WHAT ARE POLYCYCLIC AROMATIC HYDROCARBONS?
PAHs <ul><li>Polycyclic Aromatic Hydrocarbons, or PAHs, are a group of chemicals that are formed during the burning of coa...
Properties of PAHs <ul><li>Colorless, white, or pale </li></ul><ul><li>yellow-green solid </li></ul><ul><li>Evaporate quic...
Common PAHs <ul><li>Anthracene </li></ul><ul><li>Benzo(a)pyrene </li></ul><ul><li>Chrysene </li></ul><ul><li>Fluorene </li...
DISTRIBUTION OF POLYCYCLIC AROMATIC HYDROCARBONS
How do PAHs get in the Environment? <ul><li>PAHs are released to the environment through natural and man made processes. M...
Man-made Sources <ul><li>Burning of wood </li></ul><ul><li>Vehicle exhaust </li></ul><ul><li>Grilled/smoked foods </li></u...
Natural Sources <ul><li>• Forest fire </li></ul><ul><li>• Volcanoes </li></ul>
PAHs in the Environment <ul><li>PAHs stick tightly to soil particles. </li></ul><ul><li>Some PAHs evaporate into the air f...
EFFECTS OF PAHs
PAHs IN THE BODY KNOWN HUMAN EFFECTS <ul><li>Breathing ambient air </li></ul><ul><li>Cigarette smoke </li></ul><ul><li>Eat...
EFFECTS ON LABORATORY ANIMALS <ul><li>Tumors occur in some animals exposed for long periods of time. </li></ul><ul><li>PAH...
KNOWN HUMAN EFFECTS <ul><li>Individuals breathing or having skin contact with PAHs combined with other chemicals over a lo...
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Polycyclics

Published on: Mar 4, 2016
Published in: Health & Medicine      
Source: www.slideshare.net


Transcripts - Polycyclics

  • 1. WHAT ARE POLYCYCLIC AROMATIC HYDROCARBONS?
  • 2. PAHs <ul><li>Polycyclic Aromatic Hydrocarbons, or PAHs, are a group of chemicals that are formed during the burning of coal, oil, gas, garbage, tobacco or charbroiled meat. </li></ul><ul><li>PAHs occur naturally or can be man-made. </li></ul>
  • 3. Properties of PAHs <ul><li>Colorless, white, or pale </li></ul><ul><li>yellow-green solid </li></ul><ul><li>Evaporate quickly into the air when heated </li></ul><ul><li>Attach strongly to soil and other particles </li></ul><ul><li>Break down slowly </li></ul><ul><li>Do not dissolve easily in water </li></ul><ul><li>Do not burn easily </li></ul>
  • 4. Common PAHs <ul><li>Anthracene </li></ul><ul><li>Benzo(a)pyrene </li></ul><ul><li>Chrysene </li></ul><ul><li>Fluorene </li></ul><ul><li>Pyrene </li></ul>
  • 5. DISTRIBUTION OF POLYCYCLIC AROMATIC HYDROCARBONS
  • 6. How do PAHs get in the Environment? <ul><li>PAHs are released to the environment through natural and man made processes. Man-made sources contribute far more PAHs to the environment than natural sources. </li></ul>
  • 7. Man-made Sources <ul><li>Burning of wood </li></ul><ul><li>Vehicle exhaust </li></ul><ul><li>Grilled/smoked foods </li></ul><ul><li>Cigarette smoke </li></ul><ul><li>Asphalt roads/Parking lots </li></ul><ul><li>Roofing/coal tar products </li></ul><ul><li>Agricultural burning </li></ul>
  • 8. Natural Sources <ul><li>• Forest fire </li></ul><ul><li>• Volcanoes </li></ul>
  • 9. PAHs in the Environment <ul><li>PAHs stick tightly to soil particles. </li></ul><ul><li>Some PAHs evaporate into the air from soil or surface waters. </li></ul><ul><li>PAHs in air settle to the ground where they are deposited on soil, plants, or in lakes and streams. </li></ul><ul><li>PAHs stay very close to the surface of the ground or move to lakes and streams by a process called erosion. </li></ul><ul><li>PAHs that enter lakes or streams settle to the bottom and are buried in sediments. </li></ul>
  • 10. EFFECTS OF PAHs
  • 11. PAHs IN THE BODY KNOWN HUMAN EFFECTS <ul><li>Breathing ambient air </li></ul><ul><li>Cigarette smoke </li></ul><ul><li>Eating food containign PAHs or grilled meat </li></ul><ul><li>Drinking water or milk containig PAHs </li></ul><ul><li>Breathing air at work sites </li></ul>
  • 12. EFFECTS ON LABORATORY ANIMALS <ul><li>Tumors occur in some animals exposed for long periods of time. </li></ul><ul><li>PAHs have been shown to have an effect on the immune system of some animals. </li></ul><ul><li>EPA considers PAHs to be probable human carcinogens (cancer-causing substances). </li></ul>
  • 13. KNOWN HUMAN EFFECTS <ul><li>Individuals breathing or having skin contact with PAHs combined with other chemicals over a long period of time, have developed cancer. </li></ul><ul><li>There are no known studies to indicate that PAHs alone can cause cancer in people. </li></ul><ul><li>There are no other known health effects of PAHs. </li></ul>

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