Screening-level Hazard Characterization Test Rule Chemical Name Methane Dibromo- CASRN 74-95-3

U.S. Environmental Protection Agency
Hazard Characterization Document

December 2012

SCREENING-LEVEL HAZARD CHARACTERIZATION

TEST RULE CHEMICAL NAME
Methane, dibromo-
CASRN 74-95-3

The High Production Volume (HPV) Challenge Program1 was conceived as a voluntary initiative
aimed at developing and making publicly available screening-level health and environmental
effects information on chemicals manufactured in or imported into the United States in quantities
greater than one million pounds per year. In the Challenge Program, producers and importers of
HPV chemicals voluntarily sponsored chemicals; sponsorship entailed the identification and
initial assessment of the adequacy of existing toxicity data/information, conducting new testing if
adequate data did not exist, and making both new and existing data and information available to
the public. Each complete data submission contains data on 18 internationally agreed to "SIDS"

1 2

(Screening Information Data Set' ) endpoints that are screening-level indicators of potential
hazards (toxicity) for humans or the environment.

In the HPV Challenge Program, companies have sponsored more than 2200 HPV chemicals,
with approximately 1400 chemicals sponsored directly through the HPV Challenge Program and
over 860 chemicals sponsored indirectly through international efforts. Other chemicals,

however, remain unsponsored in the voluntary program. Basic hazard data for unsponsored
chemicals are being obtained through regulatory efforts such as TSCA Section 4 Test Rules and
TSCA Section 8(a)/8(d) Rules. EPA is also initiating actions, such as significant new use rules
(SNUR), to manage risks from HPV unsponsored chemicals.

The Environmental Protection Agency's Office of Pollution Prevention and Toxics (OPPT) is
evaluating the data available for HPV chemicals by developing hazard characterizations (HCs).
These HCs consist of an evaluation of the quality and completeness of the data set available.

They are not intended to be definitive statements regarding the possibility of unreasonable risk of
injury to health or the environment.

2 4

The evaluation is performed according to established EPA guidance ' and is based on hazard
data provided by submitters in response to EPA's regulatory actions, as well as other available
data; however, in preparing the hazard characterization, EPA considered its own comments and
public comments on available data as well as the submitter's responses to comments.

OPPT does not develop HCs for those HPV chemicals which have already been assessed
internationally through the HPV program of the Organization for Economic Cooperation and
Development (OECD) and for which Screening Initial Data Set (SIDS) Initial Assessment
Reports (SIAR) and SIDS Initial Assessment Profiles (SIAP) are available. These documents are
presented in an international forum that involves review and endorsement by governmental

1 U.S. EPA. High Production Volume (HPV) Challenge Program; http://www.epa.gov/chemrtk/index.htm.

2 U.S. EPA. HPV Challenge Program - Information Sources; http://www.epa.gov/chemrtk/pubs/general/guidocs.htm.

3 U.S. EPA. Regulatory Actions for Unsponsored Chemicals: http://www.epa.gov/hpv/pubs/general/regactions.htm.

4 U.S. EPA. Risk Assessment Guidelines; http://cfpub.epa.gov/ncea/raf/rafguid.cfm.

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authorities around the world. OPPT is an active participant in these meetings and accepts these
documents as reliable screening-level hazard assessments.

These hazard characterizations are technical documents intended to inform subsequent decisions
and actions by OPPT. Accordingly, the documents are not written with the goal of informing the
general public. However, they do provide a vehicle for public access to a concise assessment of
the raw technical data on HPV chemicals and provide information previously not readily
available to the public.

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Chemical Abstract Service Registry Number
(CASRN)

74-95-3

Chemical Abstract Index Name

Methane, dibromo-

Structural Formula

See Appendix

Summary

Methane, dibromo- is a clear colorless liquid with high vapor pressure and high water solubility.
It is expected to possess high mobility in soil. Microbial degradation and volatilization appear
to be the most important environmental fate processes for this substance. Limited
biodegradation data suggest the methane, dibromo- is biodegraded quickly in natural waters.
Volatilization from water is expected to be moderate given the Henry's Law constant of this
substance, but may be high from other surfaces due to its high vapor pressure. The rate of
hydrolysis is negligible. The rate of atmospheric photooxidation is negligible. Methane,
dibromo- is expected to have low persistence (PI) and low bioaccumulation potential (Bl).
However, the tendency of this substance to volatilize may increase its persistence since the
atmospheric lifetime of methane, dibromo- is quite long.

Human Health Hazard

Based on a weight of evidence approach, the acute oral toxicity of CASRN 74-95-3 is low. In a
90-day repeated-dose toxicity study, rats exposed to CASRN 74-95-3 as a vapor at 0.53 mg/L
showed hematological effects. The NOAEL for systemic toxicity in rats was 0.18 mg/L. In a
combined reproductive/developmental toxicity study in rats, administration of CASRN 74-95-3
via gavage at 500 mg/kg-bw/day showed increased pre-coital interval and a reduction in litter
size at birth due to increased post-implantation loss. The NOAEL for
reproductive/developmental toxicity was 150 mg/kg-bw/day. Systemic maternal toxicity was
observed at 500 mg/kg-bw-day as reduced body weight gain and food conversion efficiency
during gestation and lower food intake during lactation. The NOAEL for systemic maternal
toxicity was 150 mg/kg-bw-day. The NOAEL for systemic toxicity in males was 500 mg/kg-

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bw/day (highest dose tested). CASRN 74-95-3 induced gene mutations in bacteria and induced
chromosomal aberrations in mammalian cells in vitro.

Hazard to the Environment

The 96-h LC50 value of CASRN 74-95-3 for fish was 45 mg/L. The 48-h EC50 value of CASRN
74-95-3 for aquatic invertebrates was 66 mg/L. The 96-h EC50 values of CASRN 74-95-3 for
aquatic plants were 150, 95, and 87 mg/L for growth rate, yield, and biomass, respectively.

No data gaps were identified under the HPV Program.

Introduction

Methane, dibromo- (CASRN 74-95-3) was identified as a candidate chemical under the EPA
Challenge program for high production volume chemicals. As it was not sponsored in the
voluntary phase of the HPV Challenge Program, it was deemed as subject to testing requirements
under a TSCA Section 4 Test Rule (Testing of Certain High Production Volume Chemicals,

Final Rule, 71 FR 13708, March 16, 2006; Document ID EPA-HQ-OPPT-2005-0033-0197;
available at http://www.regulations.gov/#!documentDetail;D=EPA-HO-OPPT-2005-0033-0197).
The test rule required the following toxicological tests for CASRN 74-95-3: CI (consisting of
acute toxicity to fish, acute toxicity to Daphnia and toxicity to algae because log Kow < 4.2), E2
(chromosomal aberration or micronucleus test) and F2 (reproduction/developmental toxicity
screening test). Testing for other SIDS human health and ecological endpoints was not required
by the test rule because adequate data were available from the open literature to characterize
those endpoints.

In response to the test rule, Albemarle Corporation and Bromine Compounds Ltd submitted the
following studies to satisfy the toxicological testing requirements:

Dhinsa, NK; Fulcher, S. (2007) Dibromomethane: Oral (gavage) reproduction/development
toxicity screening test in the rat. SafePharm Laboratories, SPL Project Number 0466/0261, 180
pgs. Study available at http://www.regulations.gov/#!documentDetail;D=EPA-HO-OPPT-20Q5-
0033-0259 as of September 10, 2012.

Goodband, TJ; Mullee, D. (2007a) Dibromomethane: Acute toxicity to rainbow trout
(Oncorhynchus mykiss). SafePharm Laboratories, SPL Project Number 0466/0263, 47 pgs.

Study available at http://www.regulations.gov/#!documentDetail;D=EPA-HO-OPPT-2005-0Q33-
0259 as of September 10, 2012.

Goodband, TJ; Mullee, D. (2007b) Dibromomethane: Acute toxicity to Daphnia magna.
SafePharm Laboratories, SPL Project Number 0466/0264, 34 pgs. Study available at
http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2005-0033-0259 as of
September 10, 2012.

Vryenhoef, H; Mullee, D. (2007) Dibromomethane: Algal growth inhibition test. SafePharm
Laboratories, SPL Project Number 0466/0265, 68 pgs. Study available at

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http://www.regulations.gov/#!documentDetail;D=EPA-HO-OPPT-2005-0033-0254 as of
September 10, 2012.

Wright, NP; Durward, R. (2007) Dibromomethane: Chromosome aberration test in human
lymphocytes in vitro. SafePharm Laboratories, SPL Project Number 0466/0262, 27 pgs. Study
available at http://www.regulations.gov/#!documentDetail;D=EPA-HO-OPPT-2005-0033-Q254
as of September 10, 2012.

The submitted data, as well as other available data, are summarized in this hazard
characterization.

1. Chemical Identity

1.1	Identification and Purity

Studies submitted by Albemarle Corporation and Bromine Compounds Ltd in 2007 tested a
substance with 99.4% purity. Other studies did not specify purity of the test substance. The
structure of the compound is provided in the Appendix.

1.2	Physical-Chemical Properties

The physical-chemical properties of methane, dibromo- are summarized in Table 1. Methane,
dibromo- is a clear colorless liquid that is used as a solvent, gauge fluid and an ingredient in fire
extinguishing fluids. It is also produced naturally by microalgae often concentrated along
beaches and coastlines. It possesses high vapor pressure and high water solubility.

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Table 1. Physical-Chemical Properties of Methane, dibromo-1

Property

Value

CASRN

74-95-3

Molecular Weight

173.83

Physical State

Clear, colorless liquid

Melting Point

<-20 °C (measured)

Boiling Point

94°C (measured)

Vapor Pressure

35.2 mm Hg at 25°C (measured)

Dissociation Constant

Not applicable

Henry's Law Constant

8.22><10"4atm-m3/mole (measured)2

Water Solubility

8,600 mg/L at 20 °C (measured)

Log K0w

1.68 (measured)

1 Albemarle Corporation. (2007) Letter to OPPT Document Control Office, USEPA from Kim
Boudreaux, Regulatory Advisor, Albemarle Corporation, re: Final Reports submittal. EPA-HQ-OPPT-
2005-0033-0254. Available online at http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-
2005-0033-0254 as of September 10, 2012.

2 Hazardous Substance Databank (HSDB). Available online at http://toxnet.nlm.nih.gov/cgi-
bin/sis/htmlgen?HSDB as of July 13, 2012.

2. General Information on Exposure

2.1 Production Volume and Use Pattern

CASRN 74-95-3 had an aggregated production and/or import volume in the United States
between 1 to 10 million pounds during calendar year 2005.

Non-confidential information in the IUR indicated that methane, dibromo- was used in two types
of industrial processes: processing as a reactant, for which the substance is classified as an
intermediate; and processing by incorporation into a formulation, mixture or reaction product, in
which this substance is classified as a solvent. The solvent classification is further specified as
solvents used for chemical manufacture and processing and are not part of product at greater than
1% by weight. No commercial and consumer uses were reported for the chemical.

2.2 Environmental Exposure and Fate

The environmental fate properties are provided in Table 2. Methane, dibromo- is expected to
have high mobility in soil. The biodegradation potential of methane, dibromo was evaluated
using freshwater, estuarine water, seawater, and hypersaline-alkaline samples. Measured
degradation rates indicated that bacterial oxidation of methane, dibromo- was significant in all of
the waters tested, with half-lives ranging from 1-2 days. A similar study using marine surface
water collected in or near beds of Giant Kelp (M. pyrifera) showed rapid degradation of
methane, dibromo-. Extrapolating laboratory degradation rates to environmental conditions, an
estimated half-life of methane, dibromo- in kelp rich seawaters was reported as approximately 20
days. Volatilization is expected to be moderate from water given the Henry's Law constant, but
may be high from other surfaces due to high vapor pressure of this substance. The volatilization
half-life of methane, dibromo- is approximately 4-11 days depending upon the depth of the

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water layer. The hydrolysis half-life of methane, dibromo- has been estimated as over 100 years.
The rate of atmospheric photooxidation is negligible. Methane, dibromo- is expected to have
low persistence (PI) and low bioaccumulation potential (Bl). However, the tendency of this
substance to volatilize may increase its persistence since the atmospheric lifetime of methane,
dibromo- is quite long.

Table 2. Environmental Fate Characteristics of Methane, dibromo-1

Property

Value

CASRN

74-95-3

Photodegradation Half-life

146 days (estimated)

Hydrolysis Half-life

122 days at pH 33;
143 days at pH 73;
50 days atpH ll3

Biodegradation

Half-life of approximately 20 days in seawater from kelp beds4;

Half-life = 2.31 days in freshwater5;

Half-life =1.9 days in estuarine water5;

Half-life =1.6 days in coastal seawater5;

Half-life =1.2 days in hypersaline-alkaline lake water5

Bioaccumulation Factor

BAF = 5.0 (estimated)2

Log Koc

1.4 (estimated)2

Fugacity

(Level III Model)2

Air (%)

13.3

Water (%)

31.8

Soil (%)

54.9

Sediment (%)

<0.1

Persistence6

PI (low)

Bioaccumulation6

Bl (low)

1 Hazardous Substance Databank (HSDB). Available online at http://toxnct.nlm.nih.gov/cgi-
bin/sis/htm 1 gen9HSDB as of July 13, 2012.

2U.S. EPA. (2012) Estimation Programs Interface Suite™ for Microsoft® Windows, v4.10. Washington,
DC: U.S. Environmental Protection Agency. Available online at
http://www.epa.gov/opptintr/exposure/pubs/episuitedl.htm as of June 14, 2012.

3 Fackler, PH. (1989) SLS report# 89-5-2994. Submitted to Ethyl Corp., Baton Rouge, LA.

4Goodwin, KD; Lidstrom, ME; Oremland, RS. (1997). Marine bacterial degradation of brominated
methanes. Environ Sci Technol 31:3188-3192.

5	Goodwin, KD; Schaefer, JK;, Oremland, RS. (1998) Bacterial oxidation of dibromomethane and methyl
bromide in natural waters and enrichment cultures. Appl Environ Microbiol 64(12):4629-4636.

6	Federal Register. (1999) Category for persistent, bioaccumulative, and toxic new chemical substances.
U.S. Environmental Protection Agency. Federal Register 64(213):60194-60204.

Conclusion: Methane, dibromo- is a clear colorless liquid with high vapor pressure and high
water solubility. It is expected to possess high mobility in soil. Microbial degradation and
volatilization appear to be the most important environmental fate processes for this substance.
Limited biodegradation data suggest the methane, dibromo- is biodegraded quickly in natural
waters. Volatilization from water is expected to be moderate given the Henry's Law constant of
this substance, but may be high from other surfaces due to its high vapor pressure. The rate of

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hydrolysis is negligible. The rate of atmospheric photooxidation is negligible. Methane,
dibromo- is expected to have low persistence (PI) and low bioaccumulation potential (Bl). The
tendency of this substance to volatilize may increase its persistence since the atmospheric
lifetime of methane, dibromo- is quite long.

3. Human Health Hazard

A summary of health effects data for SIDS endpoints is provided in Table 3.

Acute Oral Toxicity

Although no adequate acute toxicity studies are available, the acute toxicity endpoint is satisfied
using a weight of evidence approach.

(1)	Rabbits were administered CASRN 74-95-3 via the oral route. Additional study details were
not provided. Data are from TSCATS (EPA Doc. No. 86-870002253, Fiche No. OTS0517043).
LD50 > 1000 - 2000 mg/kg-bw

(2)	Rabbits were administered CASRN 74-95-3 via the oral route. Additional study details were
not provided. Data available at

http://www.sigmaaldrich.com/MSDS/MSDS/DisplavMSDSPage.do?country=US&language=en

&productNumber=D41686&brand=ALDRICH&PageToGoToURL=http%3A%2F%2Fwww.sig

maaldrich.com%2Fcatalog%2Fsearch%3Finterface%3DAll%26term%3Ddibromomethane%261a

ng%3Den%26region%3DUS%26focus%3Dproduct%26N%3D0%2B220003048%2B219853269

%2B219853286%26mode%3Dmatch%2520partialmax as of September 13, 2012 (Sigma-

Aldrich, 2012).

LD50 = 1000 mg/kg-bw

(3)	Rats were administered CASRN 74-95-3 via the oral route. Additional study details were not
provided. Data available at

http://www.avantormaterials.com/documents/MSDS/usa/English/M4407 msds us Default.pdf
as of September 13, 2012 (J.T. Baker, 2011).

LD50 = 108 mg/kg-bw

(4)	Rats were administered CASRN 74-95-3 via the oral route. Additional study details were not
provided. Data available at

http://www.sigmaaldrich.com/MSDS/MSDS/DisplavMSDSPage.do?country=US&language=en

&productNumber=D41686&brand=ALDRICH&PageToGoToURL=http%3A%2F%2Fwww.sig

maaldrich.com%2Fcatalog%2Fsearch%3Finterface%3DAll%26term%3Ddibromomethane%261a

ng%3Den%26region%3DUS%26focus%3Dproduct%26N%3D0%2B220003048%2B219853269

%2B219853286%26mode%3Dmatch%2520partialmax as of September 13, 2012 (Sigma-

Aldrich, 2012).

TDLo = 333 mg/kg-bw

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Repeated-Dose Toxicity

Sprague-Dawley rats (115 males/group and 15 females/group) were exposed whole-body to
CASRN 74-95-3 (purity not provided) as a vapor at concentrations of 0 (control), 25, 75 or 150
ppm for 6 h/d, 5 d/wk for 90 days. These concentrations corresponded to 0, 0.18, 0.53 and 1.07
mg/L, respectively. A 2-year post-exposure holding period was implemented for 100
males/group. Endpoints included clinical signs, body weights, organ weights, hematology,
urinalysis, clinical chemistry, cytogenetics, gross pathology, and histopathology. No treatment-
related effects on mortality were observed. Treatment-related effects observed at the 90-day
sacrifice were limited to the 0.53 and 1.07 mg/L exposure groups and included increased liver
weight in females and increased blood percent carboxyhemoglobin saturations in both sexes.
Increased blood percent carboxyhemoglobin saturations were also seen in both sexes at 0.53 and
1.07 mg/L throughout the exposure period. No treatment-related histopathological effects were
observed. Treatment-related effects observed during the 2-year post-exposure period included
decreased mean body weight beginning on day 121 at the 1.07 mg/L exposure level. Gross
pathological examination of males exposed to 1.07 mg/L at the end of the 2-year post-exposure
period revealed liver atrophy, decreased incidence of small red foci, and dark red foci visible in
the liver; the study authors considered these lesions to be the result of spontaneous age-related
processes. All gross pathological (2-year observation) and histopathological (1-year
observation) neoplastic and non-neoplastic observations were considered to be spontaneous in
nature and unrelated to exposure. Histopathological examinations were not conducted at the end
of the 2-year observation period. This study is not considered adequate to assess carcinogenic
effects because the exposure duration was only 90 days, whereas an exposure duration of 2 years
is considered necessary to assess carcinogenic effects. Data are from TSCATS (EPA Doc. No.
86-870001205, FicheNo. OTS0516108).

LOAEL = 0.53 mg/L (based on increased blood percent carboxyhemoglobin saturations in both
sexes during exposure and at termination of exposure)

NOAEL = 0.18 mg/L

Reproductive/Developmental Toxicity

Sprague-Dawley rats (10/sex/group) were administered CASRN 74-95-3 (99.4% purity) in
polyethylene glycol 400 via gavage at 0 (control), 50, 150 or 500 mg/kg-bw/day for
approximately 40 days. Animals were exposed during a two-week maturation phase, pairing,
gestation, and early lactation. Males were sacrificed on day 43 of the study, and all surviving
females and offspring were sacrificed on day 5 postpartum. Evaluated endpoints included
mortality, clinical observations, body weights, food consumption and food conversion efficiency,
mating performance, fertility, gestation length, litter responses, necropsy, organ weights, and
histopathology. Treatment-related effects were observed at 500 mg/kg-bw/day and included:
decreased body weight gain and lower food conversion efficiency in females during gestation,
reduced food intake in females during gestation, increased pre-coital interval, increased gestation
length, decreased litter size and increased post-implantation loss. Decreased absolute and body
weight-relative epididymal and testes weights were observed at 150 and 500 mg/kg-bw/day in
the parental males in the absence of histopathological effects. Study available at
http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2005-0033-0259 as of
September 10, 2012 (Dhinsa and Fulcher, 2007).

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NOAEL (systemic toxicity, males) = 500 mg/kg-bw/day (highest test dose)

LOAEL (systemic toxicity, females) = 500 mg/kg-bw/day (based on reduced body weight gain
and food conversion efficiency in dams during gestation and lower food intake in dams during
lactation)

NOAEL (systemic toxicity, females) = 150 mg/kg-bw/day

LOAEL (reproductive/developmental toxicity) = 500 mg/kg-bw/day (based on increased pre-
coital interval, reduced litter size, and increased post-implantation loss)

NOAEL (reproductive/developmental toxicity) = 150 mg/kg-bw/day

Genetic Toxicity — Gene Mutation

In vitro

Salmonella typhimurium strains TA97, TA98, TA100 and TA104 were exposed to CASRN 74-
95-3 (purity not provided) in dimethyl sulfoxide (DMSO) at concentrations of 0 (control), 10, 25,
50, 100, 250, 500 or 1000 |ig/plate with and without metabolic activation. Positive and negative
controls responded appropriately. The induction of mutations was observed in all four strains in
the presence of metabolic activation. In the absence of metabolic activation, mutations were
induced in strains TA98, TA100 and TA104. No details were presented about the degree of
cytotoxicity. (Strobel and Grummt, 1987)

CASRN 74-95-3 was mutagenic in this assay.

Genetic Toxicity — Chromosomal Aberrations

In vitro

Cultured human lymphocytes were exposed to CASRN 74-95-3 (99.4% purity) in DMSO at
concentrations of 0 (control), 27.19, 54.38, 108.75, 217.5, 435 or 870 |ig/mL with and without
metabolic activation. The concentrations selected for metaphase analysis were 54.38, 108.75 and
217.5 |ig/mL, Positive and negative controls responded appropriately. The frequency of cells
with aberrations was increased in the presence and absence of metabolic activation at all
analyzed concentrations. Cytotoxicity was observed concentrations > 870 |ig/mL. Study
available at http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2005-0033-0254
as of September 10, 2012 (Wright and Durward, 2007).

CASRN 74-95-3 induced chromosome aberrations in this assay.

Conclusion:

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toxicity was 150 mg/kg-bw-day. The NOAEL for systemic toxicity in males was 500 mg/kg-
bw/day (highest dose tested). CASRN 74-95-3 induced gene mutations in bacteria and induced
chromosomal aberrations in mammalian cells in vitro.

Table 3. Summary Table of the Screening Information Data Set - Human Health Data

Endpoints

Methane, dibromo-
(CASRN 75-94-3)

Acute Oral Toxicity
LD5o (mg/kg-bw)

> 1000 - 2000
(rabbit)

1000
(rabbit)
108
(rat)
TDLo = 333
(rat)

Repeated-Dose Toxicity
NOAEL/LOAEL
Inhalation (mg/L)

NOAEL = 0.18
LOAEL = 0.53
(rat, 90-day)

Reproductive/Developmental Toxicity

NOAEL/LOAEL

Oral (mg/kg-bw/day)

Systemic toxicity

NOAEL (males) = 500 (highest tested dose)
NOAEL (females) = 150
LOAEL (females) = 500
(rat)

Reproductive/Developmental toxicity

NOAEL = 150
LOAEL = 500
(rat)

Genetic Toxicity - Gene Mutation
In vitro

Positive

Genetic Toxicity - Chromosomal Aberrations
In vitro

Positive

Measured data in bold

4. Hazard to the Environment

A summary of aquatic toxicity data submitted for SIDS endpoints is provided in Table 4.

Acute Toxicity to Fish

Rainbow trout (Oncorhynchus mykiss) were exposed to CASRN 74-95-3 (99.4% purity) at
nominal concentrations of 0 (control), 10, 18, 32, 56 or 100 mg/L under static-renewal conditions

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for 96 hours. Corresponding mean measured concentrations were 0, 11.2, 17.6, 30.6, 51.6 and
92.1 mg/L, respectively. Exposures occurred at a pH of 7.2 - 7.8, a dissolved oxygen
concentration of 6.7 - 11 mg/L and a temperature of 13.2 - 14.9 °C. Sub-lethal effects were
limited to swimming at the surface at 56 mg/L. Mortality rates of 90 and 100% were observed at
56 and 100 mg/L, respectively; no mortalities were observed at exposures < 32 mg/L. The LC50
value was based on nominal concentrations. Study available at

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2005-0033-0259 as of
September 10, 2012 (Goodband and Mullee, 2007a).

96-h LC50 = 45 mg/L

Acute Toxicity to Aquatic Invertebrates

Water fleas (Daphnia magna) were exposed to CASRN 74-95-3 (99.4% purity) at nominal
concentrations of 0 (control), 10, 18, 32, 56 and 100 mg/L under static conditions for 48 hours.
Corresponding mean measured concentrations were 0, 10.9, 18.75, 29.6, 50.1 and 90.6 mg/L,
respectively. Exposures occurred at a pH of 7.7 - 7.9, a dissolved oxygen concentration of 8.4 -
8.9 mg/L and a temperature of 19.6 - 20.4 °C. Immobilization rates of 25 and 95% were
observed at 56 and 100 mg/L, respectively; no immobilization was observed at exposures < 32
mg/L. The EC50 value was based on nominal concentrations. Study available at
http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2005-0033-0259 as of
September 10, 2012 (Goodband and Mullee, 2007b).

48-h EC50 = 66 mg/L

Toxicity to Aquatic Plants

Green algae (Pseudokirchneriella subcapitata) were exposed to CASRN 74-95-3 (99.4% purity)
at nominal concentrations of 0 (control), 10, 32, 100, 320 or 1000 mg/L under static conditions
for 96 hours. Corresponding geometric mean measured concentrations were 0, 11, 23, 77, 230
and 830 mg/L, respectively. Exposures occurred at a pH of 7.6 - 10.6 and a temperature of 24 ±
1 °C. The EC50 values were based on measured concentrations. Study available at
http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2005-0033-0254 as of
September 10, 2012 (Vryenhoef and Mullee, 2007).

96-h EC50 (growth rate) = 150 mg/L
96-h EC50 (yield) = 95 mg/L
96-h EC50 (biomass) = 87 mg/L

Conclusion: The 96-h LC50 value of CASRN 74-95-3 for fish was 45 mg/L. The 48-h EC50
value of CASRN 74-95-3 for aquatic invertebrates was 66 mg/L. The 96-h EC50 values of
CASRN 74-95-3 for aquatic plants were 150, 95, and 87 mg/L for growth rate, yield, and
biomass, respectively.

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Table 4. Summary Table of the Screening Information Data Set - Aquatic Toxicity

Endpoints

Methane, dibromo-
(CASRN 74-95-3)

Fish

96-h LC50 (mg/L)

45

Aquatic Invertebrates
48-h EC50 (mg/L)

66

Aquatic Plants
96-h EC50 (mg/L)

(growth rate)
(yield)
(biomass)

150

95

87

Measured data in bold

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5. References

Dhinsa, NK; Fulcher, S. (2007) Dibromomethane: Oral (gavage) reproduction/development
toxicity screening test in the rat. SafePharm Laboratories, SPL Project Number 0466/0261, 180
Pgs-

Goodband, TJ; Mullee, D. (2007a) Dibromomethane: Acute toxicity to rainbow trout
(Oncorhynchus mykiss). SafePharm Laboratories, SPL Project Number 0466/0263, 47 pgs.

Goodband, TJ; Mullee, D. (2007b) Dibromomethane: Acute toxicity to Daphnia magna.
SafePharm Laboratories, SPL Project Number 0466/0264, 34 pgs.

J.T. Baker. (2011) Material Safety Data Sheet on Methylene Bromide.

Sigma-Aldrich. (2012) Material Safety Data Sheet on Dibromomethane.

Strobel, K; Grummt, T. (1987) Aliphatic and aromatic halocarbons as potential mutagens in
drinking water. Part 1. Halogenated methanes. Toxicol Environ Chem 13(3-4):205-221

Vryenhoef, H; Mullee, D. (2007) Dibromomethane: Algal growth inhibition test. SafePharm
Laboratories, SPL Project Number 0466/0265, 68 pgs.

Wright, NP; Durward, R. (2007) Dibromomethane: Chromosome aberration test in human
lymphocytes in vitro. SafePharm Laboratories, SPL Project Number 0466/0262, 27 pgs.

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U.S. Environmental Protection Agency
Hazard Characterization Document

December 2012

APPENDIX

HPV Chemical

Chemical Name

CASRN

Structure

Methane, dibromo-

74-95-3

Br

B^H

SMILES: C(Br)(Br)

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