BTX (benzene, ethylbenzene, toluene and p-xylene) and meteorological parameters were measured in ambient air of an urban site located in Carmen City, Campeche, Mexico. A total of 412 samples were collected for BTX and analyzed by Gas Chromatography with Flame Ionization Detection (GC-FID). Meteorological parameters were measured by a portable station. A marked diurnal variation was found for al...

Enrichment cultures obtained from soil exposed to benzene, toluene, and xylene (BTX) mineralized benzene and toluene but cometabolized only xylene isomers, forming polymeric residues. This observation prompted us to investigate the metabolism of 14C-labeled BTX hydrocarbons in soil, either individually or as mixtures. BTX-supplemented soil was incubated aerobically for up to 4 weeks in a sealed...

The primary objective of this study was to evaluate the impact of substrate interactions on the biotransformation rates and mineralization potentials of gasoline monoaromatics and methyl tert-butyl ether (MTBE), compounds that commonly co-exist in groundwater contaminant plumes. A mixed culture was derived from gasoline-contaminated aquifer material using toluene as the enrichment substrate. Tw...

The structure of a high-loading complex of ZSM-5 with 6.4 toluene molecules per unit cell has been determined by single-crystal X-ray diffraction. At least three kinds of toluene molecules were identified in the unit cell. Two disordered toluene molecules were located at the intersection of the straight and sinusoidal channels, the third in the sinusoidal channel. One (TOL1) of the two toluene ...

Pseudomonas sp. strain T and Pseudomonas sp. strain K172 grow with toluene under denitrifying conditions. We demonstrated that anaerobic degradation of toluene was initiated by direct oxidation of the methyl group. Benzaldehyde and benzoate accumulated sequentially after toluene was added when cell suspensions were incubated at 5 degrees C. Strain T also grows anaerobically with m-xylene, and w...

This paper describes a novel idea of linking models of exposure, internal dosimetry, and health effects. Risk assessment approach that integrates predicted odor caused by volatile organic compounds (VOC-odor) of toluene/xylene concentrations in human tissues leads to predict exposure risks in livestock buildings. First, VOC transport model was developed to calculate airborne toluene/xylene conc...

The competition between ultrafast intersystem crossing and internal conversion in benzene, toluene, and p-xylene is investigated with time-resolved photoelectron spectroscopy and quantum chemical calculations. By exciting to S2 out-of-plane symmetry breaking, distortions are activated at early times whereupon spin-forbidden intersystem crossing becomes (partly) allowed. Natural bond orbital ana...

Effects of combined exposure to toluene and m-xylene in the conditions of subchronic inhalation experiments in rats were examined. Rats were exposed to vapours of individual solvents and their 1:1 mixture at concentrations of 1000 ppm or 100 ppm, 6 h/day, 5 days/week, for 3 or 6 months, respectively. In rats exposed for 3 or 6 months to toluene, m-xylene and their mixtures (1:1) at concentratio...

The primary objective of this study was to evaluate the impact of substrate interactions on the biotransformation rates and mineralization potentials of gasoline monoaromatics and methyl tert-butyl ether (MTBE), compounds that commonly co-exist in groundwater contaminant plumes. A mixed culture was derived from gasoline-contaminated aquifer material using toluene as the enrichment substrate. Tw...

A lysimeter trench was established at the Gardermoen delta (50 km north of Oslo, Norway) to study the flow of water and transport and degradation of aromatic jet fuel components (toluene and o-xylene) in the undisturbed unsaturated zone. Site investigations with ground-penetrating radar revealed the presence of dipping sedimentary layers within the foreset unit. This study has shown that the fo...