United States
Environmental Protection
Agency
Office of Water
4601
EPA 811-F-95-004q-T
October 1995
National Primary Drinking
Water Regulations
1,2,4-Trichlorobenzene
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 thresh-
old in water is 3 mg/L
BlOCONCENTRATION 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
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
carrier. Other uses include: an intermediate in the manu-
facture of herbicides and higher chlorinated benzenes;
dielectric fluid; solvent; heat-transfer medium; degreas-
ing agents; septic tank and drain cleaners; wood preser-
vatives; and abrasive formulations. It was once used as
a soil treatment for termite control.
HEALTH EFFECTS SUMMARY
RELEASE PATTERNS
: EPA has found 1,2,4-trichlorobenzene to DO- Major environmental releases of 1,2,4-trichlorobenzene
tentially cause the following health effects from acute are due to its manufacture and use as a dye earner. 1 2,4-
•* w n^» AL^ I A r A l-m r'*^^1**'* A tf+ f*lr+r\ »•* v^rAi*4i !*•*+ *"»+ L>* Aunmlt I At-s^t-is^f*
exposures at levels above the MCL: changes in liver,
kidneys and adrenal glands
Trichlorobenzene is also a product of hexachloroben-
zene dechlorination by anaerobic sewage sludge.
Drinking water levels which are considered "safe" for
short-term exposures: Fora 10-kg (22 Ib.) child consum-
ing 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 expo-
sures 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 Ibs. 1983 imports were
reportedly over 3 million Ibs.
1,2,4-Trichlorobenzene is primarily used as a dye
Tbx/c RELEASE INVENTORY -
RELEASES TO WATER AND LAND: 1987
Water
TOTALS (in pounds) 1 57,541
.
Top Fiv& StstGS
NC 80,253
VA 36,970
GA 17,639
WV 20,300
NY 1,150
Major Industries"
Finishing plants, misc 52,249
Finishing plants, synth. 47,976
Weaving, finishing mills 20,139
Alkalies, chlorine 21,773
Knitting mills, misc 9,077
Knit outerwear mills 1 ,300
* Water/Land totals only include facilities with
greater than 100 Ibs.
TO 1 993
Land
22,835
13,209
0
8,951
o
1
0
0
8,951
1
9,994
3,200
releases
October 1995
Technical Version
-------
From 1987 to 1993, according to EPA's Toxic Chemi-
cal Release Inventory, 1,2,4-trichlorcbenzene releases
to land and water totalled over 18C.JOO Ibs., 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 biode-
grade 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 microorgan-
isms 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 mea-
sured 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.
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
EPA 600/4-88-039
METHOD NUMBERS
502.2; 524.2
TREATMENT:
BEST AVAILABLE TECHNOLOGIES
Granular Activated Charcoal and Packed Tower Aeration
FOR ADDITIONAL INFORMATION:
* EPA can provide further regulatory and other general information:
• EPA Safe Drinking Water Hotline - 800/426-4791
* Other sources of lexicological 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 I
October 7995
Technical Version
Page 2
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