POLYCYCLIC AROMATIC HYDROCARBONSPAHs
What are PAHs? group of organic compoundstwo or more aromatic (benzene) rings are fused together
potential health risk due to their inner chemical stability, high reactivity to different types of degradation and high toxicity to living organisms
US EPA and in the European Union priority lists of pollutants
Physical chemical propertiesPhysical and chemical properties of PAHs vary with Mr.PAHs as pure chemicals exist as colorless, white, or pale yellow-green solids.They are non-polar, hydrophobic compounds, which do not ionize.They have a faint odor.
Enter the enviromentPAHs are introduced into the environment mainly via natural and anthropogenic burning processes.
Enter the enviroment - AirPAHs enter air as releases from volcanoes, forest fires, residental wood burning and exhausts from cars.Some PAH particles can readily evaporate into the air from soil or surface waters.
Enter the enviroment - WaterThey can also enter surface water through discharges from industrial plants and wastewater treatment plants.
Enter the enviroment - SoilMost PAHs dont dissolve easily in water.They stick to solid particles and settle to the bottoms of lakes or rivers.PAHs in soils also contaminate underground water.
How might I be exposed to PAHs?
We are most likely to be exposed to PAH vapors or PAHs that are attached to dust and other particles in the air.Sources include cigarette smoke, vehicle, exhausts, asphalt roads, coal, etc.
How likely are (PAHs) to cause cancer? Breathing or touching mixtures of PAHs and other chemicals for long periods of time have developed cancer.Some PAHs have caused cancer in laboratory animals when they breathed air containing them (lung cancer), ingested them in food (stomach cancer), or had them applied to their skin (skin cancer).
Medical tests show PAHs in the body In the body, PAHs are changed into chemicals that can attach to substances within the body.Special tests that can detect PAHs in body tissues or blood.The tests aren't usually available in your doctor's office.
Analytical determination of PAHsSamples of PAHs are mostly analysed by HPLC using fluorence detection, or by gas chromatography method with flame ionizazion detection, or mass spectrometry.
More informationFor more information you can visit this pages:http://www.atsdr.cdc.gov/toxprofiles/tp69.pdfhttp://wlapwww.gov.bc.ca/wat/wq/BCguidelines/pahs/http://www.inchem.org/documents/ehc/ehc/ehc202.htm
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