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Revised June 1996
Ethylene dibromide (EDB),
dibromoethane
Trade and Other Names:
The chemical name for EDB is 1,2-dibromoethane, and synonyms
include DBE; alpha, beta-dibromoethane; dibromoethane; ethylene
bromide; glycol bromide; glycol dibromide; and sym-dibromoethane.
Product names include Bromofume, Celmide, Dibrome, Dowfume,
EDB-85, Fumo-Gas, Kopfume, Nephis, and Soilfume.
Regulatory Status:
Ethylene dibromide (EDB) is a highly toxic compound in EPA
Toxicity Class I. It is not registered for use in the U.S. In
1983, the EPA suspended the use of EDB as a fumigant when
low-level residues were found in groundwater and some grains.
Chemical Class: Not
Available
Introduction:
Ethylene dibromide (EDB) is used extensively as a soil and
post-harvest fumigant for crops, and as a quarantine fumigant for
citrus and tropical fruits and vegetables. It also may be used as
a gas in termite and Japanese beetle control, beehive and vault
fumigation, and spot fumigation of milling machinery.
Formulation: Ethylene
dibromide (EDB) is used extensively as a soil and post-harvest
fumigant for crops, and as a quaratnine fumigant for citrus and
tropical fruits and vegetables. It may also be used as a gas in
termite and Japanese beetle control, beehive and vault
fumigation, and spot fumigation of milling machinery.
Toxicological Effects:
- Acute toxicity: EDB is highly toxic via
ingestion, with reported oral LD50 values of 108 to 146
mg/kg in rats, 250 mg/kg in mice, and 55 mg/kg in rabbits
[8]. The lowest fatal oral dose for humans was reportedly
90 mg/kg [8]. The dermal LD50 was unavailable, but EDB
can be rapidly absorbed through the skin [8]. EDB is
reportedly a severe skin and eye irritant, and can cause
skin blistering with contact [8,175]. The reported 2-hour
inhalation LC50 is 3 mg/L in rats; the reported 1-hour
inhalation LC50 is 5 mg/L, indicating high toxicity. A
woman who ingested 4.5 mL of an EDB concentrate
experienced rapid breathing, vomiting, and diarrhea prior
to expiring [8]. Liver and kidney damage were noted in
her post-mortem examination [8]. Administration of very
high single oral doses of EDB to rats and chicks caused
changes in the livers of these animals within 22 hours
[176]. In rats, inhalation of small concentrations of EDB
vapors depresses weight gain, and slightly higher levels
damage the lungs. Changes in the lungs and respiratory
tract and temporary clouding of the corneas have been
seen in animal studies after only 1 week of exposure to
workplace levels of EDB [8]. Other effects of acute
exposure may include headache, depression, and nausea or
loss of appetite. Four deaths have been attributed to
accidental poisoning by EDB [8].
- Chronic toxicity: Daily inhalation of
EDB vapors for 6 to 13 weeks at levels comparable to
human occupational exposures damaged the liver, kidney,
and testes of rats, and changed chick livers [8].
- Reproductive effects: A study of male
workers exposed to low air levels of EDB at four separate
manufacturing sites showed no consistent association
between EDB and reproductive effects [177]. However,
another study of 46 men exposed to a lower average air
concentration for 5 years showed adverse effects on sperm
number, movement, survival, and structure [8]. Bulls had
abnormal sperm after 12 to 21 days of EDB exposure [8].
Fetal deaths increased in offspring of adult male rats
given high doses of EDB in the diet for 5 days before
mating [8]. Cows and ewes given lower doses did not show
any effects on reproduction [8]. The available data
indicate that reproductive effects may be possible in
humans, but that there may be a (threshold) level below
which effects are very unlikely.
- Teratogenic effects: In one study, no
teratogenic effects were observed in offspring of
pregnant rats and mice who were exposed to various levels
of EDB vapors for 23 hours a day during the sensitive
period of gestation [178]. At all doses, both rats and
mice showed body weight decreases, and a significant
number of deaths occurred in the adults exposed to the
high doses. Since these effects occurred at doses that
caused serious adverse maternal effects, it was unclear
whether the observed fetal toxicity was caused simply by
reduced maternal health [178]. Hens fed daily diets of 1
to 2 ppm EDB had decreased egg weights [8]. The available
evidence suggest that EDB does not cause teratogenic
effects.
- Mutagenic effects: EDB has been shown to
be weakly mutagenic in several bacterial and animal test
systems [8]. It has not been shown to be mutagenic in
humans, either in cell cultures or in the whole organism
[8].
- Carcinogenic effects: Rats inhaling high
daily doses of EDB for 18 months developed tumors of the
mammary glands, spleen, adrenals, liver, and kidney
[179]. When rats were subjected to airborne EDB and also
given disulfiram orally over 14 months, increased tumors
in the liver, kidneys, thyroids, and lungs appeared. The
tumor increase was higher than that caused by EDB at the
same levels over 18 months [179]. The available evidence
indicates that EDB may be carcinogenic.
- Organ toxicity: EDB contact may damage
the lung, skin, and eyes. Acute and chronic systemic
effects may be seen in the liver, kidneys, and heart, and
other internal organs and systems. Lung injury can also
lead to secondary effects such as pneumonia and
respiratory tract infections.
- Fate in humans and animals: EDB is
readily and rapidly absorbed across the lung, skin, and
gastrointestinal tract in liquid and vapor forms [8].
Once absorbed, it is rapidly broken down, and metabolites
may be found in the urine, kidneys, liver, adrenal
glands, pancreas, and spleen of EDB-exposed animals
shortly after application [8]. About two thirds of the
applied dose are excreted through urine or expired air
[178]. EDB has a biological half-life of less than 48
hours in rats, chicks, mice, and guinea pigs [8].
Ecological Effects:
- Effects on birds: EDB is most likely to
be in vapor form, and unless birds are in the fumigation
area, during the fumigation, they are unlikely to be
exposed.
- Effects on aquatic organisms: EDB is
slightly toxic to fish [8]. The reported LC50 value in
the shiner is 40.3 mg/L. The calculated bioconcentration
factor for EDB in aquatic organisms ranges between 9.3 to
10.2, suggesting that it has a low potential for
bioaccumulation [180].
- Effects on other organisms: No data are
currently available.
Environmental Fate:
- Breakdown in soil and groundwater: The
fastest degradation of EDB occurs at or near the soil
surface. EDB is moderately persistent in the soil
environment; a representative field half-life was
estimated to be 100 days [11]. In one study, after 2
months, almost all of EDB was dissipated [11,181].
Sunlight readily degrades EDB. EDB near the soil surface
is converted to ethylene and bromide ions, and that small
percentage which remains is unchanged, possibly adsorbed
to soil organic matter or clay particles or entrapped in
soil micropores [181]. EDB thus entrapped may be
inaccessible to microbial degraders and may slowly leach
to groundwater over very long periods [181]. Such
leaching is very slow at normal temperatures, but
increases with higher temperatures [181]. Groundwater
contamination of EDB has been confirmed at levels up to
0.3 mg/L [182,183]. Usual levels of EDB found in
groundwater were approximately 0.001 to 0.02 mg/L, which
are similar to levels found in stored grain products
[182].
- Breakdown in water: EDB can be widely
distributed in aqueous systems. The primary removal
process for ethylene dibromide in water is evaporation
[182]. EDB has a half-life of slightly over 1 day in
river water, and about 5 days in lake water [182,184].
Binding to sediment is relatively low. EDB decomposes in
the presence of heat and/or light and can be slowly
broken down by moisture. The major degradation products
in water are also ethylene and bromide ions.
- Breakdown in vegetation: Because of the
inability of plants to take EDB up from soil, it is not
likely to accumulate in plants. However, EDB's breakdown
product, inorganic bromide, is taken up by plants in
small amounts. Residues of EDB persist in fumigated food
products for 6 to 12 weeks. EDB residues in grain and
feed do not accumulate in livestock to any significant
extent. Cooking may dramatically reduce the levels of EDB
residues in foods [8].
Physical Properties:
- Appearance: Ethylene dibromide is a
heavy, colorless liquid with a mildly sweet, chloroform
odor [1].
- Chemical Name: 1,2-dibromoethane [53]
- CAS Number: 109-93-4
- Molecular Weight: 187.90
- Water Solubility: 4300 mg/L @ 20 C [53]
- Solubility in Other Solvents: soluble in
alcohols, ethers, acetone, benzene, and most organic
solvents [8]
- Melting Point: 9.8 C [8]
- Vapor Pressure: 1.5 x 10^6 mPa [53]
- Partition Coefficient: 53.7-61.7
(calculated) [8]
- Adsorption Coefficient: 34 (estimated)
[53]
Exposure Guidelines:
- ADI: 1.0 mg inorganic bromide mg/kg/day
[12]
- MCL: 0.00005 mg/L [65]
- RfD: Not Available
- PEL: 154 mg/m3 (8-hour)
- HA: Not Available
- TLV: Not Available
Basic Manufacturer:
United Phosphorous Ltd.
Readymoney Terrace
167 Dr. Annie Besant Rd.
Bombay 400 018 India
- Phone: 22-493-0681
- Emergency: 22-493-2427
References:
References for the information in this PIP can be found in
Reference List Number 10
DISCLAIMER: The
information in this profile does not in any way replace or
supersede the information on the pesticide product labeling or
other regulatory requirements. Please refer to the pesticide
product labeling.