Passive Sampling Methods Research Articles

The organic pollutant status of rivers in Bosnia and Herzegovina as determined by a combination of active and passive sampling methods.

There is an overall lack of data concerning the pollution status of Bosnia Herzegovina, which is confounded by fragmented national environmental management. The present study aimed to provide some initial data for concentrations of priority substances in two major Bosnian Rivers, using two types of passive sampler (PS) as well as by using high volume water sampling (HVWS). Overall, concentrations of most persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs) and legacy pesticides, were shown to be low. However, around the town of Doboj on the Bosna River, concentrations of polycyclic aromatic hydrocarbons (PAH) breached European standards for several compounds and reached 67ngL-1 for freely dissolved concentrations and 250ngL-1 for total concentrations. In general, contamination was lower in the Neretva River compared to the Bosna, although for brominated diphenyl ethers (PBDEs), results suggested an active source of PBDEs at one location based on the ratio of congeners 47 and 99. Direct comparisons between the different sampling techniques used are not straightforward, but similar patterns of PAH contamination were shown by HVWS and PS in the Bosna River. There are both scientific and practical considerations when choosing which type of sampling technique to apply, and this should be decided based on the goals of each individual study.

Hexapod decomposers of Serra de Santa Catarina, Paraíba, Brazil: an area with high potential for conservation of Caatinga biodiversity

Abstract: In detritus-based trophic systems, springtails, dung beetles, saprophagous calyptrate flies and termites consume and fragment organic matter and control populations of decomposer microorganisms, exerting a strong influence on energy and nutrient fluxes. A faunal inventory of these four groups of hexapods was performed in Serra de Santa Catarina (SSC), an area of arboreal-shrub caatinga located in the state of Paraíba, with the purpose of characterizing the assemblages of these taxa, and highlighting their unique links to the local ecosystem. Samplings were performed in May, 2014, and April, 2015, both during the rainy season. Standard sampling protocols for biodiversity inventory of the various taxa were used, including both active and passive sampling methods. In general, 114 species of hexapods were captured, with 26 species of springtails, 20 dung beetles, 30 saprophagous calyptrate flies and 38 termites, with sampling sufficiency varying from 69.5 to 96.8% of total estimated richness. Species richness of the groups are among the highest recorded for a single area of Caatinga, with some taxa being recorded for the first time for the domain. Several morphospecies had indeterminate taxonomic status, especially springtails and termites, and are quite likely new species to science. The structure of the assemblages of springtails, dung beetles, saprophagous calyptrate flies and termites recorded in SSC, suggest that this conserved area is unique within the highly impacted landscape of Caatinga, and has great potential for the conservation of biodiversity of this domain in the Northeast Region of Brazil.

ANTIBIOTICS AND PESTICIDES IN WATER AND SEDIMENTS FROM INTENSIVE SHRIMP FARMS IN SOUTHERN VIETNAM

In recent years, shrimp farming has developed rapidly and become one of the major export sectors of Vietnam. In particular, Mekong Delta Vietnam (MDVN) accounts for over 90 % shrimp farming area in Vietnam. Shrimp industry development leads to use a large amount of antibiotics (ABs) and pesticides for disease prevention, treatment and sanitation pond. These compounds are usually discharged directly into the environment through water and sludge after harvesting. The presence of antibiotics and pesticides in the environment cause negative impacts on ecosystems and human health. In this study, the passive sampling method with POCIS sampler (Polar Organic Chemical Integrative Samplers) was used to monitor the presence of 12 ABs and 2 pesticides in water of intensive shrimp ponds and the surrounding canals at Tan Tru District (Long An province) and Can Gio District (Ho Chi Minh city) following a production cycle. The results showed that ABs and pesticides were detected in water and sediment in the pond and canals in both research sites. Two pesticides (atrazine and diuron) were detected in the pond and leading canals in both study areas with low concentrations from several ng/L to several tens of ng/L. In Tan Tru, three antibiotics (Trimethoprim, Sulfamethoxazole and Enrofloxacin) were detected in water at concentrations ranging from several tens of ng/L to 300 ng/L; in sediments of shrimp pond and canal the levels of pesticides and ABs ranged from 10 to 200 µg/kg. In Can Gio - HCMC, 4 ABs (Trimethoprim, Sulfamethoxazole, Ciprofloxacin and Enrofloxacin) were detected ranging from a few ng/L to several µg/L in water, and a few mg/kg in sediments of the pond. The results also showed that in the pond, ABs type and concentration detection varied by region and shrimp growth cycles.

Outdoor air 1,3-butadiene monitoring: Comparison of performance of Radiello® passive samplers and active multi-sorbent bed tubes

A comparison was made between the relative performance of active and passive sampling methods for the analysis of 1,3-butadiene in outdoor air. Active and passive sampling was conducted using multi-sorbent bed tubes (Carbotrap, Carbopack X, Carboxen 569) and RAD141 Radiello® diffusive samplers (filled with Carbopack X), respectively. Daily duplicate samples of multi-sorbent bed tubes were taken over a period of 14 days (9 + 5 days) at El Morell (Tarragona, Spain), near the petrochemical area. As 1,3-butadiene is a reactive pollutant and can be rapidly oxidized, half of the samplers were equipped with ozone scrubbers. Samples consisted in two tubes connected in series (front and back) to allow the determination of breakthrough. Quadruplicate samples of Radiello® tubes were taken over a period of 14 days (9 days and 5 days), too. During those days, ozone concentration was measured using RAD172 Radiello® samplers. In addition to this, daily duplicate samples of multi-sorbent bed tubes were taken in the city of Barcelona over a period of 8 days. Simultaneously, 4 samples of Radiello® tubes were exposed to outdoor air. Sampling was done throughout June and July 2017. Analysis was performed by thermal desorption coupled with gas chromatography/mass spectrometry. Analytical performance of the two sampling methods was evaluated by describing several quality assurance parameters, with results showing that performances are quite similar. They display low detection limits, good precision, linearity and desorption efficiency, low levels of blank values, and low breakthrough for multi-sorbent bed tubes. However, Radiello® samplers were not able to uptake episodic 1,3-butadiene high concentrations, leading to underestimation of real values. Hence, we can conclude that Radiello® samplers can be used for baseline 1,3-butadiene levels whereas multi-sorbent bed tubes would be advisable when relevant episodes are expected.

Investigation and application of diffusive gradients in thin-films technique for measuring endocrine disrupting chemicals in seawaters

Endocrine disrupting chemicals (EDCs) can be released to coastal waters and affect the endocrine system of marine organisms. To monitor their levels in seawaters, a simple, robust passive sampling method, the diffusive gradients in thin-films (DGT) technique, was developed with XDA-1 resin as a binding agent. Six EDCs (including three estrogens, two pesticides and bisphenol A) were used to assess the performance of the DGT. The XDA-1 binding gel showed adequate ability for adsorbing EDCs in seawaters. The DGT sampler exhibited linear accumulation for the EDCs during a 15-day deployment and diffusion coefficients and sampling rates were calculated. The DGT measurement was independent of pH in the range 7.0–9.0 and ionic strength in the range 0.4–0.8 M. Field applications of this DGT in a coast of Dalian (China) showed comparable results to those from grab sampling. Five EDCs were detected with concentrations ranging from 0.7 to 19.4 ng L−1. This study is a first attempt to apply DGT sampler for determining EDCs in seawaters.

Under glass weathering of hemp fibers reinforced polypropylene biocomposites: Impact of Volatile Organic Compounds emissions on indoor air quality

Nowadays, natural fibers reinforced composite materials can be used in closed environments such as car cabins. It has hence become a necessity to study their emissions of Volatile Organic Compounds (VOCs) to check their impact on indoor air quality. The purpose of this work was first to study the emissions of VOCs from hemp fibers reinforced polypropylene (PP) biocomposites in comparison with neat PP. The influence of under windshield glass weathering on VOCs release was then investigated. The exposition lasted one year and the fiber loading influence on emissions was studied all along the weathering. The VOCs concentration at the material/air interface was determined using a passive sampling method involving an emission cell coupled with Solid Phase MicroExtraction (SPME). VOCs analysis was then carried out by gas chromatography coupled to mass spectrometry and flame ionization detections. One of the most significant results is the drastic increase of oxygenated compounds concentration during the exposition, especially for biocomposites. Among these oxidation by-products, formaldehyde, acetaldehyde, furfural and 2-furanmethanol, recognized as Cancerogen, Mutagen and toxic for Reproduction (CMR), were detected. A broad range of alkanes, specific of PP matrix degradation was also identified. Finally, measured concentrations of substances found in this work and listed in Vehicle Indoor Air Quality (VIAQ) standards were gathered in order to discuss the biocomposites emissions impact on indoor air quality.

Bayesian Blending of Nitrogen Dioxide Air Pollution Data for Neighbourhood Estimates for Health Research

Background/Aim: Exposure to nitrogen dioxide (NO2) pollution has been associated with a range of adverse health outcomes. Annual average pollutant concentrations are often used to estimate exposure, however, these estimates can be imprecise due to difficulty modelling spatial patterns at the resolution of neighbourhoods (e.g. a scale of tens of metres) rather than at a coarse scale (around several kilometres resolution). The objective of this study was to derive improved estimates of neighbourhood level pollutant concentrations for health studies by blending air pollutant measurements with modelled predictions using Bayesian analyses. Methods: We implemented the Bayesian Maximum Entropy (BME) approach to blend 'hard' data (considered precise) and probabilistic 'soft' data (with uncertainty defined using informative priors). We compiled and harmonised NO2 data from fixed-site monitors, chemical transport models, and satellite-based land use regression models to estimate neighbourhood level annual average NO2 concentrations in Sydney, Australia. The spatial model integrated the different underlying probabilities to produce a posterior probability density function of neighbourhood exposures. The mean of the posterior density was our estimate of NO2 exposure. Results: Estimated annual average concentrations from the BME model ranged from 3 to 35 ppb.Validation using independent data from a separate set of samples (using passive sampling methods) showed improvement, with Root Mean Squared Error (RMSE) of 2.6 ppb compared with the land use regression (2.8 ppb) and chemical transport model (3.1 ppb). Conclusions: Our study implemented state-of-the-art methods for exposure assessment and demonstrated an improvement in validation test statistics. In future work we will explore the impact of these improvements on exposure misclassification bias when used in epidemiological analyses of the impact of air pollution on health.

Evaluation and Application of a Passive Air Sampler for Atmospheric Volatile Organic Compounds

In this study, we propose a passive air sampler (PAS) that mainly consists of activated charcoal sorbent, a radial diffusive body, and a protective shield for the outdoor monitoring of volatile organic compounds (VOCs). Due to its reusable accessories and small size, this PAS is cost-effective and highly convenient for outdoor deployment. The estimated sampling rates (SRs) for 28 VOCs were very close to the theoretical values over a 6-month field test. We evaluated the performance of the PAS with benzene, toluene, ethylbenzene, and xylenes (BTEX) and determined the method detection limits (MDLs) (0.02–0.04 µg m–3), recovery values (95.3 ± 9.8–99.8 ± 7.5%), repeatability (3.2 ± 2.2–4.6 ± 2.9%), and uncertainties (10.1 ± 3.8–12.9 ± 4.5%), which are comparable to those of previously reported samplers and meet the requirements of European Standards (EN) 13528. The deployment times for obtaining reliable time-weighted average (TWA) atmospheric concentrations of BTEX ranged from 2 days to a minimum of 3 months according to corresponding background concentrations in the ambient air. Moreover, the atmospheric concentrations of BTEX measured by the sampler in this study compared favorably with values from both active and passive sampling methods, with R2 ≥ 0.97 (p < 0.0001). Finally, a 12-month field test was performed after evaluating the sampler, and the results showed apparent seasonal variations of atmospheric VOC concentrations, which were dominated by the sampling location and wind direction.

Determining the suitability of a polar organic chemical integrated sampler (POCIS) for the detection of pesticide residue in the Ishikawa River and its tributary in Osaka, Japan.

The monitoring of pesticide concentrations in Japanese rivers was conducted via a grab sampling method and a passive sampling method using the polar organic chemical integrated sampler (POCIS). The results showed that cumulative detections were 84 with grab sampling and 98 with the POCIS. All of the pesticides detected by grab sampling could be quantified with a POCIS except for one (although its traces were detected). In addition, 15 detections quantified by POCIS were undetected by grab sampling. The average concentrations of pesticides detected by both the POCIS and grab sampling during the investigation period were compared. A good correlation was observed between the two methods with a slope of 1.00 and a coefficient of correlation (r) of 0.897 (n=79). Although high temporal variability was observed in the pesticide concentrations by grab sampling, the average pesticide concentrations obtained by the two methods showed similar values during the investigation period.

Assessment of bioaerosol particle characteristics at different hospital wards and operating theaters: A case study in Tehran

This study was aimed to investigate the types and number of bacterial and fungal bioaerosols in indoor air of hospitals according to the type of wards and operating theaters. Bacterial and fungal samples were collected using the passive sampling method of 1/1/1 scheme during a six months' period in the Khatam-Al-Anbia hospital, Tehran, Iran. A simple linear regression was used to determine the relationship between bioaerosol concentrations and the number of active beds. Bacterial bioaerosol concentrations were mainly higher than fungi in all sampling sites. A significant association was found between airborne fungal concentrations and the numbers of beds (R2?=?0.76, p?<?0.05), but not observed for bacteria (R2?=?0.02, p?<?0.05). Our findings provided an exposure database of airborne bacterial and fungal bioaerosol in hospital wards and operating theaters in Tehran.•Due to the importance of the exposure risk to bioaerosols for patients and medical personnel, we focused on identification of the density and diversity of bacterial and fungal bioaerosols in different wards and operating theaters.•Our results showed that the numbers of the beds have a significant effect on airborne fungal concentrations.•The results of this study can be used to set indoor air quality standards for hospital wards and operating theatres.

Passive Sampling Method for Total Volatile Organic Compounds in Indoor Air

Passive Sampling Method for Total Volatile Organic Compounds in Indoor Air

A Novel Multi-Approach Protocol for the Characterization of Occupational Exposure to Organic Dust-Swine Production Case Study.

Swine production has been associated with health risks and workers’ symptoms. In Portugal, as in other countries, large-scale swine production involves several activities in the swine environment that require direct intervention, increasing workers’ exposure to organic dust. This study describes an updated protocol for the assessment of occupational exposure to organic dust, to unveil an accurate scenario regarding occupational and environmental risks for workers’ health. The particle size distribution was characterized regarding mass concentration in five different size ranges (PM0.5, PM1, PM2.5, PM5, PM10). Bioburden was assessed, by both active and passive sampling methods, in air, on surfaces, floor covering and feed samples, and analyzed through culture based-methods and qPCR. Smaller size range particles exhibited the highest counts, with indoor particles showing higher particle counts and mass concentration than outdoor particles. The limit values suggested for total bacteria load were surpassed in 35.7% (10 out of 28) of samples and for fungi in 65.5% (19 out of 29) of samples. Among Aspergillus genera, section Circumdati was the most prevalent (55%) on malt extract agar (MEA) and Versicolores the most identified (50%) on dichloran glycerol (DG18). The results document a wide characterization of occupational exposure to organic dust on swine farms, being useful for policies and stakeholders to act to improve workers’ safety. The methods of sampling and analysis employed were the most suitable considering the purpose of the study and should be adopted as a protocol to be followed in future exposure assessments in this occupational environment.

Polycyclic aromatic hydrocarbons in indoor and outdoor air in Turkey: Estimations of sources and exposure

ABSTRACTThe aim of the current study was to measure polycyclic aromatic hydrocarbons (PAHs) in eight indoor (In both kitchen and living room) air sampling locations using a passive sampling method for collection. Passive outdoor air samples were also collected from 3 of the same sampling locations as the indoor air sampling sites. Sampling was conducted in three seasons. The summer season, when windows are generally open, was between 18th July and 01st September, 2014; the autumn and winter seasons, when windows are mostly closed, was between 18th October and 01st December, 2014, and 01st December, 2014, and 18th January, 2015, respectively.Average PAH concentrations in summer were 22 ± 21 ng/m3 and 17 ± 12 ng/m3 in the living room and kitchen, respectively, whereas living room and kitchen average PAH concentrations were 23 ± 16 ng/m3 and 20 ± 9 ng/m3, respectively, in autumn and 23 ± 13 ng/m3 and 23 ± 24 ng/m3, respectively, in winter. Outdoor air PAH concentrations in summer, autumn and winter were 7 ± 0.4 ng/m3, 22 ± 13 ng/m3 and 209 ± 33 ng/m3, respectively. An increase in outdoor PAH concentrations was measured in winter compared to the concentrations in summer and autumn, which paralleled the lower outdoor air temperature. However, PAH concentrations in the indoor environment vary according to the household characteristics and personal habits.

Biomonitoring of Atmospheric Polycyclic Aromatic Hydrocarbons: A Mini Review

Background: A number of atmospheric pollutants, such as polycyclic aromatic hydrocarbons, volatile organic compounds, and heavy metals, are monitored by environmental researchers. Among these atmospheric pollutants, polycyclic aromatic hydrocarbons play an important role owing to their nature, which is carcinogenic and toxic to human beings. A number of researchers have monitored these atmospheric pollutants using active and passive samplers, and a few have monitored their concentrations using biological specimens such as lichens and mosses. Method: We reviewed the biomonitoring of atmospheric polycyclic aromatic hydrocarbons using various biological specimens. For this purpose, we examined nearly 35 research papers published since 2013 in various reputed international journals. From this study, it is clear that biological specimens are useful for monitoring the concentrations of atmospheric polycyclic aromatic hydrocarbons. Results: A number of PAHs exist in the atmosphere, but according to the United States Environmental Protection Agency (US EPA), only the following 16 are considered priority PAHs due to the availability of data and their carcinogenic and toxic nature: Napthalene (Nap), Acenaphthylene (Acy), Acenaphthene (Acp), Fluorene (Flu), Phenanthrene (Phe), Anthracene (Ant), Fluoranthene (Flt), Pyrene(Pyr), Benz[a]anthracene (BaA), Chrysene(Chry), Benzo[b]fluoranthene (BbF), Benzo [k]fluoranthene (BkF), Benzo[a]pyrene(BaP), Indeno [1,2,3-cd]pyrene(IcdP), Dibenz[a,h]anthracene (DahA), and Benzo[ghi] perylene(BghiP). These PAHs are collected by various procedures, such as active sampling of total suspended particulate matter and PM2.5, and passive sampling. Along with these conventional methods, biological species are also used to monitor PAHs. In this study, we reviewed research papers published since 2013 that described the monitoring of atmospheric PAHs with a number of biological materials such as lichens, mosses, and other plant materials. Conclusion: Based on the review, we conclude that several researchers have successfully used biological materials to monitor the levels of atmospheric PAHs in different countries and from different sampling sites. However, the data obtained in these studies can be reliable only when they are compared with conventional instrumental methods. Most of the studies compare their results with those obtained from either active or passive air sampling methods. The major advantage of biomonitoring studies is the low cost of sampling and that provides reasonably reliable data. Keywords: Biomonitoring, polycyclic aromatic hydrocarbons, air pollutants, atmospheric pollutants, volatile organic compounds, biological specimen.

Assessment of biodegradation potential at a site contaminated by a mixture of BTEX, chlorinated pollutants and pharmaceuticals using passive sampling methods – Case study

The present study describes a pilot remediation test of a co-mingled plume containing BTEX, chlorinated pollutants and pharmaceuticals. Remediation was attempted using a combination of various approaches, including a pump and treat system applying an advanced oxidation process and targeted direct push injections of calcium peroxide. The remediation process was monitored intensively and extensively throughout the pilot test using various conventional and passive sampling methods, including next-generation amplicon sequencing. The results showed that the injection of oxygen-saturated treated water with residual hydrogen peroxide and elevated temperature enhanced the in situ removal of monoaromatics and chlorinated pollutants. In particular, in combination with the injection of calcium peroxide, the conditions facilitated the in situ bacterial biodegradation of the pollutants. The mean groundwater concentration of benzene decreased from 1349μg·L−1 prior to the test to 3μg·L−1 within 3months after the calcium peroxide injections; additionally, monochlorobenzene decreased from 1545μg·L−1 to 36μg·L−1, and toluene decreased from 143μg·L−1 to 2μg·L−1. Furthermore, significant degradation of the contaminants bound to the soil matrix in less permeable zones was observed. Based on a developed 3D model, 90% of toluene and 88% of chlorobenzene bound to the soil were removed during the pilot test, and benzene was removed almost completely. On the other hand, the psychopharmaceuticals were effectively removed by the employed advanced oxidation process only from the treated water, and their concentration in groundwater remained stagnant due to inflow from the surroundings and their absence of in situ degradation. The employment of passive sampling techniques, including passive diffusion bags (PDB) for volatile organic pollutants and their respective transformation products, polar organic compound integrative samplers (POCIS) for the pharmaceuticals and in situ soil microcosms for microbial community analysis, was proven to be suitable for monitoring remediation in saturated zones.

Different sampling intervals for bowl trapping survey of Aculeata (Hymenoptera) in a semidecidual seasonal forest fragment

Coloured bowl trapping is a passive sampling method which catches insects through a combination of interception and attraction. The method is commonly used for Aculeata, especially bees. The objective of the present study is to determine a reliable sampling interval for aculeates using bowl traps since an appropriate sampling interval is important to enable the collection of representative samples in Neotropics. For this purpose we installed eight bowl traps in a forest fragment in Southern Brazil, during one year, to compare the sampled diversity in twice and once-a-month sampling interval. We confirmed the general expectation that increasing the sample size results in a proportional greater sampling of the community. Different sampling intervals have a weak impact in rarefaction curves, as these do not reach the asymptote in any cases, and Shannon diversity index was considered statistically equal. Under our results, the twice-a-month interval was considered better than monthly sampling intervals only when we compare the extrapolation data (estimators and extrapolation curve) for Aculeata. The Shannon diversity index and the estimated species number (rarefaction) were considered the same among the treatments, so we cannot suggest a reliable sampling interval from these data.

Different sampling intervals for bowl trapping survey of Aculeata (Hymenoptera) in a semidecidual seasonal forest fragment

Coloured bowl trapping is a passive sampling method which catches insects through a combination of interception and attraction. The method is commonly used for Aculeata, especially bees. The objective of the present study is to determine a reliable sampling interval for aculeates using bowl traps since an appropriate sampling interval is important to enable the collection of representative samples in Neotropics. For this purpose we installed eight bowl traps in a forest fragment in Southern Brazil, during one year, to compare the sampled diversity in twice and once-a-month sampling interval. We confirmed the general expectation that increasing the sample size results in a proportional greater sampling of the community. Different sampling intervals have a weak impact in rarefaction curves, as these do not reach the asymptote in any cases, and Shannon diversity index was considered statistically equal. Under our results, the twice-a-month interval was considered better than monthly sampling intervals only when we compare the extrapolation data (estimators and extrapolation curve) for Aculeata. The Shannon diversity index and the estimated species number (rarefaction) were considered the same among the treatments, so we cannot suggest a reliable sampling interval from these data.

Correlation of atmospheric purity index to the diversity of lichens in the Horton Plains National Park, Sri Lanka

Horton Plains National Park (HPNP) has been declared as a world heritage site, because of its unique biodiversity. Die-back of certain areas of this park is widely believed to be due to acidic precursor depositions carried over from other parts of the country and also from neighboring countries. Air pollution data for the two pollutants, NO2 and SO2 were obtained from the passive air sampling method. The data revealed that the concentrations of ambient NO2 and SO2 were very low in the HPNP. The variations of ambient NO2 and SO2 concentrations during the study period showed insignificant positive correlation (p≥ 0.05) with the rainfall data. Considering the variations of these two pollutants with Relative Humidity and the number of vehicles visiting HPNP, both pollutants had insignificant positive correlation. The Index of Atmospheric Purity (IAP) value obtained for the whole area of the HPNP was 54.22. This value belongs to the quality level 5 which represents the ‘very low’ pollution level. The results including lichen distribution and air quality data could confirm that the ambient air quality at HPNP is very high. The high diversity of lichens and the minimum levels of air pollutants suggested that the forest health of HPNP is at a favorable level. Therefore, it is essential to maintain at least the current air pollution level of HPNP in order to conserve the forest and its biodiversity.

A comparison study between passive and active workplace personal air monitoring techniques for airborne isopropyl alcohol concentrations

This research project involved a comparison between the performance of active and passive sampling methods used to collect isopropyl alcohol vapor in an industrial setting. This field experiment was conducted in a real-world industry setting with workers exposed to isopropyl alcohol. In order to create sample sets, passive diffusive samplers (3M 3520 Organic Vapor Monitor) were paired, side-by-side, with active samplers (charcoal solid sorbent tubes). A total of 17 paired sample sets were collected, which yielded data with a non-parametric distribution. Post hoc analysis showed that 4 of the 17 paired sample sets were potential outliers. A Wilcoxon signed-rank test showed that the passive samplers were significantly different from the active air samples (alpha = 0.05), regardless whether or not the potential outliers were included or excluded from the data. A linear regression analysis found a linear relationship between active and passive sampling results. An R 2 value of 0.97 (when including potential outliers) and 0.79 (when excluding potential outliers) suggests that the model fits well with the data. Satisfactory correlation between the samplers was found when including potential outliers (r = 0.9859) and excluding potential outliers (r = 0.8863). The passive samplers reported higher concentrations than the active samplers in 15 of the 17 sample sets. On average, the passive samplers reported 25% higher results when including potential outliers and 16% higher results when excluding potential outliers when compared to the paired active sampling results. Based on the strong correlation values and the trend of passive samplers reporting higher results than the active samplers, occupational health specialists could reliably use the passive samplers in this study to demonstrate compliance to isopropyl alcohol exposure limits.

Method for sampling and analysis of volatile biomarkers in process gas from aerobic digestion of poultry carcasses using time-weighted average SPME and GC–MS

A passive sampling method, using retracted solid-phase microextraction (SPME) – gas chromatography–mass spectrometry and time-weighted averaging, was developed and validated for tracking marker volatile organic compounds (VOCs) emitted during aerobic digestion of biohazardous animal tissue. The retracted SPME configuration protects the fragile fiber from buffeting by the process gas stream, and it requires less equipment and is potentially more biosecure than conventional active sampling methods. VOC concentrations predicted via a model based on Fick’s first law of diffusion were within 6.6–12.3% of experimentally controlled values after accounting for VOC adsorption to the SPME fiber housing. Method detection limits for five marker VOCs ranged from 0.70 to 8.44ppbv and were statistically equivalent (p>0.05) to those for active sorbent-tube-based sampling. The sampling time of 30min and fiber retraction of 5mm were found to be optimal for the tissue digestion process.