POT-15: Benzene, Toluene, Xylene (BTX)

Sunday, June 29, 2008

Benzene, Toluene, Xylene (BTX)

About aromatic hydrocarbons Aromatic hydrocarbons, so named for their characteristic strong, sweet odor, are found in nature in volcanoes and wood fires. They are also produced commercially and have many industrial uses, most notably as a solvent for numerous materialsand as a fuel additive. Among the businesses that make use of aromatic hydrocarbons are the rubber and insecticide industries, chemical and pharmaceutical manufacturers, and explosive manufacturers. Benzene, toluene and xylene, the most widely used aromatic hydrocarbons, are very useful chemicals, however they are also extremely hazardous. Known to be both carcinogenic, some workers exposed long-term to benzene have been known to develop leukemia. These chemicals are also easily ignited, and while burning will produce carbon dioxideand carbon monoxide. Clearly it is essential that workers who must handle aromatic hydrocarbons be well trained in their hazard properties and safe handling techniques, and that emergency responders who must respond to an incident involving benzene, toluene or xylene be trained in proper response tactics.

ben·zene
n. A colorless, flammable, liquid aromatic hydrocarbon, C6H6, derived from petroleum and used in or to manufacture a wide variety of chemical products, including DDT, detergents, insecticides, and motor fuels. Also called benzine, benzol.
Noun 1. benzene - a colorless liquid hydrocarbon; highly inflammable; carcinogenic; the simplest of the aromatic compounds benzine, benzol aromatic hydrocarbon - a hydrocarbon that contains one or more benzene rings that are characteristic of the benzene series of organic compounds benzene formula, benzene nucleus, benzene ring, Kekule formula - a closed chain of 6 carbon atoms with hydrogen atoms attached

tol·u·ene
A colorless flammable liquid, CH3C6H5, obtained from coal tar or petroleum and used in aviation fuel and other high-octane fuels, in dyestuffs, explosives, and as a solvent for gums and lacquers. Also called methylbenzene.
[tolu (from which it was originally obtained) + -ene.]
Noun 1. toluene - a colorless flammable liquid obtained from petroleum or coal tar; used as a solvent for gums and lacquers and in high-octane fuels methylbenzene alkylbenzene - organic compound that has an alkyl group bound to a benzene ring dissolvent, dissolver, dissolving agent, resolvent, solvent - a liquid substance capable of dissolving other substances; "the solvent does not change its state in forming a solution"

xy·lene
1. Any of three flammable isomeric hydrocarbons, C6H4(CH3)2, obtained from wood and coal tar.
2. A mixture of xylene isomers used as a solvent in making lacquers and rubber cement and as an aviation fuel.

Noun 1. xylene - a colorless flammable volatile liquid hydrocarbon used as a solvent xylol dissolvent, dissolver, dissolving agent, resolvent, solvent - a liquid substance capable of dissolving other substances; "the solvent does not change its state in forming a solution"

OBJECTIVE: To examine the effects on semen and sperm quality of workers after a short and long term exposure to benzene, toluene, and xylene. METHODS: The semen and blood of 24 married workers exposed to benzene, toluene, and xylene from shoemaking, spray painting, or paint manufacturing factories were collected. The concentration of benzene, toluene, and xylene in the blood and semen was determined by using headspace chromatographic method. Routine sperm test was carried out and acrosin activity detected. RESULTS: The results showed that benzene, toluene, and xylene were found in the blood and semen of some ex-workers in a working environment where the air concentration of benzene, toluene, and xylene exceeded the maximum allowable concentration (MAC). This result was not found in workers of the control group. There were also some effects on the quality of semen in the exposed workers. For example, the percentage of semen with liquefaction time exceeding 30 minutes increased. The sperm vitality, motility and acrosin activity decreased. At the same time, there were a positive correlation between liquefaction time and the level of toluene in semen, and a negative correlation between sperm vitality, sperm activity or acrosin activity and working history.

CONCLUSIONS: The results suggested that the mixture could affect the quality of semen and sperm, which might be the main reason of the abnormal pregnancy outcome among the wives of workers exposed to benzene, toluene, and xylene. Further studies are, however, required to confirm these findings.

The effects on semen and the function of accessory gonad of workers after short and long term exposure to benzene, toluene, and xylene were examined. The semen and blood of 24 married workers exposed to benzene, toluene, and xylene were collected. Routine sperm characteristic, acrosin activity, and Lactate dehydrogenase C4 (LDH-C4) relative activity were detected. The results showed that benzene, toluene, and xylene were found in the blood and semen of some ex-workers at workplaces where the air concentration of benzene, toluene, and xylene exceeded the maximum allowable concentration (MAC). No such solvents were detected in the blood and semen of workers of the control group. The sperm vitality and sperm motility decreased in the exposed workers. The mean acrosin activity, gamma-GT activity and LDH-C4 relative activity in the exposed workers were lower, and fructose concentration was higher than those in the control. There were negative correlations between sperm vitality, sperm activity, acrosin activity, or LDH-C4 relative activity and working history. These results suggest that the mixture of these solvents could affect the sperm and the function of accessory gonad. This might be one reason of the abnormal pregnancy outcome among the wives of workers exposed to benzene, toluene, and xylene.

posted by Rahman J. @ 6/29/2008 07:32:00 PM

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