Polycyclic aromatic compounds carcinogenic

Another interesting, but rather complex system, which couples flow injection analysis, EC and GC has been recently reported (47). This system allows the determination of the total amount of potentially carcinogenic polycyclic aromatic compounds (PACs) in bitumen and bitumen fumes. This system could also be used for the analysis of specific PACs in other residual products. 

The carcinogenicity of polycyclic aromatic compound-rich tyre extender oils has lead to the proposal of a legislative ban on their use in Europe. The suitability of naphthenic oils as non-toxic plasticisers in tyre treads is discussed and results are presented of experimental studies of the use of these plasticisers in SBR, EPDM, sulphur-cured EPDM and peroxide-cured EPDM. Despite their low aromatic content, the naphthenic plasticisers are shown to give good results in SBR, probably as a result of the contribution to solvent characteristics of the naphthenic molecular structure. The use of naphthenic oils is expected to increase worldwide as they are said to be one of the best alternatives to aromatic extracts with regard to solvent properties, compatibility, performance and availability. 

Polycyclic Aromatic Compounds, Part 1, Chemical Environmental and Experimental Data International Agency for Research on Cancer Monographs on the Evaluation of the Carcinogenic Risks to Humans 32 IARC Lyon, France, 1983. 

Hydroxylation may also take place at nitrogen atoms, resulting in hydroxyl-amines (e.g., acetaminophen). Benzene, polycyclic aromatic compounds (e.g., benzopyrene), and unsaturated cyclic carbohydrates can be converted by mono-oxygenases to epoxides, highly reactive electrophiles that are hepato-toxic and possibly carcinogenic. 

Brown, R. and A. Mitteknan. 1993. Evaluation of existing methods to rank the relative carcinogenicity of polycyclic aromatic compounds PAH). Draft. Technical Resources, Inc., Contract No. 68-01-0022, for Office of Emergency and Remedial Response, Office of Sohd Waste and Emergency Response, U.S. Environmental Protection Agency, Office of Pesticides, Pollution Prevention and Toxic Substances (OPPTS). 

International Agency for Research on Cancer. lARC monographs on the evaluation of the carcinogenic risks to humans, vol. 32 polycyclic aromatic compounds, part 1, chemical environmental and experimental data. Lyon lARC 1983. 

Some of these N-, O-, and S-atom-functionalized polycyclic aromatic compounds (PACs) are powerful bacterial mutagens and animal, and possible human, carcinogens, e.g., the exocyclic nitro-substituted PAH 1-nitropyrene, VI, which is a primary pollutant in diesel exhaust (IARC, 1989). The endocyclic heterocyclic PAC dibcnz[fl,/ ]acridine, VII, is also classified as a possible human carcinogen (IARC, 1987 see Sections B and C). 

James N. Pitts, Jr., is a Research Chemist at the University of California, Irvine, and Professor Emeritus from the University of California, Riverside. He was Professor of Chemistry (1954-1988) and cofounder (1961) and Director of the Statewide Air Pollution Research Center (1970-1988) at the University of California, Riverside. His research has focused on the spectroscopy, kinetics, mechanisms, and photochemistry of species involved in a variety of homogeneous and heterogeneous atmospheric reactions, including those associated with the formation and fate of mutagenic and carcinogenic polycyclic aromatic compounds. He is the author or coauthor of more than 300 research publications and three books Atmospheric Chemistry Fundamentals and Experimental Techniques, Graduate School in the Sciences—Entrance, Survival and Careers, and Photochemistry. He has been coeditor of two series, Advances in Environmental Science and Technology and Advances in Photochemistry. He served on a number of panels in California, the United States, and internationally. These included several National Academy of Science panels and service as Chair of the State of California s Scientific Review Panel for Toxic Air Contaminants and as a member of the Scientific Advisory Committee on Acid Deposition. 

Oxidation to Arene Oxides and Arene Diols. Arene oxides and arene diols have been widely studied particularly concerning the metabolism of polycyclic aromatic compounds and their implication as intermediates responsible for the carcinogenicity and mutagenicity of polycyclic aromatic hydrocarbons.803,804... 

Some analytes, such as riboflavin (vitamin B2)16 and polycyclic aromatic compounds (an important class of carcinogens), are naturally fluorescent and can be analyzed directly. Most compounds are not luminescent. However, coupling to a fluorescent moiety provides a route to sensitive analyses. Fluorescein is a strongly fluorescent compound that can be coupled to many molecules for analytical purposes. Fluorescent labeling of fingerprints is a powerful tool in forensic analysis.17 Sensor molecules whose luminescence responds selectively to a variety of simple cations and anions are available.18 Ca2+ can be measured from the fluorescence of a complex it forms with a derivative of fluorescein called calcein. 

Benzene is a known carcinogen and is carefully regulated. Although other aromatics are less problematic, their acceptable levels are also being lowered. The presence of benzene/aromatics may increase particulate formation and/or the formation of polycyclic aromatic compounds. 

Goldstein LS, Safe S, Weyand EH. 1994. Carcinogenicity of coal tars A multidisciplinary approach. Polycyclic Aromatic Compounds 7 161-174. 

Wenzel-Hartung R, Brune H, Grimmer G, et al. 1990. Evaluation ofthe carcinogenic potency of 4 environmental polycyclic aromatic compounds following intrapulmonary application in rats. Exp Pathol 40(4) 221-227. 

Increased cancer risk caused by carcinogens in the work-place is also well-established. In addition to the effects of benzpyrene and other polycyclic aromatic compounds already mentioned, the high incidence of mesothelioma, a rare lung cancer amongst those exposed to the blue asbestos fibres is irrefutable. There is also good evidence that other cancers have been caused by such diverse chemicals as vinyl chloride (used in the manufacture... 

Roy TA, Johnson SW, Blackburn GR, et al. 1988. Correlation of mutagenic and dermal carcinogenic activities of mineral oils with polycyclic aromatic compound content. Fundam Appl Toxicol 10 466-476. 

Sauvain, J.-J., Vu Due, T., and GuiUemin, M., Exposure to carcinogenic polycyclic aromatic compounds and health risk assessment for diesel-exhaust exposed workers, Int. Arch. Occup. Environ. Health, 76, 443-455, 2003. 

The last general category—namely, the reaction of ozone with aromatic hydrocarbons, has received an enormous amount of attention by ozone chemists. Most of this attention has concerned rate and reactivity studies in an attempt to correlate these experimental quantities with some known parameters of the hydrocarbons. Several reactivity correlations have been proposed, including those with bond localization energy, atom localization energies, and oxidation-reduction potentials. This category is also represented by a paper in this section, in which a possible correlation between ozone reactivity and carcinogenicity of some polycyclic aromatic compounds is explored. 

A new nanocrystaUine Ga—Al—Zn complex-oxide (designated here as nano-GAZ) has been synthesized by a hydrothermal method, with uniform nanocrystalline particles of size around 5-lOnm and very uniform 3.8nm mesopores [123]. This new material was designed for the elimination of N-containing polycyclic aromatic compounds (NPACs) present in diesel-engine emissions, which are known to be carcinogenic and need now to be removed. For instance, the concentration of 1-nitropyrene, which is the most abundant NPAC in diesel emission extracts, is... 

Figure 2.14 Cigarette smoke contains carcinogenic polycyclic aromatic compounds.

Animal experiments with unsubstituted polycyclic aromatic compounds have shown some of the compounds with four and more rings to be carcinogenic with naphthalene, anthracene and phenanthrene, no carcinogenic effects have been established. 

Water pollution due to toxic metals and organic compounds remains a serious environmental and public problem. Moreover, faced with more and more stringent regulations, water pollution has also become a major source of concern and apriority for most industrial sectors. Heavy metal ions, aromatic compoimds (including phenolic derivatives and polycyclic aromatic compounds) and dyes are often foimd in the environment as a result of their wide industrial uses. They are common contaminants in waste water and many of them are known to be toxic or carcinogenic. 

A number of more complex polycyclic aromatic compounds are known to be carcinogens-chemicals that cause cancer. Two of these compounds are ... 

The presence of residues in humans has not been directly implicated in the induction of cancer. However, many polycyclic aromatic compounds are either known or suspected carcinogens and contribute to the total carcinogenic burden in people (Table 5.6). Consequently, exposure guidelines have been developed for many aromatics, particularly those occurring in food, potable water, and the work place. 

One of the most harmful of all the polycyclic aromatic compounds is benzo[a]pyrene, 12.13, which is a constituent of tobacco (and in greater quantities in marijuana) smoke, and was established to be the precarcinogenic compound in the cancers of the scrotum suffered by chimney sweeps in nineteenth-century Britain. In vivo, it is catalytically oxidized in the presence of various cytochromes and a hydrolase enzyme to 12.14, which is both carcinogenic and mutagenic (the epoxide group is susceptible to ring-opening reactions by nucleophiles such as the bases of DNA and proteins). 

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