| Environmental Impact | 1,2,4-Trichlorobenzene's release to the environment will occur through its manufacture
and use as a dye carrier (major use), intermediate in the manufacture of herbicides and higher
chlorinated benzenes, dielectric fluid, solvent, heat-transfer medium, and its use in degreasing
agents, septic tank and drain cleaners, wood preservatives, and abrasive formulations. If it is
released to the soil it will probably adsorb to the soil and therefore will not leach appreciably
through soil. However, 1,2,4-trichlorobenzene (1,2,4-TCB) has been detected in some
groundwater samples. 1,2,4-Trichlorobenzene will not hydrolyze or biodegrade in groundwater,
but it may biodegrade slowly in the soil based upon the data from one experiment. If
1,2,4-trichlorobenzene is released to water it will adsorb to the sediments and may bioconcentrate
in aquatic organisms. It will not hydrolyze in surface waters but it may be subject to slow
biodegradation. It is expected to evaporate from water with half-lives of 11-22 days for
evaporation from a study of a physically mixed, 5.4 m deep seawater microcosm and a half-life of
4.2 hr predicted for evaporation from a model river 1 m deep, flowing at 1 m/sec with a wind
velocity of 3 m/sec. 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. 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.
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| Environmental Fate | TERRESTRIAL FATE: If 1,2,4-trichlorobenzene (1,2,4-TCB) is released to the soil it
will be expected to adsorb to the organic matter in soil and therefore should 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. It will not hydrolyze but it may
biodegrade slowly in the soil based upon the data from one experiment ; It will not be expected
to biodegrade in the groundwater . Sorption of 1,2,4-trichlorobenzene to a series of subsurface
soil samples has been reported . Desorption of sorbate from the sorbent matrix provides better
precision than conventional solution phase concentration differences when sorption is low .
Clay mineral content influences sorption on low C sorbents . This is important in the movement
sorption on low hazardous material from soil into the groundwater . Outdoor experiments with
(14)C-1,2,4-trichlorobenzene indicate that the time course of formation and fate of bound
residues in soils and plants is characterized by a very slow decrease of residue levels in soil,
indicating that biodegradation of bound residues hardly exceeds their reformation from the parent
compound during one vegetation period . The portion of total residues occurring as bound
residues increases with time, indicating that bound residues are more persistent than the unbound
residues .
AQUATIC FATE: If 1,2,4-trichlorobenzene (1,2,4-TCB) is released to water it will be expected
to adsorb to the sediment. Bioconcentration in aquatic organisms has been measured and values
ranging from 51 to 2800 have been reported. It will not hydrolyze. Although no data were found
concerning biodegradation in natural waters, 1,2,4-trichlorobenzene may be subject to
biodegradation in such waters based on limited laboratory tests using various wastewaters as
sources for microbes. 1,2,4-Trichlorobenzene may be subject to significant evaporation from
water with half-lives of 11-22 days for evaporation from a study of a mixed, 5.4 m deep seawater
microcosm . Using a calculated Henry's Law constant, a half-life of 4.2 hr was predicted for
evaporation from a model river 1 m deep, flowing at 1 m/sec with a wind velocity of 3 m/sec.
Adsorption to sediments or absorption by microorganisms may minimize the evaporation process.
It will not be expected to appreciably directly photolyze in surface waters based on a reported
half-life for sunlight photolysis in surface water at 40 deg latitude in summer of 450 yr .
Half-lives of 2.1, 1.5 and 28 days were estimated in rivers in the Netherlands based upon
monitoring data .
ATMOSPHERIC FATE: If 1,2,4-trichlorobenzene is released into the atmosphere it will be
subject to reaction with photochemically produced hydroxyl radicals with an estimated vapor
phase half-life in the atmosphere of 18.5 days(1,SRC). It will not be expected to be subject to
appreciable direct photolysis .
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| Drinking Water Impact | DRINKING WATER: US, 1976-77, 11 cities, 91% pos, 110 samples, 0.01-0.53 ppb,
avg 0.09 ppb . Ontario, Canada, 1980, 3 cities, 1-4 parts per trillion, avg 2 parts per trillion .
Bankfiltered Rhine River tapwater, >5 ppb .
GROUNDWATER: The Netherlands, 1976, 250 groundwater pumping stations, max concn, 1.2
ppb .
SURFACE WATER: Niagara Falls and Buffalo, NY, avg 0.5 parts per trillion . In 1980: Lake
Ontario, 5 stations, 0.3-1 parts per trillion, avg 0.6 parts per trillion, Lake Huron, 0.1-0.4 parts
per trillion, avg 0.2 parts per trillion; Grand River, Ontario, not detected-8 parts per trillion, avg 2
parts per trillion; Niagara River, 4 sites, 0.1-107 parts per trillion, (max just below chemical
manufacturer's effluent discharge), avg of lowest 3 sites 6.4 parts per trillion . Niagara River,
Niagara-on-the-Lake: 1981-83, 104 samples, 100% pos, 5.8-120 parts per trillion, avg 16 parts
per trillion, median 12 parts per trillion ; 1981, 4.9-52 parts per trillion, avg 11 parts per trillion,
median 9.1 parts per trillion . Rhine River: 1977-82, detected (<0.1 ppb) ; 0.05 ppb(6).
RAIN/SNOW: Portland, OR, 1982, 4 rain events, 25% pos, 0.10 parts per trillion ; 1984, 7
sampling periods, 43% pos, 17 total days, 0.13-0.45 parts per trillion, avg pos 0.25 parts per
trillion .Southeast Portland, 1982, 5 rain events, 40% pos, 0.086 parts per trillion and 0.11
parts per trillion .
SURFACE WATER: Capillary column gas chromatography-mass spectrometry was performed
on water from a river located in the North Carolina Piedmont sampled at three locations several
times during a thirteen month period after isolation either by resin adsorption or direct methylene
chloride liquid-liquid extraction. Of the 48 distinct SOCs detected, 1,2,4-trichlorobenzene was
found frequently . Concentrations of the SOCs were in the ng/L to ug/L range .
SEAWATER: Southern North Sea (Rhine/Meuse Estuary, Aug 1983-Jul 1984) <0.3-24 parts per
trillion, 1.0 parts per trillion median concn .
EFFL: Concentration in advanced wastewater treatment plant - influent 0.11-0.46 parts per
trillion, effluent not detectable to 0.01 parts per trillion, 97.8 - >99% removed . USA, several
industrial wastewater surveys 1978-79, 3,266 samples, 0.92% pos, 12-607 ppb, avg 161 ppb .
Major Southern California municipal wastewaters, 1976, 6 sites: 2 test periods each, 5 sites:
0.018-100 ppb, avg 1.2 ppb, last site, 43 and 100 ppb, avg mass emission rates to Southern
California Bight, 1975-76, 10-1580 kg/yr . Hazardous waste incinerator effluents, concn in
extracts of effluent gases, 220,000 ppm . USA National Urban Runoff Program, 15 cities, 86
samples, not detected .
Major Southern California Municipal wastewaters, 1978, 8 stations, summer, 0.007-2.2 ppb,
winter, <0.01-0.03 ppb . Detected at 1.2 ng/cu m in stack effluent from coal-fired power plants
in Ames, IA . Detected in US industrial wastewaters (number of samples/% pos, max/avg concn
(ppb)): foundries, raw water, 2/100% pos, 1000 max/500 avg, treated water, 2/100% pos,
570/290. textile mills, raw water, 50/16% pos, 2700/410, treated water, 50/32% pos, 1400/14,
electrical/electronic components, 2/100%, 27,000/16,600 (4,500 min concn) .
1,2,4-Trichlorobenzene was detected in municipal waste water at Port Loma sewage treatment
plant, at concn of 0.23 ug/l (Fall, 1976) and 0.01 ug/l (Summer, 1976), respectively.
1,2,4-Trichlorobenzene was detected in municipal waste water at Oxnard, CA sewage treatment
plant at concn of 0.9 ug/l (Fall) and 0.25 ug/l (Summer), respectively.
1,2,4-Trichlorobenzene was detected in municipal waste water at the Orange County Sewage
Dept, LA at a concn of 0.30 ug/l.
1,2,4-Trichlorobenzene was detected in 5 mile effluent and municipal waste water at the sewage
treatment works, Hyperion, LA, at concn of 6.7 ug/l and 3.1 ug/l respectively.
1,2,4-Trichlorobenzene was detected in municipal waste water at the Joint Water Pollution
Control Plant (location not specified), at concn of 6.0 ug/l (Fall) and 1.8 ug/l (Summer, 1976).
1,2,4-Trichlorobenzene was detected in industrial discharge at Chattanooga Creek, TN, at a
concn of 500 ug/l (Spring, 1976).
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