1,2-XYLENE

(Dimethylbenzene, xylol, o-Xylene)

RECORD NUMBER: 204-150591

Three chemical forms of xylene exist (o-, m-, p-isomers)

CAS REGISTRY NUMBER: 95-47-6

CHEMICAL FAMILY:

MOLECULAR FORMULAE: C8 H10

Agricultural - solvent

Industrial - solvent

Domestic - component of petrol

DESCRIPTION: Colourless liquid with strong, sweetish, aromatic odour.

Commercial xylene is a mixture of the three isomers.

Xylene contains toluene, trimethylbenzenes, benzene and other hydrocarbons

USAGE: Xylene is used extensively as feedstock in manufacture of dyes, pharmaceuticals, plastics, as a solvent for paints, lacquers, resins, inks, adhesives, cleansers, degreasers, pesticides, paint strippers and in laboratories.

TOLERANCE & EXPOSURE LEVELS:

Time Weighted Average Exposure-(TWA):100ppm or 435 mg/m3

Short Term Exposure Limit-(STEL): 150ppm or 655 mg/m3

ROUTES OF EXPOSURE: Exposure is primarily inhalation in areas of heavy traffic, filling stations, industrial refineries or where solvents, Agricultural sprays, wood burning stoves & fires, glue for wallpaper and carpet are used or drinking contaminated underground water (leaking underground petrol tanks).

Av. Daily Intake: air-106ppb, water-2ppb (2)

Skin absorption (damaged skin enhance uptake) and ingestion can occur.

(1)

HEALTH EFFECTS:

SHORT TERM: Xylene is a fat solvent that causes Central Nervous System dysfunction and destruction of other tissues. (3)

One of earliest effects of exposure to xylene is increase in liver enzymes. Other effects of a single or short term exposure include irritation of nose, throat and eyes, headache ,nausea, vomiting, dizziness, fatigue, light headedness, irritability, abdominal pain, loss of appetite, reduced coordination, loss of consciousness. (1)

Other acute exposure effects include amnesia, brain hemorrhage, cardiac stress, dermatitis, liver and kidney damage, respiratory difficulties, tremor and xylene in blood and exhaled air. (3)

Alcohol enhances toxic effects of xylene. (1)

LONG TERM: Effects of long term or chronic exposure include inflammation of skin including dryness and cracking, reversible kidney and liver damage.

(1) Other chronic effects include anorexia, apprehension, bone marrow hyperplasia, CNS excitation and depression, dermatitis, drowsiness, eye injury, flatulence, gastrointestinal pain, memory impairment, hepatic damage, mucosal hemorrhage, nausea, red and white blood cell abnormalities [may be due to benzene contaminant, tremor and weakness. (3) Abnormal heartbeat in laboratory workers was associated with long term exposure to xylene.

(1)

CARCINOGENICITY: Studies indicate xylene is not a carcinogen. (1)

MUTAGENICITY: Studies indicate xylene is not a mutagen. (1)

REPRODUCTIVE EFFECTS: Available data indicates xylene does not cause permanent structural defects in off spring but is toxic to embryo or fetus and may reduce fertility. (1)

BIO-ACCUMULATION: Most of absorbed xylene is rapidly metabolised and eliminated in urine within a few hours, some exhaled. Metabolites are methylhippuric acids. Alcohol delays metabolism and excretion. Small amount is stored in fatty tissues from which it is slowly released. Repeated or prolonged exposure can result in accumulation of xylene in fatty tissues. (1)

Blood of 35 occupationally exposed men: av.26.6ppb (2)

Detected in the blood of North Coast NSW children in levels above USA average. (4)

Suspected Effects: Xylene is suspected of causing cholinesterase depression, epilepsy, fatty liver, hyperplasia, mutagenisis, prenatal damage, reproductive systems effects. (3)

Nervous system damage. (1)

ANIMAL TOXICITY DATA: Oral rat LD 50: 4,300 mg/kg

Inhalation rat LC50: 29.000mg/m3

Rats and dogs exposed to xylene vapour for 13 weeks at 180-810ppm showed no adverse effects related to dose or time of treatment. (1)

CARCINOGENICITY: One study indicated the irritant action of xylene on the skin increased frequency of skin tumours in animals also treated with a carcinogen. (1)

MUTAGENICITY:

REPRODUCTIVE EFFECTS: Female rats inhaling toxic levels of 700ppmn had reduced litter size, retarded development of fetus and an increase in anomolies (minor defect). (1)

Wildlife Data: Detected in rainbow trout in Colorado R. USA. (not quantified) (2)

ENVIRONMENTAL EFFECTS:

Environmental Fate: When released to air, o-xylene may degrade by reacting with hydroxyl radicals (produced photochemically) with half life of 1.5 hr in summer and 15 hr in winter.

Detected in 114 U.S. rural areas: av-0.5ppb, max-37ppb

1885 U.S. urban : av-1.9ppb, max-89ppb (2)

When spilt on land o-xylene will volatilise and leach into ground where it will degrade in either aerobic (70% degradation after 10 days) or anaerobic (6 months before degradation starts) denitrifying conditions.

Soil type and microbial acclimatization affect extent of degradation.

(2)

If released to surface water, volatilisation is main removal process with a half life of 1-5 days. Absorption to sediment will occur.

Regularly detected in U.S.treated drinking water, groundwater,surface water.

Water MRL:

EPA DATA GAPS:

NOTES:

** Disclaimer: These sheets are designed as summary information and as such are a guide only. The information is compiled from publicly available references which can be supplied on request.

References:P>

1.Canadian Department of Occupational Health Database, CCINFO Xylene 1991