Technical Factsheet on: DIBROMOCHLOROPROPANE (DBCP)
List of Contaminants
As part of the Drinking Water and Health pages, this fact sheet is part of a larger publication:
National Primary Drinking Water Regulations
Drinking Water Standards
MCLG: zero mg/L
MCL: 0.0002 mg/L
HAL(child): 1 day: 0.2 mg/L; 10-day: 0.05 mg/L
Health Effects Summary
Acute: EPA has found DBCP to potentially cause kidney and liver
damage and atrophy of 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 0.2 mg/L or a ten-day exposure to
0.05 mg/L.
Chronic: DBCP has the potential to cause kidney damage and
antifertility effects from long-term exposure at levels above the
MCL.
Cancer: There is some evidence that DBCP may have the potential
to cause cancer from a lifetime exposure at levels above the MCL.
Usage Patterns
DBCP was once used as an unclassified nematocide for soil
fumigation of cucumbers, summer squash, cabbage, cauliflower,
carrots, snap beans, okra, aster, shasta daisy, ornamental turf
(lawns), bermudagrass, centipedegrass, St Augustine grass, zoysia
grass, ardisia, azalea, camellia, forsythia, gardenia, hibiscus,
roses, and arborvitae.
Though it is also used as a chemical intermediate in the
production of a flame-retardant, essentially all of its present
use is as a soil fumigant.
Release Patterns
In the past, release of DBCP to the environment occurred
primarily from its fumigant and nematocide uses. In 1977, 831,000
pounds of DBCP was used in CA alone, mainly on grapes and
tomatoes. In 1974, USA farmers applied 9.8 million pounds of DBCP
on crops.
All registrations of end use products were cancelled in 1979
except for the use as a soil fumigant against nematodes on
pineapples in Hawaii. This use was cancelled in 1985. The use of
DBCP as a laboratory reactant is not expected to result in
significant release to the environment.
Environmental Fate
DBCP released to soil will likely volatilize or leach to
groundwater. In a model soil assumed to contain
1,2-dibromo-3-chloropropane (DBCP) evenly distributed within the
first 10 cm, the volatilization half-life of DBCP was estimated
to be 1.2 days. The observed log soil sorption coefficient (Koc)
of DBCP is 2.11 in an unspecified soil. In a soil containing 10%
moisture, the log Koc of DBCP is 1.6. Modelling predicted that
DBCP will adsorb so weakly that it will co-migrate with water
through low organic content soil.
In alkaline soils, hydrolysis may be significant and
biodegradation is possible but is expected to be slow relative to
volatilization and leaching to groundwater. Soil microorganisms
(primarily Pseudomonas and Flavobacteria) dehalogenated DBCP at a
rate of 20% in 1 week at pH 8.
In water, DBCP is expected to volatilize rapidly and hydrolyze
slowly. Using measured values of the water solubility and vapor
pressure of 1230 mg/l and 0.58 mm Hg, respectively, a Henry's Law
constant of 1.47X10-4 atm-cu m/mol was estimated. The
volatilization half-life values were 9.5 hr, 13.5 hr, and 224.2
days, respectively, for streams, rivers, and lakes.
Hydrolysis half-lives of 38 and 141 years have been reported at
25 and 15 deg C, respectively, at pH 7. In groundwater, DBCP is
expected to persist due to its low estimated rate of hydrolysis
(half-life= 141 years at 15 deg C). Biodegradation may occur, but
is expected to be slow relative to the rate of volatilization.
Sorption to sediments and bioconcentration are not expected to be
significant fate processes.
In the atmosphere, vapor phase DBCP is expected to react with
photochemically produced hydroxyl radicals with an estimated
half-life of 12.19 days.
A bioconcentration factor for 1,2-dibromo-3-chloropropane of 11
was estimated from a measured water solubility of 1,230 ppm.
Chemical/ Physical Properties
CAS Number: 96-12-8
Color/ Form/Odor: Dense yellow liquid with pungent odor; may also
be granular
M.P.: 5 C B.P.: 196 C
Vapor Pressure: 0.8 mm Hg at 21 C
Density/Spec. Grav.: 2.08 at 20 C
Octanol/Water Partition (Kow): Log Kow = 2.43 (calculated)
Solubility: 1.23 g/L of water at 25 C; Slightly soluble in
water
Soil sorption coefficient: Log Koc = 2.01; high mobility
Odor/Taste Thresholds: Taste threshold in water is 0.01 mg/L
Bioconcentration Factor: 11 (est.); low bioconcentration
potential
Henry's Law Coefficient: 1.47x10-4 atm-cu m/mole;
Trade Names/Synonyms: DBCP; BBC 12; Fumagon; Fumazone; Nemabrom;
Nemafum; Nemagon; Nemanax; Nemapaz; Nemaset; Nemazon; Gro-Tone
Nematode; Durham Nematocide EM 17.1
Other Regulatory Information
Monitoring For Ground/Surface Water Sources:
- Initial Frequency- 4 quarterly samples every 3 years
- Repeat Frequency- If no detections during initial round:
- 2 quarterly per year if serving >3300 persons;
- 1 sample per 3 years for smaller systems
- Triggers - Return to Initial Freq. if detect at > 0.00002 mg/L
Analysis:
| Reference Source |
Method Numbers |
| EPA 600/4-88-039 |
504.1; 551 |
Treatment- Best Available Technologies:
Granular Activated Charcoal
For Additional Information:
EPA can provide further regulatory and other general information:
EPA Safe Drinking Water Hotline - 800/426-4791
Other sources of toxicological and environmental fate data include:
Toxic Substance Control Act Information Line - 202/554-1404
Toxics Release Inventory, National Library of Medicine - 301/496-6531
Agency for Toxic Substances and Disease Registry - 404/639-6000
National Pesticide Hotline - 800/858-7378
List of Contaminants
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