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POLYCYCLIC AROMATIC HYDROCARBONS

Date post: 31-Dec-2015
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POLYCYCLIC AROMATIC HYDROCARBONS. PAHs. What are PAHs?. group of organic compounds t wo 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 - PowerPoint PPT Presentation
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POLYCYCLIC AROMATIC POLYCYCLIC AROMATIC HYDROCARBONS HYDROCARBONS PAHs PAHs
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Page 1: POLYCYCLIC AROMATIC HYDROCARBONS

POLYCYCLIC AROMATIC POLYCYCLIC AROMATIC HYDROCARBONSHYDROCARBONS

PAHsPAHs

Page 2: POLYCYCLIC AROMATIC HYDROCARBONS

What are PAHs?

group of organic compoundstwo or more aromatic (benzene) rings are

fused together

Page 3: POLYCYCLIC AROMATIC HYDROCARBONS

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

Page 4: POLYCYCLIC AROMATIC HYDROCARBONS

Physical – chemical properties

Physical 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.

Page 5: POLYCYCLIC AROMATIC HYDROCARBONS

Enter the enviroment

PAHs are introduced into the environment mainly via natural and anthropogenic burning processes.

Page 6: POLYCYCLIC AROMATIC HYDROCARBONS

Enter the enviroment - Air

PAHs 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.

Page 7: POLYCYCLIC AROMATIC HYDROCARBONS

Enter the enviroment - Water

They can also enter surface water through discharges from industrial plants and wastewater treatment plants.

Page 8: POLYCYCLIC AROMATIC HYDROCARBONS

Enter the enviroment - Soil

Most PAHs don‘t 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.

Page 9: POLYCYCLIC AROMATIC HYDROCARBONS

How might I be exposed to PAHs?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.

Page 10: POLYCYCLIC AROMATIC HYDROCARBONS

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).

Page 11: POLYCYCLIC AROMATIC HYDROCARBONS

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.

Page 12: POLYCYCLIC AROMATIC HYDROCARBONS

Analytical determination of PAHs

Samples of PAHs are mostly analysed by HPLC using fluorence detection, or by gas chromatography method with flame ionizazion detection, or mass spectrometry.

Page 13: POLYCYCLIC AROMATIC HYDROCARBONS

More information

For more information you can visit this pages: http://www.atsdr.cdc.gov/toxprofiles/tp69.pdf http://wlapwww.gov.bc.ca/wat/wq/BCguidelines/

pahs/ http://www.inchem.org/documents/ehc/ehc

/ehc202.htm

Page 14: POLYCYCLIC AROMATIC HYDROCARBONS

Vocabulary

fuse - splynoutlists of pollutants – seznamškodlivinpale - bledýto vary - lišit sefaint - mdlýto release - uvolňovatexhaust - výfukový plynevaporate - vypařovat sedischarge - vylučováníwastewater treatment plant -čistička odp. vod

wastewater treatment plant - čistička odp. vod

to stick - přilnout to settle - usadit se vapor - pára to develope - rozvinout se ingested - přijímat

potravou to be available - být k

dispozici to attach - připojit within - uvnitř body tissues - tělní tkáně

Page 15: POLYCYCLIC AROMATIC HYDROCARBONS

THANKS FOR YOUR ATTENTION


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