Total particulate aromatic hydrocarbon

Golden, C., and E. Sawkki. Ultrasonic extraction of total particulate aromatic hydrocarbons (TpAH) from airborne particles at room temperature. Int. J. Environ. Anal. Cliem. 4 9-23, 1975. 

Golden and Sawicki [17] studied ultrasonic extraction of almost all of the polar compounds from airborne particulate material collected on Hi-Vol filters. Full recovery of PAH and good reproducibility were achieved. Total analysis time was approximately 1.5 hours. The same research group also reported a sonication procedure for the extraction of total particulate aromatic hydrocarbon (TpAH) from airborne particles collected on glass fiber filters [18]. Significantly higher recovery of TpAH and PAH were achieved by 40 minutes of sonication than by 6 to 8 hours of Soxhlet extraction. 

Addition of fuel oil no. 2 to a laboratory marine ecosystem showed that the insoluble, saturated hydrocarbons in the oil were slowly transported to the sediment on suspended particulate material. The particulate material contained 40-50% of the total amount of aliphatics added to the system and only 3-21% of the aromatic fraction (Oviatt et al. 1982). This indicates that most aromatic hydrocarbons are dissolved in the water (Coleman et al. 1984), whereas the aliphatic hydrocarbons are not (Gearing et al. 1980 Oviatt et al. 1982). In a similar experiment, when fuel oil no. 2 was added continuously to a marine ecosystem for 24 weeks, oil concentrations in the sediment remained low until 135 days after the additions began, but then increased dramatically to levels that were 9% of the total fuel oil added (108 g/tank) and 12% of the total fuel oil saturated hydrocarbons. The fuel oil concentrations in the sediment began to decrease quite rapidly after the maximum levels were reached. The highest sediment concentrations of saturated hydrocarbons (106-527 g/g) were found in the surface flocculent layer, with concentrations decreasing with sediment depth from 22 g/g to not detectable at 2-3 cm below the sediment surface. 

Baek, S. O., M. E. Goldstone, P. W. W. Kirk, J. N. Lester, and R. Perry, Concentrations of Particulate and Gaseous Polycyclic Aromatic Hydrocarbons in London Air Following a Reduction in the Lead Content of Petrol in the United Kingdom, Sci. Total Environ., Ill, 169-199 (1992). 

Although Table I is generally self-explanatory, the carbonaceous material measurements require comment. Because of its chemical complexity, carbonaceous material is frequently characterized only on the basis of carbon measurements. These measurements attempt to divide the carbonaceous material into organic C and elemental C . Carbon present in carbonate salts, frequently a minor contributor to the total particulate carbon, can be determined independently. Elemental carbon is among the most important pollutants in visibility reduction. Polycyclic aromatic hydrocarbons (PAHs) are relatively minor constituents of the particulate carbon but are of great interest in health effects studies. PAHs can also serve as model compounds in developing improved sampling techniques for semivolatile carbonaceous materials. 

The compounds of the particle phase are collectively called tar, or total particulate matter (TPM). Tar is the oily residue left behind when moisture evaporates from burned tobacco. It contains thousands of compounds, including cancer-causing aromatic amines, nitro-samines, and polycyclic aromatic hydrocarbons that are present in both smoking and smokeless tobacco. Other harmful constituents include radioactive lead and polonium as well as arsenic, among others. 

Lee, W.-M. G. and L.-Y. Tsay. 1994. The partitioning model of polycyclic aromatic hydrocarbon between gaseous and particulate (PM-10) phases in urban atmosphere with high humidity. Sci. Total Environ. 145 163-171. 

In January and March of 1988, Radian Corporation made a comprehensive series of performance measurements on the air pollution control system at Modesto (47). As shown in Table 12, the measurements included chlorinated dibenzo-p-dioxins (CDD), chlorinated dibenzofurans (CDF), polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenols (PCB), total hydrocarbons (THC), ammonia, NOx, sulfur trioxide, sulfur dioxide, hydrochloric acid, carbon monoxide, and particulate matter. 

In addition to the need to monitor known problematic compounds, newer compounds are being identified as potential threats to humans and as such need to be monitored in the atmosphere. For example, researchers reported (10) that several chemical and instrumental analyses of HPLC fractions provided evidence for the presence of /V-nitroso compounds in extracts of airborne particles in New York City. The levels of these compounds were found to be approximately equivalent to the total concentrations of polycyclic aromatic hydrocarbons in the air. Since 90% of the N-nitroso compounds that have been tested are carcinogens (10), the newly discovered but untested materials may represent a significant environmental hazard. The procedure involved collecting samples of breathable, particulate matter from the air in New York City. -These samples were extracted with dichloro-methane. Potential interferences were-removed by sequential extractions with 0.2 N NaOH (removal of acids, phenols, nitrates, and nitrites) and 0.2 N H2S04 (removal of amines and bases). The samples were then subjected to a fractional distillation and other treatments. Readers interested in the total details should consult the original article (10). Both thin-layer chromatography (TLC) and HPLC were used to separate the compounds present in the methanolic extract. 

Madsen ES, Nielsen PA, Pedersen JC. 1982. The distribution and origin of mutagens in airborne particulates, detected by the Salmonella typhimurium microsome assay in relation to levels of lead, vanadium and polycyclic aromatic hydrocarbons. Sci Total Environ 24 13-25. 

Madany IM, Raveendran E Polycyclic aromatic hydrocarbons, nickel and vanadium in air particulate matter in Bahrain during the burning of oil fields in Kuwait. Sci Total Environ 116 281-289, 1992... 

Steinmetzer H. C., Baumeister W., and Vierle O. (1984) Analytical investigation on the contents of polycyclic aromatic hydrocarbons in airborne particulate matter from 2 Bavarian cities, Sci. Total Environ. 36, 91-96. 

Evans, W.H., N.C. Thomas, M.C. Boardman, and S.J. Nash Relationships of polycyclic aromatic hydrocarbon yields with particulate matter (water and nicotine free) yields in mainstream and sidestream cigarette smoke Sci. Total Environ. 136 (1993) 101-109. 

Bonner MR, Han D, Nie J et al (2005) Breast cancer risk and exposure in early life to polycyclic aromatic hydrocarbons using total suspended particulates as a proxy measure. Cancer Epidemiol Biomarkers Prev 14 53-60... 

The studies described above give evidence that the XAD-2 method provides a useful determination of the hydrocarbon components in dilute seawater-oil suspensions. The quantity of "total oil reported in Table I is in sharp contrast to the total hydrocarbons found in the water by the combined helium extraction/XAD extraction techniques. The discrepancy between total oil by IR and hydrocarbons found in water by component analysis was previously reported (5,11) and can be explained by the low contribution to the IR absorbance at 2927 cm 1 of the soluble aromatic constituents relative to the saturate hydrocarbons. The difference between IR analytical result and component analysis by GC becomes much greater in the filtered systems, where the total hydrocarbons found are three times that reported by the IR method. It is clear that the IR analytical technique is only useful in systems where there is a preponderance of particulate, bituminous petroleum or where it is used as a monitoring tool. It provides no information about actual levels of hydrocarbons in systems where there is a preponderance of water-soluble aromatic compounds. 

Emissions from the consumption of diesel fuel are low, however. There is virtually no evaporation. In 1969, hydrocarbon emissions from diesel-powered vehicles in the USA amounted to 200,000 t (as compared with 16.9 million t from gasoline engined vehicles) [13]. Of this figure, the Cio-C24-hydrocarbons account for a relatively low portion, but are nevertheless responsible for the offensive odour [13]. A few hundred different components have been found, some are components of the diesel oil but others are formed by combustion [13]. The more important constituents are indanes, tetralines, alkyl benzenes, naphthalenes, indoles, acenaphthenes, and benzothiophenes [13]. It appears that the quantitatively less important aromatic aldehydes and ketones are responsible for the odour [13]. At a rough estimate, the total world emissions of alkyl benzenes and naphthalenes must amount to some 200,000 t. Diesel particulate emissions contain neutral fractions with microbial mutagenic activity [26 a]. 

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