E X T O X N E T
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Pesticide
Information
Profile
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Ethylene Dibromide (EDB)
Publication Date: 9/93
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TRADE OR 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, EDB-85, Fumo-Gas, Kopfume, Nephis, and
Soilfume.
INTRODUCTION
Until recently, ethylene dibromide (EDB) was used extensively as a
soil and post-harvest fumigant for crops, and as a quarantine fumigant
for citrus and tropical fruits and vegetables. In 1983, the EPA
suspended the use of EDB as a fumigant when low-level residues were
found in groundwater and some grains. Today, EDB is principally used as
a scavenger additive in leaded gasoline. It is also registered for use
as a gas in termite and Japanese beetle control, beehive and vault
fumigation, and spot fumigation of milling machinery.
Because the odor of EDB may not be detected until concentrations
are above the recommended workplace levels, careful monitoring is
required to limit exposure.
TOXICOLOGICAL EFFECTS
ACUTE TOXICITY
EDB is a highly toxic compound and is labeled with a DANGER signal
word. Inhalation is the most hazardous route of exposure to EDB;
however it may also be toxic by skin contact or ingestion. EDB is a
severe skin and eye irritant. Direct contact can result in skin
blistering. It can also be rapidly absorbed into the body through the
skin in toxic amounts. Agricultural and food storage workers are at
highest risk. Symptoms of poisoning include headache, depression and
loss of appetite. Four deaths have been attributed to accidental
poisoning by EDB (5).
The oral LD50 of EDB is 108 mg/kg for rats, 250 mg/kg for mice, and
55 mg/kg for rabbits (15). The lowest dose that resulted in mortality
in a woman was recorded at 90 mg/kg. One woman who ingested a fatal
dose of 4.5 ml experienced rapid breathing, vomiting, and diarrhea. Her
liver and kidneys were damaged (15).
Administration of very high doses of EDB to rats and chicks caused
changes in the livers of these animals within 22 hours (2).
The inhalation LD50 for rats is 400 ppm for two hours (15) and 689
ppm for one hour. In rats, inhalation of small concentrations of EDB
vapors depresses weight gain, and slightly higher levels damage the
lungs.
CHRONIC TOXICITY
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 (14). But, another study of 46 men exposed
to a lower average air concentration for five years showed adverse
effects on sperm number, movement, survival, and structure (15). Bulls
had abnormal sperm after 12-21 days of EDB exposure (12).
Fetal deaths increased after adult male rats were given high doses
of EDB in the diet for five days before mating. Cows and ewes given
lower doses did not show any effects on reproduction (16).
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 (12). 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. While fetal death rates increased and body weights decreased,
EDB was not considered a teratogen because adverse fetal effects
primarily occurred at doses that also adversely affected the mother.
The fetal abnormalities may have been a consequence of maternal
toxicity, such as weight loss, which was brought about by EDB exposure.
Hens fed daily diets of 1-2 ppm EDB had decreased egg weights (15).
Mutagenic Effects
EDB has been reported to be mutagenic in some test systems but it
has not shown mutagenic effects on human cells (1).
Carcinogenic Effects
EDB is considered a carcinogen in rats and mice. Rats inhaling
high daily doses of EDB for 18 months developed tumors of the mammary
glands, spleen, adrenals, liver, and kidney (13).
EDB is a suspected human carcinogen (15). Data from animal studies
led the EPA to estimate nearly 100% lifetime incidence of cancer to be
expected in workers exposed to EDB for 40 years at fumigation centers.
Actual incidence has been much less-about 5%-in a group of workers
employed in EDB production plants (11).
The risk of cancer may be increased in people exposed to EDB who
are also using disulfiram, a generally safe drug that is used in the
treatment of alcoholism (13). When rats inhaled EDB and also ate
disulfiram for 14 months, many tumors in the liver, kidneys, thyroids,
and lungs appeared. The number of tumors was even higher than if the
rats inhaled the same dose of EDB by itself for 18 months (9, 13).
Organ Toxicity
Exposure to high levels of EDB may damage the lung, liver, kidneys,
heart, and other internal organs and systems (10). Lung injury can also
lead to secondary effects like pneumonia and respiratory tract
infections. Humans may become nauseated at high air concentrations,
depending on the length of exposure.
Daily inhalation of EDB vapors for six to 13 weeks at levels
comparable to human occupational exposures damaged the liver, kidney,
and testes of rats, and changed chick livers. Changes in the lungs and
respiratory tract and temporary clouding of the corneas have been seen
in animal studies after only one week of exposure to workplace levels of
EDB.
Human skin can be severely irritated when exposed to large amounts
of EDB for two hours, during which burning, itching, redness,
blistering, and swelling occurs. Rabbits exposed to a 1% EDB solution
for 14 days developed severe skin irritation (16).
Fate in Humans and Animals
EDB is readily and rapidly absorbed from the lungs when breathed as
vapors, from the gastrointestinal tract when ingested, or through the
skin when applied topically. EDB is broken down in the body to
inorganic bromide, which is found in the urine, liver, and tissues of
EDB-exposed animals. EDB has a biological half-life of less than 48
hours in rats, chicks, mice, and guinea pigs (16).
Guinea pigs' metabolic pathways are similar to those of humans. In
one experiment, guinea pigs were injected with a single high dose of
EDB. After 72 hours, two thirds of the injected EDB was excreted as
metabolites in the urine and a tenth was exhaled in its original form.
The remainder was primarily found in the kidneys, liver, adrenal glands,
pancreas, and spleen (10).
ECOLOGICAL EFFECTS
The toxic dose of EDB to non-target organisms range from 10-100
ppm, a range that is much higher than has ever been found in surface
waters. No specific lethal dose values for wildlife species were found.
EDB residues in grain and feed do not accumulate in livestock to
any significant extent. Cooking reduces the levels of EDB in baking
mixes and other grain-based food products from 78 to 99%.
ENVIRONMENTAL FATE
Because of the inability of plants to take up EDB from the 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.
The fastest degradation of EDB occurs at or near the soil surface.
In about two months, almost all (97%) of EDB near the soil surface is
converted to ethylene and bromide ions.
The EDB that persists in the topsoil remains unchanged (17). This
EDB is thought to be entrapped in small air spaces within the soil. The
EDB that is entrapped in this way is inaccessible to microbial degraders
and can slowly leach to water supplies over very long periods. Such
leaching is very slow at 25 degrees C and is highly temperature-
dependent.
EDB is soluble, stable and persistent in water. It can be widely
distributed in aqueous systems. The primary removal process for
ethylene dibromide in water is evaporation (7). EDB has a half-life of
slightly over one day in river water and about five days in lake water.
Binding to sediment is relatively low.
EDB is present in outside air, mostly as a result of emissions from
automobiles and fumigation centers. EDB is stable in the air, with a
half-life of 45 days. Sunlight degrades EDB.
The major degradation products in soil and water are ethylene and
bromide ions. One decomposition product, ethylene glycol, may further
degrade to form, formaldehyde. EDB slowly decomposes in the presence of
heat and/or light and can be slowly broken down by moisture.
Groundwater contamination of EDB has been confirmed at levels up to
300 ppb (8). Usual levels of EDB found in groundwater were very low (1-
20 ppb). These values are similar to the levels found in stored grain
products.
PHYSICAL PROPERTIES AND GUIDELINES
Ethylene dibromide is a heavy, colorless liquid with a mildly
sweet, chloroform odor. The chemical is light-sensitive and reacts with
metals, oxidizing materials, and alkalis. EDB is both a halogenated
hydrocarbon and a brominated alkane.
Exposure Guidelines:
| NOEL (water, 10 days): | 0.008 mg/l (child), 0.027 mg/l (adult) |
| ADI: | 1.0 mg inorganic bromide/kg bw |
| TOL: | 10 ppm |
| PEL: | 20 ppm OSHA TWA; 30 ppm OSHA ceiling.(15) |
| TLV: | 0.13 ppm (ceiling limit - 15 min); 0.045 ppm (TWA - 8 hours) (15) |
| Drinking water health advisory: | 0.11 ug EDB/L water, based on carcinogenic risks |
Physical Properties:
| CAS #: | 106-93-4 |
| Molecular weight: | 187.88 |
| Solubility in water: | 0.404 g/100 g water (20 degrees C) (8) |
| Solubility in solvents: | EDB is soluble in alcohols, ethers, acetone, benzene, and most organic solvents. |
| Melting point: | 9.47 degrees C |
| Boiling point: | 131.7 degrees C |
| Vapor pressure: | 9 mm Hg (20 degrees C), 11 torr (25 degrees C) |
| Log P: | 1.064 (20 degrees C) |
| Kow: | 53.7-61.7 (calculated) (3, 4, 6) |
| Koc: | 44, 14-160, 21-93 (organic matter 0.5-21.7%) |
| BCF: | 9.3-10.2 (calculated) (3, 4, 6) |
| H: | 475.8 torr/M |
BASIC MANUFACTURER
United Phosphorous Ltd.
Readymoney Terrace
167 Dr. Annie Besant Rd.
Bombay 400 018 India
Telephone 22-493-0681
Emergency 22-493-2427
Review by Basic Manufacturer:
Comments solicited: November, 1992
Comments received:
REFERENCES
Bladeren, P.J., et al. 1980. Biochem. Pharmacol 29:2975-2982.
Broda, C., Nachtomi, E., and Alumot (Olomucki), E. 1976. Gen.
Pharmac. 7:345-348.
Hunter, R., et al. 1984. User Manual for the QSAR System. Center
for Data Systems and Analysis, Montana State University.
Leo, A. 1978. Report on the Calculation of Octanol/Water Log P
Values for Structures in the EPA Files. Claremont, CA.
Letz, G.A., Pond S.M., Osterloh, J.D., Wade, R.L. and Becker, C.E.
1984. JAMA 252:2428-2431.
Li, Fred. 1982. Technical data submitted in support of the San
Luis Drain Report of Waste Discharge, File Report, Branch of Scientific
Resources, USBR Department of Interior, 2800 Cottage Way, Sacramento, CA
95825.
Mackay, D., et al. 1982. "Volatilization of Organic Pollutants
from Water." USEPA-600/53-82-019.
McConnel, J.B., et al. 1984. "Investigation of Ethylene Dibromide
(EDB) in Groundwater in Seminole County, Georgia." U.S. Geological
Survey Circular 933.
Olson, W.A., Habermann, R.T., Weisburger, E. K., Ward, J.M., and
Weisburger, J.H. 1973. J. Nat. Cancer Inst. 51:1993-1995.
Plotnick, H.B. and Connor, W.L. 1976. Res. Commun. Chem. Pathol.
Pharmacol. 13:251-258.
Ramsey, J.C., Park, C.N., Ott, M.G. and Gehring, P.J. 1979.
Toxicol. Appl. Pharmacol. 47: 411-414.
Short, R.D., et al. 1978. Toxicol. Appl. Pharmacol. 45: 173-
182.
Wong, L.C.K., Winston, J.M., Hong, C.B. and Plotnick, H. 1982.
Toxicol. Appl. Pharmacol. 63: 155-165.
Wong, O., Utidjian, H.M.D., Karten, V. 1979. J. Occupat. Med.
21:98-102.
Occupational Health Services Inc. Material Safety Data Sheet for
Ethylene Dibromide. 3/25/87.
National Library of Medicine. Hazardous Substances Databank.
Ethylene Dibromide. May, 1992
Pignatello, J.J.; Sawhney, B.L.; Frink, C.R. EDB: Persistence in
Soil. Science 236: 898.
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in nature and may no longer be applicable.
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