Hydrocarbon levels

Baumann, P.C., W.D. Smith, and M. Ribick. 1982. Hepatic tumor rates and polynuclear aromatic hydrocarbon levels in two populations of brown bullhead (Ictalurus nebulosus). Pages 93-102 in M.W. Cooke, A.J. Dennis, and G.L. Fisher (eds.). Polynuclear Aromatic Hydrocarbons Physical and Biological Chemistry. Battelle Press, Columbus, OH. 

It appears from these data that the O standard (i.e., 0.08 ppm for 1 h] could not be met if the aldehydes remained high, ICH,0] 0.10, (CH,CH01 0.06 ppm, even if nearly all of the olefrnic hydrocarbon were removed.. .. We should learn from these data that the true relationship between nonmethane hydrocarbons and maximum 1-h oxidant at low hydrocarbon levels could be a critical function of a variable which is not routinely measured now, namely the concentration of the impurity aldehydes. 

Heit M, Tan Y, Klusek C, et al. 1981. Anthropogenic trace elements and polycyclic aromatic hydrocarbon levels in sediment cores from two lakes in the Adirondack acid lake region. Water Air Soil Pollut 15 441-464. 

After excision of the transposon, the pheromone phenotype was reversed in 69 percent of the lines and the other excision lines showed generally decreased 7-unsaturated hydrocarbon levels (paralleled with similar increases in linear saturated hydrocarbons). These results clearly show the involvement of desatl in the biosynthesis of unsaturated hydrocarbons (Labeur et al., 2002). 

Carbon-14 content is measured by specially designed gas proportional counters (7. Aerosol samples are first converted to CO2 by combustion in a macroscale version of the thermal evolution technique. A clam shell oven was used to heat the sample for sequential evolution of organic and elemental carbon under equivalent conditions. Due to the possibility of thermal gradients, conditions in the macroscale apparatus were adjusted to produce the same recoveries of total carbon (yg C per cm of filter area) as for the microscale apparatus. Carbon-14 data are reported as % contemporary carbon based on the 1978 1 C02 content in the atmosphere. Aldehyde data referred to in this paper were obtained by impinger sampling in dinitrophenylhydrazine/acetonitrile solution and analysis of the derivatives by HPLC with UV detection (12). Olefin measurements were made by a specially designed ozone-chemiluminescence apparatus (13) difficulties in calibration accuracy and background drift with temperature limit its use to inferences of relative reactive hydrocarbon levels. 

Background non-methane hydrocarbon levels are generally less than 20 ppbC. A typical sample (Table I) indicates that the major components are ethane, propane and acetylene. Because only picomolar amounts of these hydrocarbons would exist in the cloud water, the effects of these background levels on aqueous-phase chemistry are expected to be negligible. The effect of the organic acids is not expected to be significant unless sources of OH exist. Formaldehyde is known to inhibit aqueous SO2 oxidation, but its concentration here is insignificant compared to the concentrations of SO2 intentionally... 

Morosini M, Schreitmiiller J, Reuter U, Ballschmiter K (1993), Environ. Sci. Technol. 27 1517-1523.. .Correlation between C-6/C-14 chlorinated hydrocarbons levels in the vegetation and in the boundary layer of the troposphere"... 

Peachey, R. B. J. (2003). Tributyltin and polycyclic aromatic hydrocarbon levels in Mobile Bay, Alabama a review. Marine Pollution Bulletin, 46, 1365-71. 

Several authors have been able to show experimentally that natural air containing trace amounts of SO2, exposed to sunlight, is photochemical-ly oxidized and that the rate of SO2 oxidation was a complex function of the trace gas composition of the air mixture (NO, NO2 - hydrocarbons level and composition). The oxidation of SO2 within the natural troposphere is therefore expected to occur largely through reactions 7,8 and 9 of table I. The main mechanism is through radicals which might be formed in various ways such as from ozone photodissociation and from the reaction ... 

This qualitative behavior is analogous to observations in the Los Angeles Basin. There hydrocarbon levels have been reduced without equivalent reduction in NO j, and presumably ozone formation in the vicinity of downtown Los Angeles has decreased while a similar decrease has not occurred in areas downwind where the reacting air mass has experienced a longer reaction time 72). 

Photochemical smog also contains unbumed hydrocarbons and carbon monoxide, both of which come from the exhaust of automobile engines. These pollutants can be reduced or eliminated from the atmosphere in a variety of ways. Cleaner running engines and catalytic converters greatly reduce NO and hydrocarbon levels. Strict federal tailpipe emission standards are encouraging automobile manufacturers to develop new cars that are powered by electricity or alternative fuels such as natural gas. 

In general, following acute exposure to chlorinated hydrocarbon insecticides, blood chlorinated hydrocarbon levels are not clinically useful for most compounds it reflects cumulative exposure over a period of months rather than recent exposure. Emesis may be indicated and is most effective if initiated within 30 min postingestion. In addition, an activated char-coal/cathartic may be given. For seizures, diazepam should be administered as an intravenous bolus. Oils should not be given by mouth. Adrenergic amines should not be administered because they may further increase myocardial irritability and produce refractory ventricular arrhythmias. If clothing is contaminated, it should be removed. 

Picer M, Picer N. 1993. Evaluation of modification o the simple spectrofluorimetry method for estimating petroleum hydrocarbon levels in sea water. Bull Environ Contam Toxicol 50(6) 802-810. 

Bopp RF, Chillrud SN, Shuster EL, et al. 1998. Trends in chlorinated hydrocarbon levels in Hudson River Basin sediments. Environ Health Perspect Suppl 106(4) 1075-1081. 

Phillips DL, Pirkle JL, Burse VW, et al. 1989b. Chlorinated hydrocarbon levels in human serum Effects of fasting and feeding. Arch Environ Contam Toxicol 18 495-500. 

Probably the most important concern about hydrocarbon levels in the oils and fats industry is in detection of contamination with petroleum products, which occasionally takes place during shipment or other handling of oils. 

From the work described in this chapter, it can be seen that the thread joining several generations of base stocks has been one of increasing saturated hydrocarbon levels and decreasing levels of mono-, di-, and polyaromatics driven by the need to improve both VI and oxidation stability. The accompanying changes on the saturates side of the equation have been to decrease polycyclic naphthenes and increase those of their mono- and dicyclic counterparts, for the same reasons. 

Menichini, E., Urban air pollution by polycyclic aromatic hydrocarbons Levels and sources of variability. Sci. Total Environ. 116, 109 (1992). 

Although the XAD-2 extraction method gives satisfactory precision at the hydrocarbon levels studied, the accuracy of the technique is dependent on the extraction efficiency of the XAD-2 resin and the recoveries of hydrocarbon experienced during the workup procedure (the helium method does not have this shortcoming since it is a direct analysis). Therefore, several experiments were performed to obtain estimates of the recovery efficiency of the resin. 

Sediment Hydrocarbon Levels at Two Sites on the Strait of Juan de Fuca, In Fate and Effects of Petroleum Hydrocarbons in Marine Organisms and Ecosystems Wilfe, D. A., Ed. Pergamon New York, 1977 pp. 385-396. 

The results of Experiment 3 are shown in Table IV. This experiment compared the ability of different methods (III and V) to extract recently added petroleum hydrocarbons from marine sediment. The more vigorous extraction (Method V) increased the yield, but the additional material returned was unresolved. It appeared that the extractions were equally effective in returning the resolved hydrocarbons. In the unresolved portions of chromatograms, it was not possible to differentiate between recently added hydrocarbons and those from long-term inputs. This differentiation may be important for determining the extent of contamination from oil spills where extensive areas are impacted and control or prespill sediment samples (to determine background hydrocarbon levels) are not available. 

Generally, the type and identity of fresh to mildly weathered oils and petroleum products can be readily revealed from their GC-FlD traces, especially where the spilled oil or petroleum product is heavy and background hydrocarbon levels are low in an impacted environment. In addition to measuring TPH and other hydrocarbon groups in samples, GC-FID chromatograms provide a distribution pattern of petroleum hydrocarbons (e.g., carbon range and profile of UCM), fingerprints of the major oil components (e.g., individual resolved n-alkanes and major isoprenoids), and... 

Practical aspects. Chemiluminescence detectors are only applicable as GC detectors because of signal quenching by high hydrocarbon levels such as solvents used as mobile phases in LC. They are primarily used for selective sulfur detection. 

No biomarkers are available to specifically identify or quantify exposure to Stoddard solvent. However, hydrocarbon levels in the blood can be used to document exposure to petroleum distillates in general. Components of white spirits have been identified in human blood, fat, and alveolar air using gas chromatography-mass spectrometry (Pedersen et al. 1984). It may be possible to identify Stoddard solvent in this way, comparing the measured sample to the spectrometrical pattern of a known Stoddard solvent standard. 

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