Xylene
http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~ZPFAYg:1
XYLENE
CASRN: 1330-20-7
Human Health Effects:
Toxicity Summary:
After inhalation exposure the retention in the
lungs is about 60% of the inhaled dose. Xylene is
efficiently metabolized. More than 90% is biotransformed to methylhippuric acid,
which is excreted in urine. Xylene does not accumulate
significantly in the human body. Acute exposure to high concentrations of xylene
can result in CNS effects and irritation in humans. ... The chronic toxicity
appears to be relatively low in laboratory animals. There is suggestive
evidence, however, that chronic CNS effects may occur in animals at moderate
concentrations of xylene. Xylene
does not appear to be a mutagen or carcinogen. The critical end point is
developmental toxicity ... The xylene isomers are of
moderate to low toxicity for aquatic organisms. ... The acute toxicity of xylene
to birds is low.
Evidence for Carcinogenicity:
Evaluation: There is inadequate evidence in
humans for the carcinogenicity of xylenes. There is inadequate evidence in
experimental animals for the carcinogenicity of xylenes. Overall classification:
Xylenes are not classifiable as to their carcinogenicity to humans (Group 3).
CLASSIFICATION: D; not classifiable as to
human carcinogenicity. BASIS FOR CLASSIFICATION: Orally administered technical xylene
mixtures did not result in significant increases in incidences in tumor
responses in rats or mice of both sexes. HUMAN CARCINOGENICITY DATA: None.
ANIMAL CARCINOGENICITY DATA: Inadequate.
A4. Not classifiableas a human carcinogen.
Human Toxicity Excerpts:
Xylene is a central
nervous system depressant that produces lightheadedness, nausea, headache, and
ataxia at low doses and confusion, respiratory depression, and coma at high
doses. Above 200 ppm, xylene causes conjunctivitis,
nasal irritation, and sore throats; it is a potent respiratory irritant at high
concentrations. ... Xylene produces a defating
dermatitis with prolonged cutaneous exposure.
Transient mildly elevated hepatic
aminotransferase levels and reversible renal failure were reported in an
estimated 10,000 ppm xylene exposure occurring during
the painting of a poorly ventilated ship compartment. Two men were comatose and
one was dead on arrival after this prolonged exposure over 18 hours. The
survivors developed no long-term sequelae. The contributions of hypoxia and a
toluene solvent could not be quantitated.
In workers exposed to organic solvents
(acetone, benzene, toluene, ethyl acetate, butyl acetate, xylene,
gasoline, and turpentine) the incidence of chronic bronchitis was higher, and
the volume of expiratory air was lower than in normal control subjects. In
smokers the incidence was higher than nonsmokers of /exposed and nonexposed/
groups. Smoking increases risk of chronic bronchitis in ... subjects /exposed to
organic solvents/.
Dermal application of xylene
caused a 20-40% decr in electrical impedance of human skin.
CNS DEFECTS WERE MORE COMMON IN CHILDREN OF
MOTHERS EXPOSED TO ORG SOLVENTS & DUSTS DURING PREGNANCY. HYDRANENCEPHALY
OCCURRED IN CHILDREN WHOSE MOTHERS HAD BEEN EXPOSED TO THE SOLVENTS TOLUENE, XYLENE,
& WHITE SPIRIT DURING MANUFACTURE OF RUBBER PRODUCTS.
Women are liable to suffer from menstrual
disorders (menorrhagia, metrorrhagia). It has been reported that female workers
exposed to ... xylene in concn which periodically
exceeded the exposure limits were also affected by pathological pregnancy
conditions (toxicosis, danger of miscarriage, hemorrhage during child birth) and
infertility.
Mixed xylenes ... at exposures of one to four
times TLV (threshold limit value) /SRP: 400 ppm/ levels were used. Subjective
reports of irritation, as well as polygraph records of eyeblink and respiration
rate were recorded during 30 min exposures. Psychomotor tests were administered
before, during, and after exposure. Both a higher incidence of eye irritation
and rate of eyeblink were reported by exposed subjects compared to controls, but
the effects were mild. There were no significant differences in respiration
rates or in tests of psychomotor function.
USING A STANDARDIZED INTERVIEW SCHEDULE,
OCCUPATIONAL EXPOSURE TO ORG SOLVENTS WAS INVESTIGATED IN 61 MALE PATIENTS WITH
DIAGNOSIS OF NON-HODGKIN'S LYMPHOMA. RESULTS INDICATE A RELATION BETWEEN
EXPOSURE TO ORG SOLVENTS & SUPRADIAPHRAGMATIC PRESENTATION OF NON-HODGKIN'S
LYMPHOMA. ELEVEN REPORTED EXPOSURE TO XYLENE. HOWEVER,
IN MOST CASES EXPOSURE TO MORE THAN ONE SOLVENT WAS REPORTED.
For the period 1961-80, 118 cases of
industrial gassings caused by the solvents methlyene chloride, xylene,
toluene and styrene were reported to Her Majesty's Factory Inspectorate. The
data were collated and analyzed according to the predetermined criteria of age,
sex, mode and circumstances of use, clinical effect and outcome. The study shows
the /SRP: CNS depressant/ effect of these solvents and underlines the dangers of
their use in confined spaces. Symptoms were most commonly attributable to the
nervous and respiratory system.
Disturbances of memory, mood, equilibrium and
sleep that occurred simultaneously with headache and indigestion, were
experienced more frequently among women working in histology who had daily
exposure to formaldehyde, xylene and toluene than in
unexposed female clerical workers in the same hospitals. Neurobehavioral
symptoms were accompanied by irritation of the eyes, upper air ways and trachea.
Formaldehyde exposure correlated better with neurobehavioral symptoms and with
respiratory and mucous membrane symptoms than did exposure to xylene/toluene
or to other agents.
... Inhalation of xylenes at concn of 435-1300
mg/cu m for 15 min to 6 hr/day for 4 days results in CNS disturbances including
changes in numerative ability, reaction time, short-term memory and
electroencephalograph.
An adverse health effect disturbance to
equilibrium has been observed in humans. ... This effect has been correlated
with blood concn ... of 30 umol/l (equivalent to 318 ug/100 ml) ... .
Mixtures of organic solvents, which include
xylenes, have been implicated as the cause of lens change in car painters. ...
Among nine pregnancies producing offspring
with caudal regression syndrome five mothers had exposure to fat solvents. These
included ... xylene.
The concentration of xylene
present in the blood, its serum or plasma, that has been reported to cause
death, or is so far above reported therapeutic or toxic concentrations that one
can judge that it might cause death in humans is 3-40 ug/ml.
The correlation between xylene
exposure and urinary excretion of methyl hippuric acid (MHA) was studied in 40
workers (35 men, 5 women) employed in the paint industry. Subjects were exposed
primarily to xylene although exposure to 11 other
solvents was possible. Personal sampling showed 8-hr TWA's for xylene
ranged from 0-865 mg/cu m with a median exposure of 69 mg/cu m. Urine was
collected over one 24-hr period for each worker. Personal air samples were
collected for each worker over the course of a complete workday. MHA excretion
was linearly correlated to the 8-hr TWA for xylene
exposure after adjustment for body weight. The total amount of MHA excreted in
the urine over 24 hr showed virtually the same correlation to xylene
exposure (r = 0.84) as the MHA excretion during the latter part of the workshift
(r = 0.81, sampling time 4-5 hr) among 37 workers exposed to 8-hr TWA xylene
concentrations of 0-200 mg/cu m.
Vapor irritates eyes and mucous membranes and
may cause dizziness, headache, nausea, and mental confusion. Liquid irritates
eyes and mucous membranes. Swallowing or absorption through skin would cause
poisoning. Prolonged exposure to skin contact may result in dermatitis.
Serum concentrations of liver enzymes were
determined for Swedish paint industry workers exposed to a mixture of organic
solvents including xylene. Mean xylene
exposure for 44 individuals was 82 mg/cu m (19 ppm) with a range of 1 to 6070
mg/cu m; five workers were exposed to a mean concentration of 865 mg/cu m (199
ppm). Serum alanine aminotransferase, aspartate aminotransferase, ornithine
carbamoyltransferase, and gamma-glutamyltransferase activities were not elevated
by these exposures. ... Occupational experience reveals complaints of
dermatitis, eczema, and irritation of the eyes and respiratory tract but rarely
serious illness. It is likely that untoward effects on the hematopoietic system
reported in the past as being caused by xylene resulted
from benzene contamination of commercial xylene.
Six volunteers were able to detect the odor of
mixed xylenes at a concentration of 60 mg/cu m; four could detect 6 mg/cu m, but
none could detect 0.6 mg/cu m. The odor threshold was calculated as 4.5 mg/cu m
or about 1 ppm for a 10-sec exposure. In a 15-min exposure period, the only
common sign of discomfort at 2000 mg/cu m (460 ppm) was eye irritation in four
of six subjects. Some transitory olfactory fatigue occurred, with recovery in 10
min.
Exposure of volunteers to technical xylene
by inhalation caused irritation of the airways; very high accidental exposure
caused pneumonitis. Ingestion of xylene caused
irritation of the gastrointestinal tract.
Repeated, prolonged exposure to fumes may
produce conjunctivitis of the eye and dryness of the nose, throat, and skin.
Direct liquid contact may result in flaky or moderate dermatitis. Inhalation of
vapors may cause CNS excitation then depression, characterized by paresthesia,
tremors, apprehension, impaired memory, weakness, nervous irritation, vertigo,
headache, anorexia, nausea, and flatulence, and may lead to anemia and mucosal
hemorrhage. Clinically, no bone marrow aplasia, but hyperplasia, moderate liver
enlargement, necrosis, and nephrosis may occur.
During an informal study in 1973 it was noted
that approx 1/3 of patients with congenital heart disease lived in a small area
in the Tucson Valley. In 1981 groundwater for nearly identical area was found to
be contaminated with trichloroethylene and to a lesser extent with
dichloroethylene and chromium. Contamination probably began during the 1950s.
Affected wells were closed after discovery of contamination. This sequence of
events allowed investigation of the prevalence of congenital heart disease in
children whose parents were exposed to the contaminated water area as compared
with children whose parents were never exposed to the contaminated water area.
The contaminated water area contained 8.8% of the Tucson Valley population and
4.5% of the labor force. Using their case registry, the authors interviewed
parents of 707 children with congenital heart disease who, between 1969 and
1987, 1) conceived their child in the Tucson Valley, and 2) spent the month
before the first trimester and the first trimester of the case pregnancy in the
Tucson Valley. Two random dialing surveys showed that only 10.5% of the Tucson
Valley population had ever had work or residence contact, or both, with the
contaminated water area, whereas 35% of parents of children with congenital
heart disease had had such contact (p < 0.005). The prevalence of congenital
cardiac disease (excluding syndromes, children with atrial tachycardia or
premature infants with patent ductus arteriosus) in the Tucson Valley was 0.7%
of live births and with syndromes was calculated to be 0.82%. The odds ratio for
congenital heart disease for children of parents with contaminated water area
times that for those without contact (p < 0.005) and decr to near unity for
new arrivals in the contaminated water area after well closure. The proportion
of infants with congenital heart disease as compared with the number of live
births was significantly higher for resident mothers in the contaminated water
area than for mothers with no exposure. No other environmental agent could be
identified that was localized to the contaminated water area, but one could have
been missed. The data show a significant assoc but not a cause and effect
relation between parental exposure to the contaminated water area and an incr
proportion of congenital heart disease among live births as compared with the
proportion of congenital heart disease among live births for parents without
contaminated water area contact.
The quantitative relationship between exposure
to xylene vapor and urinary excretion in methylhippuric
acid isomers were studied in the second half of a working wk. The participants
in the study were 121 male workers engaged in dip-coating of metal parts who
were predominantly exposed to three xylene isomers. The
intensity of exposure measured by diffusive sampling during an 8-hr shift was
such that the geometric mean vapor concn was 3.8 ppm for xylenes (0.8 ppm for o-xylene,
2.1 ppm for m-xylene, and 0.9 ppm for p-xylene),
0.8 ppm for toluene, and 0.9 ppm for ethylbenzene. Urine samples were collected
at the end of the shift and analyzed for metabolites by HPLC. The statistical
analysis showed that there is a linear relationship between the intensity of
exposure to xylenes and the concn of methylhippuric acid in urine, that the
regression line passes very close to the origin, and that the increment in
observed (i.e., noncorrected) methylhippuric acid concn as a function of incr xylene
concn was 17.8 mg/ppm. Further exam on the basis on individual xylene
isomers showed that the slopes of the regression lines for o- and m-isomers were
similar (i.e., 17.1 and 16.6 mg/L/ppm, respectively), whereas that for p-xylene
was larger (21.3 mg/L/ppm).
Human Toxicity Values:
LDLo Human oral 50 mg/kg
Skin, Eye and Respiratory Irritations:
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.
Vapor irritates eyes and mucous membranes and
may cause dizziness, headache, nausea, and mental confusion. Liquid irritates
eyes and mucous membranes.
Medical Surveillance:
EMPLOYEES EXPOSED TO XYLENE
SHOULD UNDERGO COMPREHENSIVE PREPLACEMENT & BIENNIAL MEDICAL CHECKUPS. AIR
& BIOLOGIC MONITORING PROGRAMS SHOULD BE ESTABLISHED & EVALUATED
REGULARLY.
History and examination /of workers exposed to
xylene/ should be directed toward, but not limited to,
the incidence of headaches, nausea, or other GI disturbances, dizziness, and of
alc consumption; ... attention should be focused on complaints and evidence of
eye, mucous membrane, or skin irritation; ... examination /should/ include a
complete blood count, a routine urinalysis, and ... liver function tests.
Probable Routes of Human Exposure:
Xylene can affect the
body if it is inhaled, if it comes in contact with the eyes or skin, or if it is
swallowed.
THE ADVANTAGES & DISADVANTAGES OF USING
SOFT CONTACT LENSES (IN HUMANS) IN ENVIRONMENTS WITH FUMES FROM SOLVENTS OR
SPLASHES OF STRONG ACIDS & ALKALIS WERE STUDIED EXPERIMENTALLY. UPTAKE OF XYLENE
BY LENS MATERIALS WAS UP TO 90 TIMES THAT BY PHYSIOLOGIC SALINE, USED TO
SIMULATE TEAR FLUID. WHEN EXPOSED LENSES WERE SOAKED FOR 10 & 60 MIN IN A
VERY SMALL VOLUME OF SALINE THE CONCN OF SOLVENT IN THAT SALINE WAS ONLY UP TO
23 & 11%, RESPECTIVELY, OF THAT IN DIRECT EXPOSED SALINE. SOLVENTS WERE
RELEASED MAINLY TO THE AIR. CONTACT LENSES WOULD LEAD TO A PROLONGED EXPOSURE
BUT TO A RATHER LOW CONCN AS COMPARED TO DIRECT EXPOSURE.
Exposure to organic solvent vapors was
investigated in 40 unit workplaces (with 189 workers) in 16 small scale
industries in north-east Japan ... in which synthetic urushi lacquer was applied
to produce non-metal tableware. ... Two furniture factories were also studied.
The equipment used was carbon felt dosimeters and portable PID-GC ... . ... The
gas chromatography could analyze benzene-toluene xylenes within 150 seconds. ...
Toluene was the major pollutant in the workplace air, with small quantities of
xylenes. ... Exposure did not exceed the current occupational exposure limit in
all the cases except for the two workers, who were excessively exposed due to
the generation of dense vapors in automated spraying process.
... There is a broad potential for exposure
both to industrial workers in the production and use of the xylenes and to the
general public (via vehicle exhausts, consumer products, etc). ...
Number of USA workers exposed 140,000 /Time
frame not mentioned/
NIOSH (NOES Survey 1981-1983) has
statistically estimated that 1,528,018 workers (316,320 of these are female) are
potentially exposed to xylenes in the US(1). An average xylene
concn of 0.1 ppm was detected in the breathing zones of paint shops sampled in
the US(2). Lab personnel are exposed to an average xylene
concn of 0.16 ppm and material handling personnel are exposed to an average xylene
concn of 1.6 ppm at hazardous waste facilities in the US(3). The 8 hour TWA
exposure to xylenes for personnel at organic solvent recycling plants was
measured as 1 ppm(4). A study from 1979-1987 calculated the average exposure to
xylenes in paint manufacturing plants as 2.01 ppm in breathing zone
locations(5). A survey of 97 autobody shops in the US reported the 8 hour TWA
exposure to xylenes was 3.3 ppm for painters and 0.7 ppm for non-painting
personnel(6). The 8 hour TWA for worker exposure to xylenes in a German
histology laboratory and a US histology laboratory was measured as 243-295 mg/cu
m and 11-315 mg/cu m respectively(7). The 8 hour TWA for worker exposure to
xylenes in a US hospital laboratory was measured as 3-1700 mg/cu m(7).
Occupational exposure may be through inhalation and dermal contact with this
compound at workplaces where xylenes are produced or used(SRC). The general
population will be exposed to xylenes largely via inhalation of ambient air,
particularly in areas with heavy traffic, near filling stations and near
industrial sources such as refineries(SRC). Exposure may also arise from
consuming contaminated food and drinking water(SRC). An average concn of 0.37
ppb of 3- and 4-xylene was measured in blood samples
collected from 60 persons in the US that are not occupationally exposed to
xylenes(8).
Humans are exposed to xylene
primarily from air, particularly in areas with heavy traffic, near filling
stations, near industrial sources such as refineries or where xylene
is used as a solvent. Exposure may also arise from drinking contaminated well
water near leaking underground gasoline storage tanks or from spills of
petroleum products. (SRC)
Benzene and xylenes are components of
gasoline. The US population exposed to xylenes from petroleum related sources
can be assumed to be the same as for benzene, namely: people choosing
self-service at gasoline service stations 37,000,000; people living in the
vicinity of gasoline service stations 118,000,000; petroleum refineries
6,597,000; urban exposure (auto emissions) 113,690,000(1). /Xylenes/
Body Burden:
ENVIRONMENTAL POLLUTANTS IN HUMAN MILK WERE
IDENTIFIED BY GAS CHROMATOGRAPHY/MASS SPECTROMETRY. XYLENE
WAS ONE OF THE AROMATICS IDENTIFIED.
FOLLOWING EXPOSURE OF RABBITS TO AN ATMOSPHERE
OF ABOUT 3,000 MG/CU M FOR 8 HR/DAY, 6 DAYS/WK, FOR 130 DAYS, XYLENE
WAS FOUND AT SLIGHTLY HIGHER AVG CONCENTRATIONS IN THE ADRENAL (148 PPM), BONE
MARROW (130 PPM), SPLEEN (115 PPM), & BRAIN (100 PPM) THAN IN BLOOD (91 PPM)
OR IN OTHER ORGANS.
Average Daily Intake:
AIR INTAKE: (Assume typical concn 4.0 ppb) 353
ug; WATER INTAKE: (Assume typical concn 0-1 ppb) 2 ug; FOOD INTAKE: Insufficient
data. (SRC)
Animal Toxicity Studies:
Toxicity Summary:
After inhalation exposure the retention in the
lungs is about 60% of the inhaled dose. Xylene is
efficiently metabolized. More than 90% is biotransformed to methylhippuric acid,
which is excreted in urine. Xylene does not accumulate
significantly in the human body. Acute exposure to high concentrations of xylene
can result in CNS effects and irritation in humans. ... The chronic toxicity
appears to be relatively low in laboratory animals. There is suggestive
evidence, however, that chronic CNS effects may occur in animals at moderate
concentrations of xylene. Xylene
does not appear to be a mutagen or carcinogen. The critical end point is
developmental toxicity ... The xylene isomers are of
moderate to low toxicity for aquatic organisms. ... The acute toxicity of xylene
to birds is low.
Evidence for Carcinogenicity:
Evaluation: There is inadequate evidence in
humans for the carcinogenicity of xylenes. There is inadequate evidence in
experimental animals for the carcinogenicity of xylenes. Overall classification:
Xylenes are not classifiable as to their carcinogenicity to humans (Group 3).
CLASSIFICATION: D; not classifiable as to
human carcinogenicity. BASIS FOR CLASSIFICATION: Orally administered technical xylene
mixtures did not result in significant increases in incidences in tumor
responses in rats or mice of both sexes. HUMAN CARCINOGENICITY DATA: None.
ANIMAL CARCINOGENICITY DATA: Inadequate.
A4. Not classifiableas a human carcinogen.
Non-Human Toxicity Excerpts:
/INVESTIGATORS/ ... FOUND NO ADVERSE EFFECTS
ON THE HEMATOPOIETIC SYSTEM /OF THE GUINEA PIG/ AFTER SC ADMIN AT 300 MG/KG/DAY
FOR 6 WK OR 700 MG/KG/DAY FOR 9 WK. OTHER REPORTS OF MYELOTOXICITY OF XYLENE
ARE PROBABLY RELATED TO BENZENE CONTAMINATION.
... RABBITS EXPOSED TO BENZENE-FREE XYLENE
(AT 5 MG/L, OR 1,150 PPM) FOR 40-55 DAYS HAD DECREASED RED & WHITE CELL
COUNTS.
RATS WERE EXPOSED TO XYLENE
VAPORS COMPOSED OF THE 3 XYLENE ISOMERS, ETHYLBENZENE,
TOLUENE, AROMATICS & NONAROMATICS. LC50 FOR RATS WAS 29 MG/L/4 HR (6700
PPM). CATS SUCCUMBED WITHIN 2 HR AT 41 MG/L (9500 PPM) WITH SIGNS OF CNS DAMAGE.
NO DIFFERENCES FROM CONTROL ANIMALS WERE OBSERVED IN BEAGLE DOGS & RATS THAT
INHALED 3.5, 2.0 OR 0.77 MG/L CONCN FOR 6 HR/DAY, 5 DAYS/WK FOR 13 WK.
The embryotoxic effects of xylene
were studied by exposing rats to 1000 mg/cu m of air during days 9 through 14
/of pregnancy/ ... found no teratogenic results although minor skeletal
anomalies occurred.
Data obtained from rodents indicates that
maternal exposure to mixed xylenes or individual xylene
isomers can have adverse effects on the conceptus. Fetotoxic effects were
reported following maternal inhalation exposure to mixed xylenes; altered enzyme
activities were also found in rat pups. Dermal application resulted in apparent
changes in fetal enzyme activities, while oral treatment was followed by
prenatal mortality, growth inhibition, and malformations, primarily cleft
palate. Maternal inhalation of individual isomers was associated with all the
above mentioned effects, with the exception of cleft palate. The o- and p-
isomers appeared more hazardous to the offspring than did the m-isomer.
Malformations (ie cleft palate) associated with mixed or individual isomers were
primarily reported at maternally toxic doses. Thus, a clear case for a selective
teratogenic effect due to the exposure to xylene has
yet to be presented.
EFFECTS OF COAL TAR-ASSOCIATED CHEMICALS WERE
TESTED BY SINGLE TOPICAL APPLICATION (1 MG/10 G BODY WT) TO NEONATAL RATS. THE
INDUCIBILITY OF XYLENE ON SKIN ARYL HYDROCARBON
HYDROXYLASE (AHH) WAS 8% & ON LIVER ARYL HYDROCARBON HYDROXYLASE 10%.
Male rats exposed to different concentrations
of xylene for three days /exhibited/ small but
statistically significant increase in cytochrome p450 content. Reduced
nicotinamide adenine dinucleotide cytochrome c reductase activity and O-deethylation
of 7-ethoxyresorufin in liver microsomes were detected already at an exposure
level of 75 ppm. Morphological studies of livers from rats exposed to relatively
high concentrations showed marked proliferation of smooth endoplasmic reticulum
with little changes of the rough endoplasmic reticulum. No pathological
alterations were observed. Castration of male rats influenced the response of xylene
exposure only to a minor extent. Hypophysectomy alone was shown to cause
significant increases in cytochrome p450 and cytochrome b5 content and epoxide
hydrolase activity. Induction of cytochrome p450 dependent enzymatic activities
after exposure to xylenes was reduced but qualitatively similar to that obtained
with normal male rats whereas the induction of epoxide hydrolase activity was
prevented. ...
XYLENE WAS ADMIN
ORALLY TO FEMALE WISTAR CFT STRAIN RATS. XYLENE DID NOT
PROVE LETHAL UP TO THE DOSAGE OF 6 ML/KG. HOWEVER, THE MINIMUM LETHAL DOSE WAS 7
ML/KG. SYMPTOMS MANIFESTED AT FATAL DOSES WERE DULLNESS, STUPOR, ANESTHESIA, CNS
DEPRESSION, & COMA. MORTALITY WAS DOSE-DEPENDENT.
Xylene, a widely used
industrial solvent, is a mixture of ortho-, meta-, and para- isomers. In this
study, ... the effects of each isomer, as well as a commercial-grade mixture of
xylenes, on two behavioral measures /were examined/: 1) Operant performance of
15 mice trained to lever-press under a DRL (differential reinforcement of low
rates) 10 sec schedule, and 2) motor performance of mice on an inverted screen
test. The 15 min operant sessions immediately followed 30 min exposures to
solvent vapors (500 to 7000 ppm), or air, in static inhalation chambers. Ortho-,
meta-, para-, and mixed xylenes produced similar biphasic effects on response
rates, and concentration dependent decreases in reinforcement rates.
SUBACUTE EXPOSURE OF MALE RATS TO 2000 PPM OF XYLENE,
ORTHO-XYLENE, META-XYLENE,
PARA-XYLENE, & ETHYLBENZENE PRODUCED DISCRETE
INCREASES OF DOPAMINE & NORADRENALINE LEVELS & TURNOVER IN VARIOUS PARTS
OF HYPOTHALAMUS. XYLENE ITSELF PRODUCED WIDESPREAD INCR
OF DOPAMINE TURNOVER WITHIN NEOSTRIATUM & SUBCORTICAL LIMBIC FOREBRAIN.
EXPOSURE 6 HR/DAY FOR 3 DAYS TO 2000 PPM
INCREASED HEPATIC CYTOCHROME P450 CONCENTRATIONS & NADPH CYTOCHROME C
REDUCTASE ACTIVITY IN RATS. IN KIDNEY MICROSOMES AN INCR CONCN OF CYTOCHROME
P450 WAS OBTAINED. IN LUNG MICROSOMES XYLENE CAUSED A
DECR IN CYTOCHROME P450 CONTENT.
MALLARD EGGS WERE TREATED BY IMMERSION IN XYLENE
(1% & 10%) FOR 30 SECONDS AT ROOM TEMP. XYLENE HAD
NO SIGNIFICANT EFFECTS AT CONCENTRATIONS OF 10% ON EMBRYONIC WT & LENGTH
WHEN COMPARED TO CONTROLS.
HAMSTERS RECEIVED XYLENE
TOPICALLY FOR 2 HR BETWEEN DAYS 7 & 11 & WERE KILLED AT DAY 15 OF
GESTATION. FETAL SIZE & WEIGHT DECREASED & THE INCIDENCE OF PRENATAL
DEATHS INCREASED. FETAL HEMORRHAGE & GASTROSCHISIS WERE ALSO NOTED. NO
MALFORMATIONS WERE FOUND IN CONTROLS.
PREGNANT OUTBRED ALBINO MICE RECEIVED BY
GAVAGE, 3 TIMES/DAY IN COTTONSEED OIL, A XYLENE MIXT ON
DAYS 6-15 OF GESTATION. THE MICE WHERE KILLED ON DAY 18. AT 3.6 ML/KG/DAY, XYLENE
KILLED 12 OF 38 DAMS & CAUSED A SIGNIFICANTLY SMALLER AVG WT GAIN DURING
PREGNANCY THAN DID THE COTTONSEED OIL. FETUSES FROM DAMS TREATED @ 2.4 ML/KG/DAY
HAD AVG FETAL WT SIGNIFICANTLY LOWER THAN THAT OF CONTROL FETUSES. AT 2.4, 3.0,
& 3.6 ML/KG/DAY XYLENE PRODUCED A SIGNIFICANTLY
GREATER AVG % OF MALFORMED FETUSES THAN DID THE CONTROL. CLEFT PALATE WAS THE
MAJOR MALFORMATION AT ALL 3 DOSES. WHEN BILATERAL WAVY RIBS WERE COUNTED AS A
MALFORMATION, THE AVG % OF MALFORMED FETUSES INCR FROM 7.8 TO 10.5 @ 3.0
ML/KG/DAY & FROM 9.1 TO 13.4 @ 3.6 ML/KG/DAY. THUS, XYLENE
(MIXED ISOMERS) IS TERATOGENIC TO MICE @ 2.4 & 3.0 ML/KG/DAY.
By exposing cats for several hours to
concentrations of xylene vapor which were just
sublethal /the laboratory/ succeeded in producing vacuoles in the corneal
epithelium which appeared to be analogous to those occurring in vacuolar
keratopathy occurring in workmen from exposure to solvent vapors.
Rats /exposed to/ xylene
at 230, 1900, or 3360 mg/cu m for 24 hr/day from day 7-14 of pregnancy showed no
maternal toxicity. However, bone formation was retarded in the fetuses at all 3
concn, and the number of nephrons with enzyme activity and the activity ... of
succinic dehydrogenase, alkyl phosphatase, acid phosphatase, and glucose
6-phosphatase were decreased in fetuses at the highest concn. ... The incidence
of extra ribs in fetuses increased, however, none of the concn were teratogenic.
The incidence of postimplantation fetal loss increased.
In rats, exposure to xylene
(50 or 500 mg/cu m) resulted in embryotoxic and teratogenic effects. The brain,
liver, lung, and heart were affected. The number of postimplantation losses
increased by 9.7 and 168% in the 50 and 500 mg/cu m xylene
group, respectively. The incidence of fetal skeletal abnormalities was increased
by 62 and 177%, respectively.
Rats were exposed to ... xylene
at 200-800 ppm for 30 days. After exposure, changes in the dopamine,
norepinephrine, serotonin, acetylcholine (ACH), CAMP, CGMP, GCBA, Gln, Asp, Tau,
Gly, and Ala content of different areas of the brain were investigated.
Acetylcholine in the striatum and the whole brain was reduced dose dependently
by ... xylene. ... Xylene
caused different changes in monoamine content ... but the changes were not dose
dependent. ... Glutamine content was increased by ... xylene
at 800 ppm.
In rats exposed to /xylene/
by inhalation for 2 wk (5 days/wk, 6 hr/day) ... kidney 7-ethoxycoumarin O-deethylase
activity was increased >200% ... /and/ liver UDP-glucuronosyltransferase
activity was increased ... approx 100%. ...
... Xylene reduced
the number and weight of /Agaricus bisporus/ sporophores.
Kucera reports studies in chick embryos
exposed for 60 to 240 minutes to a xylene atmosphere at
developmental periods up to the 10 somite stage. A high malformation rate was
found and nearly one-half of the defects were rumplesness, a defect resembling
caudal regression syndrome.
Exposure of male rats to /250-2000 ppm/ of xylene
for 3 days induced, in a dose related way, the in vitro liver microsomal
metabolism of antipyrine. The degree of induction was significant at an exposure
level of 250 ppm and maximal (2.5-fold incr) at 2000 ppm. This incr was of the
same magnitude as after phenobarbital treatment. Female rats had lower basal
antipyrine metabolism than males but exhibited a greater relative incr in
antipyrine metabolism following xylene exposure. ...
Exposure to lower xylene levels did not produce
significant alterations in antipyrine elimination half-life. ...
Quail eggs were treated directly by spraying
the shell with 2 or 0.05% aq suspensions of ... xylene,
or indirectly by repeated ingestion by the parental quail of contaminated feed.
/Xylene/ significantly acted upon the quail biotic
potentials by reducing the hatching rate and the embryonic viability and
increasing the fecundation rate and the weight of eggs, chickens, and adults. /Xylene/
reversed the sex ratio, so that the male birds had an advantage in number and
acted more specifically on the embryonic genital development.
... Xylene at 2 mmol/kg
decreased the metabolism of (14)C labeled benzene (2 mmol/kg) to phenol and
other metabolites in rats. The metabolism of (14)C toluene was not inhibited by
... xylene. ...
Groups of Sprague Dawley rats were exposed, by
inhalation, to ... xylene (600 ppm, 2625 mg/cu m) ...
for 4 wk. Increased liver weights and liver to body wt ratios were observed. ...
An increase in in vitro formation of certain metabolites of all substrates was
found in rats exposed to xylene. ... Xylene
was a 'phenobarbital-like' inducer of rat liver microsomal cytochrome p450.
In single administration studies, groups of
five F344/N rats and B6C3F1 mice of each sex received 500, 1,000, 2,000, 4,000,
or 6,000 mg/kg /gavage in corn oil/. Administration of xylenes caused deaths at
6,000 mg/kg in rats and mice of each sex and at 4,000 mg/kg in male rats.
Clinical signs observed /from 24 hr to 2 wk/ of dosing at 4,000 mg/kg included
prostration, muscular incoordination, and loss of limb movement. Tremors, prone
position, and slowed breathing were recorded for mice on day 3, but all mice
appeared normal by the end of the 2 wk observation period.
In 14 day studies, groups of five /rats/ ...
of each sex ... were administered 0, 125, 250, 500, 1,000, or 2,000 mg/kg and
mice received 0, 250, 500, 1,000, 2,000, or 4,000 mg/kg. Chemical related
mortality occurred only at 2,000 mg/kg in rats and 4,000 mg/kg in mice. Rats and
mice exhibited shallow breathing and prostration within 48 hr following dosing
at 2,000 mg/kg. These signs persisted until day 12 for rats, but no clinical
signs were noted during the second wk for mice.
In 13 wk studies, groups of 10 rats of each
sex received 0, 62.5, 125, 250, 500, or 1,000 mg/kg, and groups of 10 mice of
each sex received 0, 125, 250, 500, 1,000, or 2,000 mg/kg. No deaths or clinical
signs of toxicity were recorded in rats. However, high dose male rats gained 15%
less and females gained 8% less weight than did the vehicle controls. Two female
mice died at the 2,000 mg/kg level. Lethargy, short and shallow breathing,
unsteadiness, tremors, and paresis were observed for both sexes in the 2,000
mg/kg group within 5-10 min after dosing and lasted for 15-60 min.
... It is of importance to note that
coal-based solvents (eg, xylene) have been suggested to
be possible potent lymphocytic leukemogens, such as benzene, in a limited study
of the relationship between lymphocytic leukemia and exposures to benzene and
other solvents in the rubber industry. Available animal data on the
carcinogenicity of xylene(s) are inadequate to permit
an evaluation. In limited studies thus far, the individual isomers were not
found genotoxic when tested in a number of short-term tests.
Two laboratories tested multiple forms of xylene
for their developmental toxicity hazard potential (A/D ratio) by means of the
hydra assay. The three isomers, as well as a solution of mixed xylenes, all
interfered with development (D) at or near to concn that also were toxic to
adult (A) hydra. The development/adult ratios ranged from 1 to 2 in hydra as
they had in conventional tests made in pregnant laboratory animals. Each testing
laboratory concluded that xylenes were not primary development hazards but
coeffective agents capable of disrupting development only at or near to concn
also toxic to adults. In each instance every xylene
tested interfered with the same stage or developmental sequence and in a concn
related manner. The hydra assay may be useful for establishing priorities to
test agents in a more elaborate system, but substances less soluble than xylene
may exceed the test's applicability.
... Pregnant CFY rats /were exposed/ by
continuous inhalation to 1,000 mg/cu m (230 ppm) of a xylene
mixture (10% o-, 50% m-, 20% p-xylene, and 20%
ethylbenzene) on gestational days 9 through 14. At this concn, the xylene
mixture produced skeletal effects including an increased incidence of
supernumerary ribs (9/143 alizarin-stained fetuses in the dosed group compared
to 2/143 in the control group). ... Two cases of agnathia (absence of mandible)
/were reported/ in 286 pups.
RATS PRETREATED WITH XYLENE
OR PHENOBARBITAL & THEN EXPOSED TO N-HEXANE, SHOWED A MARKEDLY INCR PEAK
SERUM CONCN OF THE NEUROTOXIC METABOLITE 2,5-HEXANEDIONE.
Admin of xylenes to rats caused decr in liver
glutathione (GSH) concn, reduction in glutathione concn was most pronounced
after treatment with o-xylene isomer (4.0 mmol/kg).
Hepatocytes isolated from male Sprague-Dawley
rats (200-275 g) were exposed to halogenated and non-halogenated hydrocarbons.
Leakage of cellular enzymes and inhibition of respiration were monitored as
indicators of toxicity. Cell suspensions contained 2-3X10+6 cells/ml and were
viable for 6 hr as indicated by a < 10% increment in the fractional release
of aspartate aminotransferase activity. The hydrocarbons were added to the cell
suspension as 20% solutions in ethanol. The addition of 20 mM dimethylbenzene
(DMB) caused a rapid release, which peaked within 60 min, into the medium.
Approximately 22% (n= 4) of the total aspartate aminotransferase was found in
the medium and the release was concentration dependent. Cellular oxygen
consumption was reduced when DNB was present, and the reduction was dose
dependent. The relationship of the effects of cellular respiration to alteration
in mitochondrial function was studied using dinitrophenol (DNP) and succinate,
an NADH-independent mitochondrial substrate. DNP-induced oxygen stimulation was
abolished by 10 mM DMB. Succinate-stimulated respiration was unaffected by 2.5
mM DMB, but DPN-stimulated respiration was significantly reduced. Mitochondrial
function returned to normal within 1 hr. /Dimethylbenzene/
In some rats exposed to 3000 mg/cu m mixed
xylenes for 8 hours per day on six days per week for 110-130 days, exposure
resulted in paralysis of the hind legs, weight loss, a slight decrease in
leukocytes, increases in blood urea, urinary blood and albumin, and hyperplasia
of the bone marrow. Slight congestion of kidney, liver, heart, adrenal, lung and
spleen were observed. Cellular desquamation of glomeruli and necrosis of the
convoluted tubules were also reported.
Ten to 20 applications of undiluted mixed
xylenes on the ears or shaved abdomen of rabbits for two or four weeks resulted
in moderate to marked erythema and oedema, with superficial necrosis at both
sites. After introduction of two drops of mixed xylenes into the rabbit eye,
slight conjunctival irritation and transient corneal injury were observed.
Application of undiluted xylene to the eye caused
corneal lesions in cats.
... Two drops of mixed xylenes instilled into
rabbit eyes induced slight conjunctival irritation with very slight, transient
corneal injury.
Nine rats inhaled 690 ppm of mixed xylenes, 8
hours/day, 6 days/week for 110 to 130 days, while six rabbits inhaled 1200 ppm 8
hours/day, 6 days/week for 40 to 50 days. In some animals, exposure resulted in
paralysis of hind legs; weight loss; a slight decrease in leukocytes; increases
in blood urea, urinary blood, and albumin; and hyperplasia of the bone marrow.
Slight congestion of the kidney, liver, heart, adrenal, lung, and spleen was
observed.
Fertility and pregnancy indices were no
different among male and female rats inhaling 60, 250, or 500 ppm xylene,
6 hours/day for 131 premating days, during 20 mating days, and throughout
gestation and lactation as compared with the concurrent control animals.
Rats exposed to 300 ppm, 6 hours/day, 5
days/week for 18 weeks showed increased hepatic monooxygenation. /From table/
The effects of acute xylene
exposure on the enkephalinergic neuromodulatory system were studied in rats.
Male Sprague-Dawley rats were injected ip with 0 or 1.6 mL/kg xylene
daily for 3 consecutive days. Three hr after the last dose, they were killed and
the brains were removed. The brains were dissected into the parietal cortex.
caudate putamen, medial preoptic areas of the hypothalamus, globus pallidus,
olfactory tubercle, and central amygdaloid nuclei (CA). The various brain parts
were analyzed for changes in their met-enkephalin content by an immunostaining
technique. Xylene decr the extent of immunostaining for
met-enkephalin in the globus pallidus, olfactory tubercle, and the CA. The decr
in the globus pallidus and CA were statistically significant. The decr in the
olfactory tubercle was not significant. Immunostaining for met-enkephalin in the
other brain regions was not affected by xylene. The
authors conclude that xylene decr the met-enkephalin
content of specific brain regions. The regional specificity of these decr
suggests that enkephalins are involved in xylene
neurotoxicity.
... Mixed xylenes (60% m-, 14% p-, 9% o-xylene,
and 17% ethylbenzene) in corn oil were administered by gavage to mice and rats 5
days/week for 103 weeks. Mice received daily doses of 500 or 1000 mg/kg; rats
received 250 or 500 mg/kg. No gross or histopathological lesions were related to
these treatments; tumor incidence was similar for treated and control groups of
either species. There was no evidence for carcinogenicity. When tested for
mutagenicity, o-, m-, and p-xylene were negative by
assay in the Ames system using Salmonella typhimurium strains TA1535, TA1537,
TA1538, TA98, and TA100 with or without metabolic activation by S9 fraction
derived from livers of rats either untreated or induced with Aroclor 1254. Xylene
did not change the number of sister chromatid exchanges or the number of
chromosomal aberrations in human lymphocytes in vitro. /Xylenes/
Teratogenicity has been evaluated for a xylene
mixture (9.1% o, 60.2% m, 13.6% p, and 17.0% ethylbenzene) in pregnant albino
CD-I mice given the mixture at dosages of 2.4, 3.0, and 3.6 ml/kg/day by gavage
on days 6-15 of gestation. At these near-lethal doses, xylene
produced a significant increase in malformations, with cleft palate being the
major malformation observed. Exposure of CFY rats to 1000 mg/cu m (230 ppm) xylene
for 24 hr/day from day 9 to 14 of gestation was not teratogenic, although there
was an increase in skeletal anomalies consisting of extra ribs and fused
sternebrae.
Rats exposed 6 hr/day for 3 days to 2000 ppm
of a xylene mixture of the o, m, and p isomers showed
an increase in hepatic cytochrome p450 and NADPH-cytochrome c reductase. The p
isomer was less potent in inducing this effect that the other isomers or the
mixture. Microsomes from lung and kidney also showed increases in cytochrome
p450 for the xylene mixture and isomers except the p
isomer failed to induce cytochrome p450 in microsomes from kidney.
... Under the conditions of these 2 yr gavage
studies, there was no evidence of carcinogenicity of xylenes (mixed) for male or
female F344/N rats given 250 or 500 mg/kg or for male or female B6C3F1 mice
given 500 or 1,000 mg/kg.
National Toxicology Program Studies:
Two yr toxicology and carcinogenesis studies
were conducted by admin 0, 250, or 500 mg/kg xylenes in corn oil by gavage to
groups of 50 F344/N rats of each sex, 5 days per week for 103 weeks. Groups of
50 B6C3F1 mice of each sex were administered 0, 500, or 1,000 mg/kg xylenes on
the same schedule. ... Under the conditions of these 2 yr gavage studies, there
was no evidence of carcinogenicity of xylenes (mixed) for male or female F344/N
rats given 250 or 500 mg/kg or for male or female B6C3F1 mice given 500 or 1,000
mg/kg.
Non-Human Toxicity Values:
LD50 Rat oral 4.3 g/kg
LD50 Rat oral 10 mL/kg /Xylene/
LD50 Mouse oral 1590 mg/kg /Xylene/
LC50 Rat inhalation 6,350 ppm/4 hr
LCLo Rat inhalation 8,000 ppm/4 hr
LC50 Rat inhalation 6,350 ppm/4 hr
LC50 Mouse inhalation 3,907 ppm/6 hr
LD50 Rat oral 4.3 g/kg and 10 ml/kg /Xylene/
LD50 Mouse oral 1590 mg/kg /Xylene/
LC50 Rat oral 29,000 mg/cu m (6670 ppm) /Xylene/
LD50 Rat oral range from 3523 mg/kg to 8600
mg/kg. /Mixed Xylenes/
LD50 Mouse (B6C3F1) oral 5251 mg/kg (female)
and 5627 mg/kg (male). /Mixed Xylenes/
LD50 Rabbit dermal > 5 ml/kg (43 g/kg).
/Mixed Xylenes/
Ecotoxicity Values:
LD50 Goldfish 13 mg/l/24 hr /Conditions of
bioassay not specified, no specific isomer/
LC50 Rainbow trout 13.5 mg/l/96 hr /Conditions
of bioassay not specified, no specific isomer/
LC50 Fathead minnow 46 mg/l/1 hr; 42
mg/l/24-96 hr @ 18-22 deg C, in a static bioassay /No specific isomer/
LC50 Carassius auratus (goldfish) 16.9 ppm/96
hr /Conditions of bioassay not specified, no specific isomer/
TSCA Test Submissions:
Acute oral toxicity was evaluated in groups of
7 Sprague-Dawley male albino rats administered single doses of undiluted xylenes
by oral gavage at levels of 0.85, 2.55, 4.25, 5.95, 7.65, and 8.65 g/kg of body
weight. Mortality was observed in 3 animals in the 4.25 g/kg dose group, 5 in
the 5.95 g/kg dose group, and in all animals in the two highest dose groups. The
LD50 value was calculated to be 4.5 g/kg (3.3 - 6.2 g/kg confidence limits) by
the Litchfield and Wilcoxon method. Clinical observations included shallow,
rapid respiration and bloody discharge around the nose in the 4.25 and 5.95 g/kg
dose group and marked depression to coma, shallow respiration, lacrimation, and
bloody crusts around the eyes and nose in the 7.65 and 8.50 g/kg dose group.
Gross necropsy revealed congested to hemorrhagic lungs, pale, mottled livers and
kidneys, and excessive hyperhemia to a grey-green discoloration of the walls of
the stomach and upper intestinal tract in decedents; survivors appeared normal.
Xylene (CAS No.
1330-20-7) was tested for dermal irritation. The test substance was applied at
0.5 ml to intact and abraded skin of three groups of 6 rabbits (sex not
reported). The first group had the sites occluded for 4 hours, the second for 24
hours, and the third were unoccluded. Well-defined to moderate erythema and
edema were noted in the unoccluded and the 4-hour occluded groups. Well-defined
to moderate erythema and well-defined to severe edema were observed in the
24-hour occluded group. The primary irritation scores were 4.2, 5.2, and 4.8 for
4-hour occluded, 24-hour occluded and non-occluded groups, respectively.
Xylene (CAS No.
1330-20-7) was tested for eye irritation. The test substance was applied at 0.1
ml to the conjunctival sac of one eye of each of 6 rabbits (sex not reported)
Mild iritis was observed in most eyes at 1 hour; slight corneal opacity was
observed in 2 eyes at 24 hours, and 1 eye at 48 hours. Moderate conjunctival
irritation was present in most eyes at 1 and 24 hours, but was slight at 48 and
72 hours. All eyes were normal by 7 days.
Xylene (CAS#
1330-207) was evaluated for developmental effects in mice administered the test
substance by gavage at dose levels of 0, 0.6, 1.2, 2.4, 3.0, 3.6 or 4.2 mL/kg/day.
There were 15/15 mortalities at 4.2 mL/kg/day and 12/38 at 3.6 mL/kg/day.
Maternal body weight gain was reduced in survivors at 3.6 mL/kg/day (p<0.05).
The average maternal liver weight was increased at 2.4 and 3.0 mL/kg/day and the
average fetal weight was reduced at 2.4 and 3.0 mL/kg/day (p<0.05). The
average percent of malformed fetuses was increased at 2.4, 3.0, and 3.6 mL/kg/day
(p<0.01). Cleft palate was observed in the 1.2, 2.4, 3.0, and 3.6 mL/kg/day
groups.
Mixed xylenes (CAS# 1320-20-7) were evaluated
for developmental effects in groups of male and female Charles River rats
administered the test substance for 6 hours/day by inhalation at concentrations
of 0 (group I), 60 (group II), 250 (group III), 500 ppm (groups IV, V, and VI).
Group I consisted of 30 untreated males and 30 untreated females, groups II and
III consisted of 10 treated males and 10 treated females in each, group IV
contained 20 treated males and 40 treated females, group V contained 10 treated
males and 20 untreated females, and group VI contained 10 untreated males and 20
treated females. Treated animals were exposed for 131 days pre-mating and 20-day
mating period. Females continued to be exposed during days 1-20 of gestation and
on days 5-20 of lactation. Twenty group I (control) and 12 group IV females were
sacrificed on day 21 of gestation in order to evaluate mating performance and
pregnancy data. Group III and group VI showed mating indices which were
significantly lower than controls. High dose females (groups IV and VI) showed
an increased mean number of resorption sites. Mean fetal weight was lower in the
high dose group than in the control group (this difference was only significant
for female fetuses).
Mixed xylenes (CAS# 1320-20-7) were evaluated
for developmental effects in groups of male and female Charles River rats
administered the test substance for 6 hours/day by inhalation at concentrations
of 0 (group I), 60 (group II), 250 (group III), 500 ppm (groups IV, V, and VI).
Group I consisted of 30 untreated males and 30 untreated females, groups II and
III consisted of 10 treated males and 10 treated females in each, group IV
contained 20 treated males and 40 treated females, group V contained 10 treated
males and 20 untreated females, and group VI contained 10 untreated males and 20
treated females. Treated animals were exposed for 131 days pre-mating and 20-day
mating period. Females continued to be exposed during days 1-20 of gestation and
on days 5-20 of lactation. Twenty group I (control) and 12 group IV females were
sacrificed on day 21 of gestation in order to evaluate mating performance and
pregnancy data. Group III and group VI showed mating indices which were
significantly lower than controls. High dose females (groups IV and VI) showed
an increased mean number of resorption sites. Mean fetal weight was lower in the
high dose group than in the control group (this difference was only significant
for female fetuses).
Xylene (CAS#
1330-20-7) was evaluated for acute dermal toxicity. The test substance was
applied undiluted to the skin of New Zealand albino rabbits for 24-hours.
Dosages and mortality data are as follows: 2000 (0/1 M); 3160 (0/1 F); 5010 (1/1
M in 2-days); 7940 mg/kg body weight (1/1 F in 2-days). Clinical signs included
weight loss, increasing weakness, collapse, and death. Necropsy findings
included hemorrhagic areas of the lungs, liver, and kidney discoloration,
enlarged gall bladder, and gastrointestinal inflammation. The LD50 was
determined to be greater than 3160 mg/kg b.w.
Metabolism/Pharmacokinetics:
Metabolism/Metabolites:
IN HUMANS ... EXPOSED TO APPROX 0.2-0.4 MG/L XYLENE
ISOMERS (O-, M-, P-XYLENE) OR 1:1:1 MIXT FOR UP TO 8 HR
... MORE THAN 95% ... EXCRETED BY HUMANS INTO URINE IN FORM OF METHYLHIPPURIC
ACIDS. ... SMALL PORTION ... EXCRETED INTO URINE AS CORRESPONDING XYLENOLS.
Quantitative determination of urinary
metabolites in humans exposed to xylene using
colorimetric determination is widely used. The metabolites of ... xylene
are measured as ... methyl hippuric acid (MHA), paper chromatography and thin
layer chromatography are necessary as pretreatments of samples. The addition of
pyridine, p-dimethylaminobenzaldehyde (DAB) and acetic anhydride to glycine
conjugates gives the most stable color development. Excellect analytical
sensitivity and specificity with gas chromatographic methods requires
pretreatment with diazomethane for methylesterification of methyl hippuric acid.
... Xylene is
metabolized to a toxic aldehyde, methylbenzaldehyde ... .
The principal difference between human and
animal xylene metabolism is the production of p-methylbenzaldehyde
catalyzed by rabbit and rodent lung and liver alcohol dehydrogenase.
Glucuronidation apparently occurs after saturation of normal glycine metabolic
pathways that predominate in humans as evidenced by the methylhippuric acids in
urine. Methylbenzyl alcohol and dimethylpheonl have not been reported in human
studies.
Generally, the xylenes are metabolized to the
corresponding o-, m-, or p-toluic acids, and excreted in urine free or
conjugated with glycine as methylhippuric acid.
Absorption, Distribution & Excretion:
For exposure to xylene
at concn averaging 100 ppm, the mean methyl hippuric acid concn should average
1.5 to 2 g/g creatinine (range 1.0-3.0) in a sample collected during the second
part of the exposure period. Almost total urinary excretion of xylene
occurs by 24 hours. The rapid xylene clearance from
blood (plasma half-life of 4 hours) prevents adequate biological monitoring of
serum samples. ...
XYLENES HAVE BEEN REPORTED TO CROSS THE HUMAN
PLACENTA.
XYLENE, WHEN
INGESTED, IS READILY ABSORBED BY THE HUMAN SYSTEM, AS HAS BEEN SHOWN IN
ACCIDENTAL INGESTIONS. ABSORPTION THROUGH INTACT & BROKEN SKIN OCCURS
READILY. ... XYLENE IS ABSORBED MAINLY THROUGH MUCOUS
MEMBRANES & PULMONARY SYSTEM. ... ABSORBED XYLENE
IS TRANSLOCATED THROUGH THE VASCULAR SYSTEM. ...
The uptake of solvent by man during whole body
exposure to toluene and xylene occurs almost
exclusively through the lung; dermal uptake represents about 1% of the total
uptake.
Male rats were injected ip with benzene,
toluene, or a mixt or xylene isomers at 20 mmol
hydrocarbon/kg daily for 3 days. The effects of administration of these
hydrocarbons upon their own in vitro metabolism, as well as upon cytochrome
p450, NADPH-cytochrome c reductase, aminopyrine N-demethylase, aniline
hydroxylase, glutathione, glutathione S-transferase, and
UDP-glucuronyltransferase in liver were studied.
The correlation between xylene
exposure and urinary excretion of methyl hippuric acid (MHA) was studied in 40
workers (35 men, 5 women) employed in the paint industry. Subjects were exposed
primarily to xylene although exposure to 11 other
solvents was possible. Personal sampling showed 8 hr time weighted average for xylene
ranged from 0-865 mg/cu m with a median exposure of 69 mg/cu m. Urine was
collected over one 24 hr period for each worker. Personal air samples were
collected for each worker over the course of a complete workday. Methyl hippuric
acid excretion was linearly correlated to the 8 hr time weighted average for xylene
exposure after adjustment for body weight. The total amount of methyl hippuric
acid excreted in the urine over 24 hr showed virtually the same correlation to xylene
exposure (r= 0.84) as the methyl hippuric acid excretion during the latter part
of the workshift (r= 0.81, sampling time 4-5 hr) among 37 workers exposed to 8
hr time weighted average xylene concentrations of 0-200
mg/cu m.
Humans exposed to 46 or 92 ppm of o-, m-, p-xylene
or a mixture (1:1:1) of the three for 8 hr absorbed approx 64% of the inhaled xylene.
No difference in the absorption rate was reported due to level of exposure,
length of exposure, or the type and/or mixture of the xylene
isomers. The absorption of xylene appeared to vary
among individuals due to differences in ventilation rate. ... Individuals with
an incr ventilation rate retained less xylene.
Male Wister rats exposed to xylene
in air (80% m-xylene, 12% p-xylene)
for 6 hr/day, 5 days/week for 2 weeks accumulated 64.8 mg/xylene/g
of perirenal fat after five exposures and 127.0 mg/xylene/g
of perirenal fat after 10 exposures to xylene.
Groups of five male Wister rats were exposed
to 300 ppm of technical grade xylene (85% m-xylene,
15% other isomers) for 6 hr/day, 5 days a week for 5, 9, 14, or 18 weeks.
Analysis of the perirenal fat by gas chromatography indicated that 67.6, 57.4,
40.7, and 36.6 mg/g of tissue was present after 5, 9, 14, or 18 weeks of
exposure, respectively. The gradual decr in the xylene
content of perirenal fat as the length of exposure was incr may have been the
result of an incr metabolic rate.
Groups of six male human volunteers were
exposed to 200 or 100 ppm of a xylene mixture (49.4%
ethylbenzene) for 30 min through a breathing valve. The first group, while being
exposed to 200 ppm of the xylene mixture, exercised on
a bicycle ergometer for 90 min. The second group, exposed to 100 ppm, ... incr
their level of exercise at 30 min intervals. At rest and during light work,
pulmonary uptake ... was about 63% during the 2 hr exposure period. At a more
strenuous work level, pulmonary uptake ... was only 51% after a correction had
been applied for the incr breathing vol that occurs during heavy exercise.
15 human male volunteers exposed for 70 min
periods to 100 and 300 ppm at rest and 300 ppm while exercising absorbed a mean
of 180, 541, or 1210 mg of xylene, respectively. The xylene
absorption rate for both exposure levels was 43% while resting and 64% while
exercising, assuming inhalation volumes of 20 cu m/24 hr at rest and 10 cu m/8
hr at work.
Xylene possesses
marked solubility in adipose tissue (distribution coefficient fat/blood
approximately 100). ...
Xylene vapor is
absorbed rapidly from the lungs, and xylene liquid and
vapor are absorbed slowly through the skin. Of the xylene
absorbed, about 95% is metabolized in the liver to methylhippuric acid and 70 to
80% of metabolites are excreted in the urine within 24 hr. However, the many
variables which affect the absorption, metabolism and clearance of xylene
incl exercise, alcohol intake, cigarette smoking, co-exposure to other solvents,
gender, and GI, hepatic and renal pathology.
FOLLOWING EXPOSURE OF RABBITS TO ATMOSPHERE OF
ABOUT 3,000 MG/CU M FOR 8 HR/DAY, 6 DAYS/WK, FOR 130 DAYS, XYLENE
WAS FOUND AT SLIGHTLY HIGHER AVG CONCENTRATIONS IN THE ADRENAL (148 PPM), BONE
MARROW (130 PPM), SPLEEN (115 PPM), & BRAIN (100 PPM) THAN IN BLOOD (91 PPM)
OR IN OTHER ORGANS. /XYLENES/
IN HUMANS ... EXPOSED TO APPROX 0.2-0.4 MG/L XYLENE
ISOMERS (O-, M-, P-XYLENE) OR 1:1:1 MIXT FOR UP TO 8 HR
... PULMONARY RETENTION WAS 64%, WHICH WAS ... INDEPENDENT OF DOSAGE OR DURATION
OF EXPOSURE. AFTER EXPOSURE, ONLY 5% OF RETAINED XYLENES WERE ELIM IN EXPIRED
AIR. MORE THAN 95% ... EXCRETED BY HUMANS INTO URINE IN FORM OF METHYLHIPPURIC
ACIDS. ... SMALL PORTION ... EXCRETED INTO URINE AS CORRESPONDING XYLENOLS.
Interactions:
Concomitant ingestion of ethyl alcohol
potentiated the deleterious behavioral effects of xylene
in animals. Alcohol also potentiated the weak hepatic microsomal enzyme-inducing
effects of xylene, and the combination produced liver
damage at doses of xylene which were not effective
alone.
Daily oral administration of 55 mg balagrin in
xylene (20% balagrin-80% xylene)
for 4 months, or administration of 235 mg xylene/kg
stimulated rat serum ornithine carbamoyl transferase and leucine aminopeptidase,
and decreased the relative weight of the liver. Only balagrin plus xylene
decreased serum alpha-2 globulins, stimulated serum and liver cholinesterase,
and decreased liver triglycerides, whereas xylene alone
increased the blood leukocyte count and stimulated liver cytochrome oxidase, and
inhibited it in the testes and brain. Xylene alone
stimulated liver isocitrate dehydrogenase and glucose dehydrogenase more than
did balagrin plus xylene. ... A 79% incr in hepatic DNA
indicated repair.
... When consumed prior to exposure, ethanol
decreases the metabolic clearance of xylene by
approximately one-half.
The present study involved an investigation of
possible interactions between 3 aromatic hydrocarbons in their ability to affect
the development of the rat embryonic brain in vitro during 40 hr of the
organogenic period. The embryos were explanted on day 10.5 of gestation and
cultured in heat-inactivated rat serum to which various combinations of toluene,
xylene or benzene had been added in 0.1% DMSO as
dispersant. The actual amt of solvent present at different times in the culture
period was quantitated using GC. The results showed that the solvents affected
embryonic development in an additive manner (toluene 0.287 + or - 0.077; xylene
0.331 + or - 0.026; benzene 0.256 + or - 0.020; toluene + xylene
0.294 + or - 0.047; toluene + benzene 0.261 + or - 0.025; xylene
+ benzene 0.252 + or - 0.014 mL/mL). In each case the embryos had a small
flattened head. Also, addition of below-threshold levels of solvents alone or in
combo resulted in apparently normal embryonic development. The data indicate
that exposure to combinations of toluene, xylene and
benzene result in an additive rather than a synergistic or potentiating effect
on rat embryonic development in vitro.
The health effects of exposure to a mixture of
toluene and xylene isomers were studied on the fourth
or fifth days of a working week in factories in China. The study population
consisted of 233 exposed subjects and 241 controls. The prevalence of some
subjective symptoms significantly incr in the exposed population, and the
symptom profiles were similar to those found after exposure to toluene or
xylenes alone. Hematology and serum biochemistry did not show notable changes.
It seems reasonable to conclude that the effects of the toxicities of toluene
and xylenes in combo are additive.
Aromatic compounds are metabolized via the
p450 mixed function microsomal enzyme system in the endoplastic reticulum of the
liver. The co-ingestion of ethanol has an effect on the metabolism of xylene.
Ethanol inhibits the oxidation of the aromatic ring and also alkyl side chain
oxidation. This is probably through a direct inhibitory effect on the microsomal
oxidation by ethanol. Xylene blood concentrations
increase up to two-fold following ethanol ingestion indicating inhibition of
metabolism.
Pharmacology:
Interactions:
Concomitant ingestion of ethyl alcohol
potentiated the deleterious behavioral effects of xylene
in animals. Alcohol also potentiated the weak hepatic microsomal enzyme-inducing
effects of xylene, and the combination produced liver
damage at doses of xylene which were not effective
alone.
Daily oral administration of 55 mg balagrin in
xylene (20% balagrin-80% xylene)
for 4 months, or administration of 235 mg xylene/kg
stimulated rat serum ornithine carbamoyl transferase and leucine aminopeptidase,
and decreased the relative weight of the liver. Only balagrin plus xylene
decreased serum alpha-2 globulins, stimulated serum and liver cholinesterase,
and decreased liver triglycerides, whereas xylene alone
increased the blood leukocyte count and stimulated liver cytochrome oxidase, and
inhibited it in the testes and brain. Xylene alone
stimulated liver isocitrate dehydrogenase and glucose dehydrogenase more than
did balagrin plus xylene. ... A 79% incr in hepatic DNA
indicated repair.
... When consumed prior to exposure, ethanol
decreases the metabolic clearance of xylene by
approximately one-half.
The present study involved an investigation of
possible interactions between 3 aromatic hydrocarbons in their ability to affect
the development of the rat embryonic brain in vitro during 40 hr of the
organogenic period. The embryos were explanted on day 10.5 of gestation and
cultured in heat-inactivated rat serum to which various combinations of toluene,
xylene or benzene had been added in 0.1% DMSO as
dispersant. The actual amt of solvent present at different times in the culture
period was quantitated using GC. The results showed that the solvents affected
embryonic development in an additive manner (toluene 0.287 + or - 0.077; xylene
0.331 + or - 0.026; benzene 0.256 + or - 0.020; toluene + xylene
0.294 + or - 0.047; toluene + benzene 0.261 + or - 0.025; xylene
+ benzene 0.252 + or - 0.014 mL/mL). In each case the embryos had a small
flattened head. Also, addition of below-threshold levels of solvents alone or in
combo resulted in apparently normal embryonic development. The data indicate
that exposure to combinations of toluene, xylene and
benzene result in an additive rather than a synergistic or potentiating effect
on rat embryonic development in vitro.
The health effects of exposure to a mixture of
toluene and xylene isomers were studied on the fourth
or fifth days of a working week in factories in China. The study population
consisted of 233 exposed subjects and 241 controls. The prevalence of some
subjective symptoms significantly incr in the exposed population, and the
symptom profiles were similar to those found after exposure to toluene or
xylenes alone. Hematology and serum biochemistry did not show notable changes.
It seems reasonable to conclude that the effects of the toxicities of toluene
and xylenes in combo are additive.
Aromatic compounds are metabolized via the
p450 mixed function microsomal enzyme system in the endoplastic reticulum of the
liver. The co-ingestion of ethanol has an effect on the metabolism of xylene.
Ethanol inhibits the oxidation of the aromatic ring and also alkyl side chain
oxidation. This is probably through a direct inhibitory effect on the microsomal
oxidation by ethanol. Xylene blood concentrations
increase up to two-fold following ethanol ingestion indicating inhibition of
metabolism.
Environmental Fate & Exposure:
Environmental Fate/Exposure Summary:
Commercial xylene is
a mixture of the three xylene isomers in the following
percent ranges: 2-xylene, 10-25 percent; 3-xylene
45-70 percent; and 4-xylene 6-15 percent. Its
production and use in petroleum products, as a chemical solvent, and as an
organic synthesis reagent may result in its release to the environment through
various waste streams, including discharges from storage facilities and the use
of automobiles. Natural sources of xylene such as
petroleum, forest fires and the volatiles of plants may also account for this
compounds presence in the environment. Xylene will
enter the atmosphere primarily from fuel emissions and exhausts linked with its
use in gasoline. Based upon an experimental vapor pressure of 7.99 mm Hg at 25
deg C, xylene is expected to exist entirely in the
vapor phase in the ambient atmosphere. Vapor-phase xylene
is degraded in the atmosphere by reaction with photochemically-produced hydroxyl
radicals with an estimated atmospheric lifetime of about 1-2 days. Xylene
is expected to have moderate to high mobility in soils based upon experimental
Koc values obtained with a variety of soils at differing pH values and organic
carbon content. Volatilization from moist soil surfaces is expected based on an
experimental Henry's Law constant of 7.0X10-3 atm-cu m/mole. Biodegradation is
an important environmental fate process for xylene. In
general, it has been found that xylene is biodegraded
in soil and groundwater samples under aerobic conditions and may be degraded
under anaerobic denitrifying conditions. In water, xylene
is expected to adsorb somewhat to sediment or particulate matter based on its
measured Koc values. This compound is expected to volatilize from water surfaces
given its experimental Henry's Law constant. Estimated half-lives for a model
river and model lake are 3 and 99 hours, respectively. The potential for
bioconcentration in aquatic organisms is low based on an experimental BCF value
of 20, measured in eels. Exposure to xylene may occur
occupationally during its production or subsequent use, particularly as a
solvent or in gasoline, via dermal and respiratory routes. The main route of
exposure for the general population will be through inhalation of contaminated
air as well as ingestion of contaminated drinking water and food. Dermal contact
with household products containing xylene is also
expected to be significant. (SRC)
Probable Routes of Human Exposure:
Xylene can affect the
body if it is inhaled, if it comes in contact with the eyes or skin, or if it is
swallowed.
THE ADVANTAGES & DISADVANTAGES OF USING
SOFT CONTACT LENSES (IN HUMANS) IN ENVIRONMENTS WITH FUMES FROM SOLVENTS OR
SPLASHES OF STRONG ACIDS & ALKALIS WERE STUDIED EXPERIMENTALLY. UPTAKE OF XYLENE
BY LENS MATERIALS WAS UP TO 90 TIMES THAT BY PHYSIOLOGIC SALINE, USED TO
SIMULATE TEAR FLUID. WHEN EXPOSED LENSES WERE SOAKED FOR 10 & 60 MIN IN A
VERY SMALL VOLUME OF SALINE THE CONCN OF SOLVENT IN THAT SALINE WAS ONLY UP TO
23 & 11%, RESPECTIVELY, OF THAT IN DIRECT EXPOSED SALINE. SOLVENTS WERE
RELEASED MAINLY TO THE AIR. CONTACT LENSES WOULD LEAD TO A PROLONGED EXPOSURE
BUT TO A RATHER LOW CONCN AS COMPARED TO DIRECT EXPOSURE.
Exposure to organic solvent vapors was
investigated in 40 unit workplaces (with 189 workers) in 16 small scale
industries in north-east Japan ... in which synthetic urushi lacquer was applied
to produce non-metal tableware. ... Two furniture factories were also studied.
The equipment used was carbon felt dosimeters and portable PID-GC ... . ... The
gas chromatography could analyze benzene-toluene xylenes within 150 seconds. ...
Toluene was the major pollutant in the workplace air, with small quantities of
xylenes. ... Exposure did not exceed the current occupational exposure limit in
all the cases except for the two workers, who were excessively exposed due to
the generation of dense vapors in automated spraying process.
... There is a broad potential for exposure
both to industrial workers in the production and use of the xylenes and to the
general public (via vehicle exhausts, consumer products, etc). ...
Number of USA workers exposed 140,000 /Time
frame not mentioned/
NIOSH (NOES Survey 1981-1983) has
statistically estimated that 1,528,018 workers (316,320 of these are female) are
potentially exposed to xylenes in the US(1). An average xylene
concn of 0.1 ppm was detected in the breathing zones of paint shops sampled in
the US(2). Lab personnel are exposed to an average xylene
concn of 0.16 ppm and material handling personnel are exposed to an average xylene
concn of 1.6 ppm at hazardous waste facilities in the US(3). The 8 hour TWA
exposure to xylenes for personnel at organic solvent recycling plants was
measured as 1 ppm(4). A study from 1979-1987 calculated the average exposure to
xylenes in paint manufacturing plants as 2.01 ppm in breathing zone
locations(5). A survey of 97 autobody shops in the US reported the 8 hour TWA
exposure to xylenes was 3.3 ppm for painters and 0.7 ppm for non-painting
personnel(6). The 8 hour TWA for worker exposure to xylenes in a German
histology laboratory and a US histology laboratory was measured as 243-295 mg/cu
m and 11-315 mg/cu m respectively(7). The 8 hour TWA for worker exposure to
xylenes in a US hospital laboratory was measured as 3-1700 mg/cu m(7).
Occupational exposure may be through inhalation and dermal contact with this
compound at workplaces where xylenes are produced or used(SRC). The general
population will be exposed to xylenes largely via inhalation of ambient air,
particularly in areas with heavy traffic, near filling stations and near
industrial sources such as refineries(SRC). Exposure may also arise from
consuming contaminated food and drinking water(SRC). An average concn of 0.37
ppb of 3- and 4-xylene was measured in blood samples
collected from 60 persons in the US that are not occupationally exposed to
xylenes(8).
Humans are exposed to xylene
primarily from air, particularly in areas with heavy traffic, near filling
stations, near industrial sources such as refineries or where xylene
is used as a solvent. Exposure may also arise from drinking contaminated well
water near leaking underground gasoline storage tanks or from spills of
petroleum products. (SRC)
Benzene and xylenes are components of
gasoline. The US population exposed to xylenes from petroleum related sources
can be assumed to be the same as for benzene, namely: people choosing
self-service at gasoline service stations 37,000,000; people living in the
vicinity of gasoline service stations 118,000,000; petroleum refineries
6,597,000; urban exposure (auto emissions) 113,690,000(1). /Xylenes/
Body Burden:
ENVIRONMENTAL POLLUTANTS IN HUMAN MILK WERE
IDENTIFIED BY GAS CHROMATOGRAPHY/MASS SPECTROMETRY. XYLENE
WAS ONE OF THE AROMATICS IDENTIFIED.
FOLLOWING EXPOSURE OF RABBITS TO AN ATMOSPHERE
OF ABOUT 3,000 MG/CU M FOR 8 HR/DAY, 6 DAYS/WK, FOR 130 DAYS, XYLENE
WAS FOUND AT SLIGHTLY HIGHER AVG CONCENTRATIONS IN THE ADRENAL (148 PPM), BONE
MARROW (130 PPM), SPLEEN (115 PPM), & BRAIN (100 PPM) THAN IN BLOOD (91 PPM)
OR IN OTHER ORGANS.
Average Daily Intake:
AIR INTAKE: (Assume typical concn 4.0 ppb) 353
ug; WATER INTAKE: (Assume typical concn 0-1 ppb) 2 ug; FOOD INTAKE: Insufficient
data. (SRC)
Natural Pollution Sources:
Common naturally occurring sources of xylenes
are petroleum(1); forest fires and volatiles of plants(2).
Artificial Pollution Sources:
Agricultural spraying.
Xylene's production
and use in petroleum products, as a chemical solvent and intermediate, and for
the manufacture of terephthalic acid and herbicides(1-4) may result in its
release to the environment through various wastestreams(SRC).
Environmental Fate:
Several experimental Koc values for xylene
have been reported in soil samples with differing pH and organic carbon content
values(1-3). The reported Koc value of o-xylene is in
the range of 48-68(1). Mixtures of xylenes in silt clay soil at pH 8.5 and
organic carbon content of 0.17 percent have a reported experimental Koc of 365; xylene
in silt clay soil at pH 7.0 and organic carbon content of 1.40 percent have a
reported experimental Koc of 39; xylene in coarse sand
at pH 6.8 and organic carbon content of 0.09 percent has a reported experimental
Koc of 311; xylene in coarse sand at pH 6.6 and organic
carbon content of 0.04 percent has a reported experimental Koc of 2600(2). Xylene
in Norwegian forest soil at pH 5.6 and organic carbon content of 0.2 percent has
a reported experimental Koc of 129; xylene in Norwegian
agricultural soil at pH 7.4 and organic carbon content of 2.2 percent has a
reported experimental Koc of 158; xylene in Norwegian
forest soil at pH 4.2 and organic carbon content of 3.7 percent has a reported
experimental Koc of 289(3). Xylene isomers have been
observed to pass through soil at a dune-infiltration site on the Rhine River(4)
and to leach into groundwater under a rapid infiltration site(5). Based on an
experimental vapor pressure of 7.99(6), volatilization from dry soil surfaces is
expected(SRC). Volatilization from moist soil surfaces is expected based on an
experimental Henry's Law constant of 7.0X10-3 atm-cu m/mole(7) reported for a
mixture of xylenes. Xylene is degraded in standard
biodegradability tests using various inocula including sewage, activated sludge
and seawater(8-13).
AQUATIC FATE: Based on a recommended
classification scheme(1) and experimentally determined Koc values in the range
of 39-359(2-4), xylene is expected to adsorb somewhat
to suspended solids and sediment in water(SRC). Xylene
is expected to volatilize from water surfaces(1,SRC) based on an experimental
Henry's Law constant of 7.0X10-3 atm-cu m/mole(5) reported for a mixture of xylene
isomers. Estimated half-lives for a model river and model lake are 3 and 99
hours, respectively(1,SRC). Xylene is degraded in
standard biodegradability and field tests using various inocula including
sewage, activated sludge and seawater(6-12).
ATMOSPHERIC FATE: According to a model of
gas/particle partitioning of semivolatile organic compounds in the
atmosphere(1), xylene, which has an experimental vapor
pressure of 7.99 mm Hg at 25 deg C(2), will exist solely as a vapor in the
ambient atmosphere. Vapor-phase xylene is degraded in
the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC);
the atmospheric lifetime of xylene is about 1-2
days(3,4). Ambient levels of xylene are detected in the
atmosphere due to large emissions of this compound(SRC).
Environmental Biodegradation:
Xylenes are degraded in standard
biodegradability tests using various inocula including sewage, activated sludge
and seawater(1-7). Using a standard BOD dilution technique and a sewage inoculum,
a theoretical BOD of 52, 80 and 44% was observed over a 5 day incubation period
for 2-, 3-, and 4-xylene respectively(1). Using a
standard BOD dilution technique and a benzene acclimated sludge inoculum, a
theoretical BOD of 40, 10 and 26% was observed over an 8 day incubation period
for 2-, 3-, and 4-xylene respectively(2). An
unspecified amount of xylene was aerobically degraded
in 8 days when contaminated groundwater was percolated through a microbial
enriched soil column; the acclimation period was 3-4 days(2). A microbial
consortium enriched from subsurface sediments contaminated with chlorinated
hydrocarbons completely degraded 26 ug/l of xylene
during a 21 day incubation period(3). 2-, 3-, and 4-Xylene
at concns between 85 ug/l - 361 ug/l were degraded by a sand aquifer(4). Using a
standard BOD dilution technique and an activated sewage inoculum, a theoretical
BOD of 72 percent was observed over a 20 day incubation period for a mixture of xylene
isomers(5). The biodegradation rate constant for xylene
in an activated sludge inoculum was calculated as 0.2 hours-1, with a half-life
of 3.3 hours(6). An activated sludge inoculum obtained from a Wisconsin
wastewater treatment facility biodegraded a 5.53 ug/l sample of combined 3- and
4-xylene(7).
Environmental Abiotic Degradation:
Xylenes degrade in the atmosphere primarily by
reacting with photochemically produced hydroxyl radicals(SRC), with an
atmospheric lifetime of about 1-2 days(1,2). The rate constant for the
vapor-phase reaction of 2-, 3- and 4-xylene with
photochemically-produced hydroxyl radicals has been measured as 13.7X10-12 cu
cm/molecule-sec, 23.6X10-12 cu cm/molecule-sec and 14.3X10-12 cu cm/molecule-sec
respectively at 25 deg C(3,4). This corresponds to an atmospheric half-life of
about 28, 16 and 27 hours for 2-, 3 and 4-xylene
respectively at an atmospheric concn of 5X10+5 hydroxyl radicals per cu cm(3,4).
The rate constant for the vapor-phase reaction
of 2-, 3- and 4-xylene with photochemically-produced
nitrate radicals has been measured as 2.0X10-16 cu cm/molecule-sec(1), 7.6X10-17
cu cm/molecule-sec(2) and 1.4X10-16 cu cm/molecule-sec(2) respectively at 25 deg
C. This corresponds to an atmospheric half-life of about 80, 220 and 115 days
for 2-, 3 and 4-xylene respectively at an atmospheric
concn of 5X10+8 nitrate radicals per cu cm(3,SRC). The rate constant for the
vapor-phase reaction of a mixture of xylenes with ozone has been measured as
approximately 5.0X10-21 cu cm/molecule-sec at 25 deg C(4). This corresponds to
an atmospheric half-life of about 6 years at an atmospheric concn of 7.0X10+11
ozone molecules per cu cm(4,SRC). The photolysis of jet fuel JP-4 in water
resulted in the degradation of 3- and 4-xylene,
combined, from 1.46 to 1.38 to 1.34 to 1.20 mg/l in 0, 7, 14, and 21 days,
respectively, in pond water(5). Xylene is not expected
to undergo hydrolysis in the environment due to the lack of functional groups to
hydrolyze(SRC). Ambient levels of xylene are detected
in the atmosphere due to large emissions of this compound(SRC).
Environmental Bioconcentration:
An experimental BCF value of 20 was measured
for xylene isomers in eels exposed to petroleum for 10
days(1). According to a classification scheme(2), this BCF value suggests that
bioconcentration in aquatic organisms is low(SRC).
Soil Adsorption/Mobility:
Several experimental Koc values for xylenes
have been reported depending upon the pH and organic carbon content of the
soil(1-3). Batch experiments conducted with five low organic carbon content
(0.04-1.12%), field contaminated soils (3 silty clay and two sandy loams)
yielded Koc values ranging from 39-365(1). Xylene in
Norwegian forest soil at pH 5.6 and organic carbon content of 0.2 percent has a
reported experimental Koc of 129; xylene in Norwegian
agricultural soil at pH 7.4 and organic carbon content of 2.2 percent has a
reported experimental Koc of 158; xylene in Norwegian
forest soil at pH 4.2 and organic carbon content of 3.7 percent has a reported
experimental Koc of 289(2). Based on a recommended classification scheme(5) and
the experimentally determined Koc values, xylene is
expected to have moderate to high mobility in soils(SRC). Xylene
isomers have been observed to pass through soil at a dune-infiltration site on
the Rhine River(3) and to leach into groundwater under a rapid infiltration
site(6).
Volatilization from Water/Soil:
The Henry's Law constant for xylene
has been reported as 7.0X10-3 atm-cu m/mole(1). This value indicates that xylene
will volatilize rapidly from water surfaces(2,SRC). Based on this Henry's Law
constant, the volatilization half-life from a model river (1 m deep, flowing 1
m/sec, wind velocity of 3 m/sec) is estimated as approximately 3 hours(2,SRC).
The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec,
wind velocity of 0.5 m/sec) is estimated as approximately 99 hours(2,SRC). An
experiment which measured the rate of evaporation of xylenes from a 1:1000 jet
fuel:water mixture found that this rate averaged approximately 0.6 times the
oxygen reaeration rate(3). Combining this ratio with oxygen reaeration rates for
typical bodies of water(2), one estimates that the half-life for evaporation of xylene
from a typical river or pond is 29 and 144 hours, respectively(SRC).
Environmental Water Concentrations:
DRINKING WATER: According to a federal survey
of drinking water from groundwater supplies, xylenes are present in < 5% of
supplies(1). In a survey of 30 Canadian water treatment facilities, xylene
was detected in the drinking water in Canada with mean values of 1 ppb(2). Xylene
has been qualitatively detected in the municipal drinking water supplies of
Washington, DC(3), Philadelphia, PA(4), Cleveland, OH(5), Tuscaloosa, AL(6),
Houston, TX(7), and New Orleans, LA(8). Xylene was
detected at 0.1-2.9 ppb in drinking water wells in the vicinity of a
landfill(7). A max of 0.1 ppb has been found in bank-filtered Rhine river water
in the Netherlands(9). Xylene was detected, not
quantified, in 14 drinking water supplies in Great Britain(10). Xylene
was detected in the Woburn drinking wells in Woburn, MA(11). Xylene
was detected in the drinking water produced by offshore installations in Norway
at concns between 41-15,000 ng/l(12).
GROUNDWATER: Xylene
isomers have been found in groundwater under landfills(1) and in the hundreds
ppb range under a coal gasification site, 15 months after gasification was
completed(2). Xylene was detected in the groundwater
near the Lipari landfill site in Mantau, NJ(3). Xylene
was detected at concns of 2-9900 ppb, in the groundwater near an elementary
school located in the US(4). Xylene was detected in the
groundwater near an oil storage facility in Virginia at an average concn of 2.8
ppm(5). Xylene was detected in groundwater under a
landfill in Norman, OK(6) and under a rapid infiltration site in Phoenix, AZ(7)
at various concns. Xylene isomers were detected, not
quantified, in 10 groundwater water supplies in Great Britain(8).
SURFACE WATER: Xylene
was detected, not quantified in the Mississippi River near New Orleans(1), the
Black Warrior River in Tuscaloosa, AL(2), and the Glatt River in Switzerland(3).
Xylene was detected, not quantified in Lakes Erie and
Michigan(4). Xylene was detected at average concns of
< 1 ppb in the raw water sources of 30 Canadian cities(5). Xylene
was detected in only 1 of 204 surface water samples in the USA(6). Xylene
was detected, not quantified in northern Lake Ontario(7). Xylene
was detected in the surface waters of the Florida Bay at concns of 2-8 ug/l(8). Xylene
was detected, not quantified, in 4 surface water supplies in Great Britain(9).
SEAWATER: Xylene was
detected, not quantified in Vineland Sound, MA(1) and the Gulf of Mexico(2). Xylene
was detected in Valdez Harbor-Trans Alaskan Pipeline Terminal at concns of 0.2
and 0.7 ppb in 2 of 7 sampling sites(3). Unspecified concns of xylene
were detected in the coastal waters of France(4).
RAIN/SNOW: Xylene
isomers were detected in the rainfall around West Los Angeles, at concns in the
parts per trillion range(1). Xylene was identified in
surface Antarctic snow from 1987-1991 at concns ranging from 12 to 198 ng/l and
in deep snow samples at concns ranging from 8 to 29 ng/l(2). Xylene
isomers were quantified during seven rain events in Portland, OR in 1984, and
concns ranged from 34 to 260 ng/l(3).
Effluent Concentrations:
Xylenes were detected at a low-level
radioactive waste disposal site in Maxey Flats at concns of 0.12 and 0.48 ppm in
2 of 3 trench leachates(1). Xylene was detected in the
effluent of an industrial plant near Philadelphia at a concn of 1,000 ppb(2). Xylene
was detected in the effluent from containing ponds in Atigun river, Alaska at
concns of 1.2 ppb(3). Xylene was detected in the
treated effluents from offshore oil drilling platforms in the Gulf of Mexico at
an average concn of 0.3 ppb(3). Xylene was detected at
concns of 50 ppb and 2,250 ppb in the leachate of a steel production plant in
Sydney, Nova Scotia(4). Xylene was detected in the
leachate from selected Wisconsin landfills at concns between 1 ug/l and 100 ug/l(5).
Xylene concns of 14,900 ppb, 2,651 ppb and 10,900 ppb
were detected in gas samples at three landfill sites in Quebec, Canada(6). The
total amount of xylene emissions from four wastewater
treatment facilities in Los Angeles, CA were measured between 72-3683
kg/year(7). The concn of xylene emitted from a German
incineration facility was 7.7 ug/cu-m(8). Emissions of combined 3- and 4-xylene
and 2-xylene from an outboard boat motor into a
freshwater lake in Germany were measured as 71 mg and 37 mg respectively, for 10
minutes of operation(9). Combined 3- and 4-xylene and
2-xylene were detected at concn ranges of 61.5-427.4
mg/km and 22.6-172.9 mg/km respectively, in the emissions of automobiles under
various driving conditions in the UK(10). Xylene
isomers were detected at mean concns of 1.13-2.27 ppm in the tailpipe emissions
from automobiles in the UK(11).
Sediment/Soil Concentrations:
Xylene was detected
in the soil at the Clothier waste disposal facility in Granby, NY at an average
concn of 79 ppb(1). Xylene was detected in the soil at
a building construction site in the Netherlands at a maximum concn of 2,030
mg/kg(2). Xylene was detected at concns of about 1,500
ug/kg in the soil at a hazardous waste facility in Pemberton, New Jersey(3).
Sediment collected from the River Morava,
Slovakia, contained xylene at concns from 0.21 to 1.53
ug/kg wet weight(1). Sediment samples from the River Tees estuary, England,
contained xylene at concns from 3.4 to 250 ppb(2).
Atmospheric Concentrations:
SOURCE DOMINATED AREAS: Xylene
was detected at concns between 0.2-99.0 ppb near two landfills in New Jersey(1),
and at concns between 3-5 ppb downwind from an automobile painting plant in
Janesville, WI(2).
URBAN/SUBURBAN: Atmospheric concns of total
mixed xylenes have been determined at various locations throughout the world.
From approximately 1900 samples across the USA an average atmospheric concn of
4.0 ppb was observed(1). Atmospheric concns of xylene
for several cities were reported; Turin, Italy 15.06 ppb; Los Angeles, CA 1-18.1
ppb; Sidney, Australia 3.9 ppb; Lincoln Tunnel, NY 33 ppb; Houston, TX 38 ppb;
Philadelphia, PA 16 ppb; London, UK 2.3 ppb; Phoenix, AZ 8.6 ppb(2). Combined 3-
and 4-xylene was detected at an average concn of 18.1
ppb and 2-xylene was detected at an average concn of
7.2 ppb in 39 US cities(3). 2-, 3- and 4-Xylene were
detected in the Lincoln Tunnel, NY at concns of 114 ppb, 49 ppb and 74 ppb
respectively(4). Ambient concns of xylene isomers were
reported for several urban cities; Zurich, Switzerland 9-21 ppb(5); Berlin,
Germany 13.6-18.1 ppb(5); Paris, France 0.6-1.5 ppb(5); Johannesburg, Pretoria
and Durban South Africa 1.3-4.5 ppb(5); London, England 0.8-2.8 ppb(5); Tokyo,
Japan 0.4-1.0 ppb (5); Phoenix, AZ 1.8-4.2 ppb(5); Houston, TX 1.3-3.8 ppb(5);
St. Louis, MO 0.3-1.0 ppb(5); Denver, CO 0.6-2.9 ppb(5) and Staten Island, NY
2.6 ppb(5).
RURAL/REMOTE: The median concn of xylene
sampled at 114 areas in the USA was 0.18 ppb with a maximum concn of 78 ppb(1).
Ambient concns of xylene isomers were reported for
several rural locations; Loop Head, Ireland 0.95-2.7 parts per trillion(2);
rural Brazil 80-140 parts per trillion(2); rural Kenya 10-330 parts per
trillion(2) and Niwot Ridge, CO 2-55 parts per trillion(2).
Food Survey Values:
Unspecified concns of xylenes were detected in
cheese products obtained from dairy cattle in the French Alps(1). Unspecified
concns of xylenes were detected in mother's milk in Bayonne, NJ; Jersey City,
NJ; Baton Rouge, LA; Pittsburgh, PA; Charleston, WV(2). Unspecified amounts of
xylenes were identified in human milk by gas chromatography/mass
spectrometry(3).
Plant Concentrations:
2- and 3-Xylene were
detected, not quantified, in the volatiles of kiwi fruit flowers(1).
Fish/Seafood Concentrations:
Xylene was detected
in rainbow trout from the Colorado river and carp obtained from Las Vegas Wash,
NV at concns of 50 and 120 ppb respectively(1).
Milk Concentrations:
ENVIRONMENTAL POLLUTANTS IN HUMAN MILK WERE
IDENTIFIED BY GAS CHROMATOGRAPHY/MASS SPECTROMETRY. XYLENE
WAS ONE OF THE AROMATICS IDENTIFIED.
Unspecified amounts of xylenes were identified
in human milk by gas chromatography/mass spectrometry(1). Unspecified concns of
xylenes were detected in mother's milk in Bayonne, NJ; Jersey City, NJ; Baton
Rouge, LA; Pittsburgh, PA; Charleston, WV(2).
Environmental Standards & Regulations:
FIFRA Requirements:
Xylene is exempted
from the requirement of a tolerance when used as an aquatic herbicide applied to
irrigation conveyance systems in accordance with the following conditions: (a)
It is to be used only in programs of the Bureau of Reclamation, US Department of
Interior and cooperating water user organizations. (b) It is to be applied as an
emulsion at an initial concn not to exceed 750 ppm. (c) It is not to be applied
when there is any likelihood that the irrigation water will be used as a source
of raw water for a potable water system or where return flows of such treated
irrigation water into receiving rivers and streams would contain residues of xylene
in excess of 10 ppm. (d) Xylene to be used as an
aquatic herbicide shall meet the requirement limiting the presence of a
polynuclear aromatic hydrocarbons as listed in 172.250 of title 21, Code of
Federal Regulations. /Xylene/
As the federal pesticide law FIFRA directs,
EPA is conducting a comprehensive review of older pesticides to consider their
health and environmental effects and make decisions about their future use.
Under this pesticide reregistration program, EPA examines health and safety data
for pesticide active ingredients initially registered before November 1, 1984,
and determines whether they are eligible for reregistration. In addition, all
pesticides must meet the new safety standard of the Food Quality Protection Act
of 1996. Pesticides for which EPA had not issued Registration Standards prior to
the effective date of FIFRA, as amended in 1988, were divided into three lists
based upon their potential for human exposure and other factors, with List B
containing pesticides of greater concern and List D pesticides of less concern. Xylene
is found on List C. Case No: 3020; Pesticide type: insecticide; Case Status: OPP
is reviewing data from the pesticide's producers regarding its human health
and/or environmental effects, or OPP is determining the pesticide's eligibility
for reregistration and developing the Reregistration Eligibility Decision (RED)
document.; Active ingredient (AI): Xylene; AI Status:
Registrants of the pesticide have not made or honored a commitment to seek
reregistration, conduct the necessary studies, or pay the requisite fees, or
they have asked EPA to cancel their product registrations. Unless some other
interested party supports them, products containing the pesticide will be
cancelled.
CERCLA Reportable Quantities:
Persons in charge of vessels or facilities are
required to notify the National Response Center (NRC) immediately, when there is
a release of this designated hazardous substance, in an amount equal to or
greater than its reportable quantity of 100 lb or 45.4 kg. The toll free number
of the NRC is (800) 424-8802; In the Washington D.C. metropolitan area (202)
426-2675. The rule for determining when notification is required is stated in 40
CFR 302.4 (section IV. D.3.b).
RCRA Requirements:
F003; When xylene is
a spent solvent, it is classified as a hazardous waste from a nonspecific source
(F003), as stated in 40 CFR 261.31, and must be managed according to State
and/or Federal hazardous waste regulations.
U239; As stipulated in 40 CFR 261.33, when xylene,
as a commercial chemical product or manufacturing chemical intermediate or an
off-specification commercial chemical product or a manufacturing chemical
intermediate, becomes a waste, it must be managed according to Federal and/or
State hazardous waste regulations. Also defined as a hazardous waste is any
residue, contaminated soil, water, or other debris resulting from the cleanup of
a spill, into water or on dry land, of this waste. Generators of small
quantities of this waste may qualify for partial exclusion from hazardous waste
regulations (40 CFR 261.5).
Atmospheric Standards:
Listed as a hazardous air pollutant (HAP)
generally known or suspected to cause serious health problems. The Clean Air
Act, as amended in 1990, directs EPA to set standards requiring major sources to
sharply reduce routine emissions of toxic pollutants. EPA is required to
establish and phase in specific performance based standards for all air emission
sources that emit one or more of the listed pollutants. Xylenes are included on
this list.
Clean Water Act Requirements:
Designated as a hazardous substance under
section 311(b)(2)(A) of the Federal Water Pollution Control Act and further
regulated by the Clean Water Act Amendments of 1977 and 1978. These regulations
apply to discharges of this substance.
Federal Drinking Water Standards:
EPA 10000 ug/l
Federal Drinking Water Guidelines:
EPA 10000 ug/l
State Drinking Water Standards:
(NJ) NEW JERSEY 1000 ug/l
(WI) WISCONSIN 10000 ug/l
State Drinking Water Guidelines:
(AZ) ARIZONA 440 ug/l
(FL) FLORIDA 20 ug/l
(ME) MAINE 600 ug/l
(MN) MINNESOTA 10000 ug/l
(NC) NORTH CAROLINA 400 ug/l
(RI) RHODE ISLAND 10000 ug/l
(WI) WISCONSIN 620 ug/l
Allowable Tolerances:
Xylene is exempted
from the requirement of a tolerance when used as an aquatic herbicide applied to
irrigation conveyance systems in accordance with the following conditions: (a)
It is to be used only in programs of the Bureau of Reclamation, US Department of
Interior and cooperating water user organizations. (b) It is to be applied as an
emulsion at an initial concn not to exceed 750 ppm. (c) It is not to be applied
when there is any likelihood that the irrigation water will be used as a source
of raw water for a potable water system or where return flows of such treated
irrigation water into receiving rivers and streams would contain residues of xylene
in excess of 10 ppm. (d) Xylene to be used as an
aquatic herbicide shall meet the requirement limiting the presence of a
polynuclear aromatic hydrocarbons as listed in 172.250 of title 21, Code of
Federal Regulations. /Xylene/
Residues of xylene
are exempted from the requirement of a tolerance when used as a solvent and
cosolvent (limits: pesticide formulations for grain storage only) in accordance
with good agricultural practices as inert (or occasionally active) ingredients
in pesticide formulations applied to growing crops or to raw agricultural
commodities after harvest. /Xylene/
Xylene is exempted
from the requirement of a tolerance when used as a solvent and cosolvent in
accordance with good agricultural practice as inert (or occasionally active)
ingredients in pesticide formulations applied to growing crops only. /Xylene/
Chemical/Physical Properties:
Molecular Formula:
C8-H10
Molecular Weight:
106.16
Color/Form:
Colorless liquid
Odor:
Sweet odor
Boiling Point:
137-140 DEG C
Corrosivity:
Xylene will attack
some forms of plastics, rubber, and coatings.
Density/Specific Gravity:
0.864 @ 20 DEG C/4 DEG C
Octanol/Water Partition Coefficient:
log Kow= 3.12-3.20
Solubilities:
PRACTICALLY INSOL IN WATER; MISCIBLE WITH
ABSOLUTE ALCOHOL, ETHER, AND MANY OTHER ORGANIC LIQUIDS
Vapor Pressure:
7.99 mm Hg at 25 deg C /from experimentally
derived coefficients/
Other Chemical/Physical Properties:
Xylene can be easily
chlorinated, sulfonated, or nitrated.
Chemical Safety & Handling:
Hazards Summary:
The major hazards encountered in the use and
handling of xylene stem from its toxicologic properties
and flammability. Exposure to this clear, sweet-smelling liquid may occur during
its use as a solvent for paints, coatings, adhesives, and rubber and as a
component of gasoline. Toxic by all routes of exposure (ie, dermal, ingestion,
and inhalation), xylene can cause effects including
headache, dizziness, skin and eye irritation, kidney and liver impairment, to
pulmonary edema, coma, and death. The ACGIH recommends a workplace exposure
limit (TLV) of 100 ppm as an 8-hr time-weighted average (TWA); however, to
assure protection, wear Buna-N-rubber gloves, apron, and safety glasses. In
unknown concentrations or emergency situations, an approved organic vapor
cannister respirator with a full-face plate or self-contained breathing
apparatus and full protective clothing are recommended. If contact does occur,
immediately flush exposed eyes with running water, wash exposed skin with soap
and water, and remove contaminated clothing. Xylene is
ignitable by heat, sparks, and flame and may do so explosively in an enclosed
area. Also, vapor may travel a considerable distance to a source of ignition,
and flash back. The heat of a fire may cause containers to explode and/or cause
thermal degradation of xylene, producing irritating or
poisonous gases. Fires involving xylene may be
extinguished with dry chemical, CO2, water spray, fog, or foam. For massive
fires in enclosed areas, use unmanned hose holders or monitor nozzles. If a xylene
tank car or truck is involved in a fire, isolate 1/2 mile in all directions.
Runoff from fire control water may cause pollution, and upon entering a sewer,
may create an explosion hazard. Xylene substance should
be stored in cool, well-ventilated places, away from sources of ignition and
strong oxidizing materials. ... For small spills of xylene,
take up with sand or other non-combustible absorbent, and place in containers
for later disposal, or absorb on paper and evaporate in an appropriate exhaust
hood. For large spills on land, dike to contain or divert to impermeable holding
area (water spray may need to be applied to control flammable vapor) and remove
material with pumps or vacuum equipment. Absorb residual with sand, vermiculite,
or activated carbon and place in metal containers with covers. For large spills
on water, contain material with booms, weirs, or natural barriers. Apply a
universal gelling agent, and use (oil) skimming equipment or suction hoses to
remove slick and trapped, solidified mass. Prior to implementing land disposal
of waste residue (including waste sludge), consult environmental regulatory
agencies.
DOT Emergency Guidelines:
Fire or explosion: Highly flammable: Will be
easily ignited by heat, sparks or flames. Vapors may form explosive mixtures
with air. Vapors may travel to source of ignition and flash back. Most vapors
are heavier than air. They will spread along ground and collect in low or
confined areas (sewers, basements, tanks). Vapor explosion hazard indoors,
outdoors or in sewers. Those substances designated with a "P" may
polymerize explosively when heated or involved in a fire. Runoff to sewer may
create fire or explosion hazard. Containers may explode when heated. Many
liquids are lighter than water. /Xylenes/
Health: May cause toxic effects if inhaled or
absorbed through skin. Inhalation or contact with material may irritate or burn
skin and eyes. Fire will produce irritating, corrosive and/or toxic gases.
Vapors may cause dizziness or suffocation. Runoff from fire control or dilution
water may cause pollution. /Xylenes/
Public safety: Call Emergency Response
Telephone Number. ... Isolate spill or leak area immediately for at least 50 to
100 meters (160 to 330 feet) in all directions. Keep unauthorized personnel
away. Stay upwind. Keep out of low areas. Ventilate closed spaces before
entering. /Xylenes/
Protective clothing: Wear positive pressure
self-contained breathing apparatus (SCBA). Structural firefighters' protective
clothing will only provide limited protection. /Xylenes/
Evacuation: ... Fire: If tank, rail car or
tank truck is involved in a fire, isolate for 800 meters (1/2 mile) in all
directions; also, consider initial evacuation for 800 meters (1/2 mile) in all
directions. /Xylenes/
Fire: Caution: All these products have a very
low flash point: Use of water spray when fighting fire may be inefficient. Small
fires: Dry chemical, CO2, water spray or regular foam. Large fires: Water spray,
fog or regular foam. Do not use straight streams. Move containers from fire area
if you can do it without risk. Fire involving tanks or car/trailer loads: Fight
fire from maximum distance or use unmanned hose holders or monitor nozzles. Cool
containers with flooding quantities of water until well after fire is out.
Withdraw immediately in case of rising sound from venting safety devices or
discoloration of tank. Always stay away from tanks engulfed in fire. For massive
fire, use unmanned hose holders or monitor nozzles; if this is impossible,
withdraw from area and let fire burn. /Xylenes/
Spill or leak: Eliminate all ignition sources
(no smoking, flares, sparks or flames in immediate area). All equipment used
when handling the product must be grounded. Do not touch or walk through spilled
material. Stop leak if you can do it without risk. Prevent entry into waterways,
sewers, basements or confined areas. A vapor suppressing foam may be used to
reduce vapors. Absorb or cover with dry earth, sand or other non-combustible
material and transfer to containers. Use clean non-sparking tools to collect
absorbed material. Large spills: Dike far ahead of liquid spill for later
disposal. Water spray may reduce vapor; but may not prevent ignition in closed
spaces. /Xylenes/
First aid: Move victim to fresh air. Call 911
or emergency medical service. Apply artificial respiration if victim is not
breathing. Administer oxygen if breathing is difficult. Remove and isolate
contaminated clothing and shoes. In case of contact with substance, immediately
flush skin or eyes with running water for at least 20 minutes. Wash skin with
soap and water. Keep victim warm and quiet. Effects of exposure (inhalation,
ingestion or skin contact) to substance may be delayed. Ensure that medical
personnel are aware of the material(s) involved, and take precautions to protect
themselves. /Xylenes/
Odor Threshold:
The odor threshold was calculated as 4.5 mg/cu
m or about 1 ppm for a 10-sec exposure.
Skin, Eye and Respiratory Irritations:
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.
Vapor irritates eyes and mucous membranes and
may cause dizziness, headache, nausea, and mental confusion. Liquid irritates
eyes and mucous membranes.
NFPA Hazard Classification:
Health: 2. 2= Materials hazardous to health,
but areas may be entered freely with self-contained breathing apparatus.
Flammability: 3. 3= Liquids which can be
ignited under almost all normal temp conditions. Water may be ineffective on
these liq because of their low flash points. Solids which form coarse dusts,
solids in shredded or fibrous form that create flash fires, solids that burn
rapidly, usually because they contain their own oxygen, and any material that
ignites spontaneously at normal temp in air.
Reactivity: 0. 0= Materials which are normally
stable even under fire exposure conditions and which are not reactive with
water. Normal fire fighting procedures may be used.
Fire Fighting Procedures:
Use water spray or fog to extinquish fire.
Cool fire exposed containers with water.
If material on fire or involved in fire: Do
not extinguish fire unless flow can be stopped or safely confined. Use water in
flooding quantities as fog. Solid streams of water may spread fire. Cool all
affected containers with flooding quantities of water. Apply water from as far a
distance as possible. Use foam, dry chemical, or carbon dioxide.
Firefighting Hazards:
Vapors are heavier than air & may travel
to a source of ignition & flashback.
Electrical hazard: class 1, group D
Hazardous Reactivities & Incompatibilities:
An attempt to chlorinate xylene
with 1,3-dichloro-5,5-dimethyl-2,4-imidazolidindione (dichlorohydrantoin) caused
a violent explosion. The haloimide undergoes immediate self accelerating decomp
in the presence of solvents.
Incompatible with strong oxidizers.
Hazardous Decomposition:
When heated to decomposition, it emits acrid
smoke and fumes.
Prior History of Accidents:
The wreck of the MV Ariadne, a Panamanian flag
container ship, is examined as a case study of a hazardous substance emergency
response in a third world country. /The ship/, carrying a cargo of heavy fuel
oil, tetraethyl lead, xylene, toluene, methyl isobutyl
ketone, butyl acetate, ethyl acetate, and acetone was grounded while departing
the harbor of Mogadishu, Somalia. The Somalian government requested a team of
technical advisors to help respond appropriately to the emergency. The major
issues addressed by the advisory team were the need for additional salvage
equipment and expertise, the danger of toxic fumes from the fire and explosions
aboard the ship, the presence and possible release of tetraethyl lead, possible
port blockage by the wreck, recovery of the chemical drums, and the extent of
environmental damage caused by the release of oil, pesticides, and tetraethyl
lead into the harbor. ...
Protective Equipment & Clothing:
Employees should be provided with and required
to use impervious clothing, gloves, face shields (eight-inch minimum) ... to
prevent repeated or prolonged skin contact with liquid or solid xylene.
Clothing contaminated with xylene should be placed in
closed containers for storage until it can be discarded or until provision is
made for the removal of xylene from the clothing. If
the clothing is to be laundered ... the person performing the operation should
be informed of xylene's hazardous properties.
Breakthrough times /for natural rubber,
neoprene, and polyvinyl chloride/ less (usually significantly less) than one hr
reported by (normally) two or more testers. Breakthrough times /for polyvinyl
alcohol/ greater than one hr reported by (normally) two or more testers. Some
data suggesting breakthrough times /for nitrile rubber/ or approx an hour or
more.
Preventive Measures:
Skin that becomes contaminated with xylene
should be promptly washed with soap or mild detergent and water to remove any xylene.
Employees who handle liquid or solid xylene should wash
their hands thoroughly with soap or mild detergent and water before eating,
smoking, or using toilet facilities.
A major concern in the painting studio is
solvents, /including xylene/. ... Precautions include
... use of dilution and local exhaust ventilation, control of storage areas,
disposal of solvent soaked rags in covered containers, minimizing skin exposure
and the use of respirators and other personal protective equipment. The control
of fire hazards is also important, since many of the solvents are highly
flammable.
Contact lenses should not be worn when working
with this chemical.
SRP: The scientific literature for the use of
contact lenses in industry is conflicting. The benefit or detrimental effects of
wearing contact lenses depend not only upon the substance, but also on factors
including the form of the substance, characteristics and duration of the
exposure, the uses of other eye protection equipment, and the hygiene of the
lenses. However, there may be individual substances whose irritating or
corrosive properties are such that the wearing of contact lenses would be
harmful to the eye. In those specific cases, contact lenses should not be worn.
In any event, the usual eye protection equipment should be worn even when
contact lenses are in place.
SRP: Contaminated protective clothing should
be segregated in such a manner so that there is no direct personal contact by
personnel who handle, dispose, or clean the clothing. Quality assurance to
ascertain the completeness of the cleaning procedures should be implemented
before the decontaminated protective clothing is returned for reuse by the
workers. All contaminated clothing should not be taken home at end of shift, but
should remain at employee's place of work for cleaning.
If material not on fire and not involved in
fire: Keep sparks, flames, and other sources of ignition away. Keep material out
of water sources and sewers. Build dikes to contain flow as necessary. Attempt
to stop leak if without undue personnel hazard. Use water spray to knock-down
vapors. /Xylenes/
Personnel protection: Avoid breathing vapors.
Keep upwind. ... Do not handle broken packages unless wearing appropriate
personal protective equipment. ...
Shipment Methods and Regulations:
No person may /transport,/ offer or accept a
hazardous material for transportation in commerce unless that person is
registered in conformance ... and the hazardous material is properly classed,
described, packaged, marked, labeled, and in condition for shipment as required
or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./
The International Air Transport Association (IATA)
Dangerous Goods Regulations are published by the IATA Dangerous Goods Board
pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry
carrier regulations to be followed by all IATA Member airlines when transporting
hazardous materials.
The International Maritime Dangerous Goods
Code lays down basic principles for transporting hazardous chemicals. Detailed
recommendations for individual substances and a number of recommendations for
good practice are included in the classes dealing with such substances. A
general index of technical names has also been compiled. This index should
always be consulted when attempting to locate the appropriate procedures to be
used when shipping any substance or article.
Storage Conditions:
XYLENE SHOULD BE
STORED IN COOL, WELL-VENTILATED PLACES, AWAY FROM AREAS OF ACUTE FIRE HAZARD,
OPEN FLAMES & STRONGLY OXIDIZING MATERIALS. ALL CONTAINERS SHOULD BE CLEARLY
LABELLED & KEPT TIGHTLY CLOSED.
Cleanup Methods:
1. REMOVE ALL IGNITION SOURCES. 2. VENTILATE
AREA OF SPILL OR LEAK. 3. FOR SMALL QUANTITIES, ABSORB ON PAPER TOWELS.
EVAPORATE IN SAFE PLACE (SUCH AS FUME HOOD). ALLOW SUFFICIENT TIME FOR
EVAPORATING VAPORS TO COMPLETELY CLEAR HOOD DUCTWORK. BURN PAPER IN SUITABLE
LOCATION AWAY FROM COMBUSTIBLE MATERIALS. LARGE QUANTITIES CAN BE RECLAIMED OR
COLLECTED & ATOMIZED IN SUITABLE COMBUSTION CHAMBER. XYLENE
SHOULD NOT BE ALLOWED TO ENTER CONFINED SPACE, SUCH AS SEWER. ...
For spills on land, absorb remaining xylene
with sand or vermiculite and put in metal containers for disposal. Activated
carbon may be used on undissolved portion.
For spills on water, contain and apply a
universal gelling agent to solidify trapped mass then remove it.
Soil: construct barriers to contain spill or
divert to impermeable holding area. Remove material with pumps or vacuum
equipment. Absorb residual liquid with natural or synthetic sorbents, shovel
into containers with covers.
Water: contain with booms, weirs, or natural
barriers. Use (oil) skimming equipment or suction hoses to remove slick,
followed by application of sorbents.
Air: use water spray to control flammable
vapor. Control runoff for later treatment and/or disposal.
/Small quantities:/ Shut off all possible
sources of ignition. Wear face shield, goggles, laboratory coat, and nitrile
rubber gloves. Cover spill with a 1:1:1 mixture by weight of sodium carbonate or
calcium carbonate, clay cat litter (bentonite) and sand, then shovel into bucket
and transport to fume hood for atmospheric evaporation. Ventilate site of
spillage well to evaporate remaining liquid and dispel vapor.
Environmental considerations - air spill:
Apply water spray or mist to knock down vapors.
Environmental considerations - water spill:
Use natural barriers or oil spill control booms to limit spill travel. Use
surface active agent (eg, detergent, soaps, alcohols), if approved by EPA.
Inject "universal" gelling agent to solidify encircled spill and
increase effectiveness of booms. If dissolved, in region of 10 ppm or greater
concentration, apply activated carbon at ten times the spilled amount. Remove
trapped material with suction hoses. Use mechanical dredges or lifts to remove
immobilized masses of pollutants and precipitates.
Environmental considerations - land spill: Dig
a pit, pond, lagoon, holding area to contain liquid or solid material. /SRP: If
time permits, pits, ponds, lagoons, soak holes, or holding areas should be
sealed with an impermeable flexible membrane liner./ Dike surface flow using
soil, sand bags, foamed polyurethane, or foamed concrete. Absorb bulk liquid
with fly ash, cement powder, or commercial sorbents. Apply "universal"
gelling agent to immobilize spill. Apply appropriate foam to diminish vapor and
fire hazard.
Disposal Methods:
Generators of waste (equal to or greater than
100 kg/mo) containing this contaminant, EPA hazardous waste number U239 and
F003, must conform with USEPA regulations in storage, transportation, treatment
and disposal of waste.
Xylene is a waste
chemical stream constituent which may be subjected to ultimate disposal by
controlled incineration.
Chemical Treatability of Xylene;
Concentration Process: Biological traetment; Chemical Classification: Aromatic;
Scale of Study: Full scale, continuous flow; Type of Wastewater Used:
Industrial; Results of Study: Influent concn of 20-200 ppb decreased to 1.0-15.0
ppb effluent concn in survey of two municipal wastewater treatment plants.
A good candidate for fluidized bed
incineration at a temperature range of 450 to 980 deg C and residence times of
seconds for liquids and gases, and longer for solids. A good candidate for
rotary kiln incineration at a temperature range of 820 to 1,600 deg C and
residence times of seconds for liquids and gases, and hours for solids. A good
candidate for liquid injection incineration at a temperature range of 650 to
1,600 deg C and a residence time of 0.1 to 2 seconds.
The permeability of xylene
in fire clay has been observed to sharply increase over a 4-day period after 24
days of normal behavior. This has been attributed to slow shrinkage of the clay
which was responsible for the breakthrough. This type of breakthrough in clay
would be a problem unless such materials are co-disposed with materials with
higher dielectric constants.
Occupational Exposure Standards:
OSHA Standards:
Permissible Exposure Limit: Table Z-1 8-hr
Time Weighted Avg: 100 ppm (435 mg/cu m). /Xylenes (o-, m-, p- isomers)/
Vacated 1989 OSHA PEL TWA 100 ppm (435 mg/cu
m); STEL 150 ppm (655 mg/cu m) is still enforced in some states. /Xylenes (o-,
m-, p- isomers)/
Threshold Limit Values:
8 hr Time Weighted Avg (TWA) 100 ppm; 15 min
Short Term Exposure Limit (STEL) 150 ppm /Xylene (o-,
m-, p-isomers)/
BEI (Biological Exposure Index):
Methylhippuric acids in urine at end of shift is 1.5 g/g creatinine. /Xylenes,
technical grade/
A4. A4= Not classifiable as a human
carcinogen. /Xylene (o-,m-, & p- isomers)/
Other Occupational Permissible Levels:
Maximum acceptable concentration (MAC) USSR 50
mg/cu m
Manufacturing/Use Information:
Major Uses:
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.
Manufacturers:
Amoco Corp, Hq, 200 East Randolph Dr, Chicago
IL 60601, (312) 856-6111; Production sites: Amoco Oil Co, subsidiary, PO Box
401, Texas City, TX 77590; subsidiary, Amoco Chemicals Co, PO Box 710, Whiting,
IN 46394
Ashland Oil, Inc, Hq, 1401 Winchester Ave,
Ashland, KY 41101, (606) 329-3333; Production site: Ashland Chemical Co, Div,
Petrochemicals Div, Leach Station, Catlettsburg, KY 41129
BP Oil, 200 Public Square, Cleveland, OH
44114-2375, (216) 586-4141. Production site: Alliance, LA 70037
Chevron Corp, Hq, 225 Bush St, San Francisco,
CA 94104, (415) 894-7700; Production site: subsidiary, Chevron Chemical Co,
Aromatics and Derivatives Div, Pascagoula, MS 39567
Citgo Petroleum Corporation, 6130 South Yale
Avenue, Tulsa, OK 74136, (918) 495-5000. Production site: Chorpus Christi, TX
78469
Coastal Eagle Point Oil Company, PO Box 1000,
US Route 130&I-296, Westville, NJ 08093,(609) 853-3100. Production site:
Westville, NJ 08093
Coastal Refining and Marketing Company, 9
Greenway Plaza, Houston, TX 77046, (713) 877-7174. Production site: Chorpus
Christi, TX 78403
Exxon Corp, Hq, 1251 Avenue of Americas, New
York, NY 10020, (212) 398-3000; Production site: Exxon Chemical Co, div, Exxon
Chemical Americas, PO Box 4004, Baytown, TX 77520
Fina Oil and Chemical Company, PO Box 2159,
Dallas TX, 75221, (214) 750-2400. Production site: Port Arthur, TX, 77640
Hess Oil Virgin Islands Corp, PO Box 127,
Kingshill, VI, 00851-0127. Phone (809)778-4000. Production site: St. Croix, VI,
00851
Koch Industries, Inc, Hq, PO Box 2256,
Wichita, KS 67201, (316) 832-5500; Production site: subsidiary, Koch Refining
Co, Corpus Christi, TX 78403
Lyondell-Citgo Refining Company LTD, 12000
Lawndale, Houston TX 77017. (713) 321-4111. Production site: Houston, TX 77017
Marathon Oil, PO Box 3128, Houston, TX 77253,
(713) 629-6600. Production site: Texas City, TX 77592-1191
Mobil Chemical Company, Petroleum Division,
3225 Gallows Road, Fairfax, VA 22037-0001. (703) 846-3000. Production sites:
Beaumont, TX 77704-0216; Chalmette, Louisiana 70043
Phillips Petroleum Co, Hq, Phillips Building,
Bartlesville, OK 74004, (918) 661-6600; Production sites: subsidiary, Phillips
66 Co, Chemicals and Catalysts Div, Specialty Chemicals, PO Box 308, Sweeny, TX
77480; subsidiary, Phillips Puerto Rico Core Inc, Guayama, Puerto Rico 0065
Shell Oil Co, Hq, One Shell Plaza, Houston, TX
77001, (713) 241-6161; Production site: Shell Chemical Co, division, PO Box 100,
Deer Park, TX 77536
Sun Company, Inc, Hq, 240 Radnor-Chester Road,
St Davids, PA 19087, (215) 293-6000; Production sites: subsidiary, Sun Refining
and Marketing Co, PO Box 426, Marcus Hook, PA 19061; subsidiary, Sun Refining
and Marketing Co, PO Box 920, Toledo, OH 43601
The UNO-VEN Company, 3850 North Wilke Road,
Arlington Heights, IL 6000. (708) 818-1800. Production site: Lemont, IL
60439-3659
Methods of Manufacturing:
FIRST ISOLATED FROM A CRUDE WOOD DISTILLATE.
OBTAINED FROM COAL TAR. ... MFR FROM PSEUDOCUMENE; BY CATALYTIC ISOMERIZATION OF
HYDROCARBON FRACTION.
... FROM TOLUENE BY TRANSALKYLATION.
RECOVERY FROM PETROLEUM-DERIVED CATALYTIC
REFORMATE OR PYROLYSIS OF GASOLINE; DISPROPORTIONATION OF TOLUENE; RECOVERY FROM
CRUDE LIGHT OIL (BY-PRODUCT OF COKE MFR)
General Manufacturing Information:
The commerical product mixed xylenes (a
technical product generally containing 20% each of o-xylene,
p-xylene and ethylbenzene, as well as small quantities
of toluene) analogously to toluene is an agent of major chemical and
occupational significance. It is produced in very large quantities and is
extensively employed in a broad spectrum of applications, primarily as a solvent
for which its use is increasing as a safe replacement for benzene, and in
gasoline as part of the BTX component (benzene-toluene-xylene);
xylenes are also frequently used in the rubber industry with other solvents such
as toluene and benzene. As individual isomers they are extensively employed in
the synthesis of synthetic agents. For example, phthalic acid, isophthalic acid,
terephthalic acid, and diemthylterephthalate have very broad applications in the
further preparation of phthalate ester plasticizers and components of polyester
fiber, film and fabricated items. ... Compared with benzene and toluene, very
much less is known of the human health hazards, particularly the chronic effects
of xylenes, either as mixed xylenes, as individual isomers or in admixture with
other alkylbenzenes.
... Xylene produced
from petroleum ... contains approx 20% o-xylene, 44% m-xylene,
20% p-xylene and 15% ethylbenzene. Xylene
from coal tar generally consists of 10-15% ortho-, 45-70% meta-, 23% para-, and
6-10% ethylbenzene.
Formulations/Preparations:
The commercial product "mixed xylenes"
is a technical product generally containing approximately 40% m-xylene
and 20% each of o-xylene, p-xylene,
and ethylbenzene, as well as small quantities of toluene ... .
70% of all mixed xylene
grades produced are 3 deg and 5 deg grade.
Solvent xylene, 2 deg
C range
Grade: Nitration (bp range 137.2-140.5 deg C),
4 degrees (bp range 138-134 deg C), 5 degrees (bp range 137-142 deg C, high in
m- isomer), 10 degrees (bp range 135-145 deg C); industrial (bp 90% 40 deg C,
complete 160 deg C). Also other grades depending upon use.
Impurities:
... Commercial xylenes may contain small amt
of toluene, trimethylbenzene, phenol, thiophene, pyridine, and nonaromatic
hydrocarbons.
Unpurified xylene may
contain ... pseudocumene ... .
The possibility that commercial xylene
may ... contain benzene should not be ignored.
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/
(1993) 2.99X10+9 kg
U. S. Production:
(1982) 657,964,000 gal
(1981) 882,408,000 gal
(1967) 454,837,000 gal
(1977) 2.80X10+12 G
(1982) 2.27X10+12 G
(1985) 2.38X10+12 g
(1985) 2.03X10+12 g /high purity 98-100%/
(1987) 7.95X10+8 gal
(1990) 6.21 billion lb
(1991) 6.32 billion lb
(1992) 6.39 billion lb
(1993) 6.84 billion lb
9.37 billion lb
U. S. Imports:
(1977) 1.04X10+11 G
(1982) 1.31X10+11 G
(1984) 4.57X10+8 g /calculated/
(1985) 7.09X10+7 gal
(1986) 7.50X10+7 gal
U. S. Exports:
(1977) 2.77X10+11 G
(1982) 2.83X10+11 G
(1985) 3.41X10+7 gal
(1987) 4.75X10+7 gal
Laboratory Methods:
Clinical Laboratory Methods:
Quantitative determination of urinary
metabolites exposed to xylene using colorimetric
determination is widely used. The metabolites of ... xylene
are measured as ... methyl hippuric acid (MHA), paper chromatography and
thin-layer chromatography are necessary as pretreatments of samples. The
addition of pyridine, p-dimethylaminobenzaldehyde (DAB) and acetic anhydride to
glycine conjugates gives the most stable color development. Excellect analytical
sensitivity and specificity with gas chromatographic methods requires
pretreatment with diazomethane for methylesterification of methyl hippuric acid.
High performance liquid chromatography has been widely used for analysis of
organic solvents. Non-volatile metabolites in urine can be assayed by this
method without pretreatment.
... Phenolic metabolites /of xylene/
were quantitatively estimated in hydrolyzed urine samples by gas chromatography.
Analytic Laboratory Methods:
ANALYTE: XYLENE;
MATRIX: AIR; PROCEDURE: ADSORPTION ON CHARCOAL, DESORPTION WITH CARBON
DISULFIDE, GAS CHROMATOGRAPHY; RANGE: 218-870 MG/CU M; PRECISION: COEFFICIENT OF
VARIATION 0.060.
ORGANIC GASES WERE COLLECTED IN TUBE FILLED
WITH SOLID SORBENT. XYLENE WAS ONE OF THE GASES
IDENTIFIED BY GAS CHROMATOGRAPHY/MASS SPECTROMETRY.
Commercial heterogeneous solvent products (eg
paints, inks, and adhesives) were collected nationwide in Japan in 1980. The
vapor phase of the product containers were analyzed for volatile organic solvent
constituents by means of FID-gas chromatography on two FS-WCOT (OV-101 and
PEG-600) capillary columns. ... Organic solvent components identified, ...
/included/ xylenes /which were/ predominantly the m- (66%) and p- isomers. (61%)
Results from the measurements of benzene,
toluene, and xylenes in the city center of Oslo are presented. The samples were
collected in March and August/September 1980 at two stations used in an air
pollution monitoring program. The sampling equipment was two charcoal filters in
series, placed in a filter holder with a disk of glass fiber prefilter in front.
Analysis was by high resolution gas chromatography.
The results of a successful test of remote
fluorescence analysis of ground water contaminants by using uv lasers and fiber
optics /is described/. Several priority pollutants /including/ xylenes were
detected using this technique.
Method TO-1: Method for the Determination of
Volatile Organic Compounds in Ambient Air Using Tenax Adsorption and Gas
Chromatography/Mass Spectrometry (GC/MS). Detection limit 1 ng.
Method 8020A: Aromatic Volatile Organics by
Gas chromatography Detection limit 1 ug/l.
Method 8240A: Volatile Organics by Gas
Chromatography/Mass Spectrometry(GC/MS): Packed Column Technique. Detection
limit 5ug/l.
EPA CLP Method OHC: Organic Analysis,
Multi-Media, High Concns: Volatile Organics in air determined by methanol
extraction and gas chromatography/flame ionization detection (GC/FID). Detection
limit 2.5 mg/kg.
EPA CLP Method Olm01: Organic Analysis,
Multi-Media, High Concns: Volatile Organics in air determined by hexadecane
extraction and gas chromatography/flame ionization detection (GC/FID). Detection
limit 10 ug/l.
Sampling Procedures:
Xylene vapor is
trapped on charcoal from a known vol of air.
Special References:
Special Reports:
Von Burg R; J Appl Toxicol 2: 269-71 (1982). A
review article on the toxicity of xylene mixture and
individual isomers.
National Academy of Sciences; The Alkyl
Benzenes (1981)
Fishbein L; Sci Total Environ 43 (1-2): 165-83
(1985). A review article on the toxicology of xylenes.
NIOSH; Criteria Document: Xylene
(1975) DHEW Pub. NIOSH 75-168
USEPA; Drinking Water Criteria Document:
Xylenes (1984) EPA-600/X-84-185.
Bailey HC et al; ASTM Spec Tech Publ 891:
193-212 (1985)
NCI; Monograph on Human Exposure to Chemicals
in the Workplace: Xylene (July/1985)
USEPA; Advisory Opinion for Xylenes (Dimethyl
benzenes) (Draft) (1981)
NIOSH; Recommendations for Occupational Safety
and Health Standards 35 (1S) (1986)
U.S. Dept Health & Human Services/Agency
for Toxic Substances Disease Registry; Toxicological Profile for (Xylenes)
(Update) (1995) NTIS# PB/95/264404
Toxicology & Carcinogenesis Studies of
Xylenes in F344/N Rats and B6C3F1 Mice (gavage Studies). Technical Report Series
No. 327 (1986) NTIS Publication No. PB87-189684/AS U.S. Department of Health and
Human Services, National Toxicology Program, National Institute of Environmental
Health Sciences, Research Triangle Park, NC 27709
Synonyms and Identifiers:
Related HSDB Records:
134
[2-XYLENE] (Mixture Component)
135
[3-XYLENE] (Mixture Component)
136
[4-XYLENE] (Mixture Component)
Synonyms:
AI3-02209-X
**PEER REVIEWED**
BENZENE, DIMETHYL-
**PEER REVIEWED**
Caswell No 906
**PEER REVIEWED**
DIMETHYLBENZENE
**PEER REVIEWED**
EPA Pesticide Chemical Code 086802
**PEER REVIEWED**
KSYLEN (POLISH)
**PEER REVIEWED**
Methyltoluene
**PEER REVIEWED**
NCI-C55232
**PEER REVIEWED**
VIOLET 3
**PEER REVIEWED**
XILOLI (ITALIAN)
**PEER REVIEWED**
XYLENEN (DUTCH)
**PEER REVIEWED**
XYLENES
**PEER REVIEWED**
XYLOL
**PEER REVIEWED**
XYLOLE (GERMAN)
**PEER REVIEWED**
Formulations/Preparations:
The commercial product "mixed xylenes"
is a technical product generally containing approximately 40% m-xylene
and 20% each of o-xylene, p-xylene,
and ethylbenzene, as well as small quantities of toluene ... .
70% of all mixed xylene
grades produced are 3 deg and 5 deg grade.
Solvent xylene, 2 deg
C range
Grade: Nitration (bp range 137.2-140.5 deg C),
4 degrees (bp range 138-134 deg C), 5 degrees (bp range 137-142 deg C, high in
m- isomer), 10 degrees (bp range 135-145 deg C); industrial (bp 90% 40 deg C,
complete 160 deg C). Also other grades depending upon use.
Shipping Name/ Number DOT/UN/NA/IMO:
UN 1307; Xylenes (Xylol)
IMO 3.2; Xylenes
IMO 3.3; Xylenes
Standard Transportation Number:
49 093 50; Xylenes
EPA Hazardous Waste Number:
U239; A toxic waste when a discarded
commercial chemical product or manufacturing chemical intermediate or an
off-specification commercial chemical product.
F003; A hazardous waste from nonspecific
sources when a spent solvent.
Administrative Information:
Hazardous Substances Databank Number: 4500
Last Revision Date: 20030214
Last Review Date: Reviewed by SRP on 1/23/1997
Update History:
Complete Update on 02/14/2003, 1 field
added/edited/deleted.
Complete Update on 01/24/2003, 1 field added/edited/deleted.
Complete Update on 01/18/2002, 3 fields added/edited/deleted.
Field Update on 01/14/2002, 1 field added/edited/deleted.
Complete Update on 08/09/2001, 1 field added/edited/deleted.
Complete Update on 05/16/2001, 1 field added/edited/deleted.
Complete Update on 05/15/2001, 1 field added/edited/deleted.
Complete Update on 02/09/2001, 2 fields added/edited/deleted.
Complete Update on 12/19/2000, 1 field added/edited/deleted.
Complete Update on 04/20/2000, 2 fields added/edited/deleted.
Field Update on 03/28/2000, 1 field added/edited/deleted.
Complete Update on 03/13/2000, 1 field added/edited/deleted.
Complete Update on 02/08/2000, 1 field added/edited/deleted.
Complete Update on 02/02/2000, 1 field added/edited/deleted.
Complete Update on 09/21/1999, 1 field added/edited/deleted.
Complete Update on 08/27/1999, 1 field added/edited/deleted.
Complete Update on 03/25/1999, 2 fields added/edited/deleted.
Complete Update on 02/24/1999, 3 fields added/edited/deleted.
Complete Update on 01/27/1999, 1 field added/edited/deleted.
Complete Update on 11/17/1998, 1 field added/edited/deleted.
Complete Update on 06/02/1998, 1 field added/edited/deleted.
Complete Update on 03/08/1998, 1 field added/edited/deleted.
Complete Update on 11/26/1997, 3 fields added/edited/deleted.
Complete Update on 11/01/1997, 1 field added/edited/deleted.
Complete Update on 06/03/1997, 76 fields added/edited/deleted.
Field Update on 02/05/1997, 5 fields added/edited/deleted.
Field Update on 10/18/1996, 1 field added/edited/deleted.
Field Update on 09/04/1996, 1 field added/edited/deleted.
Complete Update on 06/11/1996, 1 field added/edited/deleted.
Complete Update on 03/29/1996, 2 fields added/edited/deleted.
Complete Update on 03/21/1996, 1 field added/edited/deleted.
Complete Update on 01/28/1996, 1 field added/edited/deleted.
Complete Update on 11/10/1995, 1 field added/edited/deleted.
Complete Update on 05/26/1995, 1 field added/edited/deleted.
Complete Update on 01/24/1995, 1 field added/edited/deleted.
Complete Update on 01/03/1995, 1 field added/edited/deleted.
Complete Update on 11/18/1994, 1 field added/edited/deleted.
Complete Update on 09/13/1994, 2 fields added/edited/deleted.
Complete Update on 08/09/1994, 1 field added/edited/deleted.
Complete Update on 06/08/1994, 1 field added/edited/deleted.
Complete Update on 05/05/1994, 1 field added/edited/deleted.
Complete Update on 03/25/1994, 1 field added/edited/deleted.
Complete Update on 09/16/1993, 1 field added/edited/deleted.
Complete Update on 08/07/1993, 1 field added/edited/deleted.
Complete Update on 04/30/1993, 1 field added/edited/deleted.
Complete Update on 02/05/1993, 1 field added/edited/deleted.
Field update on 01/02/1993, 1 field added/edited/deleted.
Complete Update on 05/29/1992, 1 field added/edited/deleted.
Complete Update on 04/27/1992, 1 field added/edited/deleted.
Complete Update on 01/28/1992, 1 field added/edited/deleted.
Complete Update on 09/26/1991, 1 field added/edited/deleted.
Complete Update on 07/09/1991, 1 field added/edited/deleted.
Complete Update on 06/11/1991, 1 field added/edited/deleted.
Complete Update on 05/31/1991, 1 field added/edited/deleted.
Field update on 03/06/1990, 1 field added/edited/deleted.
Complete Update on 02/02/1990, 3 fields added/edited/deleted.
Complete Update on 07/28/1989, 95 fields added/edited/deleted.
Field Update on 07/06/1988, 1 fields added/edited/deleted.
Complete Update on 08/12/1986
GLCC
RELATED TOXIC SUBSTANCES FOUND IN THE CAMP POND AND CAMP WATER WELL 2003 AND
2004