Polycylic hydrocarbons

Flowers, L. Ohnishi, T. Penning, T. M. DNA strand scission by polycylic hydrocarbon o-quinone role of reactive oxygen species, Cu(II)/(I) redox cycling, and o-semiquinone anion radicals. Biochemistry 1997, 36, 8640-8648. 

Polycylic Hydrocarbons, Nonaltemant Compounds with Five Fused Rings under Polycyclic Hydrocarbons, Nonaltemant Compounds with Five Fused Rings Polycyclic Hydrocarbons, Nonaltemant Compounds with More Than Five Fused Rings Polycyclic Hydrocarbons, Nonaltemant Compounds with Two or Three Fused Rings Potassium Primary Alcohols... 

Attempts to use 35C1 NQR spectroscopy to assign the structures of a number of polychlorinated polycylic hydrocarbons have also been reported90,91. 

Fetzer, J.C. The deternrination of aqueous solubility for several large PAHs, Polycylic Aromatic Hydrocarbons, 23(3-4) 321-326, 2002. 

Polycylic Aromatic Hydrocarbons with Five Fused Rings under Polycylic Aromatic Hydrocarbons, Eive-Ring Compounds... 

Polycylic aromatic hydrocarbons with both angular and linear types of ring fusion show absorption curves of a similar profile to that of benzene but with the absorption maxima shifted to longer wavelengths the greater the number of rings the more pronounced the shift. 

On occasions, animal feed has been suspected of deliberate contamination. Incidents involving contamination of animal feed by industrial by-products such as polycylic aromatic hydrocarbons (PAHs) and combustion products such as dioxins are not uncommon. A problem with animal feed is that there is sometimes inadequate control over the provenance of feed constituents. For example, spent cooking oil from food-processing plants is a legitimate feed component. Unfortunately, the temptation for the unscrupulous to dispose of other unwanted oils in this way is too great for some. In many cases such adulterants are probably diluted to such an extent that they are undetectable by conventional chemical analyses. Nevertheless, they may still represent a longterm cumulative hazard to consumers of products from animals fed on such material. 

Stange, K., Klungsoyr, J., 1997. Organochlorine contaminates in fish and polycylic aromatic hydrocarbons in sediments from the Barents Sea. ICES J. Mar. Sci. 58, 318-332. 

Page, S.H., B.A. Benner, J.A. Small, et al. 1999. Application of stir bar sorptive extraction in combination with column liquid chromatography for the determination of polycylic aromatic hydrocarbons in water samples. J. Supercrit. Fluids 14 257-270. 

Very stable polycylic phosphiranes were obtained by an intramolecular cycloaddition reaction of aminodichloro-phosphines with the C-C double bond of 577-dibenzo[ , [7]annulene (dibenzocycloheptene) under the influence of Mg-turnings. Formally, these compounds are formed by an intramolecular [2-Fl] cycloaddition of an R2N-P phosphinidene unit to the C-C double bond of the central seven-membered ring. In analogy to the hydrocarbon barbalan the amino compound is named BARBAR-Phos <1999AGE1623>. In a comparable reaction sequence, dibenzophosphasemibullvalene was obtained (Equation 25) <2003AGE3955>. 

Polycylic aromatic compounds can react with alkali metals in ether solution to produce monomeric radical ions with an extra electron in the lowest unoccupied 71 orbital of the hydrocarbon. For sodium and naphthalene, for example. 

Freeman D. J. and Cattell F. C. (1990) Wood burning as a source of polycylic aromatic hydrocarbons. Environ. Sci. Technol. 24, 1581-1585. 

Villeneuve, D.L., J.S. Khim, K. Kannan and J.P. Giesy. Relative potencies of individual polycylic aromatic hydrocarbons to induce dioxin-like and estrogenic responses in three cell lines. Environ. Toxicol. 17 128-137, 2002. 

Hills JW, Hill HH. 1993. Carbon dioxide supercritical fluid extraction with a reaction solvent modifier for the determination of polycylic aromatic hydrocarbons. J Chromatogr Sci 31 (1 ) 6-12. 

Franz TP, Eisenreich SJ, Holsen TM. 1998. Dry deposition of particulate polychlorinated biphenyls and polycylic aromatic hydrocarbons to Lake Michigan. Environ Sci Technol 32 3681-3688. 

In addition to gaps in knowledge for currently existing classes of chemicals and ecotoxicological effects, other mechanisms of actions that are currently not yet studied, or other processes, may require further studies. For example, recently it has become clear that phototoxic effects may be a realistic problem for polycylic aromatic hydrocarbons (PAHs) in aquatic and benthic organisms. The amount of UV-light which is required for phototoxicity, is thus an example of a parameter which was not introduced earlier as an important environmental parameter to describe or predict toxicity [148]. Other examples are if the internal effect concept can be used for metals and organometals in risk assessment [149,150]. 

Bestari KTJ, Robinson RD, Solomon KR, et al. 1998. Distribution and composition of polycylic aromatic hydrocarbons within experimental microcosms treated with creosote-impregnated Douglas fir pilings. Environ Toxicol Chem 17(12) 2369-2377. 

Cosmic abundances in the interstellar medium are derived by measuring elemental abundances in stellar photospheres, the atmospheric layer just above the stellar surface. Such measurements indicate the amount of elements available for the formation of molecules and particles. Cosmic dust models indicate that up to 80% of the carbon in the photon-dominated diffuse interstellar medium is incorporated into solid aromatic macromolecules and gaseous polycylic aromatic hydrocarbons (41,30). CO gas and C-based ice species (such as CO, CO2, CH3OH and others) may be responsible for up to -25 % of the carbon in cold dense interstellar regions. 

Valerio, F., and Lazzarotto, A. (1985) Photochemical degradation of polycylic aromatic hydrocarbons (PAH) in real and laboratory conditions, Int. J. Environ. Anal. Chem. 23, 135-151. 

Another way of detecting interstellar species is provided by vibrational emission spectra (Figure 3). Let us mention here the so-called Unidentified Infra-Red (UIR) bands, which have not been unambiguously assigned yet. The striking resemblance of the UIR from the Orion bar with the Raman spectrum of an auto soot clearly seems to indicate that the carriers are carbon compounds. Very certainly, it will not be possible to make a one-to-one correspondence between the observed bands and some given species. Very certainly, also, the carriers of these bands are hydrogenated carbonaceous species. Whether these species are Polycylic Aromatic Hydrocarbons [24,25,26] (thereafter PAHs), coals [27,28,29], or amorphous carbon [30] is still a matter of debates and controversies that we shall not discuss further here. The interested reader can refer to a recent series published in the Faraday Discussions (1998). 

Table 1 Toxic equivalency factors for polycylic aromatic hydrocarbons...

Fossato VU, Nasci C, Dolci (1979) 3,4-benzopyrene and perylene in mussels, Mytilus sp., from the Laguna Veneta, north-east Italy. Mar Env Res 2 47-53 Foster GD, Crosby DG (1986) Xenobiotic metabolism of p-nitrophenol derivatives by the rice field crayfish Procambrus clarkii). Environ Toxicol Chem 5 1059-1070 Foster GD, Crosby DG (1987) Comparative metabolism of nitroaromatic compounds in freshwater, brackish water and marine decapod crustaceans. Xenobiotica 17 1393-1404 Foureman GL (1989) Enzymes involved in metabolism of PAH by fishes and other aquatic animals hydrolysis and conjugation enzymes (or phase II enzymes). In Varanasi U (ed) Metabolism of polycylic aromatic hydrocarbons in the aquatic environment. CRC Press, Boca Raton, Florida, pp 185-202... 

McElroy AE, Farrington JW, Teal JM (1989) Bioavailability of polycylic aromatic hydrocarbons in the aquatic environment. In Varanasi U (ed) Metabolism of polycyclic aromatic hydrocarbons in the aquatic environment. CRC Press, Boca Raton, Florida, pp 1-139... 

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