Benzene, toluene, ethylbenzene, xylene BTEX

Monomeric aromatic hydrocarbons Benzene, toluene, ethylbenzene, xylene (BTEX) Oil industry (P,D) Gasoline stations (P) Manufactured gas plants (P,D) 6 [43]... 

Biopract provides technological products and processes for industry, agriculture, and environment. They not only produce technical enzyme preparations but also develop enzymes for applications in agriculture, food, and textile industry as well as in environmental technologies. On the later, bioremediation has been an area of service delivery from Biopract. Their activities regards microbial preparations for the bioremediation of organic contaminants (mineral oil (MKW), polycyclic aromatic hydrocarbons (PAH), benzene, toluene, ethylbenzene, xylene (BTEX), methyl-tert-butyl ether (MTBE), volatile organic hydrocarbons (VOC), and dimethyl sulfoxide (DMSO)). 

The Vaportech technology has been used in the past to treat soils contaminated with chlorinated solvents such as perchloroethylene (PERC) and trichloroethylene (TCE) benzene, toluene, ethylbenzene, xylenes (BTEX) aromatics, ketones, gasoline-range and diesel-range organics, phenols, and other cyclic and noncyclic carbon compounds including ketones, naphtha, mineral spirits, and lacquer diluter. 

The technology can potentially treat the following contaminants halogenated volatiles and semivolatiles, nonhalogenated volatiles and semivolatiles (also listed as actual), organic pes-ticides/herbicides, polynuclear aromatic compounds (PNAs), solvents, and benzene-toluene-ethylbenzene-xylene (BTEX). 

This increases the number of advective airflow paths and the volume of soil in contact with advective airflow. According to the vendor, the PSF technology used in conjunction with Terra Vac s Dual Vapor Extraction has successfully remediated benzene, toluene, ethylbenzene, xylene, (BTEX), tetrachloroethylene (PCE), trichloroethylene (TCE), dichloroethylene (DCE), trichloroethane (TCA), dichlorobenzene, trichloropropane, and gasoline. 

The vast amount of data from natural attenuation studies of petroleum hydrocarbon plumes generally supports anaerobic degradation, especially for benzene, toluene, ethylbenzene, xylenes (BTEX) under field conditions. The first-order degradation rates observed under unspecified anaerobic conditions (Suarez and Rifai, 1999) are typically one or two orders of magnitude lower than rates reported under aerobic conditions (Nielsen et al, 1996). 

Benzene/Toluene/Ethylbenzene/Xylenes (BTEX, Alkylaromatics)... 

It is not surprising that the data produced as total petroleum hydrocarbons (EPA 418.1) suffer from several shortcomings as an index of potential ground-water contamination or health risk. In fact, it does not actually measure the total petroleum hydrocarbons in the sample but rather, measures a specific range of hydrocarbon compounds. This is caused by limitations of the extraction process (solvents used and the concentration steps) and the reference standards used for instrumental analysis. The method specifically states that it does not accurately measure the lighter fractions of gasoline [benzene-toluene-ethylbenzene-xylenes fraction (BTEX)], which should include the benzene-toluene-ethylbenzene-xylenes fraction. Further, the method was originally a method for water samples that has been modified for solids, and it is subject to bias. 

ESTD, ex situ thermal desorption VOCs, volatile organic compounds TPH, total petroleum hydrocarbons BTEX, benzene, toluene, ethylbenzene, xylene PCBs, polychlorinated biphenyls PAHs, polycyclic aromatic hydrocarbons ISTD, in situ thermal desorption. 

Abbreviations 2,4,-D 2,4-dichlorophenoxyacetic acid 2,4,5-T tiichlorophenoxyacetic acid BTEX benzene, toluene, ethylbenzene, xylenes PAH polycyclic aromatic hydrocarbons. 

Some simple examples help illustrate this point. A study by Burris and MacIntyre (1984) compared the theoretical solubilities of specific chemicals in water to the solubilities of the same chemicals when they were part of such petroleum product mixtures as JP-4 jet fuel. The results are summarized in Table 5-8. Similar comparisons for all the BTEX (benzene, toluene, ethylbenzene, xylene) chemicals, based on materials presented by Potter (1993), are presented in Table 5-9. 

Benzene-toluene-ethylbenzene-xylene(s) (BTEX). In this situation, the method of choice would be GC-FID. However, as discussed previously, the optional benefits of an mass-selective detection (see PAHs) may be advantageous. 

BTEX Benzene, toluene, ethylbenzene, xylene CAH Chlorinated aliphatic hydrocarbons... 

Different bacteria are expected to display different genetic fingerprints thus making RAPD suitable for screening of bacterial strains. Cavalca et al. [89] used RAPD to screen 15 isolated strains from a BTEX (benzene, toluene, ethylbenzene, xylene)-contaminated subsoil. The isolates were foimd to belong to different species of the genera Pseudomonas and Alcaligenes. Similarly, Lloyd-Jones and Hunter [90] clustered their bacterial isolates obtained from two sites contaminated with polycyclic aromatic hydrocarbons into two... 

A related observation is that at air-ice interface the absorption speetra of aromatie eompounds undergo significant red-shifts. This justifies the finding that direet photolysis of benzene has been found to oeeur at a signifieant rate under environmentally relevant conditions. Thus direct photolysis may be an important removal path for the component of BTEX (benzene, toluene, ethylbenzene, xylenes), the main components of oil spills or leaks in snow-eovered regions, for example, in polar or urban areas contaminated. ... 

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