Technical Factsheet on: 1,2,4-TRICHLOROBENZENE
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: 0.07 mg/L
MCL: 0.07 mg/L
HAL(child): 1 day: 0.1 mg/L; Longer term: 0.1 mg/L
Health Effects Summary
Acute: EPA has found 1,2,4-trichlorobenzene to potentially cause the following health effects
from acute exposures at levels above the MCL: changes in liver, kidneys and adrenal glands
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: upto a 7-year exposure to 0.1 mg/L.
Chronic: 1,2,4-Trichlorobenzene has the potential to cause the following health effects from
long-term exposures at levels above the MCL: increased adrenal gland weights
Cancer: There is presently no evidence that 1,2,4-Trichlorobenzene has the potential to cause
cancer from a lifetime exposure in drinking water.
Usage Patterns
Current production figures on 1,2,4-trichlorobenzene are not available. EPA estimated 1983
production to be in the range of 3 to 8 million lbs. 1983 imports were reportedly over 3 million
lbs.
1,2,4-Trichlorobenzene is primarily used as a dye carrier. Other uses include: an intermediate in
the manufacture of herbicides and higher chlorinated benzenes; dielectric fluid; solvent;
heat-transfer medium; degreasing agents; septic tank and drain cleaners; wood preservatives; and
abrasive formulations. It was once used as a soil treatment for termite control.
Release Patterns
Major environmental releases of 1,2,4-trichlorobenzene are due to its manufacture and use as a
dye carrier. 1,2,4-Trichlorobenzene is also a product of hexachlorobenzene dechlorination by
anaerobic sewage sludge.
From 1987 to 1993, according to EPA's Toxic Chemical Release Inventory, 1,2,4-
trichlorobenzene releases to land and water totalled over 180,000 lbs., of which about 87% was
to water. These releases were primarily from textile finishing industries. The largest releases
occurred in North Carolina and Virginia.
Environmental Fate
If 1,2,4-trichlorobenzene (1,2,4-TCB) is released to the soil it will probably adsorb to the soil and
therefore will not leach appreciably to the groundwater. However, 1,2,4-TCB has been detected
in some groundwater samples which indicates that it can be transported there by some process.
1,2,4-TCB will not hydrolyze or biodegrade in groundwater, but it may biodegrade slowly in the
soil based upon the data from one experiment.
If released to water it will adsorb to the sediments. It will not hydrolyze in surface waters but it
may be subject to significant biodegradation. It is expected to significantly evaporate from water
with half-lives of 11-22 days for evaporation from a seawater microcosm and a half-life of 4.2 hr
predicted for evaporation from a model river. Adsorption to sediments or absorption by
microorganisms may minimize the rate of evaporation. A half-life of 450 years has been reported
for sunlight photolysis in surface waters at 40 deg latitude in summer.
If 1,2,4-trichlorobenzene is released to the atmosphere, it may react with photochemically
produced hydroxyl radicals with a resulting estimated vapor phase half-life in the atmosphere of
18.5 days.
Bioconcentration in aquatic organisms has been measured and values for fish ranging from 51 to
2800 have been reported.
Exposure to 1,2,4-trichlorobenzene will result mainly from occupational exposure during its
manufacture and use, while general population exposure will result from the ingestion of
contaminated drinking water and food, especially contaminated fish.
Chemical/Physical Properties
CAS Number: 120-82-1
Color/ Form/Odor: Aromatic, colorless liquid
M.P.: 17 C B.P.: 213.5 C
Vapor Pressure: 0.29 mm Hg at 25 C
Octanol/Water Partition (Kow): Log Kow = 4.02
Density/Spec. Grav.: 1.45 at 20 C
Solubility: 30 mg/L of water at 20 C; Slightly soluble in water
Soil sorption coefficient: Koc ranges from 1000 to 5000; moderate to high
mobility in soil
Odor/Taste Thresholds: Odor threshold in water is 3 mg/L
Bioconcentration Factor: BCFs range from 490 to 2800 in fish; expected to
bioconcentrate in aquatic organisms.
Henry's Law Coefficient: 3.9x10-3 atm-cu m/mole
Trade Names/Synonyms: 1,2,4-Trichlorobenzol, Hostetex L-PEC
Other Regulatory Information
Monitoring:
-- For Ground/Surface Water Sources:
Initial Frequency- 4 quarterly samples every 3 years
Repeat Frequency- Annually after 1 year of no detection
-- Triggers - Return to Initial Freq. if detect at > 0.0005 mg/L
Analysis
| Reference Source | Method Numbers |
|---|
| EPA 600/4-88-039 | 502.2; 524.2 |
Treatment - Best Available Technologies: Granular Activated Charcoal and Packed Tower
Aeration
Toxic Release Inventory - Releases to Water and Land, 1987 to 1993 (in pounds):
| | Water | Land |
|---|
| TOTALS (in pounds) | 157,541 | 22,835 |
|---|
| Top Five States* |
|---|
|
NC | 80,253 | 13,209
| |
VA | 36,970 | 0
| |
GA | 17,639 | 8,951
| |
WV | 20,300 | 0
| |
NY | 1,150 | 1
|
| Major Industries* |
|---|
|
Finishing plants, misc | 52,249 | 0
| |
Finishing plants, synth. | 47,976 | 0
| |
Weaving, finishing mills | 20,139 | 8,951
| |
Alkalies, chlorine | 21,773 | 1
| |
Knitting mills, misc | 9,077 | 9,994
| |
Knit outerwear mills | 1,300 | 3,200
|
* Water/Land totals only include facilities with releases greater than 100 lbs.
For Additional Information
EPA can provide further regulatory or 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
List of Contaminants
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