PAH-iron

=Polycyclic Aromatic Hydrocarbon=

PAHs are a group of chemicals that are formed during the incomplete burning of coal, oil, gas, wood, garbage, or other organic substances, such as tobacco and charbroiled meat. There are more than 100 different PAHs. PAHs generally occur as complex mixtures. As pure chemicals, PAHs generally exist as colorless, white, or pale yellow-green solids. They can have a faint, pleasant odor. Some are used in medicines and to make dyes, plastics, and pesticides. Others are contained in asphalt used in road construction. They can also be found in substances such as crude oil, coal, coal tar pitch, creosote, and roofing tar. They are found throughout the environment in the air, water, and soil. They can occur in the air, either attached to dust particles or as solids in soil or sediment.
 * __Background__**

They can irritate the eyes, nose, throat and bronchial tubes. Skin contact can cause irritation or a skin allergy. Very high levels may cause headaches, nausea, damage the red blood cells, damage the liver and kidneys, and may even cause death. The International Agency for Research on Cancer has cited a number of polycyclic aromatic hydrocarbons as 'probably carcinogenic to humans', a number of others are cited as being 'possibly carcinogenic to humans'.

They have moderate short- term toxicity to aquatic life and birds. Some cause damage and death to agricultural and ornamental crops. They have moderate to long-term toxicity to aquatic life. Insufficient data are available on the acute or chronic toxicity to land animals. Polycyclic aromatic hydrocarbons are moderately persistent in the environment, and can bio accumulate. The concentrations of polycyclic aromatic hydrocarbons found in fish and shellfish is expected to be much higher than the environment from which it was taken.

__**Human Health and Environment**__ Polycyclic aromatic hydrocarbons are lipophilic so they mix more easily with oil than water. The larger compounds are less water-soluble and less volatile. Because of these properties, PAHs in the environment are mostly found in soil, sediment and oily substances, as opposed to in water or air.  When polycyclic aromatic hydrocarbons (PAHs) are released into the environment they usually go into the air as a gas or attach on to dust particles. They are sometimes found in water and soil. But they do not dissolve completely in water, they attach to solid particles and sink to the bottom. In water microorganisms break down the PAHs, but it can take weeks or months to fully break them down. In the air PAHs break down in days or weeks by reacting with sunlight and other chemicals in the air. When they break down it turns into hydrocarbons ( a greenhouse gas). PAHs can also be found in plants and animals. The concentrate is higher in them compared to in soil and water. The only way to completely dispose of PAH's is to have a combustion where everything is burnt. The negative affects on humans are they start to shred your DNA. When your DNA starts to shred it causes many types of cancer. This can then lead to serious cancer and sometimes death. PAH can cause birth defects and heart problems. They get into your body by breathing them in, eating or drinking something that is contaminated by them, or through your skin.

__**Synthesis/Production**__ Polycyclic Aromatic Hydrocarbons are not purposely made. They are formed through incomplete combustion reactions that create rings of carbon bonds that haven’t been completely broken. The rings are the PAH’s. Anthracene (PAH) is made from retrieving and purifying anthracene oil from coal tar. It is purified by heating the substance to get rid of the contaminats


 * __Economic/Political Impact__**

There are no bans on PAH or individual strands, but there are limits on maximum contamination levels in the water. The maximum level is .2 parts per billion.

In Austin, Texas, coal-tar based pavement sealants have been banded because of high levels of PAH and their affects on the body. The thing is coal tar is more durable than asphalt and other product and you don't have to replace it often so it is more cost efficent.

There are no legal requirements or limits governing concentrations of PAH in rubber materials or plastics.

There is no way to ban PAH because it happens naturally and people are exposed to it all the time. It can be on our grilled or broiled meats, in our air and things that we touch, so we have to be cautious and take precautions by washing our hands, stay away from polluted areas, and try not to eat broiled meats. media type="custom" key="3456516"

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