EPA Technical Factsheet on: Ethylene Dibromide (EDB)
National Primary Drinking Water Regulations - EPA
Technical Factsheet on:
ETHYLENE DIBROMIDE (EDB)
Drinking Water Standards
MCLG: zero mg/l Health Effects Summary
Acute: EPA has found ethylene dibromide (EDB) to
potentially cause a variety of acute health effects, including damage
to the liver, stomach, and adrenal cortex along with significant
reproductive system toxicity, particularly the
testes.
Drinking water levels which are considered "safe" for
short-term exposures: For a 10-kg (22 lb.) child consuming 1 liter of
water per day, a one-day exposure of 0.008 mg/L or a ten-day exposure
to 0.008 mg/L.
Chronic: A lifetime exposure to EDB at levels above the
MCL has the potential to damage the respiratory system, nervous
system, liver, heart, and kidneys.
Cancer: There is some evidence that EDB may have the
potential to cause cancer from a lifetime exposure at levels above the
MCL.
Usage Patterns: Ethylene dibromide is mainly used (83%
of all use) as a scavenger for lead in anti-knock gasoline mixtures,
particularly in aviation fuel. Other uses (17%) include: solvent for
resins, gums, and waxes; in waterproofing preparations; as a chemical
intermediate in the synthesis of dyes and pharmaceuticals; and as a
fumigant, insecticide, nematicide for grains and fruit. (It's a
nerve-agent!)
Persistence can vary greatly from soil to soil. In one
laboratory screening study using 100 soils, half-lives ranging from
1.5 to 18 weeks were determined. In one field, ethylene bromide was
detected in soil 19 years after its last known application; the long
persistence was the result of entrapment in intraparticle micropores
of the soil. Low Koc values and detection in various ground waters
indicate that ethylene bromide will leach in soil. The relatively high
vapor pressure (11.2 mm Hg) indicates evaporation will occur from soil
surfaces.
In the atmosphere, ethylene dibromide will degrade by
reaction with photochemically produced hydroxyl radicals (half life 32
days).
The primary removal process for ethylene bromide in
surface water is volatilization. Under normal conditions, the
volatilization half-life from a typical river and lake are about one
day and 5 days, respectively.
In ground waters (such as aquifers) where volatilization
does not occur, ethylene bromide can be degraded by biodegradation and
hydrolysis. Uncatalyzed hydrolysis is slow, with half-lives reported
of 6 yr at 25 deg C, to 13.2
yr at pH7 and 20 deg C. But hydrolysis catalyzed by the presence of
various natural substances (such as HS ion) may be competitive with
biodegradation (half-life of 1-2 months). It
reacts with photochemically produced hydroxyl radicals with a half
life of 32 days or a 2.2% loss per sunlit day. Ethylene bromide does
not directly photolyze when exposed to uv light between 300 and 400
nm.
Biodegradation can be a primary degradation process in
soil. A review of available biodegradation data pertaining to ethylene
bromide concluded that ethylene bromide is biotransformed fairly
readily in the environment; lifetimes
can be as short as several days in surface soils and as long as many
months in aquifer materials.
MCL: 0.00005 mg/l
HAL(child): 1 day: 0.008 mg/l
10-day: 0.008 mg/l