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...

AIM The aim of this study was to characterize the microbial community involved in anaerobic degradation of petroleum hydrocarbon under low- and moderate-temperature conditions. METHODS AND RESULTS Sulfate-reducing enrichment cultures growing on crude oil and p-xylene were established at low and moderate temperatures. Bacterial community structures of the cultures were characterized by 16S rRN...

Self-assembly of a range of carboxylic acids (benzoic acid, dinicotinic acid, nicotinic acid, and isophthalic acid) with the europium complex of 5-nitro-α,α'-bis(DO3Ayl)-m-xylene (where DO3A is 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid) has been explored to establish the thermodynamics of binding in a range of solvent systems and in a range of aqueous buffer solutions. In this system,...

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...

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 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...

A physiological pharmacokinetic model of the transfer of organic solvents in the human body was developed. The model was comprised of seven compartments, i.e., lungs, vessel-rich tissues, vessel-poor tissues, muscles, fat tissues, gastrointestinal tissues, and liver, each being connected to the others by blood fiow. The transfer of organic solvents was expressed by simultaneous differential equ...

The effect of H2 on isomerization pathways and on the acid site density on WOx-ZrO2 catalysts was explored using kinetic measurements of acid-catalyzed o-xylene isomerization reactions. Initial o-xylene isomerization rates on WOx-ZrO2 at 523 K are proportional to the H2 concentration even though H atoms are not involved directly in reaction turnovers, as shown by the low deuterium content in th...

background: the removal of ethylbenzene and xylene at a concentration of 10 mg/l from aqueous solutions by single- and multi-walled carbon nanotubes (swcnt and mwcnt, respectively) and hybrid carbon nanotubes (hcnt) was evaluated at a nanomaterials dose of 1 g/l, a contact time of 10 minutes, and a ph 7. methods: synthetic samples were analyzed by gas chromatography/mass spectrometry (gc/ms). i...