Surface emission determination of volatile organic compounds (VOC) from a closed industrial waste landfill using a self-designed static flux chamber.

Closed landfills can be a source of VOC and odorous nuisances to their atmospheric surroundings. A self-designed cylindrical air flux chamber was used to measure VOC surface emissions in a closed industrial landfill located in Cerdanyola del Vallès, Catalonia, Spain. The two main objectives of the study were the evaluation of the performance of the chamber setup in typical measurement conditions and the determination of the emission rates of 60 different VOC from that industrial landfill, generating a valuable database that can be useful in future studies related to industrial landfill management. Triplicate samples were taken in five selected sampling points. VOC were sampled dynamically using multi-sorbent bed tubes (Carbotrap, Carbopack X, Carboxen 569) connected to SKC AirCheck 2000 pumps. The analysis was performed by automatic thermal desorption coupled with a capillary gas chromatograph/mass spectrometry detector. The emission rates of sixty VOC were calculated for each sampling point in an effort to characterize surface emissions. To calculate average, minimum and maximum emission values for each VOC, the results were analyzed by three different methods: Global, Kriging and Tributary area. Global and Tributary area methodologies presented similar values, with total VOC emissions of 237 ± 48 and 222 ± 46 g day(-1), respectively; however, Kriging values were lower, 77 ± 17 gd ay(-1). The main contributors to the total emission rate were aldehydes (nonanal and decanal), acetic acid, ketones (acetone), aromatic hydrocarbons and alcohols. Most aromatic hydrocarbon (except benzene, naphthalene and methylnaphthalenes) and aldehyde emission rates exhibited strong correlations with the rest of VOC of their family, indicating a possible common source of these compounds. B:T ratio obtained from the emission rates of the studied landfill suggested that the factors that regulate aromatic hydrocarbon distributions in the landfill emissions are different from the ones from urban areas. Environmental conditions (atmospheric pressure, temperature and relative humidity) did not alter the pollutant emission fluxes.

Evaluation of the effect of different sampling time periods and ambient air pollutant concentrations on the performance of the Radiello diffusive sampler for the analysis of VOCs by TD-GC/MS.

The effect of different sampling exposure times and ambient air pollutant concentrations on the performance of Radiello® samplers for analysis of volatile organic compounds (VOCs) is evaluated. Quadruplicate samples of Radiello® passive tubes were taken for 3, 4, 7 and 14 days. Samples were taken indoors during February and March 2010 and outdoors during July 2010 in La Canonja (Tarragona, Spain). The analysis was performed by automatic thermal desorption (ATD) coupled with capillary gas chromatography (GC)/mass spectrometry detection (MS). The results show significant differences (t-test, p < 0.05) between the amounts of VOCs obtained from the sum of two short sampling periods and a single equivalent longer sampling period for 65% of all the data. 17% of the results show significantly larger amounts of pollutant in the sum of two short sampling periods. Back diffusion due to changes in concentrations together with saturation and competitive effects between the compounds during longer sampling periods could be responsible for these differences. The other 48% of the results that are different show significantly larger amounts in the single equivalent longer sampling period. The remaining 35% of the results do not show significant differences. Although significant differences are observed in the amount of several VOCs collected over two shorter sampling intervals compared to the amount collected during a single equivalent longer sampling period, the ratios obtained are very close to unity (between 0.7 and 1.2 in 75% of cases). We conclude that Radiello® passive samplers are useful tools if their limitations are taken into account and the manufacturer's recommendations are followed.

Comparative study of the adsorption performance of an active multi-sorbent bed tube (Carbotrap, Carbopack X, Carboxen 569) and a Radiello(®) diffusive sampler for the analysis of VOCs.

A simple comparison is made to evaluate the relative performance of active and passive sampling methods for the analysis of volatile organic compounds (VOCs) in ambient air. The active sampling is done through a multi-sorbent bed tube (Carbotrap, Carbopack X, Carboxen 569) created in our laboratory and the passive sampling through the Radiello(®) diffusive sampler specified for thermal desorption (filled with Carbograph 4). Daily duplicate samples of multi-sorbent bed tubes were taken during a period of 14 days. During the same period of time, quadruplicate samples of Radiello(®) tubes were taken during 3 days, 4 days, 7 days and 14 days. The sampling was carried out indoors during the months of February and March 2010 and outdoors during the month of July 2010 in La Canonja (Tarragona, Spain). The analysis was performed by automatic thermal desorption (ATD) coupled with capillary gas chromatography (GC)/mass spectrometry detector (MSD). The analytical performance of the two sampling approaches was evaluated by describing several quality assurance parameters. The results show that the analytical performances of the methodologies studied are quite similar. They display low limits of detection, good precision, accuracy and desorption efficiency, and low levels of breakthrough for multi-sorbent bed tubes. However, the two monitoring methods produced varying air-borne concentration data for most of the studied compounds, and the Radiello(®) samplers generally gave higher results. Sampling rates (Q(k)) were determined experimentally, and their values were higher than those supplied by the producer. As the experimental calculation of Q(k) values is generally carried out by the suppliers in exposure chambers with only the target compounds present in the air samples, as well as in concentrations dissimilar to those found in ambient air, the use of constant settled Q(k) can lead to inaccurate results in complex samples.

Comparative study of the adsorption performance of a multi-sorbent bed (Carbotrap, Carbopack X, Carboxen 569) and a Tenax TA adsorbent tube for the analysis of volatile organic compounds (VOCs).

A comparison between two types of adsorbent tubes, the commonly used Tenax TA and a multi-sorbent bed (Carbotrap, Carbopack X, Carboxen 569) tube developed in our laboratory, has been done to evaluate their usefulness in the analysis of VOCs in ambient air. Duplicate indoor and outdoor samples of Tenax TA and multi-sorbent tubes of 10, 20, 40, 60 and 90l were taken in Barcelona city (Spain) on July and October of 2009. Breakthrough values (defined as %VOCs found in the back tube) were determined for all sampling volumes connecting two sampling tubes in series. The analysis was performed by automatic thermal desorption (ATD) coupled with capillary gas chromatography (GC)/mass spectrometry detector (MSD). Significant differences between the concentrations obtained-from multi-sorbent bed and Tenax TA tubes are observed for the very volatile compounds (56 degrees C

Occupational asthma caused by metal arc welding of iron.

Epidemiological studies have shown that exposure to welding fumes can be a cause of occupational asthma (OA), although the mechanisms implicated are unknown. We describe 3 patients (all men, mean age 42 years) with OA secondary to exposure to welding fumes generated during metal arc welding on iron. The exposure time ranged from 7 to 43 years and the time of the onset of symptoms following the start of exposure was 2-12 years. Patients were diagnosed by specific inhalation challenge (SIC). Environmental levels of Fe, Cd, Cu, Cr, Ni, NO2, NO, CO, and O3 produced during the SIC did not exceed threshold limit values. Samples of induced sputum were obtained before and after the SIC and showed an increase in neutrophils and concentrations of IL-8, TNF-α and TNF-ß after the SIC. This study presents the first clinical findings reported in welders with OA, mainly working with iron. Neutrophilic inflammation seems to play a role in this disease.

VOCs and PAHs emissions from creosote-treated wood in a field storage area.

In this study, the emissions of volatile organic compounds (VOCs, in this case aromatic hydrocarbons containing one benzene ring and furans) and polycyclic aromatic hydrocarbons (PAHs) from wood recently treated with creosote are examined. The VOCs and PAHs were identified and quantified in the gas phase. Additionally, the PAHs were quantified in the particulate phase. Glass multi-sorbent tubes (Carbotrap, Carbopack X, Carboxen-569) were used to hold the VOCs. The analysis was performed using automatic thermal desorption (ATD) coupled with capillary gas chromatography/mass spectrometry (GC/MS). PAHs vapours were collected on XAD-2 resin, and particulate matter was collected on glass fibre filters. The PAHs were analysed using GC/MS. The main components of the vapours released from the creosote-treated wood were naphthalene, toluene, m+p-xylene, ethylbenzene, o-xylene, isopropylbenzene, benzene and 2-methylnaphthalene. VOCs emission concentrations ranged from 35 mg m(-3) of air on the day of treatment to 5 mg m(-3) eight days later. PAHs emission concentrations ranged from 28 microg m(-3) of air on the day of treatment to 4 microg m(-3) eight days later. The air concentrations of PAHs in particulate matter were composed predominantly of benzo[b+j]fluoranthene, benzo[a]anthracene, chrysene, fluoranthene, benzo[e]pyrene and 1-methylnaphthalene. The emission concentrations of particulate polycyclic aromatic hydrocarbons varied between 0.2 and 43.5 ng m(-3). Finally, the emission factors of VOCs and PAHs were determined.

Indoor and outdoor BTX levels in Barcelona City metropolitan area and Catalan rural areas.

Five aromatic hydrocarbons (benzene, toluene, and three isomeric xylenes) were monitored in indoor and outdoor air of 7 public buildings and 54 private homes, located in Barcelona City metropolitan area and in several rural areas of Catalonia. The sampling was carried out over four periods: spring-summer and winter of 2000, and summer and winter of 2001. Passive ORSA 5 Dräger samplers were used for benzene, toluene, and xylenes (BTX) adsorption. BTX were extracted with carbon disulphide and analysed using a gas chromatograph coupled to a FID detector. In Barcelona metropolitan area the outdoor average concentrations of BTX were 3.5, 34.2, and 31.3 microg/m3 in urban areas, and 1.4, 9.2, and 9.2 microg/m3 in rural areas, respectively. Average indoor air concentrations of BTX were respectively 4.3, 64.8, and 47.6 microg/m3 in urban areas and 5.8, 67.0, and 51.4 microg/m3 in rural areas, respectively. A direct connection between the house and garage was one of the most influential factors for indoor BTX concentrations in rural areas. In urban areas, diffuse traffic sources were the predominant BTX source, slightly influenced by tobacco smoke in indoor air.

Use of high-performance liquid chromatography to assess airborne mycotoxins. Aflatoxins and ochratoxin A.

An HPLC analytical method combining methanol-deionised water (80:20, v/v) extraction, methanol-acetonitrile (50:50, v/v) extraction and fluorescence detection was implanted to analyse ochratoxin A and aflatoxins B1, B2, G1 and G2 of air samples collected during the usual production process in a number of workplaces of a coffee factory to assess the occupational exposure of the engaged workers. The average levels of airborne ochratoxin A and aflatoxins were less than 1.2 and 0.4 ng/m3, respectively, using 50 L air samples. When 150 L air samples were used, levels lower than 0.04 ng/m3 ochratoxin A and 0.013 ng/m3 for aflatoxins B1, B2, G1 and G2, could be detected.

Determination of chlorpyrifos in air, leaves and soil from a greenhouse by gas-chromatography with nitrogen-phosphorus detection, high-performance liquid chromatography and capillary electrophoresis.

Chlorpyrifos was determined in air, leaves and soil in a greenhouse in order to establish performance differences between gas-chromatography with nitrogen-phosphorus detection (GC-NPD) and high-performance liquid chromatographic and capillary electrophoretic methods and to assess the farm workers' risk of overexposure due to air exposure and/or skin contact with this compound. Results obtained indicate that the three analytical techniques, with the specific procedures described, can be used, although only GC-NPD provides an operative limit of detection in air. Chlorpyrifos levels in air are dependent on time and greenhouse ventilation, whereas it remains for a long time on leaf surfaces and soil. As a consequence, specific instructions can be established for farm workers in order to avoid skin and respiratory exposure to chlorpyrifos.

Assessment of chlorine exposure in swimmers during training.

The presence of a high prevalence of bronchial hyperresponsiveness and asthma-like symptoms in swimmers has been recently reported. Chlorine, a strong oxidizing agent, is an important toxic gas that the swimmer can breath during swimming. Measurements of the chlorine concentration at the breathing level (< 10 cm) were obtained randomly during five nonconsecutive days in four different swimming pool enclosures. The mean level in all the swimming pools was 0.42 +/- 0.24 mg.m-3, far below the threshold limited value (TLV) of 1.45 mg.m-3 for the work places for a day of work (8 h). The TLV could be reached and even exceeded if we consider the total amount of chlorine that a swimmer inhales in a daily training session of 2 h (4-6 g) compared with a worker during 8 h at the TLV (4-7 g). Low correlation was observed with the number of swimmers in the swimming pool during the measurements (0.446) and other variables as the water surface area of the pool, volume of the enclosure, and the chlorine-addition system in the swimming pool. A low turnover rate in the air with an increase of chlorine levels through the day (P < 0.05) was observed in all pools. The concentration of chlorine in the microenvironment where the swimmer is breathing is below the TLV concentration limit, but nevertheless results in a high total volume of chlorine inhaled by the swimmers in a given practice session. The possible role of chlorine in producing respiratory symptoms in swimmers needs further investigation.

Determination of DDT and related compounds in blood samples from agricultural workers.

An analytical method combining a solid-phase (C18) clean-up and GC-electron-capture detection using a capillary column, was implemented to determine p,p'-DDT and its metabolites (p,p'-DDD and p,p'-DDE), as well as other organochlorine pesticides in whole blood samples from 30 farmers and 24 non-occupationally exposed workers. The average concentrations for the quantified pesticides, p,p'-DDT, p,p'-DDD and p,p'-DDE, were 0.9, 1.5 and 8.0 micrograms/l whole blood for exposed workers and 0.3, 0.5 and 3.3 micrograms/l for unexposed workers, respectively. GC-MS was used to confirm the identity of the pesticides found. Solid-phase extraction and the protocol used give a cleaner analytical matrix, not only improving sensitivity and resolution, but also allowing analyses with smaller blood samples as compared to other methods.

Determination of chlorinated insecticides in blood samples of agricultural workers.

Lindane, aldrin and p,p'-DDT were determined in blood samples from 71 farmers by means of an analytical method which combines a direct whole-blood extraction with n-hexane and gas chromatography (GC)-electron-capture detection (ECD), using a capillary column, applied to the organic extract. This technique allowed the determination of pesticides at levels varying from 0.1 to 180 micrograms per l of blood, the detection limit for every pesticide being 0.1 microgram/l. GC-mass spectrometry was used to confirm the identity of each pesticide. The advantage of capillary column GC-ECD for pesticide determination is its sensitivity and high resolution, which makes it possible to separate pesticides from a complex n-hexane extract obtained in a very simple pretreatment of the blood sample, which is itself a very complex matrix.

Single column ion chromatographic determination of inorganic acids in workroom places.

Single Column Ion Chromatography (SCIC) combines low capacity-columns, low conductivity eluents and a detector with considerable electronic supression capability and enables quantitation of ions at the ppm level without the need of a suppressor column associated with other forms of Ion Chromatography. Vapors and aerosols of inorganic acids are collected on filter and silica gel tubes and analyzed directly by SCIC. A conventional liquid chromatograph with a low capacity column and a conductimetric detector is used to analyze aerosols of Cl-, Br-, NO-3 and SO=4 with good results.