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PubMedDate not supplied

A laboratory batch reactor test for assessing nonspeciated volatile organic compound biodegradation in activated sludge.

The relative rates of biodegradation and stripping and volatilization of nonspeciated volatile organic compounds (VOCs) in wastewater treated with aerobic activated-sludge processes can be quantified using a newly developed procedure. This method was adapted from the original aerated draft tube reactor test that was developed to measure biodegradation rate constants for specific volatile pollutants of interest. The original batch test has been modified to include solid-phase microextraction (SPME) fibers for sampling in the gas phase. The experimental procedure using SPME fibers does not require specific identification and quantitation of individual pollutants and can be used to evaluate wastewater with multiple VOCs. To illustrate use of this procedure, laboratory experiments were conducted using biomass and wastewater or effluent from three activated-sludge treatment systems. Each experiment consisted of two trials: a stripping-only trial without biomass and a stripping plus biodegradation trial using biomass from the activated-sludge unit of interest. Data from the two trials were used to quantify the rates of biodegradation by difference. The activated-sludge systems tested were a laboratory diffused-air reactor treating refinery wastewater, a full-scale surface aerated reactor treating a petrochemical wastewater, and a full-scale diffused-air reactor treating a variety of industrial effluents. The biodegradation rate constant data from each laboratory batch experiment were used in model calculations to quantify the fraction emitted (fe) and the fraction biodegraded (fbio) for each system. The fe values ranged from a maximum of 0.01 to a maximum of 0.32, whereas fbio values ranged from a minimum of 0.40 to a minimum 0.95. Two of these systems had been previously tested using a more complicated experimental approach, and the current results were in good agreement with previous results. These results indicate that biodegradation rate constant data from this laboratory method can be successfully used to predict the fate of VOCs in field-scale treatment units, and thus could potentially be used for demonstration of compliance with wastewater VOC emission regulations.

Biodegradation, Environmental↗

PubMed2000

Volatile organic compounds in the surface waters of northern Greece.

An investigation into the occurrence of volatile organic compounds (VOCs) was conducted for a period of two years in the surface waters of Northern Greece. Samples from four rivers and five lakes were taken seasonally and analyzed for VOCs. The analysis has been performed by purge-and-trap (PAT) gas chromatographic-mass spectrometric (GC-MS) technique. The most commonly encountered VOCs in surface waters were chloroform, carbon tetrachloride, trichloroethylene, dichlorobromomethane, tetrachloroethylene, and chlorodibromomethane.

Carbon Tetrachloride↗

PubMed2002

Multicomponent analysis of volatile organic compounds in water by automated purge and trap coupled to gas chromatography-mass spectrometry.

The performance of an automated purge and trap concentrator coupled to gas chromatography-mass spectrometric detection was evaluated by analyzing 40 volatile organic compounds of different chemical families. Compounds chosen defined as toxic for the environment and for human health were selected according to Directive 76/464/CEE. The present work includes: (i) the optimization of the purge and trap conditions, (ii) the establishment of quality parameters and in last instance (iii) the analysis of surface waters. The analytical method consisted of a modification of the EPA Method 524.2 in which water was pumped, via an automated AquaTek 70 Liquid Autosampler to a 25-ml purging device, where samples were purged and trapped in a Tenax or Tenax-Silica and Charcoal column. Afterwards, helium was used to desorb the trapped analytes that flow directly into the GC column. Mass spectrometric analysis was carried out in selected ion monitoring and scan modes to ensure quantification and confirmation of the results. Parameters optimized were the sample volume analyzed, bubbling flow-rate and time and temperature of desorption. Optimal conditions lead to mean recoveries of 80%, limits of detection between 0.002 and 0.1 microg/l, linearity from 0.01 to 2.5 microg/l and maximum standard deviation of 10%, using a Tenax trap. This protocol permitted a high precision and sample throughput and was used to determine volatile organic compounds in surface river, effluents and coastal waters of Portugal, on a routine basis.

Calibration↗

PubMed2005

Chemical interactions with snow: understanding the behavior and fate of semi-volatile organic compounds in snow.

Snow plays an important role in providing atmospherically derived semi-volatile organic compounds (SVOCs) to regions of high latitude and altitude. The accumulated winter snowpack serves as a reservoir for SVOCs, which may then be released to arctic/alpine catchments during seasonal snowmelt or entrained into deeper layers of snow and ice. This paper provides a review of the occurrence of SVOCs in snow, exploring sampling methodologies and field measurements. Furthermore, chemical fate following snowfall and the propensity of SVOCs to undergo revolatilization with snow metamorphosis are examined along with air-snow partitioning and the role of physical parameters such as snow density and snow surface area in controlling vapor-sorbed levels. Snowmelt and firnification processes are described, and the latter are related to SVOC measurements made in deeper snow layers and glacial ice cores. Evidence is provided that suggests that those SVOCs that possess relatively higher snow interfacial/air partitioning coefficients (K(iasnow)) or lower Henry's Law constants may be more efficiently retained in snow, with implications for the occurrence of currently used pesticides in the temperate mountain snowpack.

Diffusion↗

PubMedDate not supplied

Spatial and temporal variability of priority volatile organic compounds in the Scheldt estuary.

The occurrence and spatial-temporal variability of 25 volatile organic compounds (VOCs) was studied from May 1998 to November 2000 in the Scheldt estuary. Target VOCs were selected from lists of priority pollutants to the North Sea, and included chlorinated short-chain hydrocarbons (CHCs), monocyclic aromatic hydrocarbons (MAHs) and chlorinated monocyclic aromatic hydrocarbons (CMAHs). Samples were taken between Vlissingen and Temse over a 95 km trajectory, and analysed by purge-and-trap and high resolution gas chromatography-mass spectrometry. Data were attended by analyses deemed 'in control' by a rigorous quality assurance/quality control program, as proposed by Quality Assurance of Information for Marine Environmental Monitoring in Europe (QUASIMEME). CHCs were among the most commonly found VOCs in the estuary, ranging from a few ng l(-1) to several microg l(-1). Most analytes were traceable to a single input source in the upper part of the estuary, which is densely populated and highly industrialized. By contrast, the occurrence of MAHs resulted from contributions of a wide spectrum of sources. The CMAHs were less abundant in the water column, and were mainly detected as chlorobenzene and 1,4-dichlorobenzene. Concentrations of several priority VOCs have markedly decreased since 1995 owing to emission reduction efforts within international frameworks for the protection of the North Sea.

Chlorobenzenes↗

PubMed2005

[Effects of volatile organic compounds inhalation on the inflammation biomarkers in nasal lavage fluids of decoration workers].

OBJECTIVE: To study the effects of volatile organic compounds (VOCs) inhalation on the inflammation biomarkers in nasal lavage fluid (NAL), and to assess the practicability of the nasal lavage methods. METHODS: 32 volunteers joined in this study, among whom 20 Painters were chosen as exposed group, and 12 plumbers and electricians were chosen as controls. Lung function was detected, and several inflammation biomarkers (IL-4, IL-5, ECP) in nasal lavage (NAL) were determined. RESULTS: The average FEV1 of exposed group was 3.08L, which was significantly lower than the control. And the concentration levels of inflammation biomarkers in NAL of painters were higher than that of the control. Among these detected biomarkers, the ECP level was significantly higher in exposed group than in control group(the mean was 3.57 microg/L in painter and 2.79 microg/L in the control, respectively). Moreover, there was statistically negative correlation between ECP level and FEV1 (a kind of lung function parameters), the correlated coefficient was -0.381. CONCLUSION: Inhalation of VOCs could be responsible for the occurrence of respiratory inflammation and allergic illness such as rhinitis and asthma. Moreover, the method of nasal lavage is practicable for population study.

Adult↗

PubMed2002

Volatile organic compounds in the area of Madrid: a chemometrical approach.

Multivariate techniques have been applied to the set of data obtained after one year sampling of volatile organic compounds (VOCs), including volatile aldehydes in the area of Madrid in order to evaluate the possible correspondence among groups of analysed compounds, as far as modelling of different emission sources in relation to location and season. The measurements were carried out at four sites in Madrid, characteristic for urban and suburban areas. Additionally, as reference, a rural area 100 km far from the city was considered. Results of correlation analysis, factor and cluster analysis are presented. Higher correlations were found between variables related with traffic emissions. Factor analysis results showed two main significant variables related to anthropogenic and biogenic emissions respectively. In relation to cluster analysis, samples were grouped according to sampling site and seasonal variations.

Air Pollutants↗

PubMed2004

Evaluating differences between measured personal exposures to volatile organic compounds and concentrations in outdoor and indoor air.

Accurate estimation of human exposures to volatile organic compounds (VOCs) is a key element of strategies designed to protect public health from the adverse effects of hazardous air pollutants. The focus here is on examining the capability of three different exposure metrics (outdoor community concentrations, indoor residential concentrations, and a simple time-weighted model) to estimate observed personal exposures to 14 VOCs. The analysis is based on 2-day average concentrations of individual VOCs measured concurrently in outdoor (O) air in three urban neighborhoods, indoor (I) air in participant's residences, and personal (P) air near the breathing zone of 71 healthy, nonsmoking adults. A median of four matched P-I-O samples was collected for each study participant in Minneapolis/St. Paul over three seasons (spring, summer, and fall) in 1999 using charcoal-based passive air samplers (3M model 3500 organic vapor monitors). Results show a clear pattern for the 14 VOCs, with P > I > O concentrations. Intra-individual variability typically spanned at least an order of magnitude, and inter-individual variability spanned 2 or more orders of magnitude for each of the 14 VOCs. Although both O and I concentrations generally underestimated personal exposures, I concentrations provided a substantially better estimate of measured P concentrations. Mean squared error (MSE) as well as correlation measures were used to assess estimator performance at the subject-specific level, and hierarchical, mixed effects models were used to estimate the bias and variance components of MSE by tertile of personal exposure. Bias and variance both tended to increase in the upper third of the P exposure distribution for O versus P and I versus P. A simple time-weighted model incorporating measured concentrations in both outdoor community air and indoor residential air provided no improvement over I concentration alone for the estimation of P exposure.

Air Pollutants↗

PubMed2001

Development and evaluation of a mass spectrometer-based continuous emission monitor for volatile organic compound emissions from combustion devices.

A mass spectrometer-based continuous emission monitor (MS-CEM) for organic compound emissions from combustion devices was developed and evaluated at the Louisiana State University (LSU) pilot-scale rotary kiln incinerator (RKI). The MS-CEM consists of a stack probe, heat-traced sampling line, vacuum pump, particulate filter, Nafion@ dryer and mass spectrometer. The mass spectrometer includes a computer that controls and optimizes the operation of the unit. The MS-CEM is capable of continuously analyzing up to 40 different volatile organic compounds on a real-time basis. The MS-CEM is capable of analyzing, computing and recording the analytical results for each and up to 40 different organic compounds in less than 0.3 s. Four different volatile organic compounds were mixed together and injected into the baghouse inlet while simultaneously analyzing each organic component exiting the RKI stack gas. The results obtained from MS-CEM were compared with the material balance values. The system response time (including the MS-CEM) varies from 1.1 to 1.5 min.

Air Pollutants↗

PubMed2004

A comparison of indoor air pollutants in Japan and Sweden: formaldehyde, nitrogen dioxide, and chlorinated volatile organic compounds.

Indoor and outdoor concentrations of formaldehyde (HCHO), nitrogen dioxide (NO2), and selected chlorinated volatile organic compounds (chlorinated VOC) were measured in 37 urban dwellings in Nagoya, Japan, and 27 urban dwellings in Uppsala, Sweden, using the same sampling procedures and analytical methods. Indoor as well as outdoor air concentrations of HCHO, NO2, and chlorinated VOC were significantly higher in Nagoya than in Uppsala (P<0.01), with the exception of tetrachlorocarbon in outdoor air. In Nagoya, HCHO and NO2 concentrations were significantly higher in modern concrete houses than in wooden houses and higher in newer (less than 10 years) than in older dwellings (P<0.01), possibly due to less natural ventilation and more emission sources in modern buildings. Dwellings heated with unvented combustion sources had significantly higher indoor concentrations of NO2 than those with clean heating (P<0.05). Moreover, dwellings with moth repellents containing p-dichlorobenzene had significantly higher indoor concentrations of p-dichlorobenzene (P<0.01). In conclusion, there appear to be differences between Nagoya and Uppsala with respect to both indoor and outdoor pollution levels of the measured pollutants. More indoor pollution sources could be identified in Nagoya than in Uppsala, including construction and interior materials emitting VOC, use of unvented combustion space heaters, and moth repellents containing p-dichlorobenzene.

Air Pollutants↗

PubMed2002

Chemiluminescence determination of chlorinated volatile organic compounds by conversion on nanometer TiO2.

A novel method based on conversion of chlorinated volatile organic compounds (CVOCs) to chlorine using a new type of column packed with nanometer TiO2 coupled with chemiluminescence (CL) has been developed for determination of them in workplace air. CVOCs are converted to chlorine by nanometer TiO2 at 220 degrees C. The Cl2 that is produced is selectively enriched on the column and subsequently released from the column at 600 degrees C. The Cl2 that is released is determined using a postcolumn CL detector. The CL intensity was linear with CCl4 in the range of 0.1-380 ppm, and the detection limit was 40 ppb (S/N = 3). Higher sensitivity could be acquired by using a larger volume of enrichment A similar procedure could be used for the determination of other CVOCs. CL intensities of CH2Cl2, CHCl3, and CCl4 at the same concentration increased in the order CH2Cl2 < CHCl3 < CCl4. The method has been successfully applied to the determination of CCl4 in workplace air, where 0.15-150 ppm CCl4 would be detected. The possible mechanism for the long lifetime of the column packed with nanometer TiO2 was tested using Raman spectrometer, X-ray powder diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The results showed that the column packed with nanometer TiO2 could be operated in the reversible mode for determination of CVOCs under the present conditions. The method would be potentially applied to the analysis of other chlorinated compounds in environment, such as persistent organic pollutants.

Journal Article↗

PubMed2005

Link between spatial structure of microbial communities and degradation of a complex mixture of volatile organic compounds in peat biofilters.

AIMS: To investigate the relationships between the operation of the volatile organic compound (VOC) removal biofilter and the structure of microbial communities, and to study the impact on degradation activities and the structuring of microbial communities of biofilter malfunctions related to the qualitative composition of the polluted air. METHODS AND RESULTS: A microbiological study and a measurement of biodegradation activities were simultaneously carried out on two identical peat-packed columns, seeded with two different inocula, treating polluted air containing 11 VOCs. For both reactors, the spatial structure of the microbial communities was investigated by means of single-strand conformation polymorphism (SSCP) analysis. For both reactors, stratification of degradation activities in function of depth was observed. Oxygenated compounds were removed at the top of the column and aromatics at the bottom. Comparison of SSCP patterns clearly showed a shift in community structure in function of depth inside both biofilters. This distribution of biodegradation activities correlates with the spatialization of microbial density and diversity. Although the operating conditions of both reactors were identical and the biodegradation activities similar, the composition of microflora differed for biofilters A and B. Subdivision of biofilter B into two independent parts supplied with polluted air containing the complex VOC mixture showed that the microflora having colonized the bottom of biofilter B retained their potential for degrading oxygenated compounds. CONCLUSIONS: This work highlights the spatialization of biodegradation functions in a biofilter treating a complex mixture of VOCs. This distribution of biodegradation activities correlates with the spatialization of microbial density and diversity. SIGNIFICANCE AND IMPACT OF THE STUDY: This vertical structure of microbial communities must be taken into consideration when dealing with the malfunctioning of bioreactors. These results are also useful information about changes in microbial communities following natural or anthropogenic alterations in different ecosystems (soils and sediments) where structuring of microbial communities according to depth has been observed.

Air Microbiology↗

PubMed2006

Influence of different transition metals in phthalocyanines on their interaction energies with volatile organic compounds: an experimental and computational study.

Experimental partition coefficients were determined for a series of volatile organic compounds (VOCs) (acetonitrile, n-butylamine, n-octane tetrachloroethene, and toluene) for the interaction with 2,3,9,10,16,17,23,24-octakis(octyloxy)-phthalocyaninato complexes, PcM(OR)(8), with varying central metal atoms [M=H(2) (metal-free), Ni, Pd, Cu, Zn]. Large partition coefficients for toluene were observed in the case of the nickel and palladium phthalocyanines, whereas for the corresponding zinc-containing compound, interaction with n-butylamine resulted in a high value for the partition coefficient. Interaction energies for model coordination complexes were obtained at the ab initio LMP2/ LACVP* level of theory. The interaction of various small volatiles with the various PcM(OR)(8) compounds was studied using the PM3 semiempirical Hamiltonian. Large values for interaction energies correspond to particularly strong partition coefficients, suggesting that coordination of the volatiles to the central metal dominates over the often discussed pi-system stacking at the PcM(OR)(8)'s.

Acetonitriles↗

PubMed2002

Semi-volatile organic compounds at the leaf/atmosphere interface: numerical simulation of dispersal and foliar uptake.

The behaviour of (semi-)volatile organic compounds at the interface between the leaf surface and the atmosphere was investigated by finite-element numerical simulation. Three model systems with increasing complexity and closeness to the real situation were studied. The three-dimensional model systems were translated into appropriate grid structures and diffusive and convective transport in the leaf/atmosphere interface was simulated. Fenpropimorph (cis-4-[3-(4-tert-butylphenyl)-2-methylpropyl]-2,6-dimethylmorpholine) and Kresoxim-methyl ((E)-methyl-2-methoxyimino-2-[2-(o-tolyloxy-methyl)phenyl] acetate) were used as model compounds. The simulation showed that under still and convective conditions the vapours emitted by a point source rapidly form stationary envelopes around the leaves. Vapour concentrations within these unstirred layers depend on the vapour pressure of the compound in question and on its affinity to the lipoid surface layers of the leaf (cuticular waxes, cutin). The rules deduced from the numerical simulation of organic vapour behaviour in the leaf/atmosphere interface are expected to help in assessing how (semi-)volatile plant products (e.g. hormones, pheromones, secondary metabolites) and xenobiotics (e.g. pesticides, pollutants) perform on plant surfaces.

Algorithms↗

PubMed2005

Real-time detection of common microbial volatile organic compounds from medically important fungi by Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS).

We describe a new method, Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS) for the rapid and sensitive real-time detection and quantification of volatile organic compounds from medically important fungi, grown on a range of laboratory media. SIFT-MS utilises the chemical ionisation reactions of mass-selected ions to characterise volatile organic compounds (VOCs) that are produced as metabolites from fungi. This technique has the distinct advantage over others in that it readily detects low molecular weight, reactive volatiles, and allows for real-time, quantitative monitoring. The fungi examined in this study were Aspergillus flavus, Aspergillus fumigatus, Candida albicans, Mucor racemosus, Fusarium solani, and Cryptococcus neoformans grown on or in malt extract agar, Columbia agar, Sabouraud's dextrose agar, blood agar, and brain-heart infusion broth. Common metabolites (ethanol, methanol, acetone, acetaldehyde, methanethiol, and crotonaldehyde) were detected and quantified. We found the fingerprint of volatiles, in terms of presence and quantity of volatiles to be strongly dependent on the culture medium, both in terms of variety and quantity of volatiles produced, but may form the basis for species specific identification of medically important fungi.

Culture Media↗

PubMed1995

Asthmatic symptoms and volatile organic compounds, formaldehyde, and carbon dioxide in dwellings.

OBJECTIVES: As a part of the worldwide European Community respiratory health survey, possible relations between symptoms of asthma, building characteristics, and indoor concentration of volatile organic compounds (VOCs) in dwellings were studied. METHODS: The study comprised 88 subjects, aged 20-45 years, from the general population in Uppsala, a mid-Swedish urban community, selected by stratified random sampling. Room temperature, air humidity, respirable dust, carbon dioxide (CO2), VOCs, formaldehyde, and house dust mites were measured in the homes of the subjects. They underwent a structured interview, spirometry, peak expiratory flow (PEF) measurements at home, methacholine provocation test for bronchial hyperresponsiveness, and skin prick tests. In addition, serum concentration of eosinophilic cationic protein (S-ECP), blood eosinophil count, and total immunoglobulin E (S-IgE) were measured. RESULTS: Symptoms related to asthma were more common in dwellings with house dust mites, and visible signs of dampness or microbial growth in the building. Significant relations were also found between nocturnal breathlessness and presence of wall to wall carpets, and indoor concentration of CO2, formaldehyde, and VOCs. The formaldehyde concentration exceeded the Swedish limit value for dwellings (100 micrograms/m3) in one building, and CO2 exceeded the recommended limit value of 1000 ppm in 26% of the dwellings, showing insufficient outdoor air supply. Bronchial hyperresponsiveness was related to indoor concentration of limonene, the most prevalent terpene. Variability in PEF was related to two other terpenes; alpha-pinen and delta-karen. CONCLUSION: Our results suggest that indoor VOCs and formaldehyde may cause asthma-like symptoms. There is a need to increase the outdoor air supply in many dwelling, and wall to wall carpeting and dampness in the building should be avoided. Improved indoor environment can also be achieved by selecting building materials, building construction, and indoor activities on the principle that the emission of volatile organic compounds should be as low as reasonably achievable, to minimise symptoms related to asthma due to indoor air pollution.

Adult↗

PubMedDate not supplied

Determination of unique microbial volatile organic compounds produced by five Aspergillus species commonly found in problem buildings.

This study identified unique microbial volatile organic compounds (UMVOCs) produced by five Aspergillus species (A. fumigatus, A. versicolor, A. sydowi, A. flavus, and A. niger) cultivated on malt extract agar and gypsum board. The hypothesis was that UMVOCs can be used to predict the presence of Aspergillus species. During the cultivation humidified air was continually supplied and evenly distributed through each of the culture flasks. Volatile metabolites were collected using Tenax TA tubes on Days 8, 16, and 30 after inoculation. The volatile metabolites were determined by gas chromatography/mass spectroscopy after thermal desorption. Nine compounds recognized as UMVOCs--3-methyl-1-butanol; 2-methyl-1-propanol; terpineol; 2-heptanone; 1-octen-3-ol; dimethyl disulfide; 2-hexanone; 3-octanone; and 2-pentylfuran--were found on the cultures in detectable amounts. The first two compounds were detected at the highest frequency when combining both media. The first four compounds were found to be the dominant UMVOCs on gypsum board, which could be used as chemical markers of the common Aspergillus species grown indoors.

Air Pollution, Indoor↗

PubMed2004

Relations between land use and organochlorine pesticides, PCBs, and semi-volatile organic compounds in streambed sediment and fish on the island of Oahu, Hawaii.

Bed-sediment and/or fish samples were collected from 27 sites around the island of Oahu (representing urban, agricultural, mixed, and forested land use) to determine the occurrence and distribution of hydrophobic organic compounds including organochlorine pesticides, polychlorinated biphenyls (PCBs), and semi-volatile organic compounds (SVOCs). Of the 28 organochlorine compounds analyzed in the fish, 14 were detected during this study. Nineteen of the 31 organochlorine compounds and 40 of the 65 SVOCs were detected in the sediment. Urban sites had the highest number of detections and tended to have the highest concentrations of pesticides. Chlordane compounds were the most frequently detected constituents at urban sites, followed by dieldrin, polycyclic aromatic hydrocarbons (PAHs), and DDT compounds. PAHs were the most frequently detected constituents in watersheds with mixed (urban and agricultural) land use. The only pesticides detected at agricultural sites were DDT and its degradation products, DDD and DDE. No pesticides or PCBs were detected at the forested sites, but a few ubiquitous SVOCs were found in sediments at some forested sites. In general, concentrations of the most frequently detected pesticides were higher in fish than in sediment. Following a trend that has been observed elsewhere in the nation, concentrations of most organochlorine pesticides and PCBs are decreasing in Hawaii.

Agriculture↗