| Chemical Abstract Number (CAS #) |
1330207
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| Synonyms | Total xylenes |
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Benzene, dimethyl- | Xylenes | Xylene, (total) |
| Analytical Method |
EPA Method 8240B |
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| Molecular Formula | C8H10 |
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| Use | RAW MATERIAL FOR PRODUCTION OF BENZOIC ACID; AS SOLVENT;
MANUFACTURING DYES & OTHER ORGANICS; STERILIZING CATGUT;
PRODUCTION OF PHTHALIC ANHYDRIDE, ISOPHTHALIC & TEREPHTHALIC ACIDS
& THEIR DIMETHYL ESTERS USED IN MANUFACTURE OF POLYESTER FIBERS;
WITH CANADA BALSAM AS OIL-IMMERSION IN MICROSCOPY; CLEANING AGENT
IN MICROSCOPE TECHNIQUE
Manufacture of resins, paints, varnishes, general solvent for adhesives
IN AVIATION GASOLINE; PROTECTIVE COATINGS; SYNTHESIS OF ORG
CHEMICALS
SOURCE OF O-XYLENE, M-XYLENE, P-XYLENE & ETHYLBENZENE
SOLVENT-EG, FOR PAINTS, COATINGS, ADHESIVES & RUBBER
BACK-BLENDED INTO GASOLINE
UNRECOVERED COMPONENT OF GASOLINE
Used in manufacture of quartz crystal oscillators, hydrogen peroxide, perfumes, insect repellants,
epoxy resins, pharmaceuticals, and in the leather industry.
/SRP: Used in histological laboratories.
Used as a solvent in phenoxyalkanoic herbicides.
(MEDICATION) Used in manufacture of pharmaceuticals .
Used as an indirect food additive for use only as a component of adhesives.
Used as an indirect food additive polymer for use as a basic component of single and repeated
use food contact surfaces. Xylene is used as a solvent in polysulfide polymer-polyepoxide resins.
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| Consumption Patterns | SOURCE OF P-XYLENE, 61.7%; SOURCE OF O-XYLENE, 12.3%; SOLVENT FOR
PAINTS & COATINGS, 5.7%; OTHER SOLVENT USES, 3.1%; SOURCE OF
ETHYLBENZENE, 3.1%; SOURCE OF M-XYLENE, 0.9%; GASOLINE BACK-BLENDING
& MISCELLANEOUS, 13.2% (1980 RECOVERED USE)
Ortho-xylene, 15%; para-xylene, 60%; miscellaneous, 14%; exports, 11% (1982) estimate/
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| Apparent Color | CLEAR LIQUID
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| Odor | Sweet odor
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| Boiling Point | 137-140 DEG C
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| Molecular Weight | 106.16
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| Density | 0.864 @ 20 DEG C/4 DEG C
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| Odor Threshold Concentration | In air: 5.00x10-5 ppm
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| Sensitivity Data | Xylene vapor may cause irritation of the eyes, nose, and throat. At high concentrations,
xylene vapor may cause severe breathing difficulties which may be delayed in onset. Repeated or
prolonged exposure may cause a skin rash.
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| Environmental Impact | Xylenes will enter the atmosphere primarily from fugitive emissions and exhaust
connected with their use in gasoline. Industrial sources include emissions from petroleum refining
and their use as solvents and chemical intermediates. Discharges and spills on land and waterways
result from their use in diesel fuel and gasoline, and storage and transport of petroleum products.
Most of the xylenes are released into the atmosphere where they may photochemically degrade by
reaction with hydroxyl radicals (half-life 1-18 hr). The dominant removal process in water is
volatilization. Xylenes are moderately mobile in soil and may leach into groundwater where they
are known to persist for several years, despite some evidence that they biodegrade in both soil and
groundwater. Bioconcentration is not expected to be significant. The primary source of exposure
is from air, especially at occupational sites where xylenes are used and in areas with high traffic.
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| Environmental Fate | TERRESTRIAL FATE: When spilled on land, xylenes will volatilize and leach into the
ground. Xylenes may be degraded during their passage through soil . The extent of the
degradation will undoubtedly depend on their concentration, residence time in the soil, the nature
of the soil, and whether resident microbial populations have been acclimated.
AQUATIC FATE: In surface waters, volatilization appears to be the dominant removal process
(half-life 1-5.5 days(2,SRC). Some adsorption to sediment will occur. Although xylenes are
biodegradable and have been observed to degrade in seawater, there is insufficient data to access
the rate of this process in surface waters. Although they have been observed to degrade in
groundwater in one study, they are known to persist for many years in groundwater at least at
sites where the concentration might have been quite high. In a field study of an oil spill from the
Trans-Alaskan Pipeline which leaked into the Atigun River on June 10, 1979, aromatic
hydrocarbons including xylenes were absent from the 40 km long river in contaminated area 18
days after the spill .
ATMOSPHERIC FATE: When released into the atmosphere, xylenes may degrade by reaction
with photochemically produced hydroxyl radicals (half-life 1.0-1.7 hr in summer and 10-18 hr in
winter ). However, ambient levels are detected because of large emissions.
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| Drinking Water Impact | Biological oxygen demand 5 (after 5 days @ 20 deg C): 0.64 (no stated isomer). 1190]
DRINKING WATER: According to a federal survey of drinking water from groundwater
supplies, xylenes are present in < 5% of supplies . Xylenes have been detected in the drinking
water in Canada with mean values of < 1 ppb and in several USA cities including Washington,
DC , Philadelphia, PA , Cleveland, OH , Tuscaloosa, AL(6), Houston, TX(6), and New
Orleans, LA(9). Xylenes at 0.1-2.9 ppb have been found in drinking water wells in the vicinity of
a landfill(7). A max of 0.1 ppb has been found in bank-filtered Rhine R water in the
Netherlands(8). Detected in all 14 drinking water supplies studies, 10 surface and 4 ground in
Great Britain(10).
GROUNDWATER: Xylene isomers have been found in groundwater under landfills and in
the hundreds ppb range under a coal gasification site, 15 months after gasification was
completed .
SURFACE WATER: Detected, not quantified in the Mississippi River near New Orleans , the
Black Warrior River in Tuscaloosa, AL , and the Glatt River in Switzerland . Xylenes have
been found in Lakes Eire and Michigan . Detected at avg concn of < 1 ppb in the raw water
sources of 30 Canadian cities . Detected in only 1 of 204 surface water samples in the USA(6).
SEAWATER: In Vineland Sound, MA and the Gulf of Mexico . Valdez Harbor-Trans
Alaskan Pipeline Terminal - 0.2 and 0.7 ppb in 2 of 7 sampling sites .
RAIN/SNOW: West Los Angeles, part per trillion range .
EFFL: Low-level radioactive waste disposal site at Maxey Flats 0.12 and 0.48 ppm in 2 of 3
trench leachates . Industrial plant in Philadelphia area 1000 ppb including all C2 benzenes .
Effluent from containing ponds in Atigun River, Alaska 1.2 ppb, including ethyl benzene .
Treated effluents from offshore oil drilling platforms in the Gulf of Mexico 0.3 ppm avg (concn
includes ethylbenzene) .
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