Polycyclic aromatic hydrocarbons transport

Polycyclic aromatic hydrocarbons Transport specially cleansed glass bottles. 

Polycyclic aromatic hydrocarbons have been classified as human carcinogens because they induce cancers in experimental animals and because smoking and exposure to mixtures of chemicals containing polycyclic aromatic hydrocarbons in the workplace increase the risk of lung cancer in exposed individuals. In experimental animals, benzo(a)pyrene induces cancer in different organs depending on the route of administration.Furthermore, exposure to polycyclic aromatic hydrocarbons commonly occurs in occupations related to traffic (use of diesel engines in transportation and railways). 

Oxidation is intimately linked to the activation of polycyclic aromatic hydrocarbons (PAH) to carcinogens (1-3). Oxidation of PAH in animals and man is enzyme-catalyzed and is a response to the introduction of foreign compounds into the cellular environment. The most intensively studied enzyme of PAH oxidation is cytochrome P-450, which is a mixed-function oxidase that receives its electrons from NADPH via a one or two component electron transport chain (10. Some forms of this enzyme play a major role in systemic metabolism of PAH (4 ). However, there are numerous examples of carcinogens that require metabolic activation, including PAH, that induce cancer in tissues with low mixed-function oxidase activity ( 5). In order to comprehensively evaluate the metabolic activation of PAH, one must consider all cellular pathways for their oxidative activation. 

Bjprseth, A., Olufsen, B.S. (1983) Long-range transport of polycyclic aromatic Hydrocarbons. In Handbook of Polycyclic Aromatic Hydrocarbons. Bjprseth, A. Editor, pp. 50-524, Marcel Dekker, N.Y. and Basel. 

A key feature of our polyphenylene dendrimers is that they can be planarized and thus reduced in dimensionality by intramolecular dehydrogenation [29,35]. This results in large, fused polycyclic aromatic hydrocarbons (PAHs). PAHs serve as structurally distinct, two-dimensional subunits of graphite and show attractive properties such as high charge carrier mobility, liquid crystallinity, and a high thermal stability, which qualifies these materials as vectorial charge transport layers [81]. 

Based on these and other measurements of PAH levels, we suggest the following scenario for the transport of PAH. The various fuels which are burned in metropolitan areas produce airborne particulate matter (soot and fly ash) on which polycyclic aromatic hydrocarbons are adsorbed. These particles are transported by the prevailing wind for distances which are a strong function of the particle s diameter. We suggest that the long range airborne transport of small particles accounts for PAH in deep ocean sediments. 

Bjprseth, A., G. Lunde, and A. Lindskog, Long-Range Transport of Polycyclic Aromatic Hydrocarbons, Atmos. Environ., 13, 45-53 (1979). 

Lunde, G., and A. Bjprseth, Polycyclic Aromatic Hydrocarbons in Long-Range Transported Aerosols, Nature, 268, 518-519 (1977). 

Masclet, P., P. Pistikopoulos, S. Beyne, and G. Mouvier, Long Range Transport and Gas/Particle Distribution of Polycyclic Aromatic Hydrocarbons at a Remote Site in the Mediterranean Sea, Atmos. Environ., 22, 639-650 (1988). 

Pistikopoulos, P., H. M. Wortham, L. Gomes, S. Masclet-Beyne, E. B. Nguyen, P. A. Masclet, and G. Mouvier, Mechaisms of Formation of Particulate Polycyclic Aromatic Hydrocarbons in Relation to the Particle Size Distribution Effects on Meso-Scale Transport, Atmos. Environ., 24A, 2573-2584 (1990b). 

Lunde, G. and Bjorseth, a. (1977). Polycyclic aromatic hydrocarbons in long-range transported aerosols, Nature 268,518. 

Backhus, D. A., and P. M. Gschwend, Fluorescent polycyclic aromatic hydrocarbons as probes for studying the impact of colloids on pollutant transport in groundwater , Environ. Sci. Technol., 24,1214-1223 (1990). 

Keywords Gas-to-particle-phase partitioning, Long-range atmospheric transport, Organochlorines, Persistent organic pollutants, Polycyclic aromatic hydrocarbons... 

Johnson, W.P., and Amy, G.L. (1995). Facilitated transport and enhanced desorption of polycyclic aromatic hydrocarbons by natural organic matter in aquifer sediments. Environ. Sci. Technol., 29, 807-817. 

Lipiatouk, E., and Saliot, A. (1991) Fluxes and transport of anthropogenic and natural polycyclic aromatic hydrocarbons in the western Mediterranean Sea. Mar. Chem. 32, 51-71. 

Humic substances (HS) are polymeric oxidation products that result from the decomposition of plant and animal residues. As a consequence of their colloidal state in natural waters, they play an important role in the transport of organic pollutants. Thus hydrophobic organic pollutants such as polycyclic aromatic hydrocarbons, DDT, and PCBs are known to bind well to humic substances, thereby enhancing the former s water solubility. One important characteristic of... 

Occurrence and transport of HCs have important implications for health of biota as well as humans. Of the top 20 contaminants on the USEPA Hazardous Substances Priority List, 15 are hydrophobic (USEPA, 1999). These contaminants include trace elements, organochlorine compounds, and polycyclic aromatic hydrocarbons (PAHs). A major fraction of HCs are transported adhered to suspended sediment (Bradford and Horowitz, 1982 Garbarino et al., 1995 Rostad et al., 1995). 

Backus, D. A. Geshwend, P. M. Fluorescence Polycyclic Aromatic Hydrocarbons as Probes for Studying the Impact of Colloids on Pollutant Transport in Groundwater Environmental Science and Technology 1990,24 p. 1214-1223. 

Once processed into products such as motor gasoline and fuel oil, most of the petroleum is burned in engines or boilers to provide energy for transportation, space heating, or electricity. In these combustion processes, the petroleum fuel is oxidized. Because of incomplete oxidation, small amounts of hydrocarbon emissions result. These emissions often contain much larger percentages of combustion by-products such as polycyclic aromatic hydrocarbons (PAHs) than the initial petroleum products. Incomplete combustion and heat also alter the composition of crank case oils and lubricants. 

Masclet P. Pistikopoulos P, Beyne S, et al. 1988. Long range transport and gas/particle distribution of Polycyclic aromatic hydrocarbons at a remote site in the Mediterranean sea. Atmos Environ 22 639-650. 

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