| Chemical Abstract Number (CAS #) |
108383
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| Synonyms | m-Xylene |
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1,3-Dimethylbenzene |
| Analytical Methods |
EPA Method 502.2 |
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EPA Method 503.1 |
EPA Method 524.1 |
EPA Method 524.2 |
EPA Method 602 |
EPA Method 624 |
EPA Method 8020A |
EPA Method 8021A |
EPA Method 8260A |
| Molecular Formula | C8H10 |
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| Use | Solvent; intermediate for dyes & org synth; insecticides; aviation fuel
m-Xylene is used in the manufacturing of polyester and alkyl resins.
CHEM INTERMEDIATE FOR ISOPHTHALIC ACID & M-TOLUIC ACID
CHEM INTERMEDIATE FOR ISOPHTHALONITRILE
CHEM INTERMEDIATE FOR ORG CHEMS-EG, XYLIDENES (NON-USA USE)
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| Consumption Patterns | In 1976, 32 thousand metric tons of m-xylene were used in the manufacturing of
isophthalic acid in the USA.
CHEM INTERMEDIATE FOR ISOPHTHALIC ACID, 90.8%; OTHER, 9.2% (1980
NON-GASOLINE USE)
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| Apparent Color | Clear, colorless liquid ; Mobile ; Color: Saybolt units 30 (research, pure & technical
grades)
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| Odor | Sweet odor; like benzene: characteristicly aromatic
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| Boiling Point | 139.3 deg C
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| Melting Point | -47.8 deg C
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| Molecular Weight | 106.17
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| Density | 0.8684 @ 15 deg C/4 deg C
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| Odor Threshold Concentration | 4.00x10 13 mol/cc
Odor index at 20 deg C: 2100
Reduction of amenities: threshold odor concentration (TOC) in water: 1.0 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. Xylenes
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| Environmental Impact | m-Xylene will enter the atmosphere primarily from fuel emissions and exhausts linked
with its use in gasoline. Industrial sources include emissions from petroleum refining and its use as
a solvent and chemical intermediate. The primary source of exposure is from air, especially in
areas with high SRP: vehicular traffic. Discharges and spills on land and waterways result from
its use in diesel fuel and gasoline and the storage and transport of petroleum products. Most of
the m-xylene is released into the atmosphere where it may photochemically degrade by reaction
with hydroxyl radicals (half-life 1-10 hr). The dominant removal process in water is volatilization.
m-Xylene is moderately mobile in soil and may leach into groundwater where it is known to
persist for several years despite some evidence that it biodegrades in both soil and groundwater.
Bioconcentration is not expected to be significant.
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| Environmental Fate | TERRESTRIAL FATE: When spilled on land, m-xylene will volatilize and leach into the
ground. m-Xylene may be degraded during its passage through soil . The extent of the
degradation will depend on its 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(1,SRC)). Some adsorption to sediment will occur. Although m-xylene is
biodegradable and has been observed to degrade in seawater, there are insufficient data to access
the rate of this process in surface waters. Although it has been observed to degrade in
groundwater in one study, it is known to persist for many years in groundwater, at least at sites
where the concentration might have been quite high.
ATMOSPHERIC FATE: When released into the atmosphere, m-xylene may degrade by reaction
with photochemically produced hydroxyl radicals (half-life 1.0 hr in summer and 10 hr in
winter ). However, ambient levels are detected because of large emissions.
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| Drinking Water Impact | DRINKING WATER: In 12 Great Lakes municipalities tested on 1 or 2 days, 5
communities were free of m- and o-xylene combined, with median community levels of the
combined isomers in the remaining 7 municipalities being 12 ppb In a survey of 30 Canadian
water treatment facilities, the avg value of m- and o-xylene combined in the treated water was <1
ppb, with max of 8 ppb being found in the summer and 2 ppb in the winter . The frequency of
occurrence was 27% and the max values in the raw water was <1 ppb . m-Xylene has been
identified but not quantified in the drinking water in Washington, DC and Philadelphia, PA .
DRINKING WATER: In a survey of occurrences of m-xylene in drinking water from
groundwater sources, 2.1% of 280 supplies serving fewer than 10,000 persons were pos with the
median and max values of pos supplies being 0.32 and 1.5 ppb, respectively . Of 186 supplies
serving more than 10,000 persons, 1.1% were pos with the median and max values of 0.46 and
0.61 ppb respectively . The max combined amount of m- and p-xylene in bank filtered Rhine R
water in the Netherlands was 0.1 ppb . In 4 drinking water wells near a landfill, 0.1-0.8 ppb of
m-xylene was determined . Detected in all 14 drinking water supplies studied, 10 surface and 4
ground, in the lowlands of Great Britain .
GROUNDWATER: In groundwater under a coal gasification site in Wyoming, 15 months after
gasification was completed, 240-830 ppb and in a recovery well under a landfill 7 years after
landfill closed, 0.4 ppb .
SURFACE WATER: In the raw water for 30 Canadian water treatment facilities - 7 and 17% of
plants contained m- and o-xylene in summer and winter respectively, with max levels being under
1 ppb . Detected, not quantified in the Black Warrior River in Tuscaloosa, AL and the Glatt
River in Switzerland .
SEA WATER: In Vineland Sound, MA, samples taken over 15 months ranged from 4.5-66 parts
per trillion for the m- and p-xylene combined . In open and coastal sections of the Gulf of
Mexico, 2.7-24.4 parts per trillion for the m- and p-isomers combined .
RAIN/SNOW: West Los Angeles, CA - 2 parts per trillion .
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