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	Chemical Fact Sheets -- Polycyclic Aromatic Hydrocarbons (PAHs)
		PAHs can enter groundwater from ash, tar, or creosote that is improperly disposed in landfills.
		PAHs may be in groundwater near disposal sites where construction wastes or ash are buried; people may be exposed by drinking this water.
		However, PAHs may be attached to dust or ash causing lung irritation.
	www.dhfs.state.wi.us /eh/ChemFS/fs/PAH.htm (805 words)

	polycyclic aromatic hydrocarbons (PAHs)
		A group of hydrocarbons made up from multiple interconnected 6-carbon (benzene) rings, like pieces of chicken wire, the simplest of which is napthalene (the chemical in mothballs).
		Among cosmic sources of PAHs are carbonaceous chondrites, which originated in the main asteroid belt and are not associated with life as far as we know.
		On the other hand, David McKay and his colleagues have tried to show that the PAHs in the meteorite ALH 84001 are derived from ancient Martian bacteria, though this has been strongly disputed (see Martian "fossils" controversy).
	www.daviddarling.info /encyclopedia/P/PAHs.html (412 words)

	Biodegradation of Aromatic Hydrocarbons
		As is the case with aliphatic hydrocarbons, aerobic biodegradation of aromatic hydrocarbons involves the participation of molecular oxygen as a direct reactant and as the terminal electron acceptor.
		Because all of the important aromatic hydrocarbons that occur in petroleum are derivatives of benzene, a reaction that is common to all pathways that lead to mineralization of aromatic substrates is cleavage of the benzene ring.
		Aromaticity is restored by a dehydrogenase-catalyzed conversion of benzene dihydrodiol to catechol (i.e., 1,2-dihydroxybenzene), which is the ring cleavage substrate.
	www.ence.umd.edu /~eseagren/bioAHC97.htm (1299 words)

	Clean Air Strategic Alliance - Pollutants - Polycyclic Aromatic Hydrocarbons (PAH)
		Polycyclic aromatic hydrocarbons (PAHs) are a class of chemicals that are formed during the incomplete combustion of gasoline, diesel, oil, coal, wood, garbage or other organic substances.
		PAHs occur in the atmosphere in the vapour phase or attached to dust particles.
		The PAHs analyzed for are benzo(a)pyrene, benzo(b)fluoranthene, benzo(e)pyrene, indeno(1,2,3-c,d)pyrene, benzo(k)fluoranthene and benzo(g,h,i)perylene.
	www.casadata.org /pollutants/poly_hydrocarbons.asp (230 words)

	Polycyclic Aromatic Hydrocarbons (PAHs) (Site not responding. Last check: )
		PAHs are now commonly thought to be the carriers of the "unidentified" infrared bands (UIRs) and We now believe that PAHs or PAH cations (a PAH with an electron missing) are also the best candidates for the diffuse interstellar bands (DIBs).
		Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbons 1.
		Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbons 2.
	web99.arc.nasa.gov /~astrochm/PAHs.html (588 words)

	Polycyclic Aromatic Hydrocarbons (PAH) - Wood Preservation, Environment Canada
		Polycyclic aromatic hydrocarbons have been measured in water from railway and utility ditches at concentrations higher than those recognized to cause harmful effects to biota under laboratory conditions.
		Based on these considerations, it has been concluded that polycyclic aromatic hydrocarbons are entering the environment in a quantity or concentration or under conditions that may have harmful effects on the environment.
		Polycyclic aromatic hydrocarbons are not considered to constitute a danger to the environment on which human life depends.
	www.ec.gc.ca /toxics/wood-bois/over/pah_e.htm (0 words)

	Polycyclic Aromatic Hydrocarbons (PAHs)
		It will explain what polycyclic aromatic hydrocarbons are, where they are found, how they can affect your health, and what you can do to prevent or reduce your exposure to them.
		PAHs are a group of chemicals that occur naturally in coal, crude oil and gasoline.
		PAHs are found throughout the environment in the air, water and soil, and can remain in the environment for months or years.
	www.idph.state.il.us /envhealth/factsheets/polycyclicaromatichydrocarbons.htm (0 words)

	KATALYSE Institut: Innenraumschadstoffe Teil IV - Polyclyclische aromatische Kohlenwasserstoffe
		In der Öffentlichkeit wurden mögliche Polycyclische aromatische Kohlenwasserstoffe (engl.: polycyclic aromatic hydrocarbons, PAH)PAK-Belastungen in Wohnräumen 1997 bekannt.
		Neben der bekanntesten Polycyclische aromatische Kohlenwasserstoffe (engl.: polycyclic aromatic hydrocarbons, PAH)PAK-Verbindung Benzo(a)pyren besitzen auch andere, ebenfalls häufig nachweisbare Substanzen wie Chrysen und Benzo(b/k)fluoranthen eine kanzerogene (krebserzeugende) und mutagene Wirkung.
		Schließlich können Polycyclische aromatische Kohlenwasserstoffe (engl.: polycyclic aromatic hydrocarbons, PAH)PAK-Belastungen aus Gemisch aus Tausenden von Einzelsubstanzen, das bei der Koksgewinnung (Kokerei) anfällt.
	www.katalysejournal.oekoserve.net /fp/archiv/KAT-nachrichten/kat33innenraumschadstoffe4_1.php (0 words)

	Polycyclic Aromatic Hydrocarbons
		Polycyclic aromatic hydrocarbons (PAHs) are a group of over 100 different chemicals that are formed during the incomplete burning of coal, oil and gas, garbage, or other organic substances like tobacco or charbroiled meat.
		PAHs are found in coal tar, crude oil, creosote, and roofing tar, but a few are used in medicines or to make dyes, plastics, and pesticides.
		PAH contents of plants and animals may be much higher than PAH contents of soil or water in which they live.
	www.energyjustice.net /tires/files/fs_pahs.shtml (762 words)

	Polycyclic aromatic hydrocarbons, selected non-heterocyclic (EHC 202, 1998)
		As PAH are hydrophobic with low solubility in water, their affinity for the aquatic phase is very low; however, in spite of the fact that most PAH are released into the environment via the atmosphere, considerable concentrations are also found in the hydrosphere because of their low Henry's law constants.
		PAH concentrations of up to 7 mg/kg have been detected in aquatic organisms living near industrial effluents, and the average levels of PAH in aquatic animals sampled at contaminated sites were 10-500 µg/kg, although levels of up to 5 mg/kg were also detected.
		PAH metabolites and their conjugates are excreted via the urine and faeces, but conjugates excreted in the bile can be hydrolysed by enzymes of the gut flora and reabsorbed.
	www.inchem.org /documents/ehc/ehc/ehc202.htm (11378 words)

	ATSDR - Public Health Statement: Polycyclic Aromatic Hydrocarbons (PAHs)
		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.
		PAHs enter the environment mostly as releases to air from volcanoes, forest fires, residential wood burning, and exhaust from automobiles and trucks.
		PAHs are present throughout the environment, and you may be exposed to these substances at home, outside, or at the workplace.
	www.atsdr.cdc.gov /toxprofiles/phs69.html (2552 words)

	Polycyclic Aromatic Hydrocarbons and Breast Cancer Risk
		PAHs are environmental pollutants that may be found in air attached to dust particles, in soil, stream sediment, water and food.
		The PAHs were given to the animals over a long period of time by applying them to the skin, through the diet, in the air, or by injection into their veins.
		Since some individual PAHs and certain PAH mixtures cause cancer in laboratory animals, it is assumed the increased cancer risks seen in the human studies may be caused in part by PAHs, but the evidence is not conclusive.
	envirocancer.cornell.edu /FactSheet/general/fs41.pah.cfm (2470 words)

	National Pollutant Inventory Substance Profile
		Polycyclic aromatic hydrocarbons are organic compounds (carbon based) which include only carbon and hydrogen with a structure of fused rings.
		Polycyclic aromatic hydrocarbons are formed by the incomplete combustion of coal, oil, petrol, wood, tobacco, charbroiled meats, garbage, or other organic materials.
		Other emitters of polycyclic aromatic hydrocarbons are asphalt roads, road and road tar, coal, coal tar, fires of all types (bush, forest, agricultural, home heating, cooking, etc), the manufacture and use of preserved wood (creosote).
	www.npi.gov.au /database/substance-info/profiles/74.html (1713 words)

	Spitzer Feature: Understanding Polycyclic Aromatic Hydrocarbons
		The term "polycyclic aromatic hydrocarbon" may be a mouthful to say, but it describes a rather basic family of organic molecules.
		"Polycyclic" indicates that these molecules consist of multiple loops of carbon atoms, while "aromatic" refers to the kinds of strong chemical bonds that exist between the carbon atoms.
		PAHs emit strongly at the two longer wavelengths (5.8-8.0 microns), while starlight is strongest at the shorter wavelengths (3.6-4.5 microns).
	www.spitzer.caltech.edu /features/articles/20050627.shtml (925 words)

	POLYCYCLIC AROMATIC HYDROCARBONS
		PAHs are a group of more than 100 different chemicals that are formed during the incomplete burning of coal, oil, gas, wood, garbage, or other organic substances.
		PAHs generally occur as complex mixtures and usually occur naturally, but they can be manufactured as individual compounds for research purposes.
		Scorecard provides information on PAHs as a class and on specific PAHs, but not on the PAH metabolites measured by CDC.
	www.scorecard.org /about/txt/pahs.html (0 words)

	Air Toxics - Polycyclic aromatic hydrocarbons (PAHs) (Site not responding. Last check: )
		PAH is the usual acronym for polycyclic aromatic hydrocarbon.
		Polycyclic aromatic hydrocarbons are a group of over 100 chemicals.
		PAHs are found in facilities that manufacture or use petroleum, petroleum products or coal, or where wood or other plant materials are burned.
	www.environment.gov.au /atmosphere/airquality/publications/sok/profiles/polycylic.html (951 words)

	THE CARCINOGENIC EFFECTS OF POLYCYCLIC AROMATIC HYDROCARBONS
		PAHs are by-products arising from incomplete combustion of organic matter that are frequently released into our environment, and thus are ubiquitously detectable.
		The topics include: exposure to and biomonitoring of PAHs in the human population; metabolic activation of PAHs; genotoxicity and repair of PAH-induced DNA damage; and factors modulating individual susceptibility to the deleterious effects of PAHs.
		Genetic Susceptibility to Polycyclic Aromatic Hydrocarbon-Induced Carcinogenesis (A Hirvonen)
	www.worldscibooks.com /medsci/p306.html (299 words)

	Atmospheric Polycyclic Aromatic Hydrocarbons
		We have been developing new methods to analyse particulate borne polycyclic aromatic hydrocarbons (PAH), using multidimensional chromatography and supercritical fluid extraction.
		This technique is being extended to identify oxygenated polycyclic aromatic compounds.
		PAH profiles have been found to remain very steady whilst overall concentrations have been seen to vary by factors of up to 20 between one 12 hours sample and the next.
	www.chem.leeds.ac.uk /research/node11.html (270 words)

	Polycyclic Aromatic Hydrocarbons (15) (Site not responding. Last check: )
		Solubility characteristics vary for each PAH, but in general they are slightly soluble to insoluble in ethanol, and are soluble to slightly soluble in acetic acid, benzene, and acetone.
		At least 8 of the 15 PAHs are present in coal tar which is used as a fuel in the steel industry in open-hearth and blast furnaces.
		The PAHs are found in gasoline or diesel motor vehicle exhaust, by-products of open fires or refuse burning, coal tar, coal tar pitch, coke tars or coke oven emissions, creosote, mineral oils, bitumens, industrial smoke and soot, cigarette and cigar tobacco and smoke, tar, or smoke condensates, and charcoal-broiled foods.
	www.iephb.nw.ru /~spirov/hazard/pahs_15.html (2646 words)

	CHEC Chemical Summary: polycyclic aromatic hydrocarbons (PAHs)
		Polycyclic aromatic hydrocarbons (PAHs) are a group of over 100 different chemicals that are formed as byproducts of combustion (burning) of coal, oil, gas, garbage, tobacco, foods and other organic substances.
		Naphthalene is a type of PAH used in mothballs and some cleaners.
		Indoors, children experience high exposure to PAHs in homes where someone smokes tobacco, even if they are not directly exposed to the smoke, or where a fireplace or woodstove is used frequently or without proper venting.
	www.checnet.org /healthehouse/chemicals/chemicals-detail.asp?Main_ID=395 (582 words)

	ATSDR - ToxFAQs™: Polycyclic Aromatic Hydrocarbons (PAHs)
		Exposure to polycyclic aromatic hydrocarbons usually occurs by breathing air contaminated by wild fires or coal tar, or by eating foods that have been grilled.
		In soils, PAHs are most likely to stick tightly to particles; certain PAHs move through soil to contaminate underground water.
		Mice that were fed high levels of one PAH during pregnancy had difficulty reproducing and so did their offspring.
	www.atsdr.cdc.gov /tfacts69.html (1007 words)

	The UCL Cosmic Dust Lab - Spectroscopy of PAHs
		Briefly, polycyclic aromatic hydrocarbons are molecules built up of benzene rings which resemble fragments of single layers of graphite.
		Since some of the PAHs are known carcinogens [2] their presence in the environment (particularly in food) is a cause of concern to health authorities.
		Once formed the PAHs would be remarkably stable, and would resist dissociation from UV absorption (unlike most other polyatomic molecules in the ISM) since they are extremely efficient at rapidly re-emitting the absorbed energy at infra-red wavelengths [7].
	www.chem.ucl.ac.uk /cosmicdust/pah.htm (1383 words)

	NASA Astrochemistry
		In common parlance the word aromatic is used to denote something that has a fragrance (something with an aroma) and the connotation is a pleasant one as in 'aromatic herbs'.
		While many of the smaller aromatic compounds have an odor (like benzene and naphthalene which used to be the major component in mothballs) and that is probably how they got their name, what a chemist means by aromatic is that the molecule has a certain kind of electronic structure.
		PAH molecules like benzene have a ring of 4n+2 Pi electrons that are all interacting together forming a big delocalized cloud that is essentially shared by all of the carbon atoms.
	www.astrochemistry.org /PAHs.html (1576 words)

	Polycyclic Aromatic Hydrocarbons - PSL1
		AEL (Aquatic Ecostudies Limited), "Effect of Polynuclear Aromatic Hydrocarbons on the Benthic Invertebrate Fauna of Kettle Creek at Port Stanley, Ontario", prepared for the Ontario Ministry of the Environment, 21 p.
		Oris, J.T. and J.P. Giesy, "The Photo-induced Toxicity of Polycyclic Aromatic Hydrocarbons to Larvae of the Fathead Minnow Pimephales promelas", Chemosphere, 16: 1395-1404 (1987).
		Windsor, J.G. and R.A. Hites, "Polycyclic Aromatic Hydrocarbons in the Gulf of Maine Sediments and Nova Scotia Soils", Geochem.
	www.hc-sc.gc.ca /ewh-semt/pubs/contaminants/psl1-lsp1/hydrocarb_aromat_polycycl/hydrocarb_aromat_polycycl_5_e.html (5074 words)

	Polynuclear Aromatic Hydrocarbons (PAHs) Definition Page
		Polynuclear aromatic hydrocarbons (PAHs) are hydrocarbon compounds with multiple benzene rings.
		PAHs are typical components of asphalts, fuels, oils, and greases.
		Polycyclic Aromatic Hydrocarbons: Evaluation of Sources and Effects: National Academy Press, Washington, DC, 1983
	toxics.usgs.gov /definitions/pah.html (49 words)

	Hypography Science Forums
		But astronomers have found something even tougher—"polycyclic aromatic hydrocarbons," says Achim Tappe of the Harvard Center for Astrophysics.
		Polycyclic aromatic hydrocarbons (PAHs for short) are ring-shaped molecules made of carbon and hydrogen.
		They're about as well loved as roaches: PAHs are a widespread organic pollutant, appearing in auto exhaust, oil spills and cigarette smoke.
	forums.hypography.com (0 words)

	High temperature behaviour of polycyclic aromatic hydrocarbons (Site not responding. Last check: )
		This research concerns the mechanism of formation and interconversion of polycyclic aromatic hydrocarbons (PAH) under high-temperature conditions.
		It provides valuable insight into environmental aspects of combustion processes, the formation of fullerenes (buckyballs) and toxicology of polycyclic aromatic hydrocarbons.
		An example is the formation of cyclopenta-fused PAH from ethynyl substituted PAH.
	www.chem.uu.nl /foc/FVT-3.htm (50 words)

	Amazon.com: Polycyclic Aromatic Hydrocarbons: Books: Ronald G. Harvey (Site not responding. Last check: )
		Polycyclic aromatic hydrocarbons (PAHs) have found applications in a variety of industries including dyes, drugs, semiconductors, fluorescent reagents, chemiluminescent reagents, and as polychromatic and antistatic additives for plastics.
		As this important class of molecules are virtually ignored in most chemistry programs, this book will be a strong addition to the work of anyone involved in any aspect of polycyclic aromatic hydrocarbons, chemical carcinogenesis, and environmental pollution.
		Polycyclic aromatic hydrocarbons (PAHs), more simply known as polyarenes, constitute an extraordinarily large and diverse class of organic molecules.
	www.amazon.com /Polycyclic-Aromatic-Hydrocarbons-Ronald-Harvey/dp/0471186082 (987 words)

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