BTEX is the term used to describe a group of chemicals related to benzene, which include the following substances: toluene (methyl benzene), ethyl benzene, xylenes and benzene itself. Moreover, they are part of the group of compounds known as volatile organic compounds (VOCs).
BTEX are usually colourless, sweet-smelling liquids that evaporate easily.
They mix well with organic solvents but do not dissolve well in water (and may float on the surface before evaporating into the air).
These substances can be naturally present in crude oil or gas emissions from volcanoes and forest fires or can be man-made releases of BTEX compounds through emissions from motor vehicles and aircraft, and cigarette smoke.
These substances are among the most abundantly produced chemicals in the world.
Why are BTEX a hazardous substance?
Exposure to BTEX at normal environmental concentrations, and even to higher concentrations over a short time, is unlikely to damage health significantly.
However, long-term exposure to higher concentrations (usually only experienced in occupational settings) is toxic, damaging the liver, kidneys, central nervous system and eyes. Inhalation of ground-level ozone (in the formation of which BTEX can be involved) can exacerbatecompounds respiratory conditions such as asthma. Moreover, benzene is a known carcinogen.
The most common sources of exposure to BTEX com- pounds are from breathing contaminated air, particularly in areas of heavy motor vehicle traffic and petrol stations, and through cigarette smoke.
Exposure to BTEX from water contributes only a small percentage of the total daily intake, compared with inhaled air and dietary sources.
Furthermore, these substances can produce novice effects on the environment. They react with other air pollution and are broken down, returned to the earth or involved in the formation of photochemical smog. High concentrations of BTEX are moderately toxic to aquatic life.
Where can BTEX be found?
These substances are naturally present in crude oil and can be found in seawater in the vicinity of natural gas and petroleum deposits. Other natural sources of BTEX compounds include gas emissions from volcanoes and forest fires.
On the other hand, man-made releases of BTEX compounds are through emissions from motor vehicles and aircraft, and cigarette smoke.
BTEX compounds are created and used during the processing of petroleum products and the production of consumer goods such as paints and lacquers, thinners, rubber products, adhesives, inks, cosmetics and pharmaceutical products.
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This article can be found in the 2021 edition of the document. Find the full publication here:
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