Chemistry
Polycyclic Aromatic Hydrocarbons
Polycyclic aromatic hydrocarbons (PAHs) are organic compounds composed of multiple fused aromatic rings. They are formed during incomplete combustion of organic materials and are found in various environmental sources, including vehicle exhaust, cigarette smoke, and grilled meats. PAHs are of concern due to their potential carcinogenic and mutagenic properties, as well as their persistence in the environment.
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11 Key excerpts on "Polycyclic Aromatic Hydrocarbons"
eBook - PDF- Leo M.L. Nollet, Fidel Toldra(Authors)
- 2012(Publication Date)
- CRC Press(Publisher)
1003 28 Polycyclic Aromatic Hydrocarbons Silvia Amelia Verdiani Tfouni and Mônica Cristiane Rojo Camargo 28.1 Introduction Polycyclic Aromatic Hydrocarbons (PAHs) constitute a large class of organic compounds containing two or more fused aromatic rings made up of carbon and hydrogen atoms. They are formed during incom-plete combustion or pyrolysis of organic matter and are present in the environment as pollutants. PAHs can be produced and emitted from natural sources, such as forest fires and volcanoes, and from anthro-pogenic sources, which include the processing of aluminum, iron, steel, asphalt, coal tar, coke, crude oil, petroleum, and natural gas; heating in power plants and homes; burning of refuse; wood fires; oil spills and motor vehicle exhausts. These compounds are also formed during food processing (WHO, 2006; EFSA, 2008). The structure of some PAHs is given in Figure 28.1. PAHs generally occur in complex mixtures that may consist of hundreds of compounds with different composition, which may vary with the generating process (EFSA, 2008). Formation of PAHs is favored by pyrolysis or air-deficient combustion of organic matter at temperatures ranging from 500°C to 900°C, especially above 700°C (Bartle, 1991). At these high temperatures, organic compounds are fragmented (pyrolysis) and the free radicals produced recombine to form stable polynuclear aromatic compounds (pyrosynthesis) (Park and Penning, 2009). Pyrolysis of other organic matters such as proteins and carbo-hydrates might be involved, but the greatest concentrations of PAHs have been shown to arise from fat pyrolysis (Bartle, 1991). Humans are exposed to PAHs by many different pathways; for the general population, the major routes of exposure to PAH are from food and inhaled air. However, for smokers significant contribution of PAHs exposure may be attributed to cigarette smoking.
eBook - ePubEnvironmental Forensics
Contaminant Specific Guide
- Robert D. Morrison, Brian L. Murphy(Authors)
- 2010(Publication Date)
- Academic Press(Publisher)
15Polycyclic Aromatic Hydrocarbons (PAHs)
Paul D. BoehmPublisher Summary
Polycyclic Aromatic Hydrocarbons (PAHs) are sometimes referred to as polynuclear aromatic hydrocarbons (PNAs), condensed ring aromatics, or fused ring aromatics. They are a class of organic compounds consisting of two or more fused aromatic rings. Polycyclic Aromatic Hydrocarbons most commonly encountered in the environment contain two (naphthalene) to seven (coronene) fused benzene rings, though PAHs with greater number of rings are also found. Natural sources of petrogenic PAHs arise from oil seepages and erosion of petroliferous shales, while natural sources of PAHs from combustion or pyrolysis include PAHs from incomplete combustion of wood and biomass via forest and grass fires. Anthropogenic (pollution) related PAHs inputs can result in similar, but not identical, PAH compounds and assemblages of PAHs to those of natural origin. Anthropogenic inputs of PAH arise from the release into the environment of petrogenic PAHs through accidental acute petroleum spillages and through chronic non-point source and point-source inputs such as urban (storm water) runoff and municipal waste treatment plane discharges. The most common and ubiquitous sources of anthropogenic PAHs, however, are those associated with pyrogenic inputs.Contents15.1. INTRODUCTION15.2. POLYCYCLIC AROMATIC HYDROCARBON SOURCES15.3. POLYCYCLIC AROMATIC HYDROCARBON SOURCE ASSEMBLAGES15.4. ANALYTICAL STRATEGIES15.5. POLYCYCLIC AROMATIC HYDROCARBON ENVIRONMENTAL FORENSICS15.6. ALLOCATING SOURCES OF PAHREFERENCES15.1 INTRODUCTION
Polycyclic Aromatic Hydrocarbons (PAHs)—sometimes referred to as polynuclear aromatic hydrocarbons (PNAs), condensed ring aromatics, or fused ring aromatics—are a class of organic compounds consisting of two or more fused aromatic rings (Figures 15.1.1 and 15.1.2 ). Naphthalene, consisting of two fused benzene rings, is the simplest PAH. Commonly, PAHs are depicted without labeling the carbon and hydrogen atoms. Polycyclic Aromatic Hydrocarbons most commonly encountered in the environment contain two (naphthalene) to seven (coronene) fused benzene rings, though PAHs with greater number of rings are also found (Sander and Wise, 1997
eBook - PDF- Leo M.L. Nollet, Leen S. P. De Gelder, Leo M.L. Nollet, Leen S. P. De Gelder(Authors)
- 2013(Publication Date)
- CRC Press(Publisher)
807 © 2011 Taylor & Francis Group, LLC 28 Polynuclear Aromatic Hydrocarbons Chimezie Anyakora 28.1 Introduction Polynuclear aromatic hydrocarbons (PAHs) are a class of diverse organic compounds containing two or more fused aromatic rings of carbon and hydrogen atoms. They are ubiquitous environmental contami-nants found in air, water, and soil [1–4]. Hundreds of PAHs have been identified and these are usually found as complex mixtures of individual compounds [5]. PAHs are the largest class of chemical com-pounds known to be cancer-causing agents and are included in the European Union and United States Environmental Protection Agency (EPA) priority pollutant list due to their mutagenic and carcinogenic properties [6]. Some while not carcinogenic, may act as synergists [7]. At ambient temperatures, PAHs are colorless to yellow solids. The general characteristics common to the class are high melting and boil-ing points, low vapor pressures, low water solubility, and high lipid solubility; their water solubility tends to decrease with increasing molecular mass. PAHs are adsorbed strongly to the organic fraction of sediments and soils. Leaching of PAHs from the soil surface layer to groundwater is assumed to be negligible owing to the adsorption. They are very difficult to degrade. The difficulty is due to the complexity and stability of their molecular structures. The biodegradation rates decrease drastically with increasing number of aromatic rings [8]. They are classified among the semivolatile organic compounds (SVOC) having boiling points greater than 200°C. Among the several hundred different PAHs already identified, 16 are considered as priority by the US EPA because there is more information available on them and there is a greater possibility of people CONTENTS 28.1 Introduction ..................................................................................................................................
eBook - PDFHandbook of Food Analysis
Volume 2: Residues and Other Food Component Analysis
- Leo M.L. Nollet(Author)
- 2004(Publication Date)
- CRC Press(Publisher)
38 Polycyclic Aromatic Hydrocarbons in Food Katsumi Tamakawa Sendai City Institute of Public Health, Sendai, Japan I. INTRODUCTION Polycyclic Aromatic Hydrocarbons (PAHs) are organic compounds containing two or more fused aromatic rings of carbon and hydrogen atoms. They are ubi-quitous environmental pollutants and are a major class of environmental hazardous compounds due to their known or suspected carcinogenicity and/or mutagenicity. PAHs are generally produced by incom-plete combustion of material such as the burning of fossil fuels, and other forms of organic matter. They are also diffused into the environment through natural and anthropogenic processes and have been detected in air (1–6), water (7–10), soil (11–17), indoor air (18–20), work places (21–23), food, and elsewhere. Although it was suggested that PAHs could be synthesized biolog-ically from bacteria, plants, and seaweed as their metabolites, this origin is not fully accepted, yet (24). Some PAHs are commercially used as intermediates in production processes. That is, phenanthrene (Phe) for pesticides, acenaphthene (Ace) and pyrene (Py) for pigments, anthracene (An) and flouranthene (Flu) for dyes, and naphthalene (Naph) for plasticizer pro-duction. Considering their amount used for produc-tion, PAHs detected in the environment are mainly a result of incomplete combustion rather than from com-mercial use. Primary anthropogenic sources of PAHs include: motor vehicle exhaust, products from petro-leum refineries, industrial machinery manufactures, coke production, anode baking for aluminum, envi-ronmental tobacco smoke, barbecue smoke, etc. (25). The emissions of benzo[ a ]pyrene (B[ a ]P) into the air in the Federal Republic of Germany were estimated to be 18 tonnes. About 30% was caused by coke production, and 58% by heating with coal (26).
eBook - PDF- W. Kleiböhmer(Author)
- 2001(Publication Date)
- Elsevier Science(Publisher)
W. Kleib6hmer(Ed.), Environmental Analysis Handbook of Analytical Separations, Vol. 3 9 2001 ElsevierScience B.V. All rights reserved 99 CHAPTER 4 Polycyclic aromatic hydrocarbon (PAH) metabolites A. H6ner Technische Universitgit Berlin, Strasse des 17. Juni 135, D-10623 Berlin, Germany 4.1 INTRODUCTION Polycyclic Aromatic Hydrocarbons (PAHs) represent an important class of environmental pollutants and have gained special attention because some of them are strong mutagens and carcinogens [4-6]. They are present in fossil fuels and are formed upon incomplete combustion and pyrolysis of organic matter. PAHs are generated for example in forest fires and volcanic eruptions and are natural constituents of crude oil and other petrochemical products. In addition they are formed in industrial facilities such as coke plants and gasworks, in domestic heating, and in traffic. Furthermore they are one of several classes of carcinogenic chemicals in tobacco smoke and are also present in food. Their widespread generation respectively release, both from natural and anthropogenic sources, together with distribution and transport processes, is responsible for their ubiquitous occurrence. Humans are exposed to Polycyclic Aromatic Hydrocarbons from environmental, occupational, medicinal (e.g. coal tar treatment) and from dietary sources (e.g. broiled and smoked foods) [5-14]. As already mentioned, some Polycyclic Aromatic Hydrocarbons are potent carcino- gens for humans and experimental animals [15-17]. However, carcinogenic properties vary widely for individual PAHs. In addition synergistic effects play an important role and may enhance the adverse effect on living organisms [18]. Therefore analytical determinations of Polycyclic Aromatic Hydrocarbons usually include a (representative) number of analytes rather than focusing on one or two single compounds. The US Environmental Protection Agency for example classifies 16 PAHs as environmentally relevant [19].
eBook - ePub- Yolanda Picó(Author)
- 2008(Publication Date)
- Elsevier Science(Publisher)
Chapter 17 Polycyclic Aromatic HydrocarbonsKatsumi TamakawaAbstract Publisher SummaryA variety of carcinogenic substances have been detected in food so far. Among them, polycyclic aromatic hydrocarbon (PAH) is one of the major components contributing to human cancer. It is, therefore, very important to develop simple and accurate analytical methods for the routine screening of these harmful PAHs. This chapter reviews the physicochemical properties, toxicological evaluation, and analytical methods of PAHs and their occurrence in food. In the analysis of PAHs, it is important to consider the instability of these compounds at all stages to avoid their photodecomposition. To design and choose an analytical method for PAHs, their physical and chemical properties should be considered. The biological mechanisms to produce the adverse effects of the majority of PAHs are not well understood yet. Except for naphthalene (Naph), there are only a limited number of studies available for the evaluation of acute oral toxicity. The chapter examines promising analytical methods for PAHs.1 Introduction
Polycyclic Aromatic Hydrocarbons (PAHs) are a large class of well-known carcinogenic compounds. These compounds are mainly formed by pyrolytic processes, especially the incomplete combustion of organic matter through natural and anthropogenic processes, such as forest fires, processing of coal and crude oil, vehicle traffic, residential heating, industrial power generating, cooking, smoking and so on. Some PAHs are commercially used as intermediates in industrial manufacturing. Naphthalene (Naph), anthracene (An) and phenanthrene (Phe) are used as raw materials in the production of dye, celluloid, lubricants, fibres, plastics and insecticides. However, the amounts of PAHs for commercial use are much less than those generated by incomplete combustion.
eBook - PDFAir Pollution
Health and Environmental Impacts
- Bhola R. Gurjar, Luisa T. Molina, C.S. P. Ojha(Authors)
- 2010(Publication Date)
- CRC Press(Publisher)
Attention has been focused particularly on chemical carcinogens in ambient air. Polycyclic Aromatic Hydrocarbons (PAHs) were one of the first atmospheric pollutants to be identified as carcinogenic and mutagenic (IARC, 1984). PAHs are ubiquitous environmental con-taminants present in air, water, soil, and vegetation. They are also found in remote and pristine areas such as the Arctic. Belonging to a group of compounds commonly known as persistent organic pollutants (POPs), they have attracted much attention in recent years because of their inherent toxicity and ability to disperse in the environ-ment by direct emissions to the air and consequently by long-range transport. Many PAHs are potentially carcinogenic and mutagenic. There is growing evidence that priority PAHs and their derivatives have a dioxin-like potency. They are multi-aromatic ring systems composed of carbon and hydrogen atoms arranged in the form of fused aromatic rings (linear, cluster, or angular arrangement). The PAH family includes 660 substances indexed by the National Institute of Standards and Technology (Sander and Wise, 1997) and approximately 30–50 of them commonly occur in the environment. They are generally produced in incomplete combustion processes, and their occurrence and emissions have therefore been substantial during the past centuries because of the abundant use of fuels for industrial applications, heating, transport, and many other purposes. Thus, PAHs are ubiquitous contami-nants in both the general environment and in certain working environments. They are semivolatile compounds present in the atmosphere in both the vapor phase and the particulate phase as well as dissolved or suspended in precipitation. Most of the more potent carcinogens in this group have more than three rings, hence the name PAHs (or polynuclear aromatic hydrocarbons).
eBook - PDFFood Contaminants
Sources and Surveillance
- C Creaser, R Purchase(Authors)
- 1991(Publication Date)
- Woodhead Publishing(Publisher)
CHAPTER 3 Analysis and Occurrence of Polycyclic Aromatic Hydrocarbons in Food KEITH D. BARTLE 1 Nature and Biological Action of Polycyclic Aromatic Hydrocarbons Polycyclic Aromatic Hydrocarbons (PAHs) comprise the largest class of known environmental carcinogens;’ some, while not carcinogenic, may act as synergists. PAHs are found in water, air, soil, and, therefore, food; they originate from diverse sources such as tobacco smoke, engine exhausts, petroleum distillates, and coal-derived products, with combustion sources ~redominating.~-~ PAHs in food may also arise from smoke curing, charcoal broiling, food additives, and packaging as well as environmental p~llution.~ PAHs consist6 (Figure 1) of benzene units linked together, either cata-annellated [e.g. anthracene (l), linearly annellated, and phenanthrene (2), angularly annellated] or peri-condensed [e.g. pyrene (3)]. These possibilities, taken with the number of alkylated derivatives, make the ‘Environmental Carcinogens: Polycyclic Aromatic Hydrocabons’, ed. G. Grimmer, CRC Press, Boca Raton, Florida, 1983. 2M. L. Lee. M. V. Novotny and K. D. Bartle, ‘Analytical Chemistry of Polycyclic Aromatic Compounds’, Academic Press, New York, 1981, Chapter 2. p. 17. A. Bjprseth and T. Ramdahl, in ‘Handbook of Polycyclic Aromatic Hydrocarbons’, ed. A. Bjprseth and T. Ramdahl, Marcel Dekker, New York, 1985, Vol. 2, Chapter 1, p. 1. 4T. Vo-Dinh, in ‘Chemical Analysis of Polycyclic Aromatic Compounds’, ed. T. Vo-Dinh, John Wiley, New York, 1989, Chapter 1, p. 1. ST. Fazio and J. W. Howard, in ‘Handbook of Polycyclic Aromatic Hydrocarbons’, ed. A. Bjprseth, Marcel Dekker, New York, 1983, Vol. 1, Chapter 11, p. 461. M. Zander, in ‘Handbook of Polycyclic Aromatic Hydrocarbons’, ed. A. Bjerseth, Marcel Dekker, New York, 1983, Vol. 1, Chapter 1, p. 1. 41 42 Analysis and Occurrence of Polycyclic Aromatic Hydrocarbons in Food number of isomers for even a modest molecular weight enormous (Table 1) and PAH mixtures from combustion etc.
eBook - PDF- Vladimir Kutcherov, Anton Kolesnikov, Vladimir Kutcherov, Anton Kolesnikov(Authors)
- 2013(Publication Date)
- IntechOpen(Publisher)
Chapter 5 © 2013 Pampanin and Sydnes, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Polycyclic Aromatic Hydrocarbons a Constituent of Petroleum: Presence and Influence in the Aquatic Environment Daniela M. Pampanin and Magne O. Sydnes Additional information is available at the end of the chapter http://dx.doi.org/10.5772/48176 1. Introduction Crude oil is a complex mixture of hydrocarbons containing more than 17000 compounds [1]. Among the constituents of crude oil there is a group of substances called Polycyclic Aromatic Hydrocarbons (PAHs). PAHs are aromatic compounds containing from two to eight conjugated ring systems. They can have a range of substituents such as alkyl, nitro, and amino groups in their structure [2]. Nitrogen, sulfur, and oxygen atoms can also be incorporated into their ring system [2,3]. The precursors for PAHs found in crude oil are natural products, such as steroids, that have been chemically converted to aromatic hydrocarbons over time [4]. The PAHs that are present in the marine environment in relevant concentrations are divided into two groups depending on their origin, namely pyrogenic and petrogenic [5]. Pyrogenic PAHs are formed by incomplete combustion of organic material while the petrogenic PAHs are present in oil and some oil products [4,6,7]. In general the pyrogenic PAHs are composed of larger ring systems then the petrogenic PAHs. Sources for pyrogenic PAHs are forest fires [6,7,8], incomplete combustion of fossil fuels [6,7,8], and tobacco smoke [6,7]. A range of PAHs are naturally present in crude oil [4,9,10] and coal [10,11] and these compounds are referred to as petrogenic PAHs.
eBook - PDFBiochemical Toxicology
Heavy Metals and Nanomaterials
- Muharrem Ince, Olcay Kaplan Ince, Gabrijel Ondrasek, Muharrem Ince, Olcay Kaplan Ince, Gabrijel Ondrasek(Authors)
- 2020(Publication Date)
- IntechOpen(Publisher)
In particular, Polycyclic Aromatic Hydrocarbons (PAHs) have been identified as general causes of the deterioration of aquatic ecosystems in recent decades [2]. Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous and persistent environ-mental contaminants found in sediments and associated waters of urbanized estu-aries and coastal areas [3–5]. They are a class of compounds found in crude oil and are everywhere in the aquatic ecosystem [6–12]. PAHs are the most toxic pollutants of crude oil and are remembered by the United States Environmental Protection Agency (EPA) as priority toxic components because of its persistence in the envi-ronment and are toxic to fishes [13, 14]; thus, PAHs are of special interest following oil spills and in environmental control. They come from natural and anthropogenic sources. The latter can be associated to pyrolysis and incomplete combustion of Biochemical Toxicology - Heavy Metals and Nanomaterials 200 organic element [15]. Wastewater, atmospheric deposition, and petroleum spillage are some of the most important PAH sources. PAHs and their intermediate deg-radation products have the potential to generate toxic or mutagenic effects in fish [16–18] and humans [19]. PAH metabolites in the bile fluid are generally accepted as measures for PAH exposure in fish because of the rapid metabolism of PAH in most vertebrates [3]. Therefore, PAH metabolites in fish are recommended as monitoring parameters in European seas [20, 21]. In this chapter, we briefly review the origin, toxicity, and transformation of PAHs in the aquatic environment, highlighting their efficient metabolism in fish. We also review the presence of PAHs on fish bile and the works reported on that. 2. Organic contamination by Polycyclic Aromatic Hydrocarbons (PAH) 2.1 PAH origin PAHs are mainly formed during the incomplete combustion of organic matter and during the slow maturation of organic matter accumulated in deep sedimentary environments.
eBook - PDF- Victor R. Preedy, Vinood Patel(Authors)
- 2012(Publication Date)
- CRC Press(Publisher)
Areas for future development are briefly summarized, including development of 1) reporters for higher molecular weight PAHs, 2) improved bioreporter-specific assays, and 3) improved assays for bioavailability. INTRODUCTION Polycyclic Aromatic Hydrocarbons (PAHs) are a class of compounds that consist of fused aromatic rings and are one of the most widespread environmental pollutants. PAH-bearing materials usually contain a number of different individual PAHs, many of which are known or suspected to pose an environmental health threat, inclusive of being carcinogenic, mutagenic, and teratogenic. Measurement of PAHs is a prerequisite to risk assessment, and the common approach is chemical analysis. Chemical analysis has the fundamental shortcoming of not addressing bioavailability, which is important since that which is not bioavailable, is not toxic. Due to their environmental prevalence and chemical behavior, wherein there is a large variation of PAH affinity for various natural materials, bioavailability is arguably even more important to understand for PAHs than for other classes of environmental pollutants. Whole-cell bacterial biosensors, or bioreporters, combine advantages of both chemical and ecotoxicological approaches to environmental measurement and are suited for assessment of PAH environmental health issues. This chapter will describe environmentally important PAHs, their health effects, their chemical properties and important aspects of these that relate to environmental health. Subsequently the chapter details measurement, a review of progress to date in using bioreporters to assess environmental PAH bioavailability, including notable examples of bioreporter applications to oil spill studies, differentiating aspects of bioreporters, and a future outlook for technology.
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