vvEPA
united States
Environmental Protection
Agency
Office of Pesticides
and Toxic Substances
Washington, DC 20460
EPA-560/2-81-003
May 1981
Toxic Substances
Assessment of
Testing Needs:
Dichloromethane
Support Document
Proposed Health and
Environmental Effects
Test Rule
Section 4
Toxic Substances
Control Act
a.
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EPA 560/2-81-003
MAY 1981
ASSESSMENT OF TESTING NEEDS:
DICHLOROMETHANE
SUPPORT DOCUMENT, PROPOSED
HEALTH AND ENVIRONMENTAL EFFECTS TEST RULE
TOXIC SUBSTANCES CONTROL ACT SECTION 4
ASSESSMENT DIVISION
OFFICE OF TOXIC SUBSTANCES
Washington, D.C. 20460
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF PESTICIDES AND TOXIC SUBSTANCES
WASHINGTON, D.C. 20460
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TABLE OF CONTENTS
INTRODUCTION AND SUMMARY OF PROPOSED TESTING................1
PRODUCTION AND USES......................................... 5
EXPOS URE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
THE SECTION 4(A)(1) (B) (i) FINDING. .... ... .............. .....9
HEALTH EFFECTS: SUFFICIENCY OF DATA........................9
ENVIRONMENTAL EFFECTS: SUFFICIENCY OF DATA......... .......14
ENVIRONMENTAL FATE: SUFFICIENCY OF DATA....... ............17
REFERENCES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
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INTRODUCTION AND SUMMARY OF PROPOSED TESTING
Dichloromethane (CH Cl , methylene chloride, CAS number 75-09-2)
is a volatile liqui~ a~ standard temperature and pressure.
The Interagency Testing Committee (ITC), which is charged under
section 4(e) of the Toxic Substances Control Act with making
priority testing recommendations to the EPA, recommended that
dichloromethane be tested for carcinogenicity, mutagenicity,
teratogenicity, other chronic effects and environmental effects,
and that epidemiology studies be done (USEPA 1978a).
Because of the large production volume, extensive release to the
environment and numbers of people potentially exposed to
dichloromethane, both occupationally and as consumers, the EPA is
proposing testing of dichloromethane under section 4(a) (1) (B) of
the Toxic Substances Control Act. This section provides for
testing requirements if, among other conditions, a chemical
substance is produced in substantial quantities, and (I) it
enters or may reasonably he anticipated to enter the environment
in substantial quantities or (II) there may be significant or
substantial human exposure to the substance.
This document presents the EPA's basis for making the three
statutory findings required to be made under section 4(a) (l)(B)
regarding production, release and exposure, the insufficiency of
available data, and the necessity for testing, and describes the
recommended testing.
This document also supports the 4(a) (1) (A) findings for
subchronic cardiovascular effects testing and provides the
Agency's basis for not proposing testing in certain areas
recommended by the ITC.
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E f fec ts of Conc (~E'1_L!J i'lLLll-.L~ll
Ilea lth F;f fects
1\c u t "
Ora I
De rm
TrrCJtogenic
Onco'l('nic
Neuro'toxic
Environmental Rffrcts
1\'luCJt ic vr!'t<°\) l:ntc>S
1\c u te
FrrshwCJter, coldwatrr
frrshwater, warmwater
Mnrinc, coldwater
Marinc>, wnrmwCJter
Chronic
Freshwater, coldwal0r
Frr'shwnter, I-Inrmwnt'.'r
r1 a I: ill", en 1 d 1-1 at r r
Mnrine, warmwatpr
l\'1l1ilt ic invf'rl:f'hrrlt,."
1\
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(Continllen)
Effects of C,)ncern
[4(a) (1) (13)]
Tcstin~ Rccomm0nnen
-~y~-~
-~--
Chronic
,.' n~shwater
~1 -'11:- i ne
I\qllatic Plilnts
1\ 19 a (e
Fn'shwatcr
~lnrine
Vascular
Fr~shwat(~r
~larine
Rinls
l\c II t <:
Tf'rr<:stria]
Waterfowl
Chronic
Tf'I:Tcstrial
\'iill:erfow l
Mammals
I\c lit ('
Chron ire
Tf'rrestrii'l! jnvcl:-tf'hrnl"('s
TerrestriilJ pli'lnts
Se<:d <]('r[l1i nat- ion/rnot- c> l()n~at ion
Ear]y sec(lUng 'Trm"'"
Full lif(' ryrlc
n ioconc (> n t ra t ion
Aqur1t i f~ \Tet~tf'~) Lo1tC!
l\'1Uilt ic henthic inv(>t:-t('hrate
Tern',;tria 1 plant lJpl:ake
t t-alls !oc "t ion
-9-
1\00itional Testing
Proposed by the EPA [4(21)(I)(I\)J
Decision
~-~_._--
Propns('r]
Prnp0secl
Not rroposc>na
Not propos('(10
Not prornsf'clh
Not proposeol)
Pr0ros(>rl
Propos"r]
Propof1ed
Proposf'r]
Not rropos",la
Not propose(~a
Not proposer]'
Not prnpos"d"
Proposer]
Not proposf'(lh
Proposed
Not proposed"
PropOSf'r]
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(Continueo)
Ef f~c:~~o[ c'2-,~(:~~_liJ_ill.!...L~JL
1\ It'~rnt ion of miCU)OUlanism
Rcosystem effects
8nvir-onmental Fate
Pers istenc(>
Tr-ansport
fun"t ion
a) Infor-mat io" adeguatr> to nSsr'ss
b) The EPA will under-takdn
Not pr-oposcr]C1
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1.
PRODUCTION AND USES
1.1.
Production
Dichloromethane is a high production chemical. The amount of
dichloromethane produced domestically in 1979 was 634 million
pounds (288 million kilograms) (USI'rC 1980). The market has
increased substantially in the last few decades, rising from 36
million pounds (16 million kilograms) in 1951 (Malishkevich et
al. 1978), although dichloromethane production decreased more
than 15 percent in 1980. On the basis of production in the first
11 months of 1980, the estimated year's production was 537
mi llion pounds (244 mi llion ki lograms) (USITC 1980).
According to one recent source, five chemical manufacturers
produce dichlorornethane at seven sites (Anon. 1979). The TSCA
inventory showed that in 1977 there were six manufacturers and 13
importers (USEPA 1980). However imports are minimal compared to
domestic production (USEPA 1980).
The predominant process used to manufacture dichloromethane in
the United States is the catalytic vapor phase hydrochlorination
of methanol to chloromethane followed by chlorination to
dichloromethane (Ahlstrom and Steele 1979).
1. 2.
Uses
Dichloromethane is used for a variety of purposes: as a paint
remover, a urethane foam-blowing agent, a vapor degreasing and
dip so Ivent for meta 1 c leani ng, a so Ivent for aeroso 1 products, a
solvent in the pharmaceutical industry, a solvent in the
manufacture of polycar.)onates by polymerization, and as an
extractant for caffeine, spices, and hops. It is used in the
manufacture of plastics, textiles, photographic film, and
photoresistant coatings, as a solvent carrier in the manufacture
of herbicides and insecticides, and in rapid drying paints and
adhesives, carbon removers and brush cleaners. Other minor
applications include use as a low pressure refrigerant, as a low-
temperature heat transfer medium and as an air-conditioning
coolant (Ahlstrom and Steele 1979).
Distribution of dichloromethane in its major uses is shown below
(Anon. 1979):
Use
Perc ent
of Tota 1
Kgjyr, millions
(1978)
Paint remover
Aeroso Is
Metal degreasing
Export
Urethane foam b lowing agent
Other
29%
21%
18%
15%
9%
8%
75
54
46
39
23
20
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The fastest growing segment of the dichloromethane market is the
aerosol sector. This is due to the substitution of
d ich loromethane for ch lorof luoroc arbons as a so Ivent, vapor
pressure depressant, and flame retardant. Consumption by the
aerosol industry is expected to grow by as much as 15 percent
annually over the next several years and to become the largest
market for dichloromethane (Ahlstrom and Steele 1979, Lowenheim
and Moran 1975).
Dichloromethane is expected to retain popularity as a paint
remover. Although it competes with trichloroethylene and
perchloroethylene as a solvent, it is preferred as a paint
remover because of its nonreactivity with aluminum (Lowenheim ann
Horan 1975).
2.
EXPOSURE
2.1.
Human Exposure
The use of dich loromethane may resu It in sub stant ia 1 exposure of
significant numbers of workers and consumers.
The National Occupational Hazard Survey (NOHS) estimates that
approximately 2.5 million persons are exposed to dichloromethane
annually in occupational settings (NIOSH 1979). Much of this
exposure is expected to result from its use as a degreasing
solvent and paint remover, as a process solvent (e.g., in
polymerization), and as a foam-blowing agent.
Industrial degreasing operations, such as metal cleaning by the
cold cleaning and vapor degreasing processes, may lead to
substantial worker exposure. In cold cleaning, the part to be
cleaned is sprayed, dipped or agitated in the solvent. In vapor
degreasing, the object is immersed in the solvent and then
exposed to hot solvent vapor as the final step. Emissions from
these processes can result from solvent bath filling operations,
solvent bath evaporation, evaporation from cleaned objects,
equipment leaks, and solvent disposal (USEPA 1979). All such
emissions may result in worker exposure.
It was determined from sampling data obtained from the Celanese
Fibers Company plant in Rock Hill, South Carolina (SRI 1979a)
that time-weighted average exposures to dichloromethane, from
dichloromethane's use as a solvent for triacetate polymer in the
Arnel@ production and processing area, ranged from 31 ppm to 572
ppm. Area samples taken showed peak dichloromethane
concentrations as high as 1853 ppm. It was estimated that 920 of
the 1950 employees might be exposed to dichloromethane.
The process using dichloromethane in a new paint stripping
facility at Robins Air Force Base, Warner Robins, Georgia, is an
example of exposure that may occur when dichloromethane is used
(SRI 1979b). Approximately 106 persons work in the aircraft
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stripping operation. The 22 paint strippers, both male ann
female, who work on an aircraft are required to wear protective
clothing, but since there is an exhaust ventilation system,
respirators are not required. About 1000 gallons per aircraft of
Intex 857@ "mil~" stripper, containing approximately 50 percent
dichloromethane, 25 percent aliphatic and aromatic hydrocarbons,
ten percent non-volatile hydrocarbons and 14 percent water and
ammonia, is sprayed in several coats with scraping and brushing
of the surfaces between sprayings. In adnition to the stripping
personnel, there are supervisory personnel, drivers, maintenance
personnel, and others who may be exposed intermittently to
dichloromethane. The exposure duration for these workers varies;
however, for most of the paint stripping crew, the exposure to
dichloromethane may be up to eight hours per day.
A walk-throu0h survey conducted on June 15, 1978, found
dichloromethane in concentrations varying from 9 to 57 ppm for
area samples and 113 to 206 ppm for personal samples (SRI
1979b). An in-depth survey performed the week of May 14, 1979,
gave time-weighte~ average exposure concentrations which ranged
from 15.7 to 268 ppm with an average concentration of 64 ppm in
the personal samples of 12 of the 22 workers involved in the
stripping operation. The highest exposure was to a worker in the
wheel well of the aircraft.
Many dichloromethane-containing aerosol products such as paint,
paint removers, automotive parts cleaners, rust penetrants, oven
cleaners, lub r ic ants, adhes i ves, and mo Id re leases are Ii ke ly to
be used in occupational settings, many of which are small
estab lishments. There is very litt Ie information on measured
levels of dichloromethane in such situations. One study showed
concentrations in indoor atmospheres of up to 1000 times the
typical tropospheric air concentration of 20-50 ppt, some of
which could be attributed to the use or storage of aerosols (NRC
1978). The highest level found, above 23 ppb (0.023 ppm) in a
beauty parlor, was attributed to the use of aerosol hair care
products. Since the three such products listed in the Clinical
Toxicology of Commercial Products database (CTCP 1981) contained
only seven and a half to ten percent of dichloromethane, while
some other types of products listed contain much larger amounts
(e.g., a nonskid spray for rugs containing 56% dichloromethane),
the limited data cited may well understate the potential for
exposure of this type. Because above-background levels of
dichloromethane have been found in retail outlets where
dichloromethane-containing products are sold and in service
establishments such as restaurants, there is not only potential
daily exposure of large numbers of employees nationwide but also
potential occasional exposure of millions of members of the
genera 1 pub lic.
Dichloromethane is also an ingredient in many other consumer
products: cleaning agents, adhesives, paints and paint
removers. The dichloromethane content can reach 90 percent in
some products (Aviado et ale 1977). This can be expected to lead
-7-
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to a variety of exposure patterns, depending upon such factors as
the frequency of use and the adequacy of ventilation during and
after use. For example, an experiment was performed to measure
dichloromethane levels in the air after the use of a paint
remover (Otson et ale 1981). The experiment was set up to mimic
home use of the product as much as possible. In a room
approximately 8 feet by 13.5 feet, varying amounts of paint
remover were brushed on a plywood board. Air samples were then
taken at spots throughout the room at 30 an~ 480 minutes. Levels
as high as 3.41 g/m3 (989 ppm) were measured one and one/half
feet from the ground in an unventilated room 30 minutes after
application, whereas in a ventilated room, levels at 30 minutes
never rose a'Jove 0.65 g/m3 (188 ppm). When applied as an
aerosol, dichloromethane levels were higher, particularly in the
ventilated room. Immediately after use, levels were highest near
the floor, indicating that children in these areas might receive
greater exposure than adults. The authors added that stripping
of household furniture would normally require application of
greater amounts of paint remover than those used in this study,
and emphasized that even small quantities of these products
should not he used in rooms with poor ventilation, as recommended
occupational health limits can easily be exceeded.
If one takes into account the various types of consumer products
already mentioned, it appears that many millions of people are
likely to be exposed to dichloromethane at home.
2.2.
Environmental Exposure
Emissions from use are the major source of dichloromethane in the
environment, although it may be produced naturally in small
amounts by forest fires or agricu ltural burning, and possih ly hy
reactions in seawater and marine plants (NRC 1978). In 1978, 566
million pounds (257 million kilograms) of dichloromethane was
produced, and 84 percent is estimated to have been dispersed to
sewage treatment plants and surface waters, deposited on land, or
lost to the atmosphere (NRC 1978). In wastewater treatment
plants, dichloromethane concentrations are usually reduced by
aeration in ponds, which results in release to the atmosphere
(NRC 1978).
Dichloromethane was one of the more frequently detected organics
in a monitoring study by Ewing et ale (1977), being found at 32
of 204 surface water sites from which. samples were collected.
Sites were located near heavily industrialized river basins
across the United States. Concentrations reported were in the
low ppb range.
The short evaporation half-life of dichloromethane from moving
water (21~3 min) (Dilling et al. 1975) probably allows most of
the compound dissolved in water to be eventually transported into
the atmosphere. Dichloromethane in concentrations up to 400 ppm
is also readily biodegraded by bacteria (Brunner et al. 1980,
Rittmann and McCarty 1980) and may be removed from the
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4. 8 .
Epidemio logy
SRI International (1979a) conducted an epidemiologic feasibility
study on dichloromethane for the National Institute of
Occupational Safety and Health (NIOSH). During the course of the
survey, NIOSH found that the Celanese Fibers Company and Dow
Chemical Company were jointly funding an epinemiologic study on
dichloromethane-exposed workers. The results of that study are
due to be published soon in the Scandinavian Journal of ~'Jork,
Environment and Health. The EPA is not proposing epidemiology
studies until the Agency has had the opportunity to evaluate the
already completed study in order to determine whether any
additional investigation will he necessary.
4.9.
Subchronic Cardiovascu lar Effects
Cardiovascular testing is being proposed for dichloromethane
under section 4(a) (1) (A) because acute toxicity studies and data
on metabolism suggest a potential unreasonab Ie risk for
subchronic cardiovascular effects, and available data are
insufficient to assess such toxicity.
The acute toxicity tests have shown that, depending upon the
duration of exposure, inhalation of noses of 500 to 5000 ppm in
the dog appears to stimulate the cardiovascular system,
increasing arterial pressure and myocardial contractility (Ada~s
1975, Aviado et al. 1977). It is believed these changes may be
an indirect result of either sympathetic nervous system
stimulation or adrenal discharge, since the effects are blocked
by the administration of a beta blocker (Aviado et al. 1977).
Exposure to much higher concentrations of dichloromethane (15,000
ppm) appears to result in depression of medullary function,
followed by direct myocardial depression at 40,000 ppm, which
would overshadow any changes caused at lower doses (von Oettingen
et al. 1949). The cardiovascular depression is characterized by
decreases in contractility, cardiac output, and stroke volume
(Aviado et al. 1977, Taylor et al. 1976). It has also been
demonstrated that acute exposure to high levels of
dichloromethane followed by the administration of otherwise
nonhazardous doses of epinephrine can result in ventricular
arrhythmias in dogs (5,000 ppm: Adams 1975; 24,000 ppm: Clark
and Tinston 1973) and mice (200,000 ppm: Aviado and Belej 1974).
Heppel et al. (1944) exposed dogs to 5000 ppm dichloromethane for
seven hours/day, five days/week for six months. Mean arterial
blood pressures were determined on five dogs at intervals of one
to two weeks. Of 83 determinations, all but three were normal.
Histopathologic study of the heart showed no effects. However,
this study was not specifically designed to investigate the
effects on the heart and the vascular system, or those parameters
which are deemed essential to evaluate cardiovascular toxicity
(e.g., cardiac output, contractility, electrocardiographic
changes). The pathology of the heart did not indicate if full
thickness wedges were cut, thus including all the tissue from the
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endocardium to the epicardium; no mention was made of any
histopathology on the coronary arteries and the major bifurcation
of the aorta.
Douglas et al. (1980) and Loyke (1973) have demonstrated a
decrease in systolic blood pressure in both spontaneously
hypertensive and renal hypertensive rats following the
administration of multiple doses of dichloromethane;
no change in the blood pressure of normotensive animals was
ob served.
No further information on the cardiovascular effects of long term
exposure to dichloromethane was found. Dichloromethane is
metabolized in vivo to carbon monoxide (Carlsson and Hultengren
1974, Kubic et al. 1974, Stewart et al. 1972), which forms
carboxyhemoglobin. A two-hour exposure to 1,000 ppm
dichloromethane gave mean peak carboxyhemog lob in levels of ten
percent in human volunteers (Stewart et al. 1972). Chronic
exposure of dogs to 100 ppm carbon monoxide, yielding 21 percent
carboxyhemoglobin, produced degenerative changes in myocardial
muscle fibers, comparable to those resulting from experimentally
produced anoxia (Ehrich et al. 1944). Thus, dichloromethane may
act indirectly on the heart via metabolism to carbon monoxide.
The EPA is proposing that a 90-day subchronic cardiovascular
test, performed in the dog according to the test standard
described in the test rule, would provide the information needed
to assess this chemical. The dog is the species of choice for
this type of experiment because the dog has been shown to be more
sensitive than the mouse to the acute myocardial sensitization
effects of dichloromethane, and because the techniques for
cardiovascular testing have been developed adequately only in the
dog (Page et al. 1980).
5.
ENVIRONMENTAL EFFECTS:
SUFFICIENCY OF DATA
Aquatic Vertebrates
5.1.
5.1.1.
Acute Effects
The EPA is not proposing that acute toxicity tests he performed
on aquatic vertebrates, as enough information exists to be able
to assess the hazard of dichloromethane in this group.
Alexander et al. (1978) evaluated the toxicity of dichloromethane
to the fathead minnow (Pimephales promelas Rafinesque), a
freshwater, warmwater fish, in a 96-hour flow-through test,
finding an LC50 of 193 ppm. The fish were also observed for the
following effects: loss of equilibrium, melanization, narcosis
and swollen hemorrhaging gills. For dichloromethane, the
concentration that produced one or more of these effects was
99 ppm; the author did not specify which tests were positive.
Fish affected during the exposure were transferred to freshwater
at the end of the 96-hour period after which most recovered.
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Short exposures to dichloromethane at sublethal levels seemeo to
produce reversib Ie effects.
Static 96-hour bioassays have heen performed on two species of
freshwater, warmwater fish (the fathead minnow, Pimephales
promelas Rafinesque, and the blue-gill sunfish Lepomis
macrochirus) and a marine species (the sheepshead minnow,
Cyprinodon variegatus). The LC50 value for the fathead minnow is
310 ppm (Alexander et al. 1978), for the b lue-gi 11 sunfish, 224
ppm and for the sheepshead minnow. 331 ppm (USEPA 1978b).
Two additional static fish toxicity tests have been performed on
the golden orfe, Leuciscus idus (Juhnke and Ludemann 1978),
another freshwater, warmwater species. The LC50 values at two
different laboratories were 521 ppm and 528 ppm.
5.1.2.
Chronic Effects
There are no data on the chronic effects of dichloromethane in
aquatic vertebrates. Therefore, the EPA is proposing early life-
stage tests in a freshwater, warmwater species of fish, a
freshwater, coldwater species and a warmwater, marine species
according to the TSCA section 4 standards. A chronic test on a
co Idwater marine spec ies wi 11 be sponsored by the EPA because no
corresponding standards are availahle.
Aquatic Invertebrates
5.2.
5.2.1.
Acute Ef fects
The EPA is not proposing additional acute testing for aquatic
invertebrates, as existing information is adequate. The result
of a 48-hour static bioassay gave an LC50 for the freshwater
cladoceran, Daphnia magna, of 220 ppm (LeBlanc 1980). For a
marine invertebrate, Mysidopsis bahia, a 96-hour static bioassay
yielded an LC50 of 256 ppm (USEPA 1978b).
5.2.2.
Chronic Effects
There are no data on the chronic effects of dichloromethane in
aquatic invertebrates. Therefore, the EPA is proposing life-
cycle tests in a freshwater invertebrate and a marine species,
according to the TSCA section 4 test standards.
5.3.
Aquatic Plant Toxicity
5.3.1.
Algae
The EPA is not proposing additional testing of nonvascular
aquatic plants, as the information presently available is deemed
sufficient to evaluate the acute effects of dichloromethane.
Several species of algae have been investigated for their
response to dichloromethane. Bringmann and Kuhn (1978) reported
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on the levels of compound required to inhibit cell multiplication
after eight days in two freshwater species, Microcystis
aeruginosa and Scenedesmus quadricauda. The toxicity threshold,
i.e., the concentration causing the onset of inhibition, was 550
ppm for Hicrocystis and 1450 ppm for Scenec1esmus.
The EPA (USEPA 1978b) has tested the effects of dichloromethane
on two algae, a freshwater species, Selenastrum capricornutum and
a marine species, Skeletonema costatum. In both cases the
concentrations required to inhibit photosynthesis by 50 percent
and inhibit cell growth by 50 percent were greater than 662 ppm
(the highest dose tested).
5.3.2
Vascu lar Plants
A test on vascular aquatic plant toxicity is needed, but no TSCA
section 4 standards are available and therefore the EPA will
sponsor the testing.
5.4.
Birds
5.4.1.
Acute Effects
There are no data on the acute effects of dichloromethane in
birds. Therefore, the EPA is proposing acute toxicity tests on a
terrestrial bird and a waterfowl according to the TSCA section 4
standards.
5.4.2.
Chronic Effects
There are no data on the chronic effects of dichloromethane in
birds. Therefore, the EPA is proposing reproductive studies on a
terrestrial bird and a waterfowl according to the TSCA section 4
standards.
5. 5.
Terrestrial Plants
5.5.1.
Seed Germination/Root Elongation
Dichloromethane has been used as a solvent carrier for the
incorporation of compounds for testing seeds, and the effect of
dichloromethane on seed germination has been well studied.
Therefore, the EPA is not proposing that any additional testing
be performed.
Meyer and Mayer (1971) stored lettuce seeds in dichloromethane
for 24 hours wi thout loss of vi ab i Ii ty. Storage of i ntac t
cottonseed (Gossypium hirsutum L.) in dichloromethane for up to
72 hours did not alter germination (Halloin 1977). Gynoecious
cucumber (Cucumis sativa L.) seeds also showed no c1ecrease in
germination when soaked in pure dichloromethane for periods up to
24 hours (Globerson and Dagan 1973). Seeds of Lactuca sativa
(Grand Rapids lettuce) showed a statistically significant
increase in percent germination when soaked in dichloromethane
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for periods up to 12 hours (Rao et ale 1976). Pigweed seed
(Amaranthus retroflexus L.) soaked in dichloromethane for four to
five hours also showed an increase in germination rates (Brewer
and Wilson 1975). However, longer soaking, 24 hours, decreased
the germination rates (Brewer and Wilson 1975). Brewer and
Wilson (1975) also investigated the effect of dichloromethane on
oats (Avena sativa L.), showing decreases in germination at hoth
four hours and 24 hours. Hull-less oats, scarified pigweed seed
(Brewer and Wilson 1975) and cottonseeds with damaged seed coats
(Halloin 1977) all showed decreased germination rates after
treatment with dichloromethane. It is apparent that the effect
of dichloromethane on seed germination will depend upon the
condition of the seed, the species of plant and the length of
treatment.
5.5.2.
Early Seedling Growth
There are no data on the effects of dichloromethane on early
seedling growth in terrestrial plants. Therefore the EPA is
proposing that such tests be done according to the TSCA section 4
standards.
5.5.3.
Li fe-Cyc Ie Test
There are no data on the effects of dichloromethane on the life-
cycle of terrestrial plants. However, there are no corresponding
TSCA section 4 test standards, and therefore the EPA will sponsor
the testing.
5.6.
Bioconc entrat ion
No bioconcentration testing has been performed with dichloro-
methane. The EPA is proposing that testing be performed in
terrestrial plants and in an aquatic vertebrate according to TSCA
section 4 standards.
5.7.
Other Effects of Concern
The EPA is not proposing testing for other effects of concern
(toxicity to terrestrial invertebrates, alteration of
microorganism function, ecosystem effects), because no TSCA
section 4 test standards are available. Testing for such
effects, if needed, will be the responsibility of the EPA.
6.
ENVIRONMENTAL FATE:
SUFFICIENCY OF DATA
The EPA is not proposing additional physicochemical nata
acquisition because existing information is sufficient to
characterize the environmental fate of dichloromethane. Some of
these data are desc rib ed be low.
Me It i ng po i n t
-96.7°C
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Boi ling point
Specific gravity at 20/4°
Vapor density (Air = 1.02)
Vapor pressure
39.8°C
1. 320 g/ml
2.93
O°C
147 mm Hq
Water so lub i Ii ty
20° 348.6
30° 510.8
20° 13.2 g/kg
(Ahlstrom and Steele 1979)
Partition coefficient (log Poet/H20) 1.25 (Hansch et ale 1975)
Hydrolysis at pH 7.0: 25° 18 months (Dilling et ale 1975)
half life 100° 13.75 days (Fells and Moelwyn-Hughes 1958)
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REFERENCES
Adams JO. 1975. The effects of carbon monoxide and methylene chloride
on the canine heart. Ph.O. thesis. Texas A & ~1 University.
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Hansch C. Vittoria A, Silipo C, Jow PYC. 1975. partition
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* V.B.G.P.O. 720-016/1302-5993
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50277 .J 01
REPORT DOCUMENTATION :.l,-REPORT HO.
PAGE i EPA 560/2-81-003
4. TItle and s...btrtle Assessment of Testing Nee s: lC orome ane
Support Document, Proposed
Health and Environmental Effects Test Rule
T xic Substances Control Act Section 4
~-y- --.-..----
1- "__.~._n- - - -~n-
5. Report Oate
Draft 5/15/81
L
7. Author(s)
L Perlormlnc Orcanintion Rept. No.
t. Perlorminc Ol'ilaniz8tton Name end Adelress
10. ProjKtlTuk/Wortc Unit No.
11. Contract(C) or Grent(G) No.
(C)
(0)
12. Sponwrinc Orpniution Name and Address
Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Report & Period Covered
Proposed Test Rule
Support Document
14.
15. s...pplemerrtary Notes
------ -.-.
.IL Abstract (limit: 200 words)
The Interagency Testing Committee (LTC), which is charge6 under section 4(e) of the Toxic
Substances Control Act with making priority testing recommendations to the EPA, recommended
that dichloromethane be tested for carcinogenicity, mutagenicity, teratogenicity, other,
chronic effects and environmental effects and that epidemiology studies be done (USEPA 1978a
Because of the large production volume, extensive release to the environment and numberS!
of people potentially exposed to dichloromethane, both occupationally and as consumersr the I
EPA is proposing testing of dichloromethane under section 4(a) (1) (B) of the Toxic Substances
Control Act. This section provides for testing requirements ifr among other conditions,
a chemical substance is produced in substantial quantities, and (I) it enters or may
reasonably be anticipated to enter the environment in substantial quantities or (II) there
may be significant or substantial human exposure to the substance.
This document presents the EPA's basis for making the three statutory findings required
to be made under section 4(a) (1) (B) regarding production, release and exposure, the
insufficiency of available data, and the necessity for testing, and describes the
recommended testing.
This document also supports the 4(a) (1) (A) findings for subchronic cardiovascular effects
testing and provides the Agency'S basis for not proposing testing in certain areas
recommended by the ITC.
17. Ooc:umerrt Anal~is e. Oescriptors
b. Iderrtlfie,,/Open.Ended Terms
c. COSAT1 Fiefd/G",uP
Release Unlimited
19. Security crus (This Report)
Unclassified
'20. Securi~ Class fl:his Pale)
Unclassitied
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Se. InstructIons on R....,..
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