Abstract  A gas plume emanating from the Foxhall Landfill in Suffolk (U.K.) has been defined within unsaturated ferruginous sands on the basis of elevated concentrations of methane, carbon dioxide and volatile organic compounds (VOCs). The plume is relatively narrow, extends more than 100 m from the landfill boundary, and lies mainly between 2 m bgl (below ground level) and the water table at 9.5 m bgl. With increasing distance along the axis of the plume, the ratio of methane to carbon dioxide gradually decreases, while nitrogen increases. Oxygen appears beyond 80 m from the landfill boundary. Stable carbon and hydrogen isotope ratios in methane become heavier with distance, while carbon dioxide becomes isotopically lighter with respect to stable carbon. This provides strong evidence for microbially mediated methane oxidation. Zones of black reduced sediment near the landfill suggest that ferric iron (Fe(III)) may be acting as an electron acceptor for oxidation. No thermal anoma

Abstract  The potential for anaerobic biodegradation of 1,1,1-trichloro-2,2-bischlorophenylethane (DDT), 1,1-dichloro-2,2,-bischlorophenylethane (DDD), and dichlorodiphenylchloroethylene (DDE) in anoxic sediment slurries collected from the Keelung River was investigated in this study. o,p'- and p,p'-DDT were dechlorinated to o,p'- and p,p'-DDD, respectively, and then transformed to other compound(s). 1-Chloro-2,2-bis (p-chlorophenyl) ethylene (DDMU) and trace amount of dichlorobenzophenone (DBP) were detected in sediment slurries amended with p,p'-DDT or p,p'-DDD. DDMU was also detected in sediment slurries amended with p,p'-DDE. The relative transformation rates for both o,p'- and p,p'-isomers of DDT, DDD, and DDE were DDT>DDD>DDE. Re-addition of DDT, DDD, or DDE to the sediment slurries after initial removal enhanced the respective dechlorination rates. The transformation rates of the p,p'-isomers of both DDT and DDD were faster than those of the respective o,p'-isomers. p,p'-DDT dechlorination in the p,p'-DDT-adapted sediment slurries were inhibited by the addition of molybdate, or molybdate plus sulfate, but not inhibited by the addition of sulfate. Addition of bromoethane-sulfonic acid (BESA) slightly inhibited p,p'-DDT dechlorination. Non-adapted sediment slurries lost the ability to dechlorinate pentachlorophenol during adaptation to p,p'-DDT. p,p'-DDD was the major transformation product of p, p'-DDT in 3,4,4',5-tetrachlorobiphenyl-adapted sediment slurries, which suggested that the microbial community in the 3,4,4',5-CB-adapted sediment was unable to remove chlorine from the aromatic rings of p,p'-DDT.

Abstract  The degradation of filtration performance for corona-charged electret filter media exposed to ethyl benzene was assessed. Nonwoven corona-charged polypropylene fiber mats were exposed to ethyl-benzene using a custom made apparatus. Evaluated scenarios included ethyl-benzene vapor and liquid exposures. The filtration performance was evaluated using DOP as a test aerosol to measure filtration performance. It was observed that significant filtration degradation occurred only when liquid ethyl benzene came into direct contact with the filter media. No significant changes in the pressure drop or filtration efficiency was observed for any of the exposure scenarios in which the fibers were only exposed to ethyl benzene in the vapor phase.

Abstract  Stainless steel wire has been widely used as the substrate of solid-phase microextraction (SPME) fibers to overcome the shortcomings of conventional silica fibers such as fragility, by many researchers. However, in previous reports various sorbent coatings are always required in conjunction with the stainless steel wire for SPME. In this work, we report the bare stainless steel wire for SPME without the need for any additional coatings taking advantage of its high mechanical and thermal stability. To evaluate the performance of stainless steel wire for SPME, polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, ethylbenzene, chlorobenzene, n-propylbenzene, aniline, phenol, n-hexane, n-octane, n-decane, n-undecane, n-dodecane, chloroform, trichloroethylene, n-octanol, and butanol were tested as analytes. Although the stainless steel wire had almost no extraction capability toward the tested analytes before etching, it did exhibit high affinity to the tested PAHs after etching with hydrofluoric acid. The etched stainless steel wire gave a much bigger enhancement factor (2541-3981) for the PAHs than the other analytes studied (< or = 515). Etching with hydrofluoric acid produced a porous and flower-like structure with Fe(2)O(3), FeF(3), Cr(2)O(3), and CrF(2) on the surface of the stainless steel wire, giving high affinity to the PAHs due to cation-pi interaction. On the basis of the high selectivity of the etched stainless steel wire for PAHs, a new SPME method was developed for gas chromatography with flame ionization detection to determine PAHs with the detection limits of 0.24-0.63 microg L(-1). The precision for six replicate extractions using one SPME fiber ranged from 2.9% to 5.3%. The fiber-to-fiber reproducibility for three parallel prepared fibers was 4.3-8.8%. One etched stainless steel wire can stand over 250 cycles of SPME without significant loss of extraction efficiency. The developed etched stainless steel wire is very stable, highly selective, and reproducible for the SPME of PAHs.

Abstract  The isopropylation of all three xylene isomers was carried out over ultrastable zeolite Y (USY) catalyst to give corresponding dimethyl (1-methylethyl) benzenes, or in other words dimethyl cumenes (DMCs), using isopropanol as alkylating agent. The effect of reaction temperature, space velocity, substrate-to-alkylating-agent molar ratio, and time-on-stream on conversion of xylene isomers and selectivity to dimethyl cumene was studied. Isopropylation of xylenes over USY gives quite high (80 to 95%) DMC selectivity among the dimethyl cumenes, along with a 70-90% yield of DMCs in total products with respect to limiting reagents, i.e., isopropylating agents at relatively low reaction temperatures (423 +/- 10 K) and at quite high xylene conversions (85-97% of theoretical maximum value). The solid acid catalysts zeolites H-Y, H-beta, H-mordenite, as well as silica-alumina and sulfated zirconia, were included for comparative studies in the isopropylation of m-xylene. (C) 2002 Elsevier Science (USA).

Abstract  One-dimensional and comprehensive two-dimensional flow modulated gas chromatography with simultaneous flame ionization and mass spectrometric detection were applied for the identification and quantification of benzene, toluene, ethyl benzene and xylenes (BTEX) as well as of all C9-C11 aromatic hydrocarbons in the low-boiling petroleum products gasoline, reformate and fluid catalytic cracking (FCC) samples. GC x GC experiments were performed on two reversed phase polarity column sets namely SLB-IL100 (25 m x 250 mu m i.d. x 0.2 mu m d(f)) + HP-5MS (5 m x 250 mu m i.d. x 0.25 mu m d(f)) and SLB-IL111 (30 m x 250 mu m i.d. x 0.2 mu m d(f))+ HP-5MS (5 m x 250 mu m id. x 0.25 pm d(f)). The one-dimensional GC experiments were carried out on the same ionic liquid columns. The most powerful method is GC x GC on the SLB-111+ HP-5MS column combination. Quantitative analysis of individual aromatic hydrocarbons (C6-C11) present in gasoline, reformate and fluid catalytic cracking (FCC) samples was performed by GC x GC-FID using the internal normalization method. Mass spectra obtained by GC x GC-qMSD were used for identification of the aromatic hydrocarbons in these samples. (C) 2013 Elsevier B.V. All rights reserved.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM ARCTICA-ISLANDICA BIOACCUMULATION MARINE POLLUTION BENTHIC ENVIRONMENT OIL DRILLING GRAIN SIZE POLLUTANT DEPOSITION SPATIAL VARIATION DRILLING FLUID EXTRACT DISCHARGE RESIDUE

Abstract  BIOSIS COPYRIGHT: BIOL ABS. A numerical model was developed to describe the bioremediation of hydrocarbons in ground water aquifers considering aerobic degradation. The model solves the independent transport of three solutes (oxygen, hydrocarbons, and microorganisms) in ground water flow using the method of characteristics. Interactions between the three solutes, in which oxygen and hydrocarbons are consumed by microorganisms, are represented by Monod kinetics, solved using a Runge-Kutta method. Model simulations showed good correlation as compared with results of soil column experiments. The model was used to estimate the time needed to remediate the columns, which varied from one to two years.

Abstract  Baleen whale forestomach anaerobic microbes were studied for their ability to detoxify recalcitrant environmental pollutants; these include components of crude oil and some chlorinated aromatic compounds which are constituents of oil spills not biodegraded by aerobic microbes. In this study, forestomach rumen samples were collected on two occasions on the North Slope. When incubated with anthracene and naphthalene (PAH), these pollutants were degraded in the majority of sample sets. All simple aromatic hydrocarbons (benzine, toluene, xylenes, ethylbenzene) were degraded. PCBs were biodegraded by microbes from only two of the whales. Variable results were found with picric acid, trinitrotoluene (TNT), and atrazine, and were likely due to analytical difficulties. Whale forestomach bacteria have adapted to an ecological niche where flow rates, mixing, and catabolism occur at rapid rates. These rates and the ability to metabolize complex molecules far exceed those of aerobic sediment and soil bacteria in biodegradation of environmental pollutants.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM ALKYLBENZENES ALKANES ALCOHOLS POLYAROMATIC HYDROCARBONS

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM LITERATURE REVIEW WASTE MANAGEMENT RECYCLING TECHNOLOGY INSTRUMENTATION ANALYSIS PHYSICOCHEMICAL TREATMENT AEROBIC TREATMENT ANAEROBIC TREATMENT GROUNDWATER ENVIRONMENTAL IMPACT WASTEWATER TREATMENT WASTE MANAGEMENT POLLUTION

Abstract  A denitrifying consortium was used as inoculum to form a biofilm in horizontal-flow anaerobic immobilized biomass reactor. The reactor was fed with hydrocarbons, separately (benzene at 13.8, 15.4 and 26.5 mg; toluene 30.8 mg/L; ethylbenzene 33.3 mg/L; xylene 32.1 mg/L), and also with a benzene, toluene, ethylbenzene and xylene (BTEX) mix solution of approximately 5.0 ing/L. of each hydrocarbon. The hydrocarbons were dissolved in a solution containing ethanol. Organic matter removal efficiencies were of 95% with benzene and toluene amendments and about 76% with ethylbenzene, m-xylene and the BTEX-mix amendments. Hydrocarbons removal efficiencies were of 99% at an initial concentration of benzene 26.5 mg/L, toluene 30.8 mg/L, m-xylene 32.1 mg, ethylbenzene 33.3 mg/L and BTEX 26.5 mg/L. Microbial diversity assessed by a small portion of 16S DNA suggested the predominance of species related to the phylotypes Pseudomonas, Paracoccus and Bacteroides. This system showed to be an alternative to treating wastewater contaminated with nitrate, ethanol and hydrocarbons. (c) 2006 Elsevier Ltd. All rights reserved.

Abstract  Deep-sea hydrothermal vent chimneys contain a high diversity of microorganisms, yet the metabolic activity and the ecological functions of the microbial communities remain largely unexplored. In this study, a metagenomic approach was applied to characterize the metabolic potential in a Guaymas hydrothermal vent chimney and to conduct comparative genomic analysis among a variety of environments with sequenced metagenomes. Complete clustering of functional gene categories with a comparative metagenomic approach showed that this Guaymas chimney metagenome was clustered most closely with a chimney metagenome from Juan de Fuca. All chimney samples were enriched with genes involved in recombination and repair, chemotaxis and flagellar assembly, highlighting their roles in coping with the fluctuating extreme deep-sea environments. A high proportion of transposases was observed in all the metagenomes from deep-sea chimneys, supporting the previous hypothesis that horizontal gene transfer may be common in the deep-sea vent chimney biosphere. In the Guaymas chimney metagenome, thermophilic sulfate reducing microorganisms including bacteria and archaea were found predominant, and genes coding for the degradation of refractory organic compounds such as cellulose, lipid, pullullan, as well as a few hydrocarbons including toluene, ethylbenzene and o-xylene were identified. Therefore, this oil-immersed chimney supported a thermophilic microbial community capable of oxidizing a range of hydrocarbons that served as electron donors for sulphate reduction under anaerobic conditions.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM HUMAN POLYMERIC MATERIAL CONTAMINANTS DOMESTIC DUST INDOOR AIR QUALITY CONTROL

Abstract  HEEP COPYRIGHT: BIOL ABS. The effects of gasoline aromatic and Pb content on exhaust hydrocarbon reactivity were separately investigated in a large irradiation chamber. The study emphasized the the measurement of (human) eye irritation and of photochemically produced eye irritants, particularly peroxybenzoyl nitrate. Adding tetraethyllead to an unleaded commercial gasoline did not affect exhaust reactivity. Adding aromatics to a special low-aromatic gasoline increased the reactivity criteria associated with eye irritation, but had little or no effect on other reactivity criteria such as ozone or NO2 formation. Isopropyl benzene had the greatest effect, followed by o-xylene, n-propyl benzene, ethylbenzene, toluene and benzene. Comparable tests with commerical gasolines failed to show a correlation between eye irritation and total aromatic content of the gasoline. Some of the implications of the results for the blending of future gasolines are discussed.

Abstract  The purposes of the present study are (1) to develop a sensitive analytical method to measure 1-bromopropane (1-BP) in urine, (2) to examine if 1-BP or bromide ion (Br) in urine is a useful biomarker of exposure to 1-BP, and (3) to identify the lowest 1-BP exposure concentration the method thus established can biomonitor. A factory survey was carried out on Friday, and 33 workers (all men) in cleaning and painting workshops participated; each worker was equipped with a diffusive sampler (carbon cloth KF-1500 as an adsorbent) to monitor 1-BP vapour for an 8-h shift, and offered a urine sample at the end of the shift for measurement of 1-BP and Br in urine. In addition, 10 non-exposed men offered urine samples as controls. The performance of the carbon cloth diffusive sampler was examined to confirm that the sampler is suitable for monitoring time-weighted average 1-BP vapour exposure. A head-space GC technique was employed for analysis of 1-BP in urine, whereas Br in urine was analysed by ECD-GC after derivatization to methyl bromide. The workers were exposed to vapours of seven other solvents (i.e. toluene, xylenes, ethylbenzene, acetone, etc.) in addition to 1-BP vapour; the 1-BP vapour concentration was 1.4 ppm as GM and 28 ppm as the maximum. Multiple regression analysis however showed that 1-BP was the only variable that influenced urinary 1-BP significantly. There was a close correlation between 1-BP in urine and 1-BP in air; the correlation coefficient (r) was >0.9 with a narrow variation range, and the regression line passed very close to the origin so that 2 ppm 1-BP exposure can be readily biomonitored. The correlation of Br in urine with 1-BP in air was also significant, but the r (about 0.7) was smaller than that for 1-BP, and the background Br level was also substantial (about 8 mg l-1). Thus, it was concluded that 1-BP in end-of-shift urine is a reliable biomarker of occupational exposure to 1-BP vapour, and that Br in urine is less reliable.

Abstract  Plants containing flavonoids have been reported to possess biological properties. The successive extracts of Grewia asiatica leaves Were screened for in vitro antioxidant properties using standard procedures. The successive extracts such-as petroleum ether, benzene, ethyl acetate, methanol, water and 50 % crude methanol extracts exhibited IC50 values of 249.60 +/- 7.37, 16.19 +/- 2.132, 26.17 +/- 1.49, 27.38 +/- 1.80, 176.14 +/- 5.53 and 56.40 +/- 3.98 pg/mL, respectively in DPPH and 22.12 +/- 02.65, 27.00 +/- 01.62, 47.38 +/- 05.88, 56.85 +/- 06.16 +/- 52.75 5.76 and 72.75 +/- 13.76 mu g/mL, respectively in nitric oxide radical inhibition assays. These Values are comparable with standards such as an ascorbic acid and quercetin. The Grewia asiatica leaves are showing antioxidant activity.

Abstract  HEEP COPYRIGHT: BIOL ABS. Field and laboratory studies were conducted of an ocean-dumped waste containing biological sludge from a chemical biotreatment plant. During July 1977, a test dump was monitored to study the chemical behavior and dispersal of waste at a deep-water dumpsite in the western Gulf of Mexico. Nearly 100 organic compounds were detected in the waste; some heavy metals were measured in significant amounts. At the diluted levels usually encountered in the ocean, adverse effects of such a waste on phytoplankton productivity would not be measurable with the techniques used. Increased turbidity and chemical residues could not be measured in the field past 24 h.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM HUMAN VOLATILE ORGANIC COMPOUNDS COMBUSTIBLE GAS POLLUTION

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM ABSTRACT MYCOBACTERIUM-VACCAE ACETONE CYCLOHEXANE STYRENE BENZENE ETHYLBENZENE PROPYLBENZENE DIOXANE 1 2 DICHLOROETHYLENE

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM EPA ENVIRONMENTAL LAW ENVIRONMENTAL SURVEILLANCE

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM FLAME IONIZATION DETECTOR

Abstract  BIOSIS COPYRIGHT: BIOL ABS. Volatile organics in water are analyzed by first removing them from the water matrix. For example in purge and trap, the organics are sparged using an inert gas before analysis by GC or GC. The objective of this research is to develop an equivalent of a purge and trap system based on membrane extraction. Instead of purging, the VOCs are separated from the aqueous phase via membrane permeation. The permeated organics are pneumatically transported to a micro-sorbent trap referred to as the microtrap. The trapped organics are then injected into a GC by rapid desorption of the microtrap./METHODS

Abstract  Rhodococcus sp. strain DK17 is able to grow on o-xylene, benzene, toluene, and ethylbenzene. DK17 harbors at least two megaplasmids, and the genes encoding the initial steps in alkylbenzene metabolism are present on the 330-kb pDK2. The genes encoding alkylbenzene degradation were cloned in a cosmid clone and sequenced completely to reveal 35 open reading frames (ORFs). Among the ORFs, we identified two nearly exact copies (one base difference) of genes encoding large and small subunits of an iron sulfur protein terminal oxygenase that are 6 kb apart from each other. Immediately downstream of one copy of the dioxygenase genes (akbA1a and akbA2a) is a gene encoding a dioxygenase ferredoxin component (akbA3), and downstream of the other copy (akbA1b and akbA2b) are genes putatively encoding a meta-cleavage pathway. RT-PCR experiments show that the two copies of the dioxygenase genes are operonic with the downstream putative catabolic genes and that both operons are induced by o-xylene. When expressed in Escherichia coli, AkbA1a-AkbA2a-AkbA3 transformed o-xylene into 2,3- and 3,4-dimethylphenol. These were apparently derived from an unstable o-xylene cis-3,4-dihydrodiol, which readily dehydrates. This indicates a single point of attack of the dioxygenase on the aromatic ring. In contrast, attack of AkbA1a-AkbA2a-AkbA3 on ethylbenzene resulted in the formation of two different cis-dihydrodiols resulting from an oxidation at the 2,3 and the 3,4 positions on the aromatic ring, respectively.

Abstract  HEEP COPYRIGHT: BIOL ABS. RRM INDUSTRIAL POLLUTION DE TOXIFICATION