospheric Fate Processes
Appendix E discusses the atmospheric fate of the trichloroethanes
in detail. A summary is reported here. Most of the information found
related to 1,1,1-trichloroethane with relatively little information
found concerning the fate of 1,1,2-trichloroethane in the atmosphere.
The 1,1,1-isomer is long lived in the atmosphere. The residence
time based on destruction by photooxidation is estimated to be 6-10
years or longer. Consequently, 12-25% of global emissions will reach
the stratosphere to be distributed globally. Actual concentrations
vary according to location, latitude, hemisphere, and altitude. Higher
concentrations are found in the northern troposphere than in the strato-
sphere or Southern Hemisphere. Atmospheric concentration, in general,
have increased with time due to increasing use of the chemical.
Final disposition of 1,1,1-trichloroethane is in the atmosphere
due to photooxidation in both the troposphere and the stratosphere.
Chlorine atoms may be released to attack and deplete ozone. Estimates
of ozone depletion due to the 1,1,1-isomer are 0.2% to 1.2% of total
ozone. In comparison, the total depletion due to chloroflurocarbons
released in 1973 is estimated to be about 7% of total steady-state ozone.
The compound 1,1,2-trichloroethane was found to be 30-50 times
more reactive than the 1,1,1-isomer when studied in a laboratory
photochemical apparatus (see Appendix E). The 1,1,2- isomer photolyzed
"rather rapidly" forming formyl chloride, phosgene, and chloroacetyl
chloride as decomposition products. The environmental significance
of this test was not established; however, the results can be reasonably
assumed to indicate that the atmospheric lifetime of 1,1,2-trichloro-
ethane is about a factor of ten less than the lifetime of 1,1,1-
trichloroethane, i.e., about 1 year.
4.4 MODELING OF ENVIRONMENTAL DISTRIBUTION
4.4.1 Ambient Concentrations
Fugacity models can be used to estimate ambient environmental
concentrations for some chemicals; however, these models are inappropriate
for 1,1,1-trichloroethane due to the long lifetime of the chemical,
its pervasiveness, and global distribution. Distributions and releases
of 1,1,2-trichloroethane appear to be so limited that an equilibrium
modeling approach is not appropriate. The model environments and
compartments for these chemicals are not clearly defined. The
fugacity models were not applied for these reasons.
4-20
-------
.4.2 EXAMS Model Results
i i o .*?? purpose of estimating the potential fate of 1,1,1- and
1,1,2-tnchloroethane in various aquatic environments under conditions
mfdein^?n?U? dlSChar?e' the f^5 (E^osure Assessment Modeling Syste
38
nons
dlSChar?e' the f^5 (E^osure Assessment Modeling System)
38 lmPlemented^.S. EPA 1980). The physical-chemical
i / a ^action rate constants used as inputs are listed
tL nuino f arb*trary loadinS r"e of 1.0 kg/hr was chosen for
the purpose of comparing the compound's fate in different systems -
a pond, oligotrophic lake, eutrophic lake, average river, turbid river
and coastal plain river. The simulated systems represent "average"
US water bodies. Their properties (i.e., biomass, sediment concen-
°
,
rn r°Si laanf10 conditions> «re described in the model output
- ' "** ^ ^^ ^ depth are
for
Tables 4-11 through 4-15 present the output of the EXAMS simulations
in vartr" S**', ^^ are ™™** concentrations af equStt
due to dif'f^f ^ fWf "' Sediment« biota' «c.) and percentage loss
aue to different fate processes.
volatitin 8l8?lf±5
-------
TABLE 4-10. PARAMETERS FOR TRICHLOROETKANES
USED IN EXAMS ANALYSIS3
Property
Molecular Weight
Solubility
Liquid Phase Transport
Resistance
Henry's Law Coefficient
Vapor Pressure
Partition Coefficient:
• Biomass/Water
• Sediment/Water
• Octanol/Water
Chemical Oxidation Rate
• Water
• Sediment
Hydrolysis Rate
Isomer
1,1,1-
133.4
4400
0.53
3.9 x 10~3
100
81
152
320
1
1
1.7 x 10~4
1,1,2-
133.4
4500
0.53
7.4 x 10"4
19
33
56
117
1
1
1.2 x 10~7
Unit
g/mole
mg/1
unitless
m /mole
torr
Ug/g
mg/1
mg/kg
mg/1
mg/1
mg/1
mole/1/hr
mole/1/hr
mole/1/hr
•Source: SRI (1980).
4-22
-------
TABLE 4-11. FLOW AND DEPTH OF EXAMS SIMULATED SYSTEMS'
Depth (m)
.p-
1
N)
U)
System
Pond
Eu trophic Lake
Oligotrophic Lake
River
Turbid River
Coastal Plain River
Water Flow
(m /day)
0.643
4.1x5b
5b
4.1x10
2.4xlO?
2.4xlO?
2.4xl06
Water
Column
2
20 C
20°
3
3
3
Sediment
0.05
0.05
0.05
0.05
0.05
0.05
Sediment Mass
in Water
Column (kg)
600
2695(3)
525(3)
6xl04
3xl05
6000
Length (m)
NA
NA
NA
3
3
3
All data from EXAMS (1980) output.
Average flow for littoral zone, epylimnion and hypolimnion.
Includes epylimnion and hypolimnion (deepest part of lake).
-------
TABLE 4-12. STEADY-STATE CONCENTRATION IN VARIOUS CENTRALIZED AQUATIC SYSTEMS
RESULTING FROM CONTINUOUS 1,1.l-TRICHLOROETUANKS DISCHARGE AT
1.0 lqj/lird
Maximum Concentrations
Pond
*• Eutrophic
NJ Lake
01igotrophlc
Lake
R i ve r
Turbid River
Coastal Plain
River
Loading
1.0 kg/hr
Water
Total
i»fi/l)
2.6
0.13
0.14
9.9 x 10~4
9.9 x 10~*
9.3 x 10~3
Bottom
Sediment
(mg/1)
2.1
1.2 x 10~2
2.8 x 10~3
2.5 x 10~A
5.4 x 10~A
2.8 x 10~3
Maximum in
Sediment
Deposits
(ing/kg)
32
7.1 x 10~2
2 x 10~2
2.6 y 10~3
1.9 x 10~3
4.3 x 10~2
Plankton Benthos
(t'g/g) (UR/jO
210 170
10 0.9
11 0.23
8 x 10~2 2 x 10~'
8 x 10~2 4 x 10~'
0.75 0.22
Total Steady-
State Accumulation
74
310
340
0.91
0.90
8.4
a
All data simulated by EXAMS model (see text for further information).
-------
TABLE 4-1). THE FATE OF 1,1 ,1-TRICHLOROETHANE IN VARIOUS CENKKALIZED AQUATIC SYSTEMS*
J^
KJ
Cn
System
Pond
Eu trophic
Lake
Oligotrophlc
Lake
Kiver1'
Turbid
i> i vu _ d
Water at Steady-
state
71
99
>99
97
98
K, teaming in
Sediment at
Steady-state
29
1
«
2
A I rans termed
by Chemical
Processes
1
5
6
% Transformed
by Biological
Processes
0
0
0
0
% Volatll-
i zed
92
91
90
2
2
% Lost
by other
Proccessi's
7
4
4
98
98
Time for
System Sei 1 -
Purl f icat i in
2700 hours
56 days
64 days
39 hours
21 hours
Coast ;il Plain
93
0
0
14
86
180 hours
'All data simulated by the EXAMS model (see text for further information).
Including loss through physical transport out of system.
s-sre
-------
TABLE 4-14. STEADY-STATE CONCENTRATIONS IN VARIOUS GENERALIZED AQUATIC SYSTEMS
Maximum Concentrations
System Loading
Pond 1.0 kg/hr-1
Eutrophl c
Lake
Oil go trophic
Lake
T River
to
Turbid River
Coastal Plain
River
Water
Total
(mg/1)
3.4
0.14
0.15
9.9 x 10~4
9.9 x 10~4
9.4 x 10~3
Bottom
Sediment
(mg/1)
2.0
0.007
2.1 x 10~3
3 x 10~4
6.2 x 10~4
3 x 10~3
Maximum in
Sediment
Deposits
(mg/kg)
12
0.017
5.3 x 10~3
1.2 x 10~3
9.2 x 10~4
1.8 x 10~2
Total Steady-
Plankton Benthos slate Accumulation
(MB/B) (ng/g) (kg)
110 67 76
4.6 0.2 380
4.8 0.007 410
3.3 x 10~2 9.8 x 10~3 0.9
3.3 x 10~2 2 x 10~2 0.9
0.31 0.1 8.2
:l
All data simulated by EXAMS model (see text for further information).
-------
TABLE 4-15. THE KATE OF 1,1,2-TRICHLOROETIIANE IN VARIOUS GENERALIZED AQUATIC SYSTEMS1
% Residing in % Residing in
Water at Steady- Sediment at
System slate Steady-state
I'ond 89 11
En trophic 99 1
Lake
Oligotrophlc >99 <1
Lake
RlviTd 99 1
Turbid 99 1
J^~ , , .1
1 IUverd
ts>
Coasial Plain 98 2
H i vi- r d
% Transformed Z Transformed X Lost Time for
by Chemical by Biological % Volatil- by other System Scl
Processes Processes ized Processes1' Purlflcatii
0 0 91 9 1030 hours
0 0 95 5 71 days
0 0 94 6 76 days
0 0 1 99 17 hours
0 0 1 99 12 hours
0 0 12 88 64 hours
AH data simulated by the EXAMS model (see text for further information).
Including loss through physical transport out of system.
"Estimate for removal of ca. 75% of the toxicant accumulated in system. Estimated from the results of the half-lives
for the toxicant In bottom sediment and water columns, with overall cleansing time weighted according to the toxicant's
initial distribution.
d
All river systems are 3 km In length so that physical transport out of the nodeled system is dominant loss process.
The "river" system was extended to various lengths up to 1000 km from the source to determine the significance of
other fate processes (see text).
-------
N>
OO
1,1.1 — Trichloroethane
1,1.2 — Trichloroethane
300
3000
Km
FIGURE 4-2. PERCENTAGE OF TRICHLOROETHANE LOSS DUE TO VOLATILIZATION
AS FUNCTION OF DISTANCE FORM POINT SOURCE
-------
concentrations were usually two orders of magnitude greater than water
levels. The 1,1,1-isomer had a slightly greater affinity for bio-
accumulation and adsorption onto sediment than did the 1,1,2- isomer. This
behavior would be expected based on their respective partition coefficients,
shown in Table 4-10. The following conclusions can be drawn from the
EXAMS analysis about the potential environmental fate of the trichloro-
ethanes in aquatic systems. Persistence depends primarily on volatilization
since chemical degradation is minimal. The estimated half-lives (under
conditions of continuous discharge) are listed in Table 4-16. The
half-lives for the other rivers are not included because the lengths
modeled were so short that physical export of the chemical out of the
segment was responsible for over 85% of removal. Persistence would
be greater in the coastal plain river than in the average river due to
the higher biomass retaining some fraction of the chemical. Since
volatilization is so important in all systems, conditions of high
temperatures, high wind velocity, water and air turbulence, and low
biomass would all increase the rate of trichloroethanes to the atmos-
phere in real systems. This assumes negligible transformation of the
compound in both liquid and vapor form. For the 1,1,1- isomer, hydrolysis
was detectable as a mechanism of removal in static systems; however,
it was never competitive with the process of removal in static systems
and it was never competitive with the process of volatilization.
In the pond system, a half-life of 5700 hours was estimated for
chemical loss alone as compared with a significantly shorter half-life
of 60 hours due to volatilization only. As can be seen on Table 4-16,
the total system half-life for 1,1,1-trichloroethane was 50 hours,
which is quite close to the volatilization half-life.
4-29
-------
TABLE 4-16. HALF-LIVES FOR TRICHLOROETHAMES
PERSISTENCE IN GENERALIZED
AQUATIC SYSTEMS
System
Oligotrophic Lake
Eutrophic Lake
Pond
River
Persistence Chrs)
1*1.1- 1,1,2-
230
210
50
40
280
260
50
40
Source: U.S. EPA (1980c).
4-30
-------
REFERENCES
Battelle Columbus Laboratories. Multi-media levels-methyl chloroform.
EPA 560/6-77-030. Columbus, OH: Battelle Columbus Laboratories, U.S.
Environmental Protection Agency; 1977d.
Battelle Columbus Laboratories. Environmental monitoring near industrial
sites. Methyl chloroform. Columbus, OH: Battelle Columbus Laboratories,
1977b.
Brass, H. Final community water supply survey. (CWSS). Cincinatti, OH:
Office of Drinking Water, U.S. Environmental Protection Agency; 1981.
Chiou, C.T.; Peters, L.J.; Freid, V.H. A physical concept of soil-water
equilibria for nonionic organic compounds. Science 206 (4420): 831-832;
1979.
Coniglio, V.A.; Miller, K.; Mackeever, D. The occurrence of volatile
organics in drinking water. Briefing. Washington, DC: Criteria and
Standards Division, U.S. Environmental Protection Agency, 1980.
Correia, Y.; Martens, G.J.; Van Mensh, F.H.; Whim, B.P. The occurrence
of trichlorethylene, tetrachloroethylene, and 1,1,1-trichloroethane in
Western Europe in air and water. Atmos. Environ. 11(11): 1113-1116;
1977.
Cox, R.A.; Derwent, R.G., Eggleton, A.E.J.; Lovelock, J.E. Photochemical
oxidation of halocarbons in the troposphere. Atmos. Environ. 10: 305-308;
1976.
Cronn, D.R.; Rasmussen, R.A.; Robinson, E. Measurement of tropospheric
halocarbons by gas chromatography, mass spectrometry. Report for Phase
II. Research Triangle Park, NC: U.S. Environmental Protection Agency;
1977a.
Cronn, D.R.; Harsh, D.E. Determination of atmospheric halocarbon
concentrations by gas chromatography-mass spectrometry. Anal. Lett.
12(B14): 1489-1496;1979.
Cronn, D.R. Measurements of atmospheric methyl chloroform by Washington
State University. In Proceedings of the conference on methyl chloroform
and other halocarbon pollutants. Research Triangle Park, NC: U.S.
Environmental Protection Agency; 1980b.
Dickson, A.G.; Riley, J.P. The distribution of short-chain halogenated
aliphatic hydrocarbons in some marine organisms. Marine Pollution
Bulletin 7(9): 167-169; 1976.
Dilling, W.L.; Tefertiller, N.B.; Kallos, G.J. Evaporation rates of
methylene chloride, chloroform, 1,1,1-trichloroethane, trichloroethylene,
tetrachloroethylene, and other chlorinated compounds in dilute aqueous
solutions. Environ. Sci. Technol. 9(9):833-838; 1975.
4-31
-------
Billing, W.L. Interphase transfer process. II. Evaporation rates of
chlorome thanes, ethanes, ethylenes, propanes, and propylene from dilute
aqueous solutions. Comparisons with the sketical predictions. Environ.
Sci. Tecnnol. 11: 405-409; 1977.
Karickhoff, S.W. ; Brown D S •
pollute. on
Lillian, D.; Singh, H.B.; Kopleby, A.; Lobban, L. ; Arnts, R.; Gumpert,
R.; Hague, J. ; Toomey, J.; Kazazis, J. ; Antel, M. ; Hansen, D.; Scott,
B. Atmospheric fates of halogenated compounds. Environ. Sci. Technol
9:1042-1048; 1975.
McConnell, G. , Ferguson, D.M., Pearson, C.R. Chlorinated hydrocarbons
and the environment. Endeavor. 34:13-18; 1975.
Rawlings, G.D.; Sanfield, M. Toxicity removal of secondary effluents
from textile plants. EPA- 600/7- 78- 168. Washington, DC. U.S.
Environmental Protection Agency, Symp. Proc. Process. Measurement
Environ. Assess 331:153-169; 1979.
Singh, H.B.; Salos, L.J.; Cavanaugh, L.A. Distribution sources and
sinks of atmospheric halogenated compounds. J. Air Pollut. Cont
Assoc. 27:332-336; 1977.
Singh, H.B.; Salas, L. J. ; Sheigeishi, H. ; Smith, A.H. Fate of halogenated
compounds in the atmosphere. Menlo Park, CA; Stanford Research Institute-
1978 Available from NTIS PB 278198.
Singh, H.B.; Salas, L.J.; Smith, A.; Shigeish, H. Atmospheric measure-
ments of selected toxic organic chemicals, First Year Interim Report.
Research Triangle Park, NC: Environmental Sciences Research Laboratory,
U.S. Environmental Protection Agency; 1979.
Singh, H.B. ; Salas, L.J.; Smith, A.; Shigeish, H. Selected hazardous
organic chemicals, Draft Second Year Interim Report; 1980.
Symons, J.M. ; Bellar, T.A. ; Caldwell, J.K. ; Kropp, K.L.; Robeck, G.G.;
Seeger, D.R.; Slocum, C.J.; Smith, B.L.; Stevens, A. A. National
Organics Monitoring Survey for halogenated organics. J. Am. Water Works
Ass. 67:634-636; 1975.
Su, C. ; Goldberg, E.D. Environmental concentrations of some halocarbons .
Windom, L. ; Duce, R.A. eds. Marine pollutant transfer. Lexington, MA:
Lexington Books; 1976.
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.
4-32
-------
Tabak, H.H.; Aqave, S.A.; J. Mashni, C.I.; Barth, E.F. Biodegradation
studies with priority pollutant organic compounds. Cincinnati, OH:
Water Research Division, U.S. Environmental Protection Agency; 1980.
U.S. Environmental Protection Agency (U.S.EPA). Monitoring to detect
previously unrecognized pollutants in surface water. Washington, DC:
Office of Toxic Substances, U.S. Environmental Protection Agency; 1977.
U.S. Environmental Protection Agency (U.S.EPA). Data Sheet for results
of Phase I of special monitoring regulations (NOMS) finished drinking
water in 113 U.S. cities. Washington, D.C.: Monitoring Data Support
Division, Office of Water Planning and Standards; undated.
Verschueren, K. Handbook of environmental data on organic chemicals.
New York, NY: Van Nostrand Reinhold; 1977.
Wilson, J.T.; Enkrel, C.G.; Dunlap, W.J.; Cosby, R.L.; Foster, O.K.;
Baskxn, L.B. Transport and rate of selected organic pollutants in
a sandy soil. Undated manuscript received as personal communication
from R.S. Kerr Env. Res. Lab, Ada, OK, U.S. Environmental Protection
Agency; 1980.
-------
5.0 EFFECTS AND EXPOSURES— HUMANS
5.1 HUMAN TOXICITY
5.1.1 1 , 1, 1-Trlchloroethane
5.1.1.1 Introduction
The principal human exposure route to 1,1, 1-trichloroethane, a vola-
tile halogenated hydrocarbon, is by inhalation. It is also readily ab-
sorbed from the gastrointestinal tract and via dermal contact. Although
anesthetic concentrations of 1,1, 1-tr ichloroethane are capable of depres-
sing the central nervous system, this compound has a fairly low toxicity
due to its rapid and almost total elimination as unchanged 1,1, 1-trichloro-
ethane.
Commercial samples of 1,1, 1-tr ichloroethane available in the United
States contain 3 to 8% by volume of added stabilizers such as p-dioxane,
nitromethane, N-methylpyrrole, butylene oxide, 1,3-dioxolane and secondary
butyl alcohols (IARC 1979). The following discussion states, whenever possible
whether or not the pure or technical (i.e., stabilized) product was tested.
5.1.1.2 Metabolism and Bioaccumulation
Absorption and Distribution
In both man and rodents, 1,1, 1-trichloroethane is rapidly absorbed
through the lungs and gastrointestinal tract, and somewhat slower through
skin (Stewart 1968, Tsurata 1975).
Studies with humans have demonstrated that between 60-90% of inhaled
1,1, 1-tr ichloroethane is rapidly expired unchanged (Monster 1979, Monster
£tfll. 1979, Humbert and Fernandez 1977). Monster et al. (1979) reported
recoveries of 80% and 74% respectively, following ix"po7ure of human vol-
unteers to 382 or 792 mg/m3 1,1, 1-trichloroethane for 4 hours. Total in-
dividual uptake was 2.2 times greater with the higher concentration over
the 4-hour period. The addition of two 30-minute work periods during the
4-hour exposure increased uptake 2-fold above that noted with exposures
at rest, resulting in elimination of 62% of the inhaled dose.
Due to a low blood/gas partition coefficient, retention of 1,1,1-tri-
chloroe thane decreases with exposure time, as a steady state is reached.
Several _ studies have noted that pulmonary excretion of 1,1, 1-trichloro-
ethane is a function of both exposure duration and concentration. Ex-
posures ranged from a single breath inhalation of the compound to an 8-
Ue *" ^ "*'* ' ^ reSUltS °f theSe Studie* are summarized
°f b°th li£Iuid LI, 1-trichloroethane and its vapor through
1SQ77SO,^en tem°nstrated ^Stewart and Dodd 1964, Fukabori §
, 1977, Riihimaki and Pfaffli 1978). Stewart and Dodd (1964)
5-1
-------
TABLE 5-1
PULMONARY ELIMINATION OF 1,1,1-TRICHLOROETHANE
IN HUMANS
Exposure
382 or 1163 mg/m for
8 hr
382 or 792 mg/m3 for
4 hr
775 mg/m for 4 hr with
two 30 mln. work
periods ,
1910 mg/m3 for 1 hr
1910 mg/m for 7.5 hr
single breath
Amount of 1,1,1-Tri-
chloroethane
Expired Unchanged
98% by 8 days
70-80% by 8 days
62% by 8 days
820 mg/m- immediately
5.4 mg/m at 24 hr
3
1365 mg/m immediately
44 mg/m3 at 16 hr
44% within 1 hr
Reference
Humbert and Fer-
nandez (1977)
Monster et_ al.
(1979)
Monster et_ al.
(1979)
Stewart et al,
(1975)
Stewart et al
(1975) ~~
Morgan et al.
(1972)
5-2
-------
observed rather slow absorption of 1,1,1-trichloroethane during immersion
lll^r- ™ V1 thUfS ir° the S°1Vent °r t0piCal -PPlicatlon to the hand,
? / I 30 minutes duration. Average peak breath concentrations were 117
5.4 and 3.5 mg/m^, respectively (only 14% of an estimated 820 mg/m3 ex- '
posure) while average, breath concentrations 2 hours post-exposure were
ii «^J!nJ 1'7*8/m resPe"^ely, indicating that amount of absorption
is related to skin area and duration of contact. Continuous 30-minute
ST?77nn i 3°C* handS VaS estimated to equal a 30-minute exposure to
fntv I ?-m?^ t ^compound. Skin absorption would thus present
only a limited health hazard according to these results.
ethan10^* C°TkerS (1976' 197?) 3pplied (*u .-trichlo
ethane (15 ml) dxrectly to the forearm skin of human volunteers for 2
airrr;a.Mf a?f ^1>1/13tJiC!:10r0et:hane W3S quickly detected in exPi"d
air reaching 16-38 mg/m3 by 2 hours. Repetition of this procedure for
l !T A?, /I aT ag? alveolar air concentrations of 27 mg/m3 on day
L^t f ^8!T °ni y A* In an°ther exPerim*nt, repeated dipping of both
hands into the solvent, 7 times per day for 4 days resulted in blood
levels of 6-9 ug 1,1,1-trichloroethane/ml by the fifth day.
Riihimaki and Pf af fli (1978) examined the absorption of 1,1,1-tri-
intact human skin. Two human volunteers with
1 1 1 trilnr exPosed » 3276 mg/m3 laboratory-grade
"
y-gr
c an exposure chamber (15 m3) for 3.5 hours.
Steady and quantitatively increasing blood concentrations of 1,1,1-tri-
auink°rf ^ r" nf 6d dUring Percu^neous exposure in contr.it to the
?±laM rSPld a"a,lnment of a stead^ state in blood subsequent to
inhalation exposure.. Peak blood concentration at 3.5 hours was ^90 ug/1-
identical exposures to thes sove« ncen-
Pharmacokinetic studies by various routes of exposure with rats
brain, kidney muscle, lung and blood (Stahl et al 1969) '
^-"•s^^s^^
brain at a given exposure concentration, while concentrations in the
liver were much higher. Tissue concentrations (especially in the Uvert
were much greater (nearly 10 times) when animals were exposed to a high
5-3
-------
air concentration for a short exposure time compared to either a low air
concentration for a short exposure time or a low air concentration for
a long exposure time even though total exposures (mg/m^ x hr.) were the
same. Exposures ranged from 55 to 54,600 mg/m3 1,1,1-trichloroethane for
durations of 0.5 to 24 hours. The biological half-life of 1,1,1-trichloro-
ethane in the blood, liver, kidney and brain was approximately 20 minutes
(Holmberg _et al. 1977).
Larsby and coworkers (1978) reported crossing of the blood-brain
barrier by 1,1,1-trichloroethane in rabbits. The animals were contin-
uously infused at a rate of 7-19 mg/min intravenously. A near equili-
brium between blood and cerebrospinal fluid was achieved very quickly.
The rate of elimination after cessation of infusion was rapid during the
first 20 minutes, with the concentration of solvent in the cerebrospinal
fluid appearing to follow the arterial concentration, but at a lower
level.
Biotransformation and Excretion
i
In controlled human studies, approximately 3.5% of the total uptake
is metabolized and excreted in the urine as trichloroethanol or tri-
chloroacetic acid. Monster (1979) suggests that metabolism takes place
in the liver by hydroxylation to trichloroethanol followed by subsequent
partial oxidation to trichloroacetic acid. The maximum concentration of
trichloroethanol in the blood and exhaled air after a 4-hour exposure
to 382 or 792 mg/nr* 1,1,1-trichloroethane appeared to occur at about
2 hours post-exposure, and declined rapidly thereafter with a half-life
of 10-12 hours. In the post-exposure period, the concentration of tri-
chloroethanol in the blood was approximately 14,000 times greater than
that in mixed exhaled air. The maximum concentration of trichloroacetic
acid was reached at 20-40 hours after exposure, and decreased exponen-
tially after 60 hours with a half-life of 70-85 hours. Urinary excretion
of the major portion of trichloroethanol occurred during the first 24
hours, while only about 30% of the trichloroacetic acid was excreted in
the urine by 70 hours. Some 70 hours after exposure, the amount of tri-
chloroethanol and trichloroacetic acid excreted in the urine represented
only about 2.0% and 0.5%, respectively, of the uptake; of 1,1,1-trichloro-
ethane (Monster 1979, Monster _et^ al. 1979). Humbert and Fernandez (1977)
observed that urinary excretion of the metabolites continued for up to
12 days following an 8-hour exposure to similar concentrations (382 or
1162 mg/m^) of 1,1,1-trichloroethane.
Similar findings were reported by Ikeda and Ohtsuji (1972) for Wistar
rats exposed to 1092 mg/kg 1^C-labelled 1,1,1-trichloroethane for 8 hours.
Urine samples collected for 48 hours from initiation of treatment con-
tained 0.5 mg/kg body weight trichloroacetic acid and 3.1 mg/kg trichloro-
ethanol. Rats intraperitoneally injected with an equimolar dose of 1,1,1-
trichloroethane excreted essentially the same levels of both metabolites.
5-4
-------
In summary, absorption of 1,1,1-trichloroethane occurs in both
humans and animals through inhalation and dermal contact. However,
most of the absorbed dose is rapidly eliminated unchanged via the lungs.
The small percentage retained and metabolized is converted to trichloro-
ethanol with subsequent conversion to trichloroacetic acid, and excreted
in urine. Absorption by the inhalation route appears to be a function
of duration as well as concentration. Percutaneous absorption of both
liquid and vapor 1,1,1-trichloroethane has been demonstrated in humans
but relative to inhalation exposure, dermal contact presents a limited
risk.
5.1.1.3 Human and Animal Studies
Carcinogenicity
Three studies have examined the carcinogenicity of 1,1,1-trichloro-
ethane — by inhalation in rats and by gavage in both rats and mice
(Rampy _et al. 1977, Quast et al. 1979, NCI 1977). Poor survival or in-
adequate duration of study, however, render the data from these studies
inadequate for the assessment of human carcinogenic risk.
Technical grade 1,1,1-trichloroethane (95%) stabilized with 3%
p-dioxane and containing 2% impurities, was administered in corn oil by
gavage to Osborne-Mendel rats (50 per sex per group) at dosages of 750
or 1500 mg/kg, 5 days/wk for 78 weeks and to B6C3F1 mice (50 per sex per
group) at time-weighted doses of 2807 or 5615 mg/kg, 5 days/wk for 78
weeks. Rats were observed through 110 weeks, mice through 90 weeks. A
slight decrease in average body weight gain was noted for all treated
animals of each species. Although no statistically significant increase in
either the total number of neoplasms or any specific type of neoplasm
was observed in either group of treated rats or mice, an abnormally high
early mortality, most probably from chronic murine pneumonia, was such
that the number of survivors (3% treated rats, 31% treated mice were
alive at termination) render suspect any assessment of carcinogenic
risk (NCI 1977). 6
Rampy et al. (1977) and Quast et al. (1979) reported no appreciable
increase in tumor incidence in Sprague-Dawley rats (90-96 per sex per
group) exposed by inhalation to 4.7 or 9.5 g/m3 1,1,1-trichloroethane
6 hours/day, 5 days/wk for 12 months, followed by an additional 18 months
of observation. No differences in body weight, terminal organ weight or mor-
tality were observed. The only reported sign of toxicity was an increased
incidence of focal hepatocellular alterations in female rats at the higher
dose. No appreciable difference in tumor incidence between treated and
control rats was evident. However, the length of treatment was less than
lifetime (12 months) and there is a .question as to whether or not the
maximum tolerated dose was used. These studies, therefore, do not pro-
vide adequate data on which to base assessment of carcinogenic risk.
5-5
-------
Mutagenicity
_The 1,1,1- isomer was weakly inutagenic in Salmonella typhimurium
strain TA-100 in an Ames test, with or without microsomal activation
(.binnnon et al. 1977) .
Price et al. (1978) reported in vitro transformation of F1706
Fischer rat embryo cells to tumor producing cells following exposure to
1,1,1-trichloroethane. ^differentiated fibrosarcomas were produced
at the site of inoculation in newborn Fischer rats injected subcutan-
eously with transformed cells.
Adverse Reproductive Effects
No embryotoxic or teratogenic effects were noted in offspring of
Sprague-Dawley rats or Swiss Webster mice exposed by inhalation to 4.7
g/m 1,1,1-trichloroethane, 7 hours/day on days 6-15 of gestation. The
average number of implantation sites per litter, litter size, incidence
°f fp'a1 "" fetal sex ratio, fetal body measurements, and the
Elovarra and coworkers (1979) noted embryotoxic effects in chick
embryos subsequent to direct injection of 0.6 to 13.3 ug 1,1,1-tri-
chloroethane/egg on day 3 or 6 of incubation. Weight and growth measure-
' ^ ** ** ^ d°SS Whl
wer i °J f T?^'* LD5° °f 6'7-13'3 yg/e^' Malformations
were increased fourfold above control values but the lack of anatomic
and physiologic maternal-fetal relationships and the ultras ens itivity
?Lo I* tSSv S?St?m render iC UTlsuitab1^ for assessing potential tera-
togenic risks in humans, particularly in view of negative results in
two species that possess placentae.
Other lexicological Effects
Several comprehensive reviews are available on the acute and chronic
aT 1976 ^SH^QT^^r11 1'1'1-trichi— thane exposure (Aviado et
Jl. 1976, NIOSH 1976a, Walter et al. 1976, Kover 1975, MRI 1979). We
r°rr;w°?iyeliShliSht th°Se —that «
-------
Liver and kidney damage have been reported in man but only with
very high exposures to 1,1,1-trichloroethane. Unlike the CNS effects,
however, these changes are irreversible, consisting of actual cellular
or biochemical damage including increases in weight accompanied by fatty
changes and hemorrhagic necrosis (NIOSH 1976). Dornette and Jones (1960)
found no liver damage (measured as serum transaminase) in subjects anes-
thetized with 32,760-141,960 mg/m3 1,1,1-trichloroethane for up to 2
hours, while Aviado j£t al. (1976) report clinically detectable effects
on the liver with inhalation of approximately 142,000 mg/m3 for 15 min-
utes. Exposures of 2730 mg/m3 for 78 minutes caused some signs of ad-
verse kidney effects, 4900 mg/m3 for 20 minutes produced elevated uri-
nary urobilinogen and increasing levels from 0-14,500 mg/m3 over 15
minutes produced red blood cells in the urine and/or a positive urinary
urobilinogen (Stewart e^ al. 1961).
Inhalation of 54 to 3000 mg/m elicited effects on the cardiovascular
system in humans including bradycardia and hypotension within the first
few minutes of exposure; in addition to these effects, various altera-
tions in electrocardiogram patterns such as premature ventricular con-
traction, depressed S-T segments and changes in nodal rhythm were pro-
duced with anesthetic levels of 32,760-141,960 mg/m3 for up to 2 hours
(Dornette and Jones 1960).
At least 30 deaths have been attributed to 1,1,1-trichloroethane
from deliberate or occupational inhalation exposure, most of which re-
sulted from suffocation with acute edema and congestion of the lungs,
liver, brain, kidney and/or spleen (Stahl et al. 1969, Caplan et al.
1976, Bass 1970, Hall and Hine 1966). Tissue concentrations oFTTT,!-
trichloroethane were highest in the liver followed by brain, kidney,
muscle, lung and blood. Bass (1970) reported 29 cases of sudden death
attributed to cardiac sensitization to endogenous catecholamines, while
Travers (1974) noted a death from cardiac arrest, all following inhala-
tion of 1,1,1-trichloroethane. Garriott and Petty (1980) reported three
fatalities following inhalations of liquid paper solvent containing 0.4-
0.7 mg/100 ml 1,1,1-trichloroethane.
A case of accidental ingestion of 600 mg/kg 1,1,1-trichloroethane
resulted in initial signs of CNS depression and gastrointestinal effects.
Clinical tests showed no adverse effects on CNS, ECG, SGPT, blood urea
nitrogen, SCOT, hematocrit and hemoglobin, while some kidney and liver
pathology was suggested by red blood cells and protein in the urine and
increased serum bilirubin (Stewart and Andrews 1966).
Limited quantitative data are available concerning any toxic effects
specifically related to long-term exposure to 1,1,1-trichloroethane by
any route of administration. Stewart et al. (1969) reported normal
clinical chemistry tests for 11 males after inhalation exposure of 2730
mg/mJ 1,1,1-trichloroethane for 6.5-7 hr/day for 5 days. Subjective
reports listed some signs or irritation and slight central nervous ef-
fects resulting from exposure.
5-7
-------
No clinically pertinent findings (primarily regarding cardiovascu-
lar and hepatic effects) were recorded in an epidemiologic study involv-
ing two adjacent textile plants, one of which utilized stabilized 1,1,1-
trichloroethane as a general cleaning solvent. A total of 151 matched
pairs of employees were examined. Employees from the exposed group had
occupational exposures to 1,1,1-trichloroethane ranging from 5.5 to 1360
mg/m^ for up to 6 years (Kramer _et al. 1978). A study of health effects
associated with air concentrations of 30-1660 mg/m3 1,1,1-trichloroethane
to 170 factory employees also revealed no existing hazard (Hervin and
Lucas 1973). Maroni et al. (1977) reported no signs attributed to cen-
tral or peripheral nervous system impairment in 22 factory workers ex-
posed to air concentrations between 600 and 5400 mg/m3 for up to 6 years.
Animal studies reflect the same general toxic responses noted in
humans. Exposure by various routes, of administration to high concentra-
tions of 1,1,1-trichloroethane in various species of animals induces toxic
effects on the central nervous system, the cardiovascular and pulmonary
systems and in renal and hepatic tissues (Parker e£ al. 1979, Horiguchi
and Horiguchi 1971, Tsapko and Rappoport 1972, Herd et al. 1974, Torkel-
son et al. 1958, MacEwen and Vernot 1974). In general, the LD50ls for
1,1,1-trichloroethane in most species are in the range of 5,000-12,000
mg/kg bw via oral intake, and 76,450-98,300 mg/m3 for 3-7 hours via in-
halation (MRI 1979) .
Torkelson et al. (1958) found slight liver and lung pathologv in
guinea pigs exposed to 5,460 or 11,000 mg/m3 1,1,1-trichloroethane for
90 or 30 min/day- (respectively) for 3 months. Lung irritation was ob-
served in guinea pigs exposed to 5,460 mg/m3 for 72 min/day or 11,000
mg/m for 12 min/day, both for 69 exposures- No irritation was evident
.with exposure to the lower concentration for 36 min/day for 69 exposures.
MacEwen and Vernot (1974) reported no pathology, no hematological
effects, normal clinical chemistry tests and no liver lesions in dogs
monkeys, mice and rats with continuous inhalation of 1,365 or 5>460 mg/m3
i"^1CJ10!0ethanxe f°r 14 Weeks' Lun8 chan§es (slight congestion in
one half of the rats) was observed at both dose levels, while fatty livers
and elevated levels of liver triglycerides in mice were found only at the
higher dose. in addition to these effects seen in the mice, McNutt et
al. (1975) observed microscopic pathology indicated by centrilobular —
nepatocyte hypertrophy, focal necrosis and inflammation at week 10 and
vacuolization at week 12 with continuous inhalation of 5,460 mg/m3 for
14 weeks; these effects were not apparent at 1,365 mg/m3.
In similar studies, Prendergast et al. (1967) found no microscopic
pathology, some body weight loss, some leukopenia, normal clinical chem-
istry tests and some non-specific inflammatory changes in the lungs of
monkeys, dogs, rabbits, rats and guinea pigs exposed to 900-2,457 mg/m3
1,1,1-trichloroethane continuously for 90 days or 14,742 mg/m5 8 hr/day
5 days/wk for 6 weeks. Adams et al. (1950) reported similar results for
these species with exposures up to 27,300 mg/m3, 7 hr/day, 5 days/wk for
31-32 exposures.
5-8
-------
5.1.2 1,1,2-Trichloroethane
5,1.2.1 Introduction
Although very little data are available concerning toxic, carcin-
ogenic, mutagenic or teratogenic effects in animals or humans, the
evidence suggests that 1,1,2-trichloroethane is more toxic that its
isomer, 1,1,1-trichloroethane.
5.1.2.2 Metabolism and Bioaccumulation
Available pharmacokinetic data on 1,1,2-trichloroethane indicate
that it is readily absorbed from injection sites, skin and via the
lungs. Yllner (1971) found that greater than 90% of an intraperitone-
al dose of 100-200 mg/kg bw 11+C-labelled 1,1,2-trichlorethane in mice
was eliminated within 24 hours. Expiration accounted for 16-20% of
the administered dose (40% of which was excreted unchanged, 60% as
C02), and urinary excretion, for 73-87% of the dose. Major urinary
metabolites were S-carboxymethyl cysteine (29-46% free, 3-10% bound),
chloroacetic acid (6-31%) and thiodiacetic acid (38-42%). Minor met-
abolites included oxalic acid, glycolic acid, 2,2-dichloroethanol,
2,2,2-trichloroethanol, and trichloroacetic acid, suggesting metabol-
ism via formation of chloracetalydehyde. Only 1-3% remained in the
animal after 3 days; 0.1-2.0% was in the feces.
Intraperitoneal injection of guinea pigs with 50 yl of pure
1,1,2-trichloroethane resulted in rapidly increasing blood levels of
the solvent, reaching a maximum of nearly 15 yg/ml at 2 hours, then
declining over the next 10 hours. Intracutaneous or subcutaneous in-
jection of 50 yl resulted in a slower, more even uptake of the solvent
from a depot in or under the skin, and a subsequent slow disappearance
from blood (Jakobson et^ al. 1977).
Rapid dermal absorption of 1,1,2-trichloroethane has been docu-
mented for guinea pigs (Jakobson et_ al.. 1977) and rats (Tsurata 1975,
1977). The compound was detected in the blood of guinea pigs five
minutes after application of 1 ml of pure 1,1,2-trichloroethane to the
skin. Blood concentrations increased during the first 30 minutes
post-dosing, peaking at approximately 3.7 mg/ml. Blood levels dropped
to a minimum value (^2.5 mg/ml) at one hour, but then increased
steadily thereafter reaching a concentration of ^5 mg/ml at 12 hours
(length of observation). No indications of blood saturation were
noted during this period. A second application at another skin depot,
at the point when blood levels were at the minimum from the first ex-
posure, resulted in a distinct short second maximum followed by a sec-
ond minimum and increase (Jakobson e_t al. 1977). The complex toxi-
cokinetics characteristic of percutaneous application are most likely
due to a local effect on and/or within the skin and not to a systemic
effect. Jakobson speculates that an increased barrier function of the
skin during the first 1-2 hours post-treatment results in a decreased
5-9
-------
uptake of the solvent into the blood. With time, this barrier is over-
come (presumably due to progressive skin damage), leading to a gradual
increase in the blood concentration of 1,1,2-trichloroethane.
Another investigator (Tsurata 1975) calculated an in vivo dermal
penetration rate for 1,1,2-trichloroethane in rats of 5.6 mg/min/cm2
skin and a percutaneous absorption rate of 17.4 mg/min/cm2 skin. In an
in vitro, study (Tsurata 1977), with application of 1 ml solvent to
excised rat skin (3.7 cm2 area), 0.53, 1.56 and 3.04 milligrams of sol-
vent had penetrated the skin by 1, 2, and 3 hours, respectively. The
penetration curve of 1,1,2-trichloroethane consisted of a lag phase
(time period required to establish a steady state diffusion, 0.64 hr)
followed by a steady state phase.
The 1,1,2- isomer of trichloroethane is also absorbed via the lungs,
Wistar rats exposed by inhalation to 1092 mg/m3 1,1,2-trichloroethane
for 8 hours excreted 0.3 mg/kg bw each of trichloroacetic acid and tri-
chlorethanol in their urine during, and up to 40 hours after exposure
(Ikeda and Ohtsuji 1972). An equimolar dose given by intraperitoneal
injection (370 mg/kg bw) resulted in similar urinary levels (0.4 mg/kg
bw TCA and 0.2 mg/kg bw trichloroethanol) (Ikeda and Ohtsuji 1972).
Van Dyke (1977) reported 9.3% enzymatic dechlorination of 1,1,2-
trichloroethane in vitro by rat Liver microsomes. Dechlorination was
maximal in the presence of 02 and required NADPH; in a nitrogen
atmosphere, dechlorination was reduced to approximately 1/3 - 1/2 the
rate under aerobic conditions.
In summation, ready absorption of 1,1,2-trichloroethane from skin,
lung and injection site has been demonstrated in laboratory animals.
An in vivo dermal absorption rate of 17.4 mg/min/cm2 had been calculated
for the rat. Prolonged dermal contact results in a complex pharmaco-
kinetic pattern in guinea pigs which may reflect increased absorption
over time resulting from progressive skin damage. Once absorbed, 1,1,2-
trichloroethane appears to be rapidly cleared in the urine of rats and
mice. Major urinary metabolites identified in mouse urine include S-
carboxymethyl cysteine, chloroacetic acid and thiodiacetic acid. Small
amounts of trichloroethanol and trichloroacetic acid are also present.
5.1.2.3 Human and Animal Studies
Carcinogenicity
Osborne-Mendel rats (50 per sex per group) were fed technical grade
1,1,2-trichloroethane via stomach tube at time-weighted doses of 46 or
92 mg/kg, 5 days/wk for 78 weeks, followed by observation until
week 113. No increased incidence of tumors or appreciable differences
in weight gain patterns, appearance or behavior were observed. Survi-
val was such that adequate numbers of rats in all groups were at risk
from late-developing tumors (NCI 1978).
5-10
-------
In a separate experiment, B6C3F1 mice (50 per sex per group) were
fed technical grade 1,1,2-trichloroethane via stomach tube at time-
weighted doses of 195 or 390 mg/kg, 5 days/wk for 78 weeks with
observation until week 91. A highly significant increased incidence
of hepatocellular carcinoma was observed in all mice treated with
1,1,2-trichloroethane (see data below). A positive association between
the incidence of pheochromocytoma of the adrenal gland and 1,1,2-tri-
chloroethane exposure was also noted. Adrenal pheochromocytomas were
found in 17% (8/48) of high dose males and 28% (12/43) high dose fe-
males, but not in low dose groups or controls (NCI 1978).
TABLE 5-2 INCIDENCE OF HEPATOCELLULAR CARCINOMA
IN B6C3F1 MICE FED 1,1,2-TRICHLORO-
ETHANE FOR 78 WEEKS
Group Male Female
Vehicle Control 2/10 (10%) 0/20 (0%)
Low Dose (195 mg/kg/5 days/ 18/49 (37%) p=.022 16/48 (33%) p-.002
wk)
High Dose (390 mg/kg/5 days/ 37/49 (76%) p<.001 40/45 (89%) p<.001
wk)
Source: NCI (1978)
Mutagenicity
A negative mutagenic response was noted with 1,1,2-trichloroethane
(8 mg/plate) in a plate assay with Salmonella typhimurium strain TA1535
in the presence or absence of a microsomal activation system (Rannug
et_ al. 1978). No other data were found concerning possible mutagenic
effects of 1,1,2-trichloroethane.
Adverse Reproductive Effects
The embryotoxic effects of 1,1,2-trichloroethane on chick embryos
was studied by Elovarra and coworkers (1979). Concentrations of 0.6
to 13.3 ug of 1,1,2-trichloroethane/egg were injected directly in the
air sac on day 3 or 6 of incubation. A clear dose-response relation-
ship with respect to survival of the embryos at day 14 was noted re-
gardless of the day of treatment. An approximate LDso value of 6.7-
13.3 wg/egg was obtained. Measured weight and growth for live em-
bryos, however, were affected only at the highest dose (13.3 yg/egg).
Macroscopic malformations including exteriorization of visera, skeletal
and eye abnormalities and profound edema were increased twofold above
controls at doses of 0.6 to 13.3 ug/egg. The lack of anatomic and
physiologic maternal-fetal relationships and the resultant ultrasensi-
tivity of this system, however, render it unsuitable for assessing po-
tential teratogenic risks to humans.
5-11
-------
No additional information was available concerning potential ad-
oIthane?CtiVS ^^ aSS°ciate
Other lexicological Effectjs
_ Reports in the literature have linked acute exposure to 1 1 2-
trichloroethane with central nervous system effects in mice, kidney
necrosis in mice (0.17 ml/kg ip) and dogs (0.4 ml/kg ip) and liver
necrosis in both mice and dogs following intraperitoneal injection of
8 " 3nd Plaal966> 1967> Plaa an
skin ofi applicati°n °f °'5 to 2 ^ of 1,1,2-trichloroethane to the
SKin of guinea pigs resulted in the death of 30 to 75% of the animals
within one week (Wahlberg and Boman 1979). In another study, dermal
application of 1 ml of the solvent to the skin of guinea pigi produced
effects within 15 minutes (pyknotic nuclei in epidermal cells with
perinuclear edema in basal cells). After 30 minutes, epidermal sep-
aration from the cerium and vesicle formation was evident, while with-
in 1-12 hours all layers of epidermis showed cellular degeneration.
Damage was localized exclusively to the epidermis (Kronevi et al. 1977)
In humans, a narcotic action and irritant effects of eyes and
mucous membranes of the respiratory tract are noted following exposure
to low concentrations of 1,1,2-trichloroethane. It produced cracking
and erythema when in contact with the skin. Long-ter^exposure to the
t, gaStric S^P<^, ^t deposition
the kidneys and damage to the lungs (Hardie 1964). The lowest
reported oral lethal dose in man is 50 mg/kg (RTECS 1980).
No case reports or epidemiological studies were available with
regard to human exposure to 1,1,2-trichloroethane.
5.1.3 Overview
5.1.3.1 Ambient Water Quality Criteria — Human Health
The U.S. EPA (1980a) has established a water quality criterion for
1,1,1-trichloroethane of 18.4 mg/l for the maximum protection of human
health. The criterion is based on reduced survival noted in Osborne-
Mendel rats administered 750 mg/kg of this compound by gavage, 5 days
per week for 78 weeks (i.e. 536 mg/kg/day) (NCI 1977) . Assuming a 70 kg
body weight and a safety factor of 1000, an acceptable daily intake
UDI) of 37.5 mg/day was calculated. The criterion level of 1 1 1-
trichloroethane for drinking water, corresponding to this ADI,'is 18 4
m/l.
5-12
-------
For the maximum protection of human health from potential carcino-
genic effects of exposure to 1,1,2-trichloroethane through ingestion of
water and contaminated aquatic organisms, the U.S. EPA (1980a) has set
the ambient water concentration at zero. The concentration of 1,1,2-
trichloroethane calculated to keep lifetime cancer risk below 10~5 is
6 ug/1. The criterion is based on the induction of hepatocellular car-
cinoma in male B6C3F1 mice given time-weighted average oral doses of
195 or 390 mg/kg, 5 days per week for 78 weeks (i.e., 139 and 279 me/
kg/day, respectively) (NCI 1978).
5.1.3.2 Other Human Effects Considerations
The widely used industrial solvent 1,1,1-trichloroethane has a
fairly low toxicity due to rapid and almost total elimination of the
compound, unchanged, via the lungs. Pulmonary elimination appears to
be a function of both concentration and exposure duration, with reten-
tion increasing with concentration but decreasing with increased expos-
ure time. The small amount that is metabolized (^3.5% of an inhaled
dose) is converted by the liver to trichloroethanol and trichloroacetic
acid and excreted in urine. Urinary clearance has an approximate half-
life in man of 10-12 hours for trichloroethanol and 70-85 hours for tri-
chloroacetic acid. Although inhalation exposure is most common, percu-
taneous absorption of both liquid and vapor 1,1,1-trichloroethane, as
well as exposure via ingestion, has been demonstrated in humans.
In laboratory animals, acute LD5()'s range from 5,000-12,000 mg/kg
via oral administration and 75,450-987300 mg/m3 for 3-7 hours via in-
halation exposure. Principal effects of acute exposure in laboratory
animals are depression of the central nervous system and disturbances
in pulmonary and cardiac function, including sensitization of the heart
Subchronic ^halation studies, monkeys, dogs, rabbits,
,
v 14'75° mg/m 8 hours ?er d*y> 5 days per
>
7 showed some leukopenia, body weight reduction and non-
irS iC ±"?1rajto?r changes. The liver appeared to be most susceptible
to histopathological changes in guinea pigs and mice.
No adequate carcinogenicity studies are available for the determi-
nation of carcinogenic risks associated with exposure to 1,1,1-trichloro-
ethane. In three studies, 1,1,1-trichloroethane caused no significant
increase in tumor incidence in B6C3F1 mice (4010 mg/kg/day by gavage)
d1 Hra/,S (1°^/kg/day * S-age) - * P» ue-Dawley ra§t '
6 hr/day' 5 days Per week for I2 months); however/poor
T I5 Snd lnsufficlent ^ration of study rendered
er d n q ^ USe ln an assessment of carcinogenicity. Fur-
ther data on carcinogenicity and mutagenicity are extremely limited-
'fd6 I"1*" ™*™^** ** -entrain (TA^ oTslltnell*
and in one mammalian cell transformation assay. No terato-
S a l.l.l-trlchloro.th«e expos^e were ob-
on
5-13
-------
At low exposures of 1,1,1-trichloroethane (_< 5460 mg/m3) the primary
effects in man are psychophysiological, including dose-related impairment
of perception and coordination and relatively little disturbance in body
functions. At anesthetic levels (>43,700 mg/m3), functional depression
of the central nervous system leading to respiratory or cardiac failure
are noted. Acute exposures to high levels of the compound (>5460 mg/m3)
by accidental contact or abuse, may result in transient kidney and "
liver dysfunction. The effects of chronic low-level exposures are not
Known.
Data concerning the toxicity, carcinogenicity, mutagenicity or
teratogenicity of 1,1,2-trichloroethane are very limited or non-existent
particularly regarding adverse effects to man. However, based on the
evidence available, 1,1,2-trichloroethane is considered much more toxic
than its isomer, 1,1,1-trichloroethane. The greater toxicity of the
1,1,2-isomer may be due to its greater rate of absorption and slower
excretion than 1,1,1-trichloroethane.
Absorption of 1,1,2-trichloroethane has been demonstrated in labor-
atory animals following inhalation exposure or dermal contact. An in
vivo dermal absorption rate of 17.4 mg/min/cm 2 has been calculated fo~r
the rat. Prolonged dermal contact results in a complex pharmacokinetic
pattern in guinea pigs which may reflect increased absorption over time
SN^s??38*6331^ skin damage. Once absorbed, fairly rapid excretion
or ii-*i7. of an absorbed dose occurs via the urine, and 6-8% of the ab-
sorbed dose is expired unchanged. Major urinary metabolites in mice
are S-carboxymethyl cysteine, chloroacetic acid, and thiodiacetic acid,
and minor amounts of trichloroethanol and trichloroacetic acid.
Exposure to 1,1,2-trichloroethane has'been shown to cause central
nervous system depression in mice and damage to the liver and kidnev
in mice and dogs following single intraperitoneal injections of 0.07-
c pff' /°Ute exP°sure in man appears to be characterized by a nar-
o,^ "n the central nervous system and eye and skin irritation,
Kidney, lung and gastrointestinal damage may result from
exposure.
Data from a study on carcinogenic effects indicated that 1,1,2-tri-
BFl^ fT^ hePatocellular carcinomas and pheochromocytomas in
B6C3F1 mice of both sexes at time-weighted doses of 139 and 279 mg/kg
bw/day administered by gavage. Carcinogenicity data from a similar
study with Osborne-Mendel rats were inconclusive. No adequate data re-
garding mutagenic or teratogenic effects associated with 1,1,2-trichloro-
ethane exposure have been reported.
5-14
-------
5.1.4 Estimates of Human Dose-Response Relationships
5.1.4.1 1,1,1-Trichloroethane
Poor survival or inadequate exposure duration render the three
carcinogenicity studies conducted with 1,1,1-trichloroethane inadequate
for the determination of carcinogenic risks. Extremely limited teratogenic
and mutagenic data suggest no teratogenic effects in either mice or rats
exposed to 4780 mg/m3 on days 6-15 of gestation and a weakly positive
mutagenic response in an _in vitro neoplastic transformation assay and a
single bacterial strain. The sole lifetime exposure data available for
estimation of noncarcinogenic risk are the NCI (1977) findings of reduced
survival, most probably from chronic murine pneumonia, in Osborne
Mendel rats administered 750 mg 1,1,1-trichloroethane/kg by gavage,
5 days/week for 78 weeks (i.e., 750 mg/kg x 5/7 days - 536 mg/kg/day).
An acceptable daily intake (ADI) can'be calculated from these data for
an average 70 kg human adult. An uncertainty factor of 1000 was included
due to the limited chronic toxicity data available for this compound.
From these data, an ADI of 37.5 mg/day was obtained.
An, /750 mg/kg '5/7 days\ /_„ , \
I innn/ I 70 k§ J = 37.5 mg/day
\ J.UUU / \ /
5.1.4.2 1,1,2-Trichloroethane
Introduction
The potential carcinogenic risk to humans due to 1,1,2-trichloroethane
exposure is estimated below.
Ideally, this problem would be dealt with in two ways:
1) Various extrapolation models would be applied to occupational
vs. ambient* human exposure data (from retrospective studies)
in order to obtain an approximate dose/response relationship.
2) These same models would be applied to data from controlled
experiments on laboratory animals, and the animal dose/
response relationship would be converted to an estimated
human dose/response.
In the first approach, the overriding uncertainty is in the data
themselves; usually the exposure levels, lengths of exposure, and even
response rates (responses per number exposed) are "best estimates,"
and, furthermore, unknown factors (background effects, etc.) may bias
the data. In the second approach, the data are usually more accurate,
but the relationship between animal and human response rates must be
questioned, and at present there is no universally accepted solution to
this problem. (In short, in the former case relevant data are of
questionable accuracy, whereas in the latter accurate data are of question-
able relevance.) If it is possible to perform both analyses and the results
*(or ambient, location A vs. ambient, location B)
5-15
-------
corroborate each other, confidence is gained in these results. If, on
the other hand, data are not available for one of the analyses and some
result is assumed to be better than no result, the analysis must be
performed based upon the available data.
Further complicating the issue is that at present there is no basis
for judging the relative merits of the various extrapolation models.
It is impossible to say which, if any, of them is correct. However, the
models as applied here are believed to be conservative, i.e., tend to
overestimate the true risk.
The available data concerning human and other mammalian effects were
discussed in Section 5.1.2. For 1,1,2-trichloroethane, the only quan-
titative carcinogenicity data currently available are from an NCI study
on Osborne-Mendel rats and B6C3F1 mice. The data selected for extrapolation
are listed in Table 5-2.
Data from a study on carcinogenic effects indicated that 1,1,2-
trichloroethane caused hepatocellular carcinoma in B6C3F1 mice of both
sexes at time-weighted doses of 139 and 279 mg/kg bw/day administered by
gavage. A relatively minor incidence of pheochromocytomas of the adrenal
gland in the high-dose males and females has not been included. The test
performed on Osborne-Mendel rats, also with 1,1,2-trichloroethane by
stomach tube, yielded negative results (U.S. EPA 1930a).
To deal with the uncertainties inherent in extrapolation, three
commonly used dose/response models have been applied to the data in Table 5-3
to establish a range of potential human risk. The assessment of potential
human risk based on these models is subject to important qualifications:
• Though positive carcinogenic findings exist,, there have also
been negative findings in tests with other species (see above).
In view of possible species differences in susceptability,
phannaco-kinetics, and repair mechanisms, the carcinogenicity
of 1,1,2-trichloroethane to humans is far from certain.
• Assuming that the positive findings indeed provide a basis for
extrapolation to humans, the estimation of equivalent human
doses involves considerable uncertainty. Scaling factors may
be based on a number of variables, including relative body
weights, body surface areas, and life spans.
• The large difference between the typically high experimental
data and the actual human exposure levels introduce uncertainty
into the extrapolation from animals to humans. Due to inadequate
understanding of the mechanisms of carcinogenesis, there is no
scientific basis for selecting among several alternate dose/
response models, which yield differing results.
5-16
-------
TABLE 5-3. CONVERSION OF CARCINOCENICITY DATA FOR 1,1,2-TRICHLOROETHANE IN THE
MOUSE INTO EQUIVALENT HUMAN DOSES
Percent
V
M
^J
Animal Dose3
(mg/kg/day)
Male 390
Mice 195
0
(vehicle
control)
0
Female 390
Mice 195
0
(vehicle
control)
0
Equivalent
Human Dose^
(mg/day)
1120
560
0
0
1120
560
0
0
Response
37/49
18/49
2/20
2/17
40/45
16/48
0/20
2/20
Percent
76
37
10
12
89
33
0
10
Excess
Over Averaged
Controls
65
26
—
—
84
28
—
—
Source: NCI (1977)
5 days per week for 78 weeks of a 96-week lifetime.
Human Dose - Animal Dose x Animal Weight x ( HiHlaJL WelBht
2/3
(mg/day) (mg/kg/day)
(kg)
Animal Weight'
days
) x
' X
96 wks
)
-------
Calculations of Human Equivalent Doses
' "
£c:ss.:f.r£ 1:1; %^s?z> % h™ ^ -1*- ««
£ -sas.2: s?s.£ v. ::-
-. . .
introduces an uncertainty of a factor of ten at least.
70 L f'"et ^A J10"1 thlS ln'°^«on and assumed body weight! of
From this, a dose of 1 intr/kg/day for a mouse is calculated to be
equivalent to 2.9 mg/day for a human. -u.uj.ated to be
Estimation of Response per Unit of Exposure
P (response at dose x) » 1 -
function' The log-probit model assumes
^^
5-18
-------
For the linear one-hit model, the equation
P(x) - 1 -e~Bx,
where P(x) is the probability of response to dose x, is solved for the
parameter B.
It may be shown that for a test group subjected to dose x:
1 - P
1
B - - log
^e?? *! ^ aVerTage c°ntrol group response and P (x) is the response
the test group. We assume that B is given by
B" (B*i' \
1 2
the geometric mean of the BX from experimental data, and determine that
a. —3
B - 1 x 10 per mg/day.
">"«<" <".rc.pt A results
POO - * (A + log
where $ is the cumulative normal distribution function, and P(x) is the
-^
This equation makes the assumption that the log-probit dose/
^^ ^ U^ Sl°pe With respect to the log-dose. From
- i?V rd ^T1 distributi°n, A (the geometric mean of
individually determined A ) is found to be approximately equal to
Tr.L/ e W3S USe* t0 detennine the probability of a response
at various concentrations according to the above equation.
The multistage model with a quadratic hazard rate function,
2
h(x) » ax -I- bx + c,
was also fit to the data. For estimating the parameters a b and c
a maxamum likelihood method was used, aided by a computer program ^hat
r^TlVTOTx0 foea5rCh f°r C£eabeSt f2iC- Zt ~ Su^fS
a - x x iu , b * 1 x 10 Jt and c 4 8 x 10-2. Th probabilitv of
response attributable to dose x is then given by pr°bablllty of
P(x) - 1 - e"(ax + bx)
52 2T4S-J1.1S?
5-19
-------
roughly 1 mg/day. Further, since P(x) depends heavily on the quadratic
term in the high dose region, the excess risk predicted by the multi-
stage model in the low dose (linear) region is significantly below
the risk predicted by the linear one-hit model.
No attempt was made to determine statistical confidence bounds for
any of the three models. The uncertainties inherent (a) in choosing a
dose/response model and (b) in determining a human equivalent dose make
suspect any further purely statistical analyses of the data.
Table 5-4 summarizes the probability (risk) estimates obtained from
these three models. Also included in .the table are probability (risk)
estimates based on the findings of the CAG (U.S. EPA 1980a). The CAG deter-
mined an upper bound on excess lifetime probability (risk) due to
1>1»2-trichloroethane ingestion of 5.73 x 10~2 per mg/kg/day - 819 x
10-6 per mg/day (assuming a human mass of 70 kg). (Table 5-3 shows
only one significant digit.) The discrepancies between the CAG proba-
bility predictions and those derived here arise from differing assumptions
about the data and about human equivalent dose, from mathematical differ-
ences in the dose/response models, and from the fact that the CAG uses a
95% upper confidence bound in calculating its predicted probability.
Predicted excess lifetime probability per capita is shown in Table 5-4
for doses ranging from 1 ug/day to 100 mg/day.
According to the U.S. EPA's Water Quality Criteria Document for
Chlorinated Ethanes (U.S. EPA 1980a), the maximum allowable concentra-
tion of 1,1,2-trichloroethane in water to keep lifetime cancer probability
below 10-3 is 6.0 yg/r, or about 0.01 mg/day, assuming a daily water
consumption of 2 I/day for humans. (Note that the 6.0 ug/1 figure is
based on assumptions about indirect as well as direct exposure, particu-
larly on average ingestion by humans of fish inhabiting waters at this
concentration, and on the concentration in fish arising from this con-
centration in the water.) The four dose/response models predict an
upper bound for probability foe this concentration and intake between
roughly 10~7 and 10~5.
The estimates in Table 5-4 represent probable upper bounds on the
true probability, since the dose/response models are believed to be
conservative, and the estimation of human equivalent dose is believed
to be conservative as well. Note, however, that the gap between the
estimates is large in the low-dose region, so there is a substantial
range of uncertainty concerning the actual carcinogenic effects of
1,1,2-trichloroethane. However, present scientific methods do not
permit a more accurate or definitive assessment of human risk.
5-20
-------
TABLE 5-4. ESTIMATED LIFETIME EXCESS PROBABILITY OF CANCER IN HUMANS DUE TO
1,1,2-TRlCULOROETllANE ABSORPTION AT VARIOUS DAILY DOSE LEVELS
BASED ON FOUR EXTRAPOLATION MODELS3
I
N)
Extrapolation F.*P««,,r.M,««l ~ :-.u ^.. U/._OU.K^. UL inuicateu Exposure Levels
Model (mg/day): 0.001 0.01 0.1 1 in inn
Linear
Log-Probit
Multistage
CAG
1 x 10~6 1 x 10 5 1 x 10~4 1 x 10~3 1 x 10~2 1 x 10'1
<1 x 10~8 1 x 10~6 7 x- 10~5 3 x 10~3 4 x 10~2 2 x 10~X
1 x 10"8 1 x 10~7 1 x 10~6 1 x 10"5 2 x 10~4 1 x 10~2
8 x 10~ 8 x 10~6 8 x 10~5 8 x 10~4 8 x 10~3 8 x 10~2
A range of probability is given, based on four different dose-response extrapolation models. The
lifetime excess probability of cancer represents the increase in probability of cancer over the
normal background incidence, assuming that an individual is continuously exposed to 1 1 2-trichloro-
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 or"
several conservative assumptions that were utilized (see Section 5.1.4.2), it Is likely that these
predictions overestimate the actual risk to humans. AiKeiy that these
-------
5.2 HL7MAN EXPOSURE
5.2.1 Introduction
Monitoring data presented previously in Chapter 4 indicate that
trichloroethanes are widely detectable in environmental media, including
drinking water and foods. The fate analysis also demonstrated that the
trichloroethanes may occur in all environmental media — air, water,
soil, and sediment. As discussed earlier in this chapter, absorption
of trichloroethanes can occur via all exposure routes — ingestion,
inhalation, and dermal contact., Therefore, the potential absorption
of the trichloroethanes by these three routes was considered in the
human exposure analysis. Both the human effects considerations and
the monitoring data indicate that the assessment of risk for the
trichloroethanes should be conducted for each isomer separately. There-
fore, exposure routes were considered separately for 1,1,1-trichloro-
ethane and the 1,1,2- isomer.
5.2.2 Exposure through Ingestion
Data presented previously in Table 4-2 indicate that both isomers
of trichloroethane have been detected in some surface and ground sources
of drinking water. It is difficult, however, to estimate the level
of exposure to trichloroethanes via drinking water on the basis of the
available data. In most cases, the concentrations reported were below
the detection limits for the analytic procedures used. As will be
discussed below, the relative contribution from drinking water to the
total human exposure to trichloroethanes appears to be quite small in
most cases.
5.2.2.1 1,1,1-Trichloroethane
Coniglio and coworkers (1980) summarized the data on 1,1,1-trichloro-
ethane from federally sponsored surveys of finished drinking water from
surface and ground sources (see Table 4-2). Their compilations indicated
that approximately 22% of all finished water supplies (both surface
and ground sources) contained detectable levels of 1,1,1-trichloroethane.
The mean concentration in finished surface-water supply samples where
it was detected was 0.56 yg/1; positive samples from finished ground
water supplies had a mean concentration of 2.1 yg/1, although the data
base for groundwater is much less extensive than for surface water.
The EPA STORET data presented previously in Table 4-4 indicate that most
quantified samples (14% were quantified) from ambient U.S. water supplies
were in the 1-10 yg/1 interval. From these data (Coniglio et jd. 1980,
U.S. EPA 1980b), one can make a rough approximation that about 20% of
the population may be exposed to 1,1,1-trichloroethane in their drinking
water at levels greater than 1 as/l, and in isolated cases subpopulations
may be exposed to levels greater than 10 yg/1. It should be noted that
this estimate of the size of the exposed population is at best a very
rough approximation since there is wide variation in the size of water
supplies, and it is not likely that the available monitoring data for
-------
trichloroethanes constitute a representative sample, by size, of the
total U.S. water supply.
The above estimation would also indicate that the major portion of the
U.S. population, i.e., about 80%, might be exposed to 1,1,1-trichloro-
ethane In drinking water at levels below detection limits. Detection
limits vary considerably depending upon the survey, but it is inferred
from the data of Coniglio and coworkers (1980), the STORE! data (U.S.
EPA 1980b) and Brass (1981) that the detection limits range between
0.1 yg/1 and 1 yg/1 for most surveys.
Thus, for purposes of this study, it is estimated that some 20%
of the U.S. population may ingest greater than 2 yg/day of 1,1,1-
trichloroethane via drinking water, assuming ingestion of 2 liters of
drinking water per day (ICRP 1974). The remaining 80% of the population
would, therefore, ingest less than 2 yg/day in drinking water. These
values are given in Table 5-4.
A single study by McConnell e_t al. (1975) reported levels of
1,1,1-trichloroethane measured in various foods (see Table 4-7). These
data are from Great Britain and may not be representative of levels in
food in the U.S. Nevertheless, these data were utilized to estimate
the potential exposure to 1,1,1-trichloroethane from food. The quantity
of each food or food group normally consumed, as cited by the USDA (1980),
was used to estimate daily intake as shown in Table 5-4, The estimated
amount of 1,1,1-trichloroethane ingested in food could be perhaps
2.8 yg/day.
5.2.2.2 1,1.2-Trichloroethane
The monitoring data for the trichloroethanes in water distinguish
in some cases between the two isomers, but the data showing positive and
quantifiable amounts of 1,1,2-trichloroethane are few. Results of
available studies indicate that the isomer is not pervasive at concen-
trations above detection limits (VL.5 yg/1).
Coniglio et al. (1980) reported on findings for ground water supplies
in New Jersey, which indicated that median levels for both isomers
were less than 1 ig/1; the maximum level of 1,1,2-trichloroethane, however,
was over 100 yg/1 (actual values not given). Levels of the 1,1,2- isomer
in well water from Long Island's Nassau County were as high as 310 ug/1.
These maxima are thought to be very atypical of U.S. water supplies because
there is limited use of the 1,1,2- isomer, much of it in captive processes.
The materials balance for 1,1,2-trichloroethane also indicates that
relatively little is released into the environment (see Chapter 3.0).
No data are available concerning levels of 1,1,2,-trichloroethane
in food.
5-23
-------
5-2.3 Exposure through Inhalation
5.2.3.1 1,1, 1-Trichlo roe thane
Atmospheric monitoring data, provided in detail in Table 4-la,
indicate the ubiquitous presence of 1,1,1-trichloroethane in air.
Urban air clearly contains higher concentrations than most rural and
remote areas that have been monitored. Concentrations in air near
producers and users of 1,1,1-trichloroethane tend, to be higher than
in urban areas and show wide fluctuations.
In order to estimate inhalation absorption of trichloroethanes
a respiratory retention of 50% was assumed (Riihimaki and Pfaffli
1^78, Lapp etal. 1979). The breathing rate was taken to be 22.4
m /day (1.2 mj/hr for 16 hours falling to 0.4 m3/hr while asleep.)
(ICRP 1974). In the following discussion it will become evident that
inhalation absorption contributes the majority of the total daily dose
of 1,1,1-trichloroethane and thus proximity to major sources of air
emissions have been taken as a basis for depicting four comprehensive
exposure scenarios as follows:
1) Rural Remote - air concentration data for seven areas of the
United States considered to represent "background" (see Table 4-la)
average about 0.5 yg/m3. There is little variation, ranging from
a mean of 0.37 ug/mj for White Face Mountain, N.Y. to 0.598 ug/m3
for Point Arena, CA. The. coefficient of variation (- - x 100)
for all of these remote areas was only about 10%. Tout? the
average inhalation absorption in rural/remote areas of the U.S.
is estimated to be about 6 ug/day and may range from an average
of 4.1 ug/day to 6.7 ug/day depending upon local conditions.
2} Urban - air concentration data presented in Table 4-la indicated
that most urban air concentrations are considerably higher than
rural axr concentrations. The data for seven cities from the
survey by Singh et al. (1979,1980) is the most: recent - averaging
3.3 ug/m->. This value was taken as a representative mean urban
air concentration. The range of mean urban air concentrations of
J J .r-oroethane atsor near ground level from various U.S.
cities is from 0.55 ug/mj for Delaware City, DE to highs of
27 ug/mJ for Claremont, CA. A wide range of potential exposure
* by the high coeffi'ient °f variation of
about 60% for the air concentration data.
_ Thus, the typical inhalation absorption of urban dwellers is
estimated to be 37 ug/day and may range from 6 ug/day to 300 ug/day
depending upon the urban area. y
3) Near Producers and Users - air concentrations show extremely wide
fluctuations, probably caused by variations in emission rates and
local meteorological conditions. A representative mean could not
be estimated from the available data. As an approximation of a
5-24
-------
level to which this subpopulation could be exposed on a
continuous basis, the mean of the high values and mean of
the low values were taken, i.e., 1.8-200 ug/m3, giving an
estimated range of potential inhalation absorption of 20-
2200 ug/day. Estimates of inhalation absorption given by
Lapp et al.(1979) for persons living near user/manufacturing
sites generally fall within the range calculated here.
4) Occupational - a fourth scenario is presented for contrast,
Occupational exposures to 1,1,1-trichloroethane were analyzed
at the OSHA standard and over a range of observed concentra-
tions in the workplace in order to provide a basis for
comparison with the environmental exposure scenarios. The
standard set by OSHA for the 1,1,1-isomer is 350 ppm (1900
mg/m3) as a time-wighted-average (TWA) for the 40-hour
work week (NIOSH 1976). NIOSH (1976) reports that the air
levels in occupational settings range from 5.4 mg/m3 to
2200 mg/m3. The estimated absorbed dose via inhalation
at the TWA is 9,100 mg per 8-hr, work day.
One of the uses of 1,1,1-trichloroethane is as part of the
propellant gas in aerosol cans, especially those for paint products.
About 5,670 kkg/yr were estimated as actual atmospheric releases
from this application (Chapter 3.0). There are, at present, no
data to indicate levels of 1,1,1-trichloroethane in the air in the
immediate vicinity during or after the use of such aerosol cans.
Without such data, it is not possible to estimate actual exposure
levels. These exposures would presumably be short-term and would
affect only small non-occupational subpopulations.
The results of the calculations of exposure for each of the four
scenarios are summarized in Table 5-5.
5.2.3.2 1.1.2-Trichloroethane
Available monitoring data for 1,1,2-trichloroethane, which are
detailed in Table 4-lb, indicate that an average air concentration
in an urban environment is about 0.12 ug/m3. The highest value reported
was a mean of 0.23 ug/m3 in Riverside, CA. and the lowest reported 0.04
Ug/m for Oakland, CA. It is unclear how representative these cities
are for all U.S. cities since no other data were available. On
the basis of these data, the inhalation absorption of 1,1,2-trichloro-
ethane for urban inhabitants is estimated to average 1.3 ug/day and may
range from 0.45 ug/day to 2.6 ug/day. These results are presented in
Table 5-6.
5-25
-------
TABLE 5-5. ESTIMATED DATLY HUMAN EXPOSURE TO 1,1,1,-TRICIILOROETHANE
ROUTE
INGESTTON
Drinking Water
20% U.S. population
80% U.S. population
Food Stuffsb
Observed Concentration
Mean Range
Meat
Oils and Fats
Fruits and Vegetables
Bread
Teac
INHALATION**
Rural/Remote
Urban
Near User/Producer
Occupational
Percutaneous (Occupational)
Liquid (both hands)
Vapor
Exposure Rate or Intake
(fc/day)
Exposure
Typ Leal Range
_
-
^
_
—
—
-
(
0.5
3.3
-
1900
j_f
—
. — .---. .....i. — J.. ** — -^-
<1
(Mg/kg)
3-6
5-10
1-4
2
7
,m/m3)
0.37-0.60
0.55-27
1.8-200
(mg/m )
5-2200
_
5-2200
2
2
(g/day)
207
8
343
62
28
(m3/day)
22.4
22.4
22.4
9.6
hrs./day
0.08-0.2
8
>2
<2
0.6-1.2
0.04-0.08
0.3-1.4
0.1
0.0006
(p g/day)
6 4.1-6.7
37 6-300
20-2200
(mg/day )
9100 24-10600
13-460
0.03-13
a) Based on selected data from Table 4-2.
b) Based on data from McConnell ejt al. 1975 (Table 4-7) and food consumption data from USDA (1980)
c) 20 grams tea leaves per 227 g tea was assumed.
d) Based on selected data from Table 4-la. A respiratory retention of about 50% was assumed (see text).
e) Based on findings of Riihimaki and Pfaffli (1978) and Stewart and Dodd (1964). Calculations discussed in text.
-------
TABLE 5-6. ESTIMATED DAILY HUMAN EXPOSURE TO 1,1,2-TRICHLOROETHANE
Exposure Rontie Observed Concentrations
01
N>
Mean Range
Ingestion Mg/1
Drinking Water
- Ground <1.0 <1-300 *a>
Foodstuff No data
3
Inhalation Mg/m
Urban Areas 0.12 0.04-0.23
Rural Areas No data
Typical Range
2 I/day - ND(<3)
2 I/day <2 <2-600
No data
22.4 m3/day 1.3 0.45-2.6
Data from New Jersey and Nassau County wells only. These data are not believed to be representative
of widespread conditions although no other data were found.
-------
5.2.4 Percutaneous_Exposure
5.2.4.1 1,1,1-Trichloroethane
Human experimental data demonstrated that percutaneous absorption
of both vapor and liquid 1,1,1-trichloroethane can occur, (see Section
5.1.1.2), although these exposures would occur primarily in occupa-
tional settings. The data of Riihimaki and Pfaffli (1978) indicate that
absorption of 1,1,1-trichloroethane vapor would be slow, even at high
concentrations. These authors found that at a concentration of 3,263 mg/m3,
an absorption rate of 2.1 mg/hr was observed for 1,1,1-trichloroethane
vapor across the total body surface (1.8 m^) of human volunteers. Utiliz-
ing the Riihimaki and Pfaffli (1978) data, a permeability factor of
0.0004 m3/(m2xhr) was calculated for human skin with 1,1,1-trichloro-
ethane vapor. [Absorption rate (mg/hr) » concentration (mg/m^) x surface
area (m2) x permeability (m^/m^ • hr)]. Utilizing this factor, the
absorption rate across the unprotected total body surface area at the
time-weighted average occupational standard of 1900 mg/m^ would be approxi-
mately 1.4 mg/hr or 11 mg/work day.
Dermal absorption of liquid 1,1,1-trichloroethane can be very
rapid because it dissolves the fat out of the skin aiaking the skin very
permeable. The experiments of Stewart and Dodd (1964) indicated that
immersion of both hands in 1,1,1-trichloroethane for 0.5 hour was
approximately equivalent in terms of absorbed dose to inhalation of
vapors at concentrations between 546 pg/m3 and 7730 ug/m3. Assuming a 50%
respiratory retention (Riihimaki and Pfaffli 1978, Lapp e_t al. 1980)
and a respiratory rate of 0.6 m3/hr (sedentary rate) (ICRP 1974), the
initial absorption rate from both hands is estimated to be between
160-2300 mg/hr. If dermal absorption occurs in certain occupations,
it is thought to be short duration, sporadic, and to occur to a small
subpopulation of workers. Table 5-5 presents an estimate of potential
absorption of the 1,1,1- isomer in the occupational setting for compara-
tive purposes.
5.2.4.2 1,1,2-Trichloroethane
Percutaneous absorption of either vapor or liquid 1,1,2-trichloro-
ethane presumably could occur to approximately the ssame extent as for
the 1,1,1- isomer. More limited use of the 1,1,2- Isomer and a much
lower TWA (10 ppm or 54 mg/m3) imply that occupational absorption
via the dermal route is not likely to occur to a significant degree.
5-28
-------
5.2.5 Total Exposure Scenarios
5.2.5.1 1,1, 1-Trichloroe thane
Table 5-7 estimates total absorption of 1,1,1-trichloroethane for
three general population scenarios and for an occupational scenario.
For the urban scenario, inhalation is the major route of exposure to
1,1,1-trichloroethane. As indicated in Tables 4-la and 5-5, the range
of concentrations and, therefore, of estimated daily absorbed dose, is
from 10 yg/day to 300 yg/day via inhalation alone. Approximately 74%
of the U.S. population (150,000,000 based on the 1970 census) is
estimated to be exposed at these levels (U.S. Bureau of the Census 1979).
For the rural scenario, inhalation is still the major exposure route,
although ingestion is estimated to contribute about one-third of the
total estimated exposure of 9 yg/day. This level of exposure is
estimated to apply to 26% of the U.S. population or 54 million people.
For the scenario considering persons who live and work near sites
where 1,1,1-trichloroethane is manufactured or used, the range of
potential total absorption was estimated to be between 20 yg/day and
2200 yg/day. Inhalation was again the predominant exposure route.
The size of this subpopulation was not estimated, although it could be
quite large given the widely distributed use of 1,1,1-trichloroethane
as a degreasing agent.
In contrast, occupational exposure to 1,1,1-trichloroethane is
estimated to be at least one thousand times greater than in the urban
scenario. Again, inhalation absorption is probably the most significant
contributor to total daily dose, although percutaneous absorptio'n rn^y be
quite high for that small subpopulation of workers who use 1,1,1-trichloro-
ethane without appropriate protection for their hands. At the OSHA
belllOO »! r HPPm °I ^?° mg/m ' inhalation Absorption is estimated to
be 9100 mg per day. As discussed in Section 5.1 (see Table 5-1) at
least 602, and as much as 98%, may be rapidly excreted unchanged 'via
exp ir ed air.
5.2.5.2 1,1, 2-Trichloroethane
in TaM detail6^ in Tables 4~lb a*d 4-2 have been summarized
in Table 5-6. Exposure of populations through contaminated water
^n^- %r! bly/Stimated °n the basis of the Bailable data. Certain
contaminated ground sources, notably in New Jersey and Long Island
suggest that for an unknown subpopulation, exposure through drinking
water may be significant.
Consistent with the monitoring data for the 1,1,1- isomer and with
considerations of the fate of the trichloroethanes inhalation is
thought to be the major daily exposure route. On the basis of rather
5-29
-------
TABLE 5-7 TOTAL EXPOSURE SCENARIOS FOR 1,1,1-TRICHLOROETHANE
Estimated Daily Absorbed Dose (Ranee)
Route ^ban Rural Near Sites Occupational
Ingestion
Water <2yg <2yg <2yg <2yg
Foodstuff 3yg 3yg 3yg 3ug
Inhalation 37 (6-300)yg 6 (4-7)yg - (20-2200)ug - (24-10,600)n
Percutaneous - - - 0.03-460 mg
Total 42 (ll-3C5)ug 11 (9-12)yg >25 (25-2205)ug - (27-11,000)u
5-30
-------
limited air monitoring data for some large cities, the average daily
absorbed dose from inhalation is estimated to be 1.3 yg/day, with a range
of 0.45-2.6 ug/day. Since the majority of urban inhabitants receive
their water from surface sources and the monitoring data available
suggest that the 1,1,2- isomer is not detectable in most surface
supplies, the total daily dose has been taken to be given by the
inhalation dose. This level of exposure may involve 74% of the
U.S. population or the 150,000,000 urban inhabitants (U.S. Bureau of
the Census 1979).
5-31
-------
REFERENCES
Adams, E.; Spencer, H. ; Rowe,V.; Irish, D. Vapor toxicicy of 1,1,1-
trichloroethane (methylchloroform) determined by experiments of laboratory
animals. AMA Arch. Ind. Hyg. Occup. Med. 1:225-236; 1950. (As cited in
MRI 1979, TSCA 1978).
Arthur D. Little, Inc. An integrated approach to exposure and risk
assessment. Draft Contract 68-01-3857. Washington, DC: Monitoring
and Data Support Division, U.S. EPA; 1980.
Arthur D. Little, Inc. Technology assessment and economic compact study
of OSHA regulations for tetrachloroethylene, trichloroetylene and
methylchloroform. Draft. Washington, DC: Occupational Safety and
Health Administration, U.S. Department of Labor; 1979.
Aviado, D.M. Preclinical pharmacology and toxicology of halogenated
solvents and propellants. Nat. Inst. Drug Abuse Res. Monogr. Ser.
15:154-184, 1977.
Aviado, D.M.; Zakhari, S. ; Simaan, J.A. ; Ulsamer, A.G. Methylchloroform
and trichloroethylene in the environment. L. Golbe.rg, ed. , CRC Press,
Cleveland, Ohio, pp 102; 1976. (As cited in MRI 1979, Aviado 1977).
Bass, M. Sudden sniffing death. J.A.M.A. 212:2175-2179; 1970. (As
cited in MRI 1979).
Brass, H. Final community water supply survey (CWSS) . Cincinnati, OH:
Office of Drinking Water, U.S. Environmental Protection Agency; 1981.
Caplan, Y.H.; Backer, R.C.; Whitaker, J.Q. 1,1,1-Trichloroethane .
report of a fatal intoxication. Clin. Toxicol. 9:69-74; 1976. (As
cited in IARC 1979).
Coniglio, W.A.; Miller, K. ; MacKeever, D. The occurrence of
organics in drinking water. Washington, DC.: Criteria and Standards
Division, U.S. Environmental Protection Agency; 1980.
Dornette, W. ; Jones, J. Clinical experiences with 1,1,1-trichloroethane:
A preliminary report of 50 anesthetic administrations. Anesth. Analg.
39:249-253; 1960. (As cited in MRI 1979, Aviado 1977).
Elovaara, E.; Hemminki, K. ; Vainio, H. Effects of methylene chloride,
trichloroethane, trichloroethylene, tetrachloroethylene and toluene on
the development of chick embryos. Toxicology 12:111-119; 1979.
Federal Register, Vol. 44, No. 52, Thursday, March 15, 1979, Appendix C,
Guidelines and Methodology Used in the Preparation of Health Effect
Assessment Chapter of the Consent Decree Water Criteria Documents.
Fukabori, S.; Nakaaki, K. ; Yonemoto, J.; Tada, 0. Induction of hepatic
drug metabolism in rats by methyl chloroform inhalation. J. Pharmacol.
Exp. Ther. 175:311-317; 1976. (As cited in HRI 1979).
Fukabori, S.; Nakaaki, K. ; Yonemoto, J.; Tada, 0. On the cutaneous
absorption of 1,1,1-trichloroethane. The J. of Science and Labour
53(l):89-95; 1977.
5-32
-------
Gamberale, F. ; Hultengren, M. Methylchloroform exposure. II. Pyscho-
physiological functions. Work Environ. Health 10:82-92- 1973 (L
cited in IARC 1977, EPA 1979, MRI 1979).
SrJn?"' J;;cPe,tty> C ^^ Health' 13:226; 1971' "As cited tn
°f 1'1»1- trichloroethane. Studv
5-33
-------
Jakobson, I.; Holmberg, B.; Wahlberg, J.E. Variations in the blood
concentrations of 1,1,2-trichloroethane by percutaneous absorption and
other routes of administration in the guinea pig. Acta pharmacol.
et toxicol. 41:497-506; 1977.
Klaasen, C.; Plaa, G. Relative effects of various chlorinated hydro-
carbons on liver and kidney function in dogs. Toxicol. Appl. Pharmacol.
10:119-131; 1967. (As cited in MRI 1979, Aviado 1977, EPA 1979.)
Klaasen, C.D.; Plaa, G.L. Relative effects of various chlorinated hydro-
carbons on liver and kidney function in mice. Toxicol. Appl. Pharmacol.
9:139-151; 1966. (As cited in Aviado 1977, MRI 1979, EPA 1979, IARC 1979.)
Kover, F.D. Preliminary study of selected potential environmental
contaminants. Optical brighteners, methyl chloroform, trichloroethylene,
and ion exchange resins. NTIS-Rep. PB-243910. Natl. Tech. Inf. Serv.,
Springfield, Virginia; 1975. (As cited in USEPA 1930.)
Kramer, C.G.; Ott, M.G.; Fulkerson, J.E.; Hicks, N. Health of workers
exposed to 1,1,1-trichloroethane: A matched-pair study. Arch. Environ.
Health 33(6):331-342; 1978.
Kronevi, T.; Wahlberg, J.; Holmberg, B. Morphological lesions in guinea
pigs during skin exposure to 1,1,2-trichloroethane. Acta pharmacol. et
toxicol. 41:298-305; 1977.
Lapp, T.W.; Hernon, B.L.; Mumma, C.E.; Tippit, A.D.; Reisdorf, R.P.
An assessment of the need for limitations on trichloroethylene, methyl
chloroform, and perchloroethylene. Washington, DC: Office of Toxic
Substances, U.S. Environmental Protection Agency; 1979.
Larsby, B.; Tham, R.; Odkvist, L.M.; Norlander, B.; Hyden, D.; Aschan, G.;
Rubin, A. Exposure of rabbits to methylchloroform. Vestibular dis-
turbances correlated to blood and cerebrospinal fluid levels. Int.
Arch. Occup. Environ. Hlth. 41:7-15; 1978.
MacEwen, J.D.; Vernot, E.H. The biologic effect of continuous inhalation
exposure of 1,1,1-trichloroethane (methyl chloroform) on animals; AMRL-
TR-74-78; Toxic hazards research unit annual technical report, Wright-
Patterson AFB, Aerospace Med. Res. Lab., NIOSH-NASA (joint study).
pp 81-90; 1974. (As cited in MRI 1979.)
Maroni, M.; Bulgheroni, C.; Cassitto, M.G.; Merluzzi, F.; Gilioli, R.;
Foa, V. A clinical neurophysiological and behavioral study of female
workers exposed to 1,1,1-trichloroethane. Scand. J. Work and Health
3:16-22; 1977.
5-34
-------
McConnell.G.; Ferguson, D.M.; Pearson, C.R. Chlorinated hydrocarbons
and the environment. Endeavor 34(12)13-18; 1975.
McNutt, M.; Amster, R.; McConnell, E.; Morris, F. Hepatic lesions in
mice after continuous inhalation exposure to 1,1,1-trichloroethane.
Lab. Invest. 32:642-654; 1975. (As cited in URC 1979, MRI 1979.)
Midwest Research Institute (MRI). As assessment of the need for limitations
on trichloroethylene, methylchloroform, and perchloroethylene. Draft
final report. EPA Contract No. 68-01-4121. MRI Project No. 4276-L:
Office of Toxic Substances, U.S. Environmental Protection Agency,
Washington, D.C.; 1979. pp 5-133 - 5-225.
Monster, A.C. Difference in uptake, elimination, metabolism in exposure
to trichloroethylene, 1,1,1-trichloroethane and tetrachloroethylene.
Int. Arch. Environ. Health 42:311-317; 1979.
Monster, A.C.; Boersma, G.; Steenweg, H. Kinetics of 1,1,1-trichloroethane
in volunteers: influence of exposure concentration and workload. Int.
Arch. Occup. Environ. Health 42:293-301; 1979.
Morgan, A.; _e_t al. Absorption of halogenated hydrocarbons and their
excretion in breath using chlorine-38 tracer techniques. Ann. Occup.
Hyg. 15:273; 1972. (As cited in USEPA 1980a.)
National Cancer Institute (NCI). Bioassay of 1,1,1-trichloroethane for
possible carcinogenicity. Carcinogenesis. Technical Report Series No. 3.
CAS no. 71-55-6. NCI-CG-TR-3. U.S. Department of Health Education and
Welfare. Public Health Service. National Institutes of Health.
Publication No. (NIH) 77-303; 1977. 70 p.
National Cancer Institute (NCI). Bioassay of 1,1,2-trichloroethane for
possible carcinogenicity. Carcinogenesis. Technical Report Series NO. 74.
CAS No. 79-00-5. NCI-CG-TR-74. U.S. Department of Health Education and
Welfare. Public Health Services. National Institutes of Health. Publication
No. (NIH) 78-1324; 1978. 48 p.
National Institute for Occupational Safety and Health (NIOSH). Criteria for
recommended standard—occupational exposure to 1,1,1-trichloroethane
(methyl chloroform). NIOSH, U.S. Department of HEW, DHEW Publication No.
NIOSH 76-184. 179 pp.; 1976. (As cited in MRI 1979.)
Parker, J.C.; Casey, G.E.; Bahlman, L.J.; Leidel, N.A.; Rose, D.; Stein,
H.P. Chloroethanes: review of toxicity. NIOSH Current Intelligence
Bulletin #27. Am. Ind. Hyg. Assoc. J. 40:A-46-A-60; 1979.
5-35
a
-------
Plaa, G.; Evans, E.; Hine, C. Relative hepatotoxicity of seven
halogenated hydrocarbons. J. Phannacol. Exp. Ther. 123:224-229- 1958
(As cited in Aviado 1977, IARC 1979). '
Plaa, G.L.; Larson, R.E. Relative nephrotoxic properties of chlorinated
7n?a^'//ethfo! = and,ethylene derivatives in mice. Toxicol. Appl. Pharmacol.
/U;: 37-44; 1965. (As cited in MRI 1979, IARC 1979).
Prendergast, J.; Jones, R.A.; Jenkins, L. Jr.; Siegel, J. Effects on
experimental animals of long-term inhalation of trlchloroethylene
carbon tetrachloride, 1,1,1-trichloroethane, dichlorodifluoromethane, and
1,1-dichloroethylene. Toxicol. Appl. Pharmacol. 10:270-289- 1967
(As cited in MRI 1979.) '
Price, P.J.; Hassett, C.M.; Mansfield, J.I. Transforming activities of
trlchloroethylene and proposed industrial adternatives. In Vitro
14:290-293; 1978 (As cited in EPA 1979).
Quast, J.F.; Rampy, L.W.; Balmer, M.F.; Leong, B.D.J.; Gehring, P.J.
Toxicological and carcinogenic evaluation of a 1,1,1-trichloroethane
formulation by chronic inhalation in rats. Available from Dow Chemical Co.
Midland, Michigan 48640. Preprint written in 1979; 1978. (As cited in
MRI 1979.)
Rannug, U.; Sundvall, A.; Ramel, C. The mutagenic effect of 1,2-dichloro-
ethane on Salmonella tvphimurium. I. Activation through conjugation with
glutathion in vitro. Chem. biol. Interact. 20:1-16; 1978. (As cited
fay IARC 1979.)
Rampy, L.W.; Quast, J.F.; Leong, B.K.J.; Gehring, P.J. Results of
long-term inhalation toxicity studies on rats of 1,1,1-trichloroethane
and perchloroethylene formulations (Abstract) In: Proceedings of the
International Congress of Toxicology, Toronto, Canada, 1977, p. 27-
1977. (As cited in IARC 1979.)
Registry of Toxic Effects of Chemical Substances (RTECS); On line computer
search: 1,1,1-trichloroethane; 1,1,2-trichloroethane; July 1980.
Riihimaki, V.; Pfaffli, P. Percutaneous absorption of solvent vapors
in man. Scand. j. Work Environ, and Health 4:73-85; 1978.
Schwetz, B.A.; Leong, B.K.J.; Gehring, P.J. The effect of maternally
inhaled trichloroethylene, perchloroethylene, methyl chloroform, and
methylene chloride on embryonal and fetal development in mice and rats.
Toxicology and Applied Pharmacology 32:84-96; 1975.
Simmon, V.K.; Kauhanen, K.; Tardiff, R.G. Mutagenic activity of chemicals
identified in drinking water. In: Scott, D.; Bridges, B.A.; Sobels, F.H.,
eds., Progress in Genetic Toxicology, Amsterdam, Elsevier/North Holland
pp. 249-258; 1977.
Singh, H.B.; Salas, L.J.; Smith, A.; Shigeish, H. "Atmospheric measure-
ments of selected toxic organic chemicals, First Year Interim Report,"
Research Triangle Park, NC: Environmental Sciences Research Laboratory,
U.S. Environmental Protection Agency; 1979.
5-36
-------
Singh, H.B.; Salas, L.J.; Smith, A,; Shigeish, H. Selected hazardous
organic chemicals, Draft Second Year Interim Report; 1980.
Stahl, C.J.; Fatteh, A.V.; Dominguez, A.M. Trichloroethane poisoning:
observations on the pathology and toxicology in six fatal cases. J.
Forensic Sci. Soc. 14:393-397; 1969. (As cited in IARC 1979, MRI 1979,
TSAC 1978, EPA 1979.)
Stewart, R.D. Toxicology of 1,1,1-trichloroethane. Ann. Occup. Hyg.
11: 71-79; 1968. (As cited in MRI 1979).
Stewart, R.D.; Andrews, J.T. Acute intoxication with methyl chloroform.
J.A.M.A. 195:904-906; 1966. (As cited in MRI 1979, Aviado 1977.)
Stewart, R.D.; Dodd, H.C. Absorption of carbon tetrachloride, trichloro-
ethylene, tetrachloroethylene, methyl chloride and 1,1,1-trichloroethane
through the human skin. Am. Ind. Assoc. J. 25:439-446; 1964. (As cited
in MRI 1979, EPA 1979).
Stewart, R.D.; Gay, H.H.; Erley, D.; Hake, C.; Schaffer, A. Human
exposure to 1,1,1-trichloroethane vapor: relationship of expired air
and blood concentrations to exposure and toxicity. Amer. Ind. Hyg.
Assoc. J. 22:252-262; 1961. (As cited in MRI 1979, EPA 1979.)
Stewart, R.D.; Gay, H.H.; Schaffer, A.W.; Erley, D.S.; Rowe, V.K.
Experimental human exposure to methyl chloroform vapor. Arch. Environ.
Health 19:467-474; 1969. (As cited in MRI 1979.)
Stewart, R.D.; Hake, C.L.; Wu, A.; Graff, A.; Forster, H.V.; Lebrun, A.J.;
Newton, P.E.; Soto, R.J. 1,1,1-trichloroethane—development of a biologic
standard for the worker by breath analysis. Report No. NIOSH-MCOW-ENVM-
1,1,1-1-75-4. University of Wisconsin Medical College, Department of
Environmental Medicine, Wisconsin. 102 pp; 1975. (As cited in EPA 1979
MRI 1979). •
Torkelson, T.R.; Oyen, F.; McCollister, D.; Rowe, V. Toxicity of 1,1,1-
trichloroethane as determined on laboratory animals and human subjects.
Am. Ind. Hyg. Assn. J. 19:353-362; 1958. (As cited in Aviado 1977, MEI 1979.)
Travers, H. Death from 1,1,1-trichloroethane abuse: Case report. Mil.
Med. 139:889-893; 1974. (As cited in Aviado 1977).
Tsapko, V.G.; Rappoport, H.B. Effect of methylchloroform vapors on
animals. Farmakol. Toksikol. (KIEV) 7:149; 1972. (As cited in USEPA 1980.)
TSCA Interagency Testing Committee, Washington, D.C. Second report of the
TSCA Interagency Testing Committee to the Administrator, Environmental
Protection Agency and Information Dossiers on Substances Designated.
1,1,1-trichloroethane; 1978. pp VIII-3 - VIII-26. U.S. Department of
Commerce National Technical Information Service. No. PB-285-439.
Tsurata, H. Ind. Health 13:227; 1975. (As cited in Tsurata 1977.)
5-37
-------
Tsurata, H. Percutaneous absorption of organic solvents. 2) A method
for measuring the penetration rate of chlorinated solvents through
excised rat skin. Industrial Health 15:131-139; 1977.
U.S. Bureau of the Census. Population and land area of urbanized areas
for the U.S.; 1970 and 1960. Washington, D.C.; U.S. Department of
Commerce. April, 1979.
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 1977-73, Preliminary Report No. 2. Science and
Education Administration, Washington, D.C.; 1980.
U.S. Environmental Protection Agency (USEPA) . Ambient water quality
criteria for chlorinated ethanes. Washington, D.C.: Criteria and
Standards division, Office of Water Regulations and. Standards; 1980a.
U.S. Environmental Protection Agency (U.S. EPA). STORET. Washington
DC: Monitoring and Data Support Division. Office of Water Regulations
and Standards, U.S. Environmental Protection Agency; 1980b.
Van Dyke, R.A. Dechlorination mechanisms of chlorinated olefins.
Environmental Health Perspectives 21:121-124; 1977,,
Wahlberg, J.E.; Boman, A. Comparative percutaneous toxicity of ten
Walter, P.; e£ al.. Chlorinated hydrocarbon toxicity (1,1,1-trichloroethane,
trichloroethylene, and tetrachloroethylene) : a monograph. PB Rep.
PB-257185. Natl. Tech. Inf. Serv. , Springfield, Virginia; 1976. (As
cited in USEPA 1980.)
Yllner, S. Metabolism of l,l,2-trichloroethane-l,2-14C in the mouse
Acta. Pharmacol. Toxicol. 30:248-256; 1971. (As cited by EPA 1979,
IARC 1979) .
5-38
-------
6.0 EFFECTS AND EXPOSURE—NON-HUMAN BIOTA
6.1 EFFECTS ON BIOTA
This section provides information concerning the levels of tri-
chloroethanes that cause mortality or disrupt physiological functions
and processes in aquatic organisms. Toxicity information for the tri-
chloroethanes is limited and includes data for only four freshwater
and three marine species. Only one study on chronic effects was
available.
Both 1,1,1-trichloroethane and 1,1,2-trichloroethane are liquids
in the ambient temperature range and are soluble enough in water to be
of potential concern as water pollutants. No information was available
on the environmental factors that may influence toxicity.
6.1.1 Freshwater Species
Acute toxicity levels in freshwater organisms were determined for
bluegill (Lepomis macrochirus). Daphnia magna, fathead minnows, and the
alga Selenastrum capricomutum. The lowest concentration at which
lethal effects occurred was 18.0 mg/1 of 1,1,2-trichloroethane in
Daphnia. Toxicity data for freshwater species are presented in Table
6-1. The highest concentration tested, 669 mg/1, did not affect the
algae (Selenastrum). A chronic value of 0.4 mg/1 1,1,2-trichloroethane
was determined for the fathead minnow in embryo-larval tests (U.S. EPA
1980). No other chronic data were available.
6.1.2 Saltwater Species
The acute toxicity data base for 1,1,1-trichloroethane to saltwater
to organisms is limited to the sheepshead minnow, mysid shrimp, the
algae Skeletonema costatum. and barnacle larvae (Table 6-2). No data
on toxicity of 1,1,2-trichloroethane to marine species were available.
The effects of salinity, temperature, or other water characteristics
are also unknown. The 1,1,1-isomer was not toxic to Skeletonema at
the highest test concentration.
6.1.3 Phytotoxicity
The toxicity of 1,1,1-trichloroetuane to the green freshwater algae
Selenastrum capricomutum and the saltwater algae Skeletonema costatum
were tested, using chlorophyll and a cell number as indicators of growth.
Both species were relatively tolerant of the compound at the levels
tested. No acute effects were observed at the highest concentrations
tested, 669 mg/1, for either S. capricomutum or S. costatum (U.S. EPA
1980). No data are available on the effects of trichloroethanes on
vascular plants.
6-1
-------
TABLE 6-1. ACUTE TOXICITY OF 1,1,1- AND 1,1,2-TRICHLOROETHANE
FOR FRESHWATER SPECIES
96-hr
Species Isomer
Fathead minnow 1,1,1-
Pimephales promelas 1,1,2-
Bluegill 1,1,1-
Lepomis macrochirus 1,1,2-
LC (mg/1) Reference
52.8 (FT)1 105. 0(S)2 Alexander _e_t al
81.7 U.S. EPA (1980)
69.7 U.S. EPA (1978)
40.2 U.S. EPA (1978)
Cladoceran
Daphnia magna
1,1,2-
43.0
Adema (1978)
Species
TABLE 6-2. ACUTE TOXICITY OF 1,1,1-TRICHLOROETHANE
FOR SALTWATER SPECIES
96-hr
LC5Q(mg/l) Reference
Mysid Shrimp
Mysidopsis bahia
31.2 mg/1
U.S. EPA (1978)
Sheepshead minnow
Cyrpinodon variegatus
70 mg/1
U.S. EPA (1978)
Barnacle larva
Flominius modestus
7.5 mg/1
U.S. EPA (1978)
6-2
-------
6.1.4 Biological Fate
The high fat solubility and low chemical reactivity of 1,1,1-tri-
?« «f?«?a?e tfldS " °a^e bioconcentration; however, this tendency
is offset by the compound's high vapor pressure (100 mm at 20°C)
and resultant volatility. Neither of the trichloroethanes bioaccumulate
strongly; a steady-state bioconcentration factor of 9 for 1 1 1-tri-
chloroethane was measured for Bluegill. Based on the octanolI water
partition coefficient of 117, a BCF of 22 was estimated for 1,1,2-tri-
chloroethane (U.S. EPA 1978,1980).
In field experiments where 1,1,1-trichloroethane was detected at
0.5 jig/1 in water, fish concentrations were found up to 100 times the
concentration in water. No evidence indicated accumulation through
food chains, however. Algae have been found to accumulate 1,1,1-tri-
4-K inn ft W lfi^ range, at bioconcentration factors less
labnJLn, K^— *%' 1979)' SeCti°n 4'3-3'4 discusses the results of
laboratory biodegradation tests on the trichloroethanes. No natural
biodegradation of the trichloroethanes has been demonstrated.
6.1.5 Conclusions
The lowest level at which adverse effects to aquatic organisms
have been experimentally determined for the trichloroethanes is 7.5
mg/1 for barnacle larvae. The most sensitive fish species tested is
the Bluegill (69.7 mg/1 for 1,1,1-trichloroethane; 40?2 mg/1 "or 1 1 2-
in thfrangeTl'mg^trSf'7 T^* ^ ^^ ^ inver^br^^s ««e
chloroethanes/ N^acute effeSs^n a^gae were obseJverin'tes't'con-1"
centrations up to 670 mg/1.
6.2 EXPOSURE OF BIOTA
water^^^viilabirfrom1^613 °f 1>1!1-trichloroethane in nondrinking
sites upstream and dnJ!=4fIf^J!^!1.!3; ,Bftte^1f, (1977? m°nitored
e pstdd e
facturers' d^ch downstream !rom fiv« 1,1,1-trichloroethane manu-
facturers discharge points and at the outfall pipes. In general
es.
the results show that the average concentration found in
11
waters
ecforne
n^' ,.;?,* W h an 3Verage °f 132 ug/1 (5° m upstream of the
plant s outfall). Downstream of the plants, concentrations of 1,1, J!
tnchloroethane were higher than those upstream in all cases with
average concentrations ranging from a low of 0.8 ug/1 to" high value
of 169 ug/1. Battelle also sampled a user site, at which 1 1 l-tri^
chloroethane is used for metal cleaning operations. The highest con-
" B
6-3
-------
The University of Illinois has conducted a study to detect 1,1,1-
trichloroethane in surface water at different sites in the United States.
Of the 204 sites sampled, 95% showed less than 6 ug/1. Approximately
75% of the sites sampled showed
-------
REFERENCES
Alexander, H.C. Toxicity of perchloroethylene, trichloroethylene,
1,1,1-trichloroethane, and methylene chloride to fathead minnows.
Bull. Environ. Contain. Toxicol. 20:344; 1978.
Battelle Columbus Laboratories. Determination and evaluation of environ-
mental levels of methyl chloroform and trichloroethylene. EPA 560/16-
77-030.Columbus, OH: U.S. Environmental Protection Agency; 1977.
Lapp, T.W.; Herndon, B.L.; Mumma, C.E.; Tippit, A.D.; Reisdorf, R.B.
An assessment of the need for limitations on trichloroethylene, methyl
chloroform, and perchloroethylene. Washington, DC : Office of Toxic
Substances, U.S. Environmental Protection Agency; 1979.
National Science Foundation. Second Report of the TSCA Interagency
Testing Committee to the Administrator, Environmental Protection Agency,
and Information Dossiers on Substances Designated. Washington, DC
National Science Foundation; 1978.
U.S. Environmental Protection Agency (U.S. EPA) In depth studies on
health and environmental impacts of selected water pollutants. EPA
68-01-4646 Washington, DC : U.S. Environmental Protection Agency;
1972.
U.S. Environmental Protection Agency (U.S. EPA) Ambient Water Quality
Criteria Document for Chlorinated Ethanes. EPA 400/5-80-02; Washington,
DC : Office of Water Planning and Standards, U.S. Environmental Pro-
tection Agency; 1980.
6-5
-------
7.0 RISK CONSIDERATIONS
7.1 RISKS TO HUMANS
7.1.1 1,1,1-Trichloroe thane
The compound 1,1,1-trichloroethane does not appear to present
carcinogenic risks based on data avialable at this time. In addition, no
positive mammalian mutagenic or teratogenic effects have been demonstrated
However, if exposure levels are high enough, acute or chronic toxic
effects may be not.ed. An acceptable daily intake (ADI) of 37.5 mg/day
has been estimated from findings of reduced survival in rats (see
5.1.4.1). Estimated exposures for urban and rural exposed populations
are considerably lower than the estimated ADI. Only the estimated
absorption by the occupationally exposed population is in the range of
the ADI.
Exposure Scenario Estimated Exposure (absorbed dose)
Urban Exposure 42 yg/day
Rural Exposure 11 yg/day ADI: 37.5 mg/day
Near Sites 25-2,200 yg/day
Occupational 27-11,000 mg/day
Consequent!*7, urban and rural populations and populations near user and
manufacturing sites appear not to be at risk from chronic exposure to
1,1,1-trichloroethane. Urban exposures are more than 500 times lower
than the ADI, which has a safety factor of 1000 included. Rural
exposures are 4000 tines lower than the ADI. Some of the 130,000 occu-
pationally exposed individuals might be subject to adverse toxic effects
from 1,1,1-trichloroethane since their estimated exposure levels are
similar to the estimated ADI for 1,1,1-trichloroethane.
7.1.2 1,1,2-Trichloroethane
Because of very limited monitoring data and the consequent limited
exposure estimates developed in Chapter 5.0, only very tentative risk
predictions can be made regarding 1,1,2-trichloroethane. For the urban
population, the average daily exposure from inhalation alone was estimated
7-1
-------
to be 1.3 ug/day. Table 7-1 presents the estimated excess lifetime
cancers per million exposed population at this daily dose using four
risk extrapolation models. If this daily dose of 1,1,2-trichloroethane
can be taken as representative of that experienced by the urban popula-
tion (estimated to be 150 million), the incidence of excess lifetime
cancers in this population is estimated to be between 1.5 and 150 (i.e.,
150 x 0.01 and 150 x 1).
A small subpopulation may be exposed to much higher levels via
contaminated drinking water from certain groundwater sources. The size
of this population has not been estimated. The range of excess lifetime
cancers per million persons exposed to a daily lifetime dose of 0,6 mg/day
in this manner is estimated from the four extrapolation models to be
between 6 and 1,350. This level of exposure is thought to be extremely
atypical, even though monitoring data are limited.
There is considerable uncertainty associated with the estimates in
Table 7-1, as considerable controversy exists 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 calculations, the
results shown in Table 7-1 most likely overestimate the actual risk to
humans.
7.2 RISK TO AQUATIC BIOTA
The toxicity data base for 1,1,1- and 1,1,2-trichloroethane is
limited to one invertebrate fish and algal species for both fresh and
salt water. The lowest level at which adverse effects to aquatic
organisms have been detected in the laboratory is 7.5 mg/1 for salt water
barnacle larvae. The most sensitive fish species tested is the bluegill
(69..7 mg/1 for 1,1,1-trichloroe thane; 40.2 mg/1 for 1,1,2-trichloro-
ethane) . All toxicity values for fish and invertebrates ranged from
1.0 mg/1 to 100 mg/1. Neither of the trichloroethanes bioaccumulated
strongly; a bioconcentration factor of 9 was measured for 1,1,1-tri-
chloroethane (bluegill Lepomis macrochirus), and 22 was estimated for
1,1,2-trichloroethane.
The monitoring data indicate that the concentrations found
in most major river basin samples and near production and user sites
were in the low ug/1 range. The highest reported 1,,1,1-trichloroethane
level, detected near a manufacturing site, was 169 yg/1. Although no
known fish kills or other short-term high concentrations of trichloro-
ethanes have been reported, the possible episodic occurrence of levels
of trichloroethanes greater than 10 mg/1 would be of greater potential
concern than those levels reported heretofore in the monitoring data.
The water quality criteria for trichloroethanes (5300 ug/1 finished
7-2
-------
TABLE 7-1. ESTIMATED LIFETIME EXCESS PROBABILITY OF CANCER IN HUMANS DUE
TO ABSORPTION OF 1,1,2-TRICHLOROETHANE AT DOSES OF 0.6 mg/DAY
AND 1.3 ug/DAY ON THE BASIS OF FOUR EXTRAPOLATION MODELS3
Estimated Lifetime Excess Cancer Incidence
(per million exposed population)3
Risk Extrapolation Model
Absorbed Dose Linear Log-Probit Multistage
GAG
i
OJ
1.3 pg/day
0.6 mg/day
1
600
0.02
1350
0.01 1
6 480
dlfferlf ,lncldence is 8iven Per million population exposed, based on four
-y «'e application of
-------
water, 240 ug/1 surface water for 1,1,1-trichloroethane, 310 ug/1 for
1,1,2-trichloroethane) are not exceeded in ambient and effluent waters
in the United States, based on information reported in this document.
Exposure levels and known effects levels do not overlap. No acute or
chronic effects are known to occur at less than 400 ug/1. Risk to
aquatic organisms is, therefore, determined to be negligible on a wide-
spread chronic basis.
7-4
-------
APPENDIX A
NQT£ 1; Total VOC emission ratio from distillation v«nt in
n1^1uC^1PrideciDrOCeSS = °'19 9/kg of 1,1,1-trichloroethane produced =
0.19 kg/kkg. Given a 90% removal efficiency for aqueous scrubbers
where the VOC emissions are comprised solely of 1,1,1-trichloroethane,
then 0.17 kg were captured by control devices and sent to water per
I Kkg of 1,1,1-trichloroethane produced. The remainino 0.02 kg p°r
1 k that which *^ would
emit 0.01 kg VOC/1 kkg of 1,1,1-trichloroethane produced. Also the
n^fnr^f °^^°? ?f.t!l? d1st^^tion vent gases from a model
TJ^^J^^nlsS'J'i^n^?^?"8,1? ?5% 1.1.1-tnchloroethane.
.oj vu •<•'•>• Kg vuL,j/i KKg 1,1,1-trichloroethane produced =
^ 4; If 5% of the total VOC wastes are emitted to air
(derived in note 3), then 95% was captured by glycol pot control
devices and sent to landfill. If the air emission ratio =3 0035 kg
Jhen 8 kl°nr0enhnfln?,e?,;tted/1 ^ °f LU-trlchloroethane producld.
mPtHr ;? c9 J ?875 kkg were e™tted to the atmosphere when 25,000
of 11 1 tr^nr^ ™r* ^' ^efzre, the ratio of kilograms
• ° roethane captured by control devices per metric >on Of
^
as a semisolid waste
^•if-t-iii j j u • L r "-"—" """ ' ' •'- = ' cu "/ur-utdroon szream is
rl^n i high-boiling chlorinated hydrocarbons (polymers) are
removed as a waste stream. Alternatively, spent catalyst and
polymeric material may be removed in a single steS by d?stl"laMon
although this simplification is at the expense of 1 1 1-tr rhloro
ethane yields.* The overhead from this column ?s farther
catafys°C(l°ri'n£fl?n-cS f3V°red 1" the prssence of Frledel-Crafts
distillation temperatures). C "V ^ LerT1Perat-res (e.g.
A-l
-------
fractionated into two streams: (1) the lighter components primarily
vinyl chloride) hydrogen chloride, and (2) 1,1-dichloroethene and
1,1-dichloroethane. The lighter components are recycled to the
hydrochlorination reactor and the 1,1-dichloroethane product is
removed at the bottom stream.
1,1-Dichloroethane and chlorine react in the chlorination reactor
at temperatures between 350-400°C and pressures of 2-5 atmospheres.
To minimize by-product formation, low molar ratios (e.g., 0.35-0.70)
of chlorine to 1,1-dichloroethane are used. Table 33 in Appendix B
presents typical reactor effluents found in patent examples. Hydrogen
chloride and low boiling organic hydrocarbons are taken overhead.
This stream is normally used to supply the hydrogen chloride
requirements of this process although it may be used in other
oxy-chlorination processes. The bottom stream from the hydrogen
chloride column is further fractionated; 1,1,1-trichloroethane is
removed overhead and, after the addition of a stabilizer, is stored.
The bottom stream from the 1,1,1-trichloroethane column, comprised
largely of 1,1,2-trichloroethane, is used as a feedstock for
production of other chlorinated hydrocarbons (e.g., tetrachloroethane,
trichloroethene and vinylidene chloride).
i
NOTE 6: Chlorine and ethane react in an adiabatic reactor at
approximately 400°C and a pressure of 6 atm. with a residence time of
approximately 15 seconds. The reactor effluent (containing ethane,
ethene, vinyl chloride, ethylchloride, vinylidene chloride,
1,1-dichloroethane 1,2-dichloroethane, 1,1,1-trichloroethane,
1,1,2-trichloroethane, a small amount of other chlorinated
hydrocarbons, and hydrogen chloride) is quenched and cooled. The
bottom stream from the quench column, primarily tetrachloroethane and
hexachloroethane, is removed and the overhead product is fractionated
in the HC1 column into a chlorinated hydrocarbon stream and light
products stream -- ethane, ethene, and hydrogen chloride. The bottom
stream from the hydrogen chloride column is sent to the heavy-ends
column where it is separated into two streams. 1,2-Dichloroethane and
1,1,1-trichloroethane are removed as a bottom stream and are suitable
as feedstock for other chlorinated hydrocarbon processes. The
overhead product (principally 1,1,1-trichloroethane, vinyl chloride, .
vinylidene chloride, ethyl chloride, and 1,1-dichloroethane) is
.fractionated and 1,1,1-trichloroethane removed as a bottom product.
The overhead stream from the 1,1,1-trichloroethane column is fed to
the 1,1-dichloroethane column, where 1,1-dichloroethane is separated
as the bottom stream and recycled to the chlorination reactor.
Vinyl chloride, vinylidene chloride, and ethyl chloride (the
overhead stream) produced as a result of the direct chlorination of
ethene are fed to the hydrochlorination reactor, where vinyl chloride
and vinylidene chloride react with hydrogen chloride to form
A-2
-------
1,1-dichloroethane and 1,1,1-trichloroethane, respectively.
Hydrochlori nation reaction conditions are approximately 65°C and 4
atm. The reactor effluent stream is neutralized with ammonia. The
resulting complex (ammonium chloride - ferric chloride - ammonia) is
removed by the spent catalyst filter as a semi sol id waste. The
filtered hydrocarbon stream is fractionated further: the bottom
fraction (primarily 1,1,1-trichloroethane) is recycled to the
1,1,1-trichloroethane column, while the overhead stream (primarily
ethyl chloride and 1,1-dichloroethane) is recycled to the chlorination
reactor «
NOTE. .7:. ^. most cases the vent gases from direct chlorination
and oxy-ch ion nation processes are incinerated or catalytically
combusted to recover HC1 (EPA, 1975a; McPherson, et aj.. f 1979).
NOTE1: Calculations for quantity of 1,1,1-trichloroethane
contained in heavy ends wastes generated by vinyl chloride "balanced
Sn°?Q7A i(!ex- APpendl'*B> Fl'9Ure B3' for waste source ^cation), based
on 1978 1,2-dichloroethane production figures. '
In 1978, approximately 5.1 x 106 kkg of 1,2-dichloroethane
were produced by the "balanced process", ^here'approx Sat* 29 kg of
l I ^vh3?^ £6aVy end,S Ve?ctor tar*) were generated per 1 kkgof
1,2-dichloroethane produced, (Lunde, 1965).* Of the total solid
if
°ff kk1 ?Vyal,so11d waste' then; 1-48 x 10 kko (total wasted
kkg or 1,2-dichloroethane 5.1 x 10 1,2-dichloroethane
similarily applies; and 96% of 1.48 x 105 = 1.42 x 105 kka of
heavy ends wastes. According to an EPA report (1975a), approximately
0.8% (by weight) of vinyl chloride heavy ends was 1,1 i-trichloro-
w tMn'thl Href0re',1>13^kk? °f M.l-trlchloroethini were Stained
within the heavy ends. The lower end of the range, 20 kkg which
' p°f 1.1.1-tHchloroethane iX heavyendl was
Based on quantities of vinyl chloride product
1n 1978 (l'-e" 3'15 x 10^ kk and
oOQ08 kn nh -" ' x g and
0.0008 kkg of heavy ends were generated per 1 kkg of vinyl chloride
197^ ?fSn°£ ^52° kkE ?f heavy ends wastes were generated (EPA
i?hJn}' J 8% (t>^ WS1ght) Of the heav^ ends 1-s 1.1,1-trlchlorS-
cont^J f ahPPr°xlmats^ 20 kkg of 1,1,1-trichloroethane were
contained in the heavy ends wastes (EPA, 1975a).
*The figure representing 1978 1,2-dichloroethane production quantity
u at variance with data reported by the United States Inte^a?ionaf
8 Production ^ ^ intermediate
A-3
-------
NOTE
_9: Calculation of 1,1,1-trichloroethane contained in vinyl
\art^rtV» ^ ^ W»^ f^-\/% C * X«* i U.A Q ^ ~ .. 4 _ _ »JJ_ r\ ^ _ _ __!_
chloride reactor tars (see Figure S3 in Appendix 3 for waste source
location).
Based on 1978 1,2-dichloroethane production figures via the
"balanced process" (5.1 x 106 :
-------
Plant No
12119
12161
12204
12257
12311
12420
12439
12447
Influent (vo/1 )
110
3
27
110
17
110
251
720,000
Effluent (uq/1)
10
__
33
110
--
110
12
--
Flow rate (mad)
0.05
1.00
0.20
0.50
0.16
0.17
0.01
1.50
g/day
discharged
2
-0-
25
208
-0-
71
.45
-0-
NOTE 12: Based on EPA data (1980c), average POP^ influent
equalled 66 yg/1 ; effluent equalled 10 x 4 ug/l . Using a total
nationwide POTW flow of 10n I/day and 365 day/yr operation, 2,410
kkg of 1,1,1-Trichloroethane were contained in POTW influent; 380 kkg
in effluent. Based on raw sludge concentration of 30.8 ug/1 of
1,1,1-trichloroethane, and a total of 6 x 106 kkg dry sludge
generated per year which is 9555 water (by weight), 4 kkg of
1,1,1-trichloroethane were contained in land-destined POTW sludqe in
1978.
I/day x 66 yg/l x 365 day/year = 2,410 kkg/yr.
1011 I/day x 10 x 4 yg/l x 365 day /year = 380 kkg/yr.
.05 x = 6 x 106 x = 1.2 x 108 kkg 1.2 x lO^1 1
1.2 x 1011 1 x 30.8 yg/1 = 3.69 kkg
NOTE 13: Estimated production of 1,1,2-trichloroethane is
calculated as follows: 122,450 kkg 1,1-dichloroethylene/yr x 1.528
kkg 1,1,2-trichloroethane per kkg 1,1-dichloroethylene = 187,100 kkg
1 ,1 ,2-triehloroethane.
NOTE 14: Some 1,1,2-trichloroethane is discharged with the solid
waste generated during 1,2-dichloroethane production. Based on 1975
discharge rates: 2 kg of 1,1,2-trichloroethane discharged/kkg 1,2-di-
chloroethane produced by direct chlori nation x 2.08 x 10° kkg
1,2-dichloroethane produced = 4,000 kkg of 1,1,2-trichloroethane
generated and contained in solid waste.
A-5
-------
APPENDIX B
VINYL CHLORIDE MANUFACTURE VIA
THE BALANCED PROCESS
In addition to direct chlorination and oxy-chlori nation
processes, a pyrolysis (dehydrochlorination) process with attendant
purification process has been added. Current yields of dehydro-
ch onnation of 1,2-dichloroethane are on the order of 50 to 60*, with
selectivity to vinyl chloride of 96-99+% (McPnerson et al., 1979
Based on the current yield of 1,2-dichloroethane pyrolyTis" with
equimolar production of hydrogen chloride (and allowing for losses)
capacities of oxy-chlorination and direct chlorination processes are
approximately equal.
Crude 1,2-dichloroethane from the oxy-chlorination process is
!LW1Jh ? ll*tS,Cauf?1c *? remove h^dr°9en chloride and chlorinated
:rS? 5 ("?tably chloral) and dried. "Crude" 1,2-dichloroethane
from direct chlonnation may be combined with this stream and purified
for pyrolysis; alternatively 1 ,2-dichloroethane from direct
pure for pyrolysis without further
After dehydrochlorination, the reactor effluent is
quenched with 1,2-dichloroethane and separated by fractional
JiriJ]8^?" •" ;.ser1es of co1umns. Hydrogen chloride is recycled to
the oxy-chlorination reactor while recovered 1,2-dichloroethane is
returned to the 1,2-dichloroethane purification system.
8-1
-------
1AQLE B.I 1,1,1-Trlchloroolhano Releases to tho Environment from Vinyl Chloride Process In 1979
(kkg)
I'rodiict-r
(I n< uI inn)
(Jiuiil ity Produced
(x ll)3 kkl)t' ™»\ vent cor, eel Ion of
condensers condensers major leaks
none none refrigerated relri.j«raled detection and none
wcllt *«••<• correction of
condensers condensers major leaks
recycled none none refrigerated refrl.jeraled detect ion a, one
vtilt\ v«-'"1 correction of
condensers condensers major leaks
CO
ISJ
()iiantity Dispersed
rc
f|e
IIIC
I'S
CroUucur
(local ion)
^^J^l^l^!!_^.^^^ Waler^ Airland Wale. Air Un7 Wat^7,7, and""Ja« ^U,
IILHJ" J iiou'1 iieq'1 itco*1 111*11'* 1 ( ..., fi ii i . h i .
•" " * J IIL*I I J III'CJ /I II ikitji" £. I f It li i I I
"'9 oi !> nt'(|" ney" NA1 n«i|" neii1' (ft/
"l!y '' ' ""'J1 10 3 wey'1 neii'1 NA' ncu'1 ni-n'1 i?^
„
„
lul.il
"' "
»
«••
«/
-------
Table H.I (concluded)
a) Soo text and Noto 5 In Appendix A fur supplemental Information.
l») Assuming production quantities per plant are similar to those production quantities In 1978; and total production
quantity equal to difference between total quantity of 1,I,l-trIcliloroethane produced (321,830 kkg, Harris, 1980)
and quantity of I,I,l-trIchloroethane produced by direct chlorlnatlon of ethane (25,000 kkg, Phillips, I9fl0).
c) TC = 1,1,1-trlchloroolhano column vent; Fj = filter, IIEC - heavy ends column, PS = product storage; II »
handling; F2 = fugitive emissions; and W = wastewaters from steam stripping; vent losses of
1,1,l-trIchloroothano from light ends column and Intermediate storage (I.e., vents LEG and IS, Figure B.I) are
negligible (see Appendix A, note 2) are assumed to bo negligible (EPA, 1979); see Figure B1 for location of waste
s11os.
d) Kilograms of I,1,l-trIchloroothane dispersed to air (and water)/kkg produced from TC vent with aqueous scrubltors Is
0.02 (and 0.17), see nolo 1, Appendix A; fromF, vent sent to landfill Is 0.022, (Elkln, 1969); from IIEC vent
w11 limit controls Is <0.001; from PS, H, and F2 waste sources controlled with refrigerated vent condensers, or
through detection and correction of major leaks, are 0.103, 0.00 and 0.039 to air, respectively, and 0.58, 0.5 and
0 10 wator, respectively; and W discharges (uncontrolled) are
-------
TAUI t H.2 Environmental Keloasos from I, I, l-Trlchloroolhane Product Ion via Dlroct Cli lor I nation of FKicino Procoss, 19/U (kkg/yr)'
()
negl
neg
1
negf
6
'
ili
2
negf
13
it.
1
negl
negl
neg
Soiine: ll'A, lrils are %, H'j. ft5. IIS and 90*
respectively and already included in wasle cinission/dischargc/disposal ratios lie low.
e) Kdl i<» «f kilograms of 1 .1 .l-tricliloroethdiie dispersed to air and (water) per nioli ic Ion protluced from fC with
glycol (Hit conlrol device is O.OOJ'j (see Appendix A. nole 3) and (().()(,/); for uncontrolled ,nr ctuissions frmn
inc iner.il ion and releases to landfill from I, and I) comUined (assuming wasles lo he solely composed of
I ,1 ,1-lrichloroethane) is < 0.001; from US. l"j and II controlled hy ref rigei «led venl condensers are (I.Ojg, 0.103
and 0.0'JO to air. respecl ively and 0.221, O.WI and O.bl lo water, respectively; 1 2 a|r emissions (assuming to
l>e solely composed of 1 .1 ,1 -Iricfifuroelhane) controlled hy detection and correction of iiMjor leaks is 0.17U; and W
dischai ijes (unconlrol li.-d) is 0.001.
I ) He-jl Hjible, i.e.,
-------
Table 8.3 Vapor Phase Chlorination of 1,1-Dichloroethane
Product Stream, Mole %
Reaction Product Process Aa Process 3b
Vinyl Chloride
1,1-Dicnloroethane
1,1-Dichloroethene
1 , 1 , l-7richloroethane
1,1,2-Tricnloroethane
cis-l,2-Dichloroetnene
trans- 1,2-Oichloroetnene
Tetrachloroe thane
Tricnloroethene
Tetrachloroethene
Pentachloroethane
Unknown
22.7
4.6
34.9
25.9
1.]
2.7
2.3
1.5
2.9
0.2
0.1
1.2
19
38
6
36
1.5
0.5
0.5
w • v
__
^ —
— —
--
a) Tuoular nickel reactor 6.1 m x 6.35 mm ID. Reactor
conditions: 4500C, 3.55 atm., 1 sec. residence
time, molar ratio C12/1,1-dichloroethane: 0.7,
1,300 ppm C02 added to gaseous feed. Source-
Rideout and Monsell, 1980.
b) Glass reactor 0.75 m x 50 mm ID. Reactor
conditions: 4lqoc, 1 atm., 8 sec. residence
time, molar ratio C12/1,1-dichloroethane: 0.45.
Source: Campoell and Carruthers, 1972.
3-5
-------
Table 3.4 Industrial Classes Utilizing Degreasing
Source Type
Industrial decreasing
Metal furniture 25
Primary metals 33
Fabricated products 34
Nonelectric machinery 35
Electric-equipment 36
Transportation equipment 37
Instruments and clocks 38
Miscellaneous 39
Automotive3
Auto repair shops and garages ?5
Automotive dealers 55
Gasoline stations 55
Maintenance shops a
Textile plants (fabric scouring) 22
a) No applicable SIC for this category.
Source: EPA, 1979c.
3-5
-------
Table B.5 Industrial Wastewaters
Been Detected
in which 1,1,1-Trichloroethane Has
Industry
Adhesives/Sealants
Batteries
Coal Coating
Coal Mining
Electrical
Electroplating
Foundries
Iron/Steel
Laundries
Leather
Mechanical Products
Nonferrous Metals
Organic Chemicals
Organics/Plastics
Paint/Ink
Pesticides
Petroleum Refining
Pharmaceuticals
Phosphates
Photographic
POTWs
Printing/Publishing
Pulp/Paper
Rubber
Steam/Electric
Textiles
Timber
Number of Times
Detected
1
1
2
18
9
3
3
1
8
3
26
3
4
122
45
10
7
18
1
7
12
• 12
4
7
/
11
A 4
i
i
1
Number of Samples
Taken
•3
o
12
1 £.
249
-5C
O3
10
10
G.A.
01
4^1
HOi
56
^u
SI
01
7^
Oi>
173
723
QA
:?f
147
7fi
/O
0£
rD
-5 -3
jj
oc
CJ
40
*tv
109
no
yo
^ *7
o7
O>1
84
121
285
a) False positives
b) Not given.
are accepted.
Source: EPA, 1980b.
3-7
-------
Table 3.5 Industrial Uastewaters in which 1,1,2-Trichlcroethane has
Been Detected
Type of Wastewater
Adhesives/Sealants
Foundries
Iron/Steel
Laundries
Mechanical Products
Organics/Plastics
Paint/Ink
Petroleum Refining
Pharmaceuticals
Phosphates
Printing/Publishing
Timber
Number of Times
Detected3
1
1
2
2
7
22
8
7
4
1
1
1
Number of Samples
Taken
11
34
431
56
35
723
94
76
95
33
109
285
a) False positives are accepted
Source: EPA, 1980b.
B-3
-------
•j
I
£»
OvlH
i«vouo-
F,
IICI
iLOLUMU
CO-UMU
•n
rj
r
t
c
J]
J'. 1-S
u
DC
t
1.^?^!
. I Ctti.rtu.iUA.Yioj
—^ RAALTTUH-
^
r .. f.Ui^rr'^t
H
MISCELLANEOUS
WASTEWATER
V SOURCES
W
n«jure R.I Flow Diagram for 1.1,1-Trlchorocthane Production from Vinyl Chloride and Point and Nonpolnt Waste Sources3
footnoLos, next page
-------
CO
I
o
Figure B.I (concluded)
a) F2=Fugitive Emissions; TC=l,l,l-Trichloroethane Column Vent; Fi=Filter; HEC=lleavy Ends Column Vent;
LEC=Light Ends Column Vent; IS=Iritermediate Storage; PS-Product Storage; ll=llandling; and W^Miscellaneous
Wastewaters.
b) This stream is primarily composed of hydrogen chloride gas and low-boiling organic compounds and is
either used to supply the hydrogen chloride requirements of other chlorinated organic processes directly
or is purified and then used.
c) This bottom stream is composed primarily of 1,1,2-trichloroethane, which is kept in-house as a feed
material to other chlorinated organic processes.
Source: EPA, 1979a and 1979b.
-------
If I MCI
•>uni|»c*T»O«j
r*
pdlLORINATION
REACTOR
PRODUCT
RECOVERY
COLUMN
MISCELLANEOUS
WASTEWATER
SOURCES I
W
Figure B.2 Flow Diagram for 1,1,1-Trlchloroethane Production from Ft.hane anH Point anH Nonpoint Wast.. Sources^
a) F2^FugiLive omissions; Q=quench column vent; TC=l,l,l-trichloroothane column, 1,1-dichloroethane column and product
recovery column vents combined; Fi=fliter (catalyst) vent; RS=recycle storage vent; PS=product storage vent;
ll-handliny; and W-wastewaters from steam stripping.
b) Wdsl.es from the hydrogen chloride column overhead stream contains IICI, ethane and cthylene.
c) Wastes in (.his bottoms stream (primarily 1,2-dichloroethane and 1,1,2-trichloroethane) are transferred as feed to
other chlorinated hydrocarbon processes.
SourceT'Tl'A, 197'Jli and 197%.
-------
1IC1
Mil
co
i
Cl.
i »
IlKACTOIl
NuOII
1
-/WASIIHIl j
i
OXYCIJLOHINATION
nillKCT CIH.OHINATION
1UIAGT011
WASTH-
WATliIl
o
o
^.UGIIT
HNDS
O
o
Y
IIKAVY
ENDS
c/»
Ml
U»(J
>* rf
»-l -x
K
o
O
as
0.
en
O
O
1.2-DIGIIf.OIlOHTIIANH
Ui:CYGLH
Figure B.3 The Balanced Process for Vinyl Chloride Manufacture and Waste Sources
VINYL
CIILOIU
TARS
Source: EPA, 1979d.
-------
APPENDIX C
SOLVENT RECYCLE CALCULATIONS
Derivations of the total quantity of solvent used 1979, including
the amount recycled from the previous year is shown below; fable Cl
gives values used to derive variable y.
Quantity Recycled = x • quantity wasted x = .45 (45X of waste is
recycled)
Quantity Used = quantity virgin solvent + quantity recycled or
used = virgin solvent + .45 waste.
Quantity Wasted = y . quantity used or y (virgin solvent + .45 waste)
y « percent wasted solvent 68,630_ = 312
220,130
'Solving for waste:
Waste = y (virgin solvent) + .45 y waste
waste = 0.363 (virgin solvent)
Then:
Recycle * .45 waste
- (.45) (.363) (virgin solvent)
=0.162 virgin solvent
Also: Use = Virgin solvent + recycle
Use - 0.1404 Use = virgin solvent
Use = 1.16 (virgin solvent)
C-l
-------
Table C.I Waste Solvent Generation by Degreasi'ng Operation
Operation
Virgin
Solvent Used
Precent (%)Solvent Wasted
Solvent Wasted (kkg)
Cold Cleaning:
Manufacturing
Maintenance
23,310
29,700
40-60(50)
50-75(62.5)
11,660
18,560
Open-top vapor 106,280
degreasing
Conveyorized vapor
degreasing 45,530
Conveyorized
nonboi1i ng
20-25(22.5)
10-20(15)
a) Totals do not add due to rounding.
23,910
6,830
degreasing
Fabric scouring
Total3
. 12,070
3,260
220,130
40-60(50)
40-60(50)
6,040
1,630
68,630
C-2
-------
APPENDIX C
AMBIENT LEVELS OF 1,1,1-TRICHLOROETHANE
The compound 1,1,1-trichloroethane has been found in a broad
range of environmental redia such as: freshwaters, saltwaters, soils
sediments, and the atmosphere (Table Cl). The concentration of
1,1,1-trichloroethane in these media depends upon many factors (i.e.
location of sampling site and meteorological conditions). '
According to Singh and his associates (1977), 1,1,1-trichloro-
ethane is present in the environment due to the activities of mankind
and has no known natural source. Furthermore, the urban-rural
relationship of 1,1,1-trichloroethane is typical of an urban-sourced
pollutant (Table Cl), and in fact, the average concentration ratio of
rnnc!£6o1«M Durban and rural air is about 15 (Sinah et al. 1977).
Consequently, 1,1,1-tnchloroethane wastes found in the environment
are most likely released from man's activities.
C-3
-------
Table C.2 Concentrations of 1,1,1-Trichloroethane in Select Environmental Samples
Environment^ «ei:a Sarple Location5
U R
.„. .ar ..j^^. -.
PGTV5
Fresriv.ate- In'lusnt to
Tas »atsr »
Surfac* «ata' (law) •'
Seav.a-.5-- (coastal } /
Soil ^
Sediments (lake) •'
Air
Air ^
Air
Air /
Air
Air /
Air /
Air S
Air /
Kean Concentration (spt)
16,530
16.50C
22, COO
5u
140
530
430
S4
330
100(sl5)
-•<3CO
610
1,530
57
95
33
Infcrration Source
EPA, 1975
Sel'ar, Lic.itsnoa'g,
and Krone'', 137C
EPA, 1377C
E?A, 1377C
Sincn, Sa'as, ana
Cavar.agn, 1377
EPA, 1377C
EPA, 1977C
Sinah, Salas, ar.c
Cavanagn, 1977
Lillian, ft. aj... 15
1975
£?A, 1977c
Lillian, fj.. jj. , 19
"5
36f
75
Lillian, et. al.. 1975
Lillian, et. a]., 13
Russell and Shaacff,
1977
Russell and Shasof*.
1577
75
>} y « Ursan; S « Sural
b) Before Trei—.an:
C-4
-------
APPENDIX D
D.I ESTIMATION OF VOLATILIZATION FROM WATER
Volatilization from water can be estimated using procedures described
in the literature. The mathematical modeling of volatilization involves
interphase exchange coefficients that depend on the chemical and physical
properties of the chemical in question, the presence of other pollutants,
and the physical properties of the water body and atmosphere above it.
Basic factors controlling volatilization are solubility, molecular weight,
and the vapor pressure of the chemical and the nature of the air-water
interface through which the chemical must pass.
Volatilization estimates can be based on available laboratory and
environmental data. Because of the lack of data for most chemicals,
however, estimates of volatilization rates from surface waters on the
basis of mathematical data and laboratory measurements are necessarily
of unknown precision. Still, comparisons of experimental results with
theoretical predictions indicate that these predictive techniques generally
agree with actual processes within a factor of two or three in most cases.
The methods described below have been used to estimate volatilization
from natural surface water (see Section 4.12). The EXAMS Model has been
used to investigate behavior in natural surface water bodies, however,
this method was not used as input to EXAMS. An input parameter similar
to the reaeration coefficients described below is used in EXAMS to
estimate volatilization; this value was obtained elsewhere.
The following procedures can be used to estimate the volatilization
rate of a chemical. Minimum data required are:
• Chemical properties—vapor pressure, aqueous solubility,
molecular weight;
• Environmental characteristics—wind speed, current speed,
depth of water body;
(1) Find or estimate the Henry's Law constant H from:
H = P/S atm-m /mole
where P = vapor pressure, atm
S = aqueous solubility, mole/m .
When calculating H as a ratio of vapor pressure to solubility, it is
essential to have these data at about the same temperature and applicable
to the same physical state of the compound. Data for pure compounds
should be used because vapor pressure and solubilities of mixtures mav
be suspect.
D-l
-------
(2) If H<3 x 10 atm-m /mole, volatilization can be considered unim-
portant as an intermedia transfer mechanism and no further calculations
are necessary.
-7 3
(3) If H>3 x 10 atm-m /mole, the chemical can be considered volatile.
The nondimensional Henry's Law constant H' should be determined from:
H' = H/RT (2)
where R » gas constant, 8.2 x 10 atm-m /mole K
T - temperature, K.
At 20C (293K) RT is 2.4 x 10"2 atm-m3/mole.
(4) The liquid phase exchange coefficient k& must be estimated. This
coefficient is from a method that analyzes the volatilization process
on the basis of a two-layer film, one water and one air, which separates
the bulk of the water body from the bulk of the air (Liss and Slater 1974)
For a low molecular weight compound (1565, kjj, can be estimated from equations developed by Southworth
(1979). Because this method is different from Equation (3) / the esti-
mated values may vary. If the average wind speed is < 1.9 m/sec,
T0.969\
/
(
\
.673/
curr _ 1 J32_
where V » water current velocity, m/sec
Z « depth of water body, m.
If wind speed is >1.9 m/sec and <5 m/sec,
,0.969'.
0.526 (V . ,-1.9) ..
i wind cm/hr (5)
where V . , = windspeed, m/sec.
wind
If wind speed is >5 m/sec, liquid phase exchange coefficients are diffi-
cult to predict and may range up to 70 cm/hr.
(5) The gas phase exchange coefficient must be estimated. This too is
based on the two-film analysis. For a compound of 15
-------
Slater (1974),
k - 3000 yia/M* cm/hr (6)
If M>65 (Southworth 1979),
kg = 1137.5 (Vw.nd + V) li/S cm/hr .
(6) The Henry s Law constant and gas and liquid phase exchange coefficients
are used to compute the overall liquid phase mass transfer coefficient,
KL (Liss and Slater 1974), which is an indicator of the volatilization' •
rate: f
(H/RT)k k£ H kgk£
\ = (H/RT)k +k " H'k + k Cm/hr (8)
g 4 g i
(7) The volatilization rate constant k is:
v
hr"1
( 9}
where 7. is in cm.
(8) Assuming a first order volatilization process, the concentration
in the stream in the absence of continuing inputs at the location at
which volatilization occurs, is
c(t) - c/V (1Q)
where c(t) = pollutant concentration in the water column at time t
co " initial pollutant concentration in the water column.
(9) The half-life in the water column for the pollutant volatilizing at
a first order rate is:
r = 0-69 Z
\ KT hr' (11)
Another method for computing k for highly volatile chemicals with
H>10 atm-mJ/mole is based on reaeration rate coefficients (Smith and
Bomberger 1977, Smith et al. 1979, Tsivoglou 1967). The following data
are required:
• Ratio of reaeration rate of chemical to that of water,
• Reaeration rate of oxygen for water bodies in the environment
or steamflow parameters (velocity, stream bed slope, depth).
D-3
-------
If the oxygen reaeration rate is known for a given water body or type
of water body, the volatilization rate constant for the pollutant can
be estimated from (Smith and Bomberger 1979):
(kv
(12)
where kv - first order volatilization rate constant for the
particular chemical (hr~^);
o -i
k^ * reaeration rate constant for oxygen (hr );
env= designates values applicable to environmental
situations;
lab - designates laboratory measured values.
This equation applies particularly to rivers. For lakes and ponds, the
following equation may be more accurate:
(k ) » (k /k ) ' (k°) t-i -n
v env v v lab v env ^-L-5'
Typical values of (k°)env are given in the literature and reported by
Smith et. al (1979):
Water Body
Pond 0.0046-0.0096
River 0.008, 0.04- 0.39
Lake . 0.004-0.013
The values for ponds and lakes are speculative and depend on depth.
Mackay and Yuen (1979) present the equations listed below that cor-
relate k° with river flow velocity, depth, and slope:
Tsivoglou-Wallace: k° = 638 V s hr'1 (14)
Parkhurst-Pomeroy: k° = 1.08 (1 + 0.17 F2) (V s)°*0375 hr'1 (]
Churchill et al.: k° = 0.00102V2^5 Z'3'085 s~0.823 ^-1 (lg)
If no slope data are available:
Isaccs-Gundy: k° = 0.223V Z~1>5 hr'1 (17)
Langbein-Durum: k° = 0.241 V z'1'33 hr'1
v curr
D-4
-------
where VCUTT - river flow velocity (m/s) ;
s - river bed slope = m drop/m run (nondimensional) ;
Z = river depth (m) ;
g = acceleration of gravity =9.8 m/s2.
Because none of the foregoing is clearly superior to the others,
the best approach is probably to use all that are applicable and then
average the results. For a river 2 m deep, flowing at 1 m/sec, the re-
aeration rate is estimated as 0.042/hr. (kj/kj)^ is known for some
chemicals (See Table D.I). If a In prjnciPle' kv is the same as (KL/2) ; however, due to the use of
<*v'env» W has the depth and other water body characteristics embedded
within it. Therefore, no adjustment is required for use in the first
order volatilization equation.
D'2 ESTIMATION OF VOLATILIZATION RATE FOR TRICHLOROETHANES
The half-lives for trichloroethanes at 20° C in a river 1 meter deep
flowing at 1 m/s will be estimated. Wind speed is 3 m/sec.
D.2.1 1,1, 1-Trichloroethane
Vapor pressure of 1,1,1-trichloroethane at 20°C is 100 mm Hg
is 440°
1. Calculate the Henry's Law constant:
,, 0.13 atm •?
H = - j = °-0039 atm-m /mole
33 moles/m
2. Because H>10~3 atm-m3/mole, 1,1,1-trichloroethane is highly
3. The nondimensional Henry's Law constant is H/RT,
H' = 0.0039/0.024 = 0.16 at 20°C.
4. Because M>65 and Vwind >1.9 m/sec, the liquid phase exchange
ic
1-».20.5 cm/hr.
coefficient kjj, is:
kl - 23.51
5. The gas phase exchange constant is:
kg = 1137.5 (3 + DN18/133.4 = 1700 cm/hr.
D-5
-------
TABLE D.I
MEASURED RE AERATION
COEFFICIENT
RATIOS
FOR HIGH VOLATILITY COMPOUNDS
Compound
Chloroform
1 , 1-Dichloroethane
Oxygen
Benzo [b] thiophene
Dibenzothiophene
Benzene
Carbon dioxide
Carbon tetrachloride
Dicyclopentadiene
Ethylene
Krypton
Propane
Radon
Tetrachloroethyene
Trichloroethylene
H
atm-m3/
mole
3.8 x 10~3
5.8 x 10~3
7.2 x 10-2
2.7 x 1Q-1*
4.4 x 10~^
5.5 x 10~3
2.3 x 10- 2
8.6
8.3 x 10-3
1 x 10~2
Measured
. c /. o
k /k.
V V
,57 ± .02
.66 ± .11
.71 ± .11
1.0
.38 ± .08
.14
.57 ± .02
.89 ± .03
.63 ± .07
.54 ± .02
.87 ± .02
.82 ± .08
.72 ± .01
.70 ± .08
.52 ± .09
.57 ± .15
Source: Smith et al. (1979).
D-6
-------
6. The overall liquid phase exchange coefficient is:
r . (0.16X1700) (?n. 5)
L (0.16)(1700)+(20.5) = 19 cm'hr-
7. The volatilization rate constant is:
kv - 19/100 - .19 hr.
8. The half-life for volatilization is:
Tl/2 " °-69/0-19 " 3.6 hr.
Alternatively, by the reaeration coefficient method:
(17) a"nd ^^eaeration rate constant can be estimated by equations
(kv}env = °'223 (Da)"' » 0.223/hr,
v'env
-c°)
v'env
'Oenv - °-2A1 aXD"1'33 - 0.241/hr.
rM rlues is about °-23/hr- ™is ±
in the table of reaeration rates (0.008 - 0.39/hr for rivers).
2. A laboratory measured value of k£/k° is not available for 111
trichloroethane. Using the kv/k$ value fTom^able D.I for a chSlc.1
with a similar H, chloroform (H = 3.8 x 10~3) , cnemicai
GSP = (°- 62) (0.23) = 0.14/hr.
value of KL
3. Using equation (11), the half -life is:
T1/2 » 0.69/(kJ)env » 0.69/0.14 = 4.9 hr.
.. by the
D-2.2 1,1, 2 -Trichloroethane
Vapor pressure of 1,1, 2-trichloroethane at 20°C is 19 mm Hs f 025
and soluwuty is 450° " "
1. Calculate the Henry's Law constant:
H - 0-025 atm _ , -4 .
~ 33.7 mole/m^ = 7.4x10 atm-m3/mole.
D-7
-------
2. Because H > 3x 10"7 but < 10~3, 1,1,2-trichloroethane is only
moderately volatile.
3. The nondiznensional Henry's law constant is H/RT,
Hf = 7.4xlO"4/0.024 = 3.1xlO~2.
4,5. ki and kg are the same as for 1,1,1-trichloroethane because
molecular weights are equal:
k£ » 20.5 cm/hr
kg = 1700 cm/hr.
6. The overall liquid phase exchange constant is:
(3.1xlO-2)a700K20.5) ,, ,.
(3.1x10-2) (1700)+ 20.5 * 15 cm/hr*
7. The volatilization rate constant is:
k - 15/100 = 0.15/hr.
v
i
8. The half-life for volatilization is:
Tl/2 = °-69/0-15 = 4.6 hr.
Because 1,1,2-trichloroethane is not highly volatile, the reaeration
coefficient method is not used to estimate volatility.
D-3
-------
REFERENCES
> P. G. Flux of
Y' T'' V°U"liz*"°n rates of organic contaminants
Smith, J. H., Bomberger, D. C. Prediction of volatilization rates of
chemcals in water. Water: AICHE Symposium Series 190, 75: 375-381,
' Jf\*'i Boferfr' D' c" Ha>-". D- L. Prediction of volatilization
Southworth, G. R. The role of volatilization in removing polycycllc
Cl
D-9
-------
APPENDIX E
ATMOSPHERIC FATE OF TRICHLOROETHANES
There must be a mechanism for removal of 1,1,1-trichloroethane
from the atmosphere since cumulative world production (and assumed
emissions) up to December 1975 uniformly mixed in the atmosphere would
yield atmospheric levels about 75% higher than concentrations actually
measured (Singh e_t al. 1977). This appendix discusses removal mech-
anisms for the trichloroethanes, although most information relates to
1,1,1-trichloroethane.
The compound 1,1,1-trichloroethane is resistant to photo-oxidation
(Hanst 1978). In the laboratory, no decay occurred when the compound
was irradiated with black light-blue lamps in the presence of 500 pphm
N02 and 502 relative humidity (Lillian et, al . 1975). Less than 57, de-
composition was noted in 23.5 hr when 1,1,1-trichloroethane at 10 ppm*
and NO at 5 ppm was irradiated by a lamp with a UV short wavelength cut-
off at 290 nm. Less than 57, decomposition was noted in 28 days at 50 ppm
1,1,1 trichloroethane and 10 ppm NO- (Billing ejt al. 1975). In studies
with about 25 times the chlorine required to initiate photo-oxidation in
the chlorinated ethanes in comparable times, the following reaction pro-
ducts were "noted: CO, HClt~CC1^0~ (phosgene) , and CO . Phosgene was
found to be the only chlorine-containing product, comprising 50% of
the 1,1,1-isomer consumed. The 1,1,1-isomer was found to be the least
reactive of the chlorinated ethanes, some 30-50 times less reactive
than 1,1,2-trichloroethane. The 1,1,2-isomer photo-oxidized rather
rapidly, forming formyl chloride (HCC10) , phosgene (CC1 0) , and chloro-
acetyl chloride (CC12HCOC1) . Formyl chloride accounted for 44% of the
chemical consumed (Spence and Hanst
The rate of photo-oxidation is a function of latitude since OH
concentration ([OH]) is a function of latitude. Altshuller (1980) estimates
that at 40°N latitude it would take 177 days in January and 11 days
in July for 1% of atmospheric 1,1,1-trichloroethane to be consumed by
OH.
Because of 1,1,1-trichloroethane's long atmospheric lifetime and
pervasive use, it is distributed worldwide even though an estimated
97% of the world's use occurs in the Northern Hemisphere (Neely and
Agin 1980) . The compound exists long enough for a portion to be trans-
ported into the stratosphere. Lifetime in the atmosphere has been
estimated to be between 1.1 years and 15 years with 6-10 years a
reasonable "average" estimate (Hanst 1978, Cox _et al. 1976, Singh et al.
1978, Altshuller. 1980,. Rowland 1980, Neely and Agin 1980, Singh et al.
1980, and Campbell 1980).
Concentrations were originally reported in ppm, ppb, etc. Those
units will be maintained in this section to facilitate comparison
of concentrations. Ippm =5.46 mg/m for 1,1,1 trichloroethane.
E-l
-------
Concentrations vary with location, altitude, latitude, and hemisphere
(Cronn et al. 1977, Singh et al. 1980, Cronn 1980, Campbell 1980,
Singh st. alj.978, Spence and Hanst 1973). The concentration in the lower
stratosphere is noticeably lower than that in the troposphere (see
Figures E-l, E-2, E-3). The worldwide background in the troposphere is
up to two times higher than concentrations at 13-14 km altitude, the
lower reaches of the stratosphere (Spence and Hanst 1973). The transport
mechanism causing this distribution is the influx of troposhperic air
into the stratosphere. Daily fluctuations in the lower stratosphere
are usually due to meteorologic considerations. In the intertropical
convergence zone, it was noted that the rate of decline in concentrations
was lower than in mid-latitude of the northern hemisphere, probably
because the tropics are an area of upward transport of tropospheric air
into the stratosphere (Cronn 1980).
Concentrations in the Southern Hemisphere are about 60% of concen-
trations in the Northern Hemisphere (Singh .et al. 1980). In May, 1976,
the (average Southern Hemisphere)/(average Northern Hemisphere) concen-
tration ratio was 0.42 (Singh et al. 1978). Above 30°N, 1,1,1-trichloro-
ethane is well mixed in the Northern Hemisphere; between 20°N and 20°S,
a sharp decline is noted, and below 20°S, the concentration is lower
(see Figures E-4 and E-5). This is probably due to higher OH concen-
trations, and hence higher removal rate around the Equator, due to amounts
of sunlight and water vapor, and not to a normal mixing process. The
exchange time between hemispheres is about 14-17 months (Rowland 1980,
Neely and Agin 1980). Calculations indicate that one-half of all l,l|l-
trichloroethane removal occurs between 16°S and 16°N, with the rate
varying with altitude. More than one-half of the removal occurs in the
atmosphere below 2.4 km (Campbell 1980).
Concentrations differ between urban and rural areas. Average urban
concentrations are about eight times background levels (Singh et_ al_. 1978).
These higher urban levels may persist for days (Cronn 1980). AtTHmes,
local meteorological factors are more important than local emission pat-
terns (Lillian et. al. 1975). During an inversion situation in Wilmington,
OH, 1,1,1-trichloroethane concentrations at 460 m, below the inversion
height, were about three times higher than concentrations above 1500 m.
Localized and short-term variations in concentrations in an urban area
and in the plume downwind are indicative of complex variable emission
patterns with a strong dependence on meteorological factors.
Due to a long atmospheric lifetime, 1,1,1-trichloroethane is a good
tracer for the transport of urban pollutants. Figure E-6 illustrates these
observations where airborne concentrations in New York City are seen to
increase during the middle of the day. In the White Face Mountains of
New York, concentrations are seen to increase later in the day (see
Figure E-7). Relative variations and time dependence of the variations
at each location reinforce the relationship between the urban and rural
measurements.
E-2
-------
«4
•3
•2
-4-
«20
•10
«S
-10-
-15-
-«- -10
4O
(300ml
* • I
• • •
A A • .
TROPOPAUSE
K1»CH i.ItT*
•ARCH t, I»T«
• AKCN 10, l*r<
MAKCN ll.l«?«
MAHCM I2.I§T«
•«lCM2t.l»7t
(0
Ppt
—I
1)0
Source: Cronn et al. (1976)
100 110 120
Note: 1 ppt = 5.46 ng/m3
FIGURE E-1 MIXING RATIO DISTRIBUTION OF 1.1.1 - TRICHLOROETHAIME
AS A FUNCTION OF TROPOPAUSE HEIGHT, MARCH 1976
47aN LATITUDE
••-
•5-
»«-
•20.
-9-
•»-
*
-10-
(1001*1
4 *
* A
* •
TRCPOfiftCSe/
'x •'
X"
90
«o no
130
Source: Cronn et al. (1976)
FIGURE E-2 MIXING RATIO DISTRIBUTION OF 1,1,1 - TRICHLOROETHANE
AS A FUNCTION OF TROPOPAUSE HEIGHT, APRIL 1977
37° N LATITUDE
E-3
-------
DATE WKXEAIR
KU
a-
18-
13-
12-
9-
rr
70-H
SO-
SO -
40-
30-
20-
_ ,.
V*
7/1*
A, , -31 , 7/23 v
7X2S •
^_ y j^ o
* ^" 7/tai »
^ .
' 1
T
>
L
0 . V
•0- FOR CEARJCT VALUES
1 i _. I
CO 8O lOO IZO I4O I6O
CH,CO.j MtXNG RATO, pp«
Source: Cronn and Robinson (1978)
FIGURE E-3 1,1,1 - TRICHLOROETHANE MIXING RATIO DISTRIBUTION AS
A FUNCTION OF TROPOPAUSE HEIGHT, JULY 1977,9° N LATITUDE
E-4
-------
200
a
a
50
fB
e
lOO
."SO -
o
o
77" ppt
113' QOt
j L
•90'-aO* -60* -40* -20* 0* 20* «0« 60* 80*90*
s Latitude (deg) N
* A weighted average concentration is used to represent the total burden of the species
in the hemisphere since a significant gradient within the hemisphere is observed.
Source: Singh et al. (1980)
FIGURE E-4 GLOBAL DISTRIBUTION BY LATITUDE OF
1.1.1 -TRICHLOROETHANE IN LATE 1977
120-
100 H
c.
a
.28(H
«j
cc
c-
JeoH
*
S -80 -60
\
"Six
X AEROCOMMANOER FLIGHT. SEPT, 1978
* C-130 FLIGHTS, NOV., 1978
• AVERAGE OF HOURLY GROUND
MEASUREMENTS, OCT.-NOV., 1973
& GROUND SAMPLES, APRIL 8 JULY. 1978
o GROUND SAMPLES. NOV. 1978
LATITUDE
60
80 N
Source: Singh et al. (1980)
FIGURE E-5 LATITUDINAL GRADIENT OF 1,1,1 - TRICHLOROETHANE
CORRECTED TO NOVEMBER 1978
E-5
-------
12
.3
-—
.5
c
8
§
o
CO
o
U
CO
I
u
10
8
6
4
0
Location: New York
City
(45th St. and
Lexington
6/27/74
CH3CCI3
•
_^f ^.
_-—^*"^ \
1 1 1 1 1 1 1 ! 1 I^»— .
Ave)
»f-T
100 500 1000 1500
Time (Hours)
FIGURE E-6 DIURNAL VARIATIONS IN
1.1.1 -TRICHLOROETHANE
LEVELS IN NEW YORK CITY
26
1 22
I 18
"^
CO
I 14
J 10
CO
6
_
O
Location: White Face Mountains
(Elev. 3000 FT)
N.Y. State 9/17/74
CH3CCI3
L L i L L_ i t
60
50
40
30
20
10
600 1000
1500 2000
Time (Hours)
2500 3000
FIGURE E-7 1,1.1 - TRICHLOROETHANE LEVELS IN
NON URBAN AREAS DUE TO TRANSPORT
FROM URBAN AREAS
E-6
-------
Over the past few years, atmospheric concentrations and emissions have
North" ^^ 1980)' ^ the 1975'77 Peri°d' concentrations In the
Northern Hemisphere at temperate latitudes increased at 12-17%/yr
(Singh |t al. 1980, Singh et al. 1978, Singh et al. 1979), a
a somewhat lower rate than expected (Singh et "al~ 978) . Emissions
growth over the same period was also exponential (Singh et al. 1978) with
available emissions data indicating about 15-25%/yr (SinglT eT al. 1979)
On the basis of these observations, it appears that atmosphe7i~con-
centrations have not increased as rapidly as emissions. Figures E-8
fc-y, and E-10 show atmospheric concentrations as a function of time.'
_ The long tropospheric lifetime of the chlorinated compound 1,1 1-
trichloroethane and the past and continuing dispersive losses are of
possibly serious significance (Altshuller 1980, Hanst 1978). From 12 to
(ILlt 8i ? hl'r,l~^±ChlOTOethane ^ssions may reach the stratosphere
(Singh e^ al. 1980, Singh et al. 1979), where Cl atoms may be released bv
photolysis to attach and deplete ozone (Hanst 1978, Lillian et al. 1975,'
,
98°Neely ^ A§in 198°' SinSh et al. 1979,
and
Mff v ,
Schiff 1978 The ozone situation can be put into perspective by com-
parison of 1,1,1-trichloroethane with the chlorofluoromethanes (CFM's)
The annual stratospheric flux of chlorine atoms due to 1,1,1-trichloro-
ethane is about ten times less than the flux due to Freon-11 and Freon-12
t!ke L*5S ^ ^ ,/3Sed °n SeVeral reaS°na ble ^sumptions, it would
the Jf ,-7?ar8iaV 67'^ 1,1,1-trichloroethane growth rate to reach
^Mnrn !t Ve u°f °Z°ne dePletion ^ CFM. The amount of 1,1,1-tri-
chloroethane reaching stratospheric 0. may be less than 6-12% of yearly
emissions since in the lower stratosphere', [OHJ is high enough and dif-
fusion and mixing to the stratosphere is sufficiently slow so that more
1,1,1-trichloroethane than previously estimated (the 12-25% reported bv
Singh et £. 1979) may degrade due solely to tropospheric reactions be-
dpn^J6 ^Jn ?! stratosPhere and ^e 03 layer. The steady state ozone
depletion (A03) due to CFM release at 1973 levels is estimated to be 6.6-
7.5^ of the unperturbed value (McConnell and Schiff 1978). When 111-
trichloroethane is added to the calculations, the steady state A03'is
7.8 an increase of 20% over the 6.6% AOo. If steady-state CFM levels
~
U A03 decrease
With a release schedule of 1,1,1-trichloroethane added (10%/
year increase until 1982, then 7%/year until 1990), A03 goes to 4.6% a
HU/s increase.
Crutzen et al. (1978) have simulated ozone depletion due to many
chlorinated compounds in the atmosphere. According to their calculations
1,1,1-trichloroethane in 1978 was contributing about 0.2% reduction in
total ozone. Estimates of future ozone reductions due only to 1,1 1-
trichloroethane use and release increases of 13%/year arTthown in
Figure E-11. Other curves for other chlorinated chemicals are also
shown for comparison.
Since 1,1,1-trichloroethane has a relatively short lifetime in the
atmosphere when compared with CFM's, it would contribute little to Q\
depletion 25 years after termination of emissions. This is due to the
E-7
-------
_ s.
CC
C
'x
i
o
u
n
o
8
,
tr
I
JULY
1977
—, 1 1 I
OCTOBER JANUARY APRIL JULY
1978
OCTOBER JANUARY
-H
Source: Cronn (1980)
FIGURE E-8 WEEKLY AVERAGES FOR CONTINUOUS GROUND MONITORING OF
1.1,1 - TRICHLOROETHANE LEVELS. JUNE 1977 - JANUARY 1979,
47° N LATITUDE. EASTERN WASHINGTON STATE
2001
100-
| 50-
oe
z
10-
f
g *
2
1
l<
NORTH :j
•1
•.
•
SOUTH •
>70 19
ssrf
;jS!||||?f:*
; •;. .:".::"-::-.-"T"
• • ••.."• ° X ?
—
i
l
0
o
72 1974 1976
YEAR
S^ '.'.••'.".•• "
/•e/^uu
CRVHrl
LOVELOCK
RASMUSSEN
ROBINSON
ROWLAND
SINGH
1978 I960
Source: Cronn (1980)
FIGURE E-9 OBSERVED NH AND SH MIXING RATIOS OF
1.1.1 - TRICHLOROETHANE LEVELS, 1972 - 1978
F-R
-------
Source: Various data cited by Neely and Agin (1980)
FIGURE E-10 ATMOSPHERIC LEVELS OF 1,1,1 - TRICHLORETHANE
1972 - 1978. NORTHERN HEMISPHERE
1940 1960
1980
2000 2020 2040 2060
Loss due to
C2H5CI3 on|V
10
18
Year
Source: Crutzen et al. (1978)
FIGURE E-11 TOTAL OZONE LOSSES FOR VARIOUS SCENARIOS
E-9
-------
tropospheric sink rather than a stratospheric sink, where most ozone is
found and where Cl release is of more concern.
For the reasons discussed above, 1,1,1-trichloroethane may con-
tribute to ozone destruction, but at a level less than that of the
chlorofluoromethanes.
E-10
-------
REFERENCES
of trace gases
_ cu aurma rue -r,-.
Washington, B.C.:
._..„ «„ ._ . , ^ i97g^
:^
and other halocarbon poUutants a I ?" On ""y^hlorofonn
vironmental Protection Agency i980a? Trian§le Park' NC: U'S' ^n-
n o.
363, 1978. (As cited by C^n ^80?.*
to esma
on inethylchloroform and other fialocarbon ^ i r°Ceedlng of the conference
Park, NC: U.S. Environoental
' =i-u«*nes, propanes and nrnn i f -«•«.=.« WJ.
solutions. Comparisons with th^nr**-!,. i py^fnes from dilute aqueous f
Tech. 405-409, 1976. theoretical predictions. Environ. Sci.
Hanst, P.L. Noxious trac o-
lutants. Chemistry 51(2): 6-12 lQ7fl ' Halogenated pol-
L
E-ll
-------
Lillian, D.; Singh, G.B.; Appleby, A.; Lobban, L-;Arats, R.jGumpert, R. 5
Haque, R.;Tooney, J.; Angell, M.; Hansen, D.; Scott, B. Atmospheric fate
of halogenerated compounds. Environ. Sci. Tech. 9: 1042-1048, 1975.
McConnell, J.C.; Schiff, H.I. Methylchloroform: Impact on stratospheric
ozone. Science 199: 174-177, 1978.
Neely, W.B.; Agin, G. Environmental fate of methylchloroform. EPA.600/9-
80-003. Proceedings of the conference on methylchloroform and other halo-
carbon pollutants. Research Triangle Park, NC: U.S. Environmental Pro-
tection Agency, 1980.
Rowland, F.S. Status of the stratospheric ozone depletion issue, including
comments on methylchloroform. EPA 600/9-80-003. Proceedings of the
conference on methylchloroform and other halocarbon pollutants. Research
Triangle Park, NC: U.S. Environmental Protection Agency, 1980.
Singh, H. B.; Fowler, D.P.; Peyton, T.O. Atmospheric carbon tetrachloride:
another man-made pollutant. Science 192: 1231-1234, 1976. (As cited by
Singh ejt al. 1980).
Singh, H.B.; Salas, L.J.J Cavanaugh, L.A. Distribution sources and sinks
of atmospheric halogenated compounds. J. Air. Pollut. Control. Assoc.
27: 332-336, 1977.
Singh, H.B.', Salas, L.J.,'.Shigeishi, H. J Scribner, E. Atmospheric
halocarbons, hydrocarbons, and sulfur hexaflouride: global distributions,
sources, and sinks. Science 203: 899-903, 1979.
Singh, H.B.', Salas, L.J.', Shiseishi, H.', Smith, A.H. Fate of halo-
genated compounds in the atmosphere. Menlo Park, CA: Stanford Research
Institute, 1978. Available from NTIS PB 2781980.
Singh, H.B.; Salas, L.J.,* ShigeishI, H. Halogenated trace constituents
in the global environment. Proceedings of the conference on methylchloro-
form and other halocarbon pollutants. Research Triangle Park, NC: U.S.
Environmental Protection Agency, 1980.
Spence, J.W.; Hanst, P.L. Oxidation of chlorinated ethanes. J. Air.
Pollut. Control. Assoc. 28: 250-253, 1978.
U.S. Environmental Protection Agency (U.S.EPA). Proceedings of the con-
ference on methylchloroform and other halocarbon pollutants. Research
Triangle Park, NC: Office of Research and Development, U.S. Environmental
Protection Agency, 1980.
E-12
-------
------- |