The effects of dissolved organic matter and pH on sampling rates for polar organic chemical integrative samplers (POCIS)

The effect of solution pH and levels of dissolved organic matter (DOM) on the sampling rates for model pharmaceuticals and personal care products (PPCPs) and endocrine disrupting substance (EDS) by polar organic chemical integrative samplers (POCIS) was investigated in laboratory experiments. A commercially available POCIS configuration containing neutral Oasis HLB (hydrophilic-lipophilic balance) resin (i.e. pharmaceutical POCIS) and two POCIS configurations prepared in-house containing MAX and MCX anion and cation exchange resins, respectively were tested for uptake of 21 model PPCPs and EDS, including acidic, phenolic, basic and neutral compounds. Laboratory experiments were conducted with dechlorinated tap water over a pH range of 3, 7 and 9. The effects of DOM were studied using natural water from an oligotrophic lake in Ontario, Canada (i.e. Plastic Lake) spiked with different amounts of DOM (the concentration of dissolved organic carbon ranged from 3 to 5 mg L⁻¹ in uptake experiments). In experiments with the commercial (HLB) POCIS, the MCX-POCIS and the MAX-POCIS, the sampling rates generally increased with pH for basic compounds and declined with pH for acidic compounds. However, the sampling rates were relatively constant across the pH range for phenols with high pKa values (i.e. bisphenol A, estrone, estradiol, triclosan) and for the neutral pharmaceutical, carbamazepine. Thus, uptake was greatest when the amount of the neutral species in solution was maximized relative to the ionized species. Although the solution pH affected the uptake of some model ionic compounds, the effect was by less than a factor of 3. There was no significant effect of DOM on sampling rates from Plastic Lake. However, uptake rates in different aqueous matrixes declined in the order of deionized water > Plastic Lake water > dechlorinated tap water, so other parameters must affect uptake into POCIS, although this influence will be minor. MAX-POCIS and MCX-POCIS showed little advantage over the commercial POCIS configuration for monitoring in natural waters.     

Polar organic chemical integrative sampler (POCIS) uptake rates for 17 polar pesticides and degradation products: laboratory calibration

Polar organic chemical integrative samplers (POCIS) are useful for monitoring a wide range of chemicals, including polar pesticides, in water bodies. However, few calibration data are available, which limits the use of these samplers for time-weighted average concentration measurements in an aquatic medium. This work deals with the laboratory calibration of the pharmaceutical configuration of a polar organic chemical integrative sampler (pharm-POCIS) for calculating the sampling rates of 17 polar pesticides (1.15?≤?logK _ow?≤?3.71) commonly found in water. The experiment, conducted for 21 days in a continuous water flow-through exposure system, showed an integrative accumulation of all studied pesticides for 15 days. Three compounds (metalaxyl, azoxystrobine, and terbuthylazine) remained integrative for the 21-day experiment. The sampling rates measured ranged from 67.9 to 279 mL?day^?1 and increased with the hydrophobicity of the pesticides until reaching a plateau where no significant variation in sampling rate is observed when increasing the hydrophobicity.     

Semipermeable membrane devices accumulate conserved ratios of sterane and hopane petroleum biomarkers

Semipermeable membrane devices (SPMDs) are commonly used as a time-integrated measure of aqueous concentrations of persistent hydrophobic chemicals, including PAH, pesticides, dioxins, and PCBs. Another class of persistent hydrophobic chemicals is petroleum biomarker compounds (hopanes and steranes) that are used for hydrocarbon source identification and allocation. In this study three different passive sampling device designs were exposed to a complex hydrocarbon mixture (Alaska North Slope crude) in a laboratory experiment to determine uptake rates of biomarkers into SPMDs. In addition to the standard triolein filled SPMDs, iso-octane filled SPMDs (ISPMDs) and unfilled low-density polyethylene strips (PESDs) were tested. Uptake rates and effective sampling rates were determined for 53 compounds. There was little variation in sampling rates among the individual biomarkers; average values (ld(-1)) for hopanes were 0.43+/-0.07 (PESD), 0.33+/-0.06 (SPMD), and 0.44+/-0.03 (ISPMD) and average sterane sampling rates were 0.57+/-0.04 (PESD), 0.42+/-0.03 (SPMD), and 0.53+/-0.03 (ISPMD). The primary reason for biomarker analysis is for source discrimination of petroleum. Nineteen different diagnostic ratios were measured, and were found to be remarkably well conserved between the oil, water, and all three devices. This indicates that SPMDs, PESDs, and ISPMDs should each be effective for source discrimination studies of petroleum contamination.     

Passive samplers versus surfactant extraction for the evaluation of PAH availability in sediments with variable levels of contamination

The purpose of this study was to test the efficiency of passive solid samplers, polyoxymethylene (POM) strips and polydimethylsiloxane (PDMS) silicon tubing, to predict the bioavailability of native PAHs in contaminated sediments. Results were compared with worm bioaccumulation data and solid/liquid extraction using the surfactant Brij((R)) 700 (B700). The two passive samplers were found to act differently. The PDMS sampler overestimated the availability of PAHs in all studied sediments. The POM method provided results in accordance with those obtained with the B700 extraction. However, POM and B700 methods underestimated PAH availability in low contaminated sediments where biological factors (digestible organic matter) become important. Bioavailability of total PAHs was correctly predicted by POM and B700 in highly contaminated aluminum smelter sediments. A closer examination of individual PAH results indicated that both techniques overestimated the availability of large molecules with logK(ow)>6 suggesting a biological mechanism limiting uptake of larger PAHs which seems to be related to the molecular size of compounds.     

Passive sampling of perfluorinated acids and sulfonates using polar organic chemical integrative samplers

The applicability of a polar organic chemical integrative sampler (POCIS) for detection and determination of perfluorinated acids and sulfonates in water was studied under field conditions. Standard POCIS configurations (i.e., pharmaceutical and pesticide) were deployed in effluent from a wastewater treatment plant for 1, 2, and 3 weeks. Ten of 15 target compounds were found in POCIS, five of which were quantified in wastewater. Pest-POCIS appeared more effective for the sampling, while Pharm-POCIS had a more rapid uptake kinetic, which leads to faster saturation or equilibrium. The results showed that the pesticide configuration is probably more suitable for the sampling of this class of compounds. Based on average concentration in water over the sampling period and amount of compound adsorbed in the POCIS, we calculated sampling rates for five studied compounds and obtained values of 0.034 to 0.222 L?day^?1.     

Simultaneous monitoring of profiles of polycyclic aromatic hydrocarbons in contaminated air with semipermeable membrane devices and spruce needles

Gaseous emissions of combusted electronic scrap, PVC, carpet and wood were monitored for polycyclic aromatic hydrocarbons (PAHs) by simultaneous use of semipermeable membrane devices (SPMDs) and shoots of spruce needles (Picea abies). It was found that phenanthrene, acenaphthylene and fluorene were the dominating PAHs in all samples. SPMDs and needles mainly sequestered PAH associated with the vapor phase. Particle-bound PAHs were only detected in small amounts, at which the needles tended to uptake more of these compounds in comparison to the SPMDs. Nevertheless, the logarithm of the concentrations of PAHs analyzed in both passive samplers after the same sampling period exhibited a significant linear correlation with correlation coefficients larger than 0.8073. SPMDs and spruce needles can complement each other in passive air sampling for compounds with a preference to the gas phase rather than aerosols.     

Comparative application of solid-phase microextraction fibre assemblies and semi-permeable membrane devices as passive air samplers for semi-volatile chlorinated organic compounds. A case study on the landfill "Grube Antonie" in Bitterfeld, Germany

Solid phase microextraction (SPME) fibres coated with Carbowax/divinylbenzene and semi-permeable membrane devices (SPMDs) of standard configuration were used to obtain time-weighted average (TWA) field air concentrations of selected chlorinated semi-volatile compounds on a landfill, where large amounts of lindane by-products were deposited, together with other hazardous chemical residues in the past. Additionally, spot sampling with SPME fibres was performed to identify the emission hotspot and sampling rates were determined/predicted for the substances of interest. Both samplers yield comparable TWA air concentrations of lindane and its isomers and of DDT with its metabolites and gain in certainty about the landfill as remaining source of air pollution with these compounds in the region. Both SPME fibres and SPMDs (respective their modifications) can be recommended as sampling tools in process studies and larger air monitoring programmes. However, further calibration studies and field tests are necessary to obtain reliable sampling rates for a wider range of semi-volatile compounds.     

A directional passive air sampler for monitoring polycyclic aromatic hydrocarbons (PAHs) in air mass

A passive air sampler was developed for collecting polycyclic aromatic hydrocarbons (PAHs) in air mass from various directions. The airflow velocity within the sampler was assessed for its responses to ambient wind speed and direction. The sampler was examined for trapped particles, evaluated quantitatively for influence of airflow velocity and temperature on PAH uptake, examined for PAH uptake kinetics, calibrated against active sampling, and finally tested in the field. The airflow volume passing the sampler was linearly proportional to ambient wind speed and sensitive to wind direction. The uptake rate for an individual PAH was a function of airflow velocity, temperature and the octanol-air partitioning coefficient of the PAH. For all PAHs with more than two rings, the passive sampler operated in a linear uptake phase for three weeks. Different PAH concentrations were obtained in air masses from different directions in the field test.     

Uptake of weakly hydrophobic nitroaromatics from water by semipermeable membrane devices (SPMDs) and by goldfish (Carassius auratus)

Semipermeable membrane devices (SPMDs) filled with triolein, and goldfish (Carassius auratus) were simultaneously exposed to nine weakly hydrophobic nitroaromatics in a laboratory continuous-flow experiment. The results showed that the device concentrated the compounds in most cases to a larger extent than fish and that the overall uptake rate constants (Kmu) and average pollutant sampling rates (R(S)) were similar. We conclude that the SPMDs may be used to determine the levels of weakly hydrophobic nitroaromatics in water. It is obvious, however, that more researches at laboratory in order to establish kinetic database for a wide spectrum of compounds varying in lipophilicity and other properties are needed to elucidate various theoretical and practical aspects of the use of membranes in the environmental research and for related practical applications.     

Uptake of PAHs into polyoxymethylene and application to oil-soot (lampblack)-impacted soil samples

Polyoxymethylene (POM) is a polymeric material used increasingly in passive sampling of hydrophobic organic contaminants such as PAHs and PCBs in soils and sediments. In this study, we examined the sorption behavior of 12 PAH compounds to POM and observed linear isotherms spanning two orders of magnitude of aqueous concentrations. Uptake kinetic studies performed in batch systems for up to 54 d with two different volume ratios of POM-to-aqueous phase were evaluated with coupled diffusion and mass transfer models to simulate the movement of PAHs during the uptake process and to assess the physicochemical properties and experimental conditions that control uptake rates. Diffusion coefficients of PAHs in POM were estimated to be well correlated with diffusants' molecular weights as D(POM) proportional, variant(MW)(-3), descending from 2.3 x 10(-10) cm(2) s(-1) for naphthalene to 7.0 x 10(-11) cm(2) s(-1) for pyrene. The uptake rates for PAHs with log K(ow)<5.8 were controlled by the POM phase and the hydrophobicity of PAH compounds. For more hydrophobic PAH compounds, the aqueous boundary layer played an increasingly important role in determining the overall mass transfer rate. The POM partitioning technique was demonstrated to agree well with two other procedures for measuring PAH soil-water distribution coefficients in oil-soot (lampblack) containing soil samples.     

Passive sampling of selected endocrine disrupting compounds using polar organic chemical integrative samplers

Two types of polar organic chemical integrative samplers (pharmaceutical POCIS and pesticide POCIS) were examined for their sampling efficiency of selected endocrine disrupting compounds (EDCs). Laboratory-based calibration of POCISs was conducted by exposing them at high and low concentrations of 14 EDCs (4-alkyl-phenols, their ethoxylate oligomers, bisphenol A, selected estrogens and synthetic steroids) for different time periods. The kinetic studies showed an integrative uptake up to 28 days. The sampling rates for the individual compounds were obtained. The use of POCISs could result in an integrative approach to the quality status of the aquatic systems especially in the case of high variation of water concentrations of EDCs. The sampling efficiency of POCISs under various field conditions was assessed after their deployment in different aquatic environments.     

Calibration of polyurethane foam (PUF) disk passive air samplers for quantitative measurement of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs): factors influencing sampling rates

PUF disk passive air samplers are increasingly employed for monitoring of POPs in ambient air. In order to utilize them as quantitative sampling devices, a calibration experiment was conducted. Time integrated indoor air concentrations of PCBs and PBDEs were obtained from a low volume air sampler operated over a 50 d period alongside the PUF disk samplers in the same office microenvironment. Passive sampling rates for the fully-sheltered sampler design employed in our research were determined for the 51 PCB and 7 PBDE congeners detected in all calibration samples. These values varied from 0.57 to 1.55 m3 d(-1) for individual PCBs and from 1.1 to 1.9 m3 d(-1) for PBDEs. These values are appreciably lower than those reported elsewhere for different PUF disk sampler designs (e.g. partially sheltered) employed under different conditions (e.g. in outdoor air), and derived using different calibration experiment configurations. This suggests that sampling rates derived for a specific sampler configuration deployed under specific environmental conditions, should not be extrapolated to different sampler configurations. Furthermore, our observation of variable congener-specific sampling rates (consistent with other studies), implies that more research is required in order to understand fully the factors that influence sampling rates. Analysis of wipe samples taken from the inside of the sampler housing, revealed evidence that the housing surface scavenges particle bound PBDEs.     

Comparison of active and passive sampling for the determination of persistent organic pollutants (POPs) in sewage treatment plants

Semipermeable membrane devices (SPMDs) and conventional active sampling methods were used for the sampling of wastewater from the wastewater treatment plant of Thessaloniki, northern Greece. The occurrence of 22 POPs was shown by both sampling methods. The most abundant compounds were heptachlor-exo-epoxide and PCBs-52; -101 and -180. Concentrations of POPs detected by active sampling and those estimated by the SPMDs matched very well in some cases, but significant mismatches were also observed. Regression analysis of the results detected by both methods showed moderate correlations. The highest uptake rate of hydrophobic compounds by SPMDs was observed for analytes with log K(OW) between 5.5 and 6.0. Our data suggest that active and passive sampling are complimentary, and that at least for the outflow of a WWTP, SPMDs could be used for the routine monitoring of compounds that are listed at the Water Framework Directive of the European Commissions.     

Little effect of excessive biofouling on the uptake of organic contaminants by semipermeable membrane devices

The effects of water flow rate and antifouling agents on the extent of biofouling and on the uptake of non-polar organic contaminants by semipermeable membrane devices (SPMDs) were studied during four field experiments in the Western Wadden Sea. Biofouling densities on the sampler surface ranged from 0.3 to 16 g dry weight dm⁻². Water sampling rates were estimated from the dissipation rates of performance reference compounds (PRCs). The antifouling agents Irgarol and capsaicin (33 mg per ml triolein) had no noticeable effect on the extent of fouling, and caused only a 5–10% increase in the absorbed amounts. Enhanced flow rates had only a minimal effect on the amount of biofouling, but caused the water sampling rates to increase by a factor of 1.2–2. Increases in PRC-derived sampling rates were reflected by increases in the absorbed amounts for compounds that were in the linear uptake stage of the sampling process. The results imply (1) that extreme biofouling does not always result in reduced sampling rates, (2) that extreme biofouling does not preclude the existence of flow effects on the sampling rates, and (3) that differences in uptake rates are quantitatively reflected by the dissipation rates of PRCs.     

Passive water sampling via semipermfable membrane devices (SPMDS) in concert with bivalves in the Sacramento/San Joaquin River Delta

Freshwater clams (Corbicula fluminea) and the Huckins et al. (1) semi-permeable membrane sampling device (SPMD) were simultaneously deployed at three sites on the Sacramento and San Joaquin rivers in 1990. Both clams and the SPMDs were analyzed for sequestered pesticides and polychlorinated biphenyls (PCBs) by gas chromatography with electron capture detection (GC/ECD). Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and non-ortho PCBs were quantified by high resolution mass spectrometry (MS). In general, levels of organochlorine compounds were approximately 1.6 times higher in clams on a wet weight basis than in the SPMDs, and trends in accumulation were similar except where biofouling of the SPMD membranes decreased uptake rates. Comparisons between the normalized, average levels of PCDDs accumulated showed that while octachlorodibenzo-p-dioxin (OCDD) was most prevalent in both clams and SPMDs, much higher levels of 2,3,7,8 TCDD were found in the SPMDs than in the clams; 2,3,7,8 TCDD was 32% of the profile relative to the OCDD level for the SPMDs and <1% of the clam OCDD level. PCB levels showed the clams primarily accumulated hexachlorinated PCBs while the pentachlorinated and tetrachlorinated congeners were higher in the SPMDs. Differences in profiles for homologous series among the PCBs reveal that some congeners, especially those with 2,4,5 substitution, are more likely to bioaccumulate than those with lower chlorination or adjacent unsubstituted sites. GC/MS chromatograms indicate the SPMDs also sequestered several polyaromatic hydrocarbons. GC/ECD chromatograms indicate the presence of several unidentified, early eluting compounds in the SPMDs.     

In situ monitoring of urban air in Southern Italy with the Tradescantia micronucleus bioassay and semipermeable membrane devices (SPMDs)

This study was designed to assess toxic and genotoxic compounds in the urban air of Caserta, South Italy using cuttings from the plant Tradescantia #4430. In situ monitoring of gaseous pollutans was made at 17 sampling points in two seasons of the year. Genotoxicity was evaluated by recording the micronuclei in meiotic pollen mother cells (Trad-MCN assay). In addition, the passive sampler semipermeable membrane devices (SPMDs) were deployed at the sampling points with a significant increase in micronuclei frequency. SPMDs concentrated priority organic pollutants were identified by high performance liquid chromatography and gas chromatography, while toxicity and mutagenesis were assessed on the bacterium Vibrio fischeri using the Microtox and Mutatox systems respectively. Significant toxic and mutagenic effects were observed at different points on the town grid and SPMDs effectively concentrated trace contaminants. The relationship between what was present in the air sampled by SPMDs and the micronuclei frequency was also explored.     

Application of semipermeable membrane device (SPMD) to assess air genotoxicity in an occupational environment

Semipermeable membrane device (SPMD) is a passive sampler that sequesters lipophilic contaminants, mimicking the bioconcentration in the fatty tissue of organisms. This study was designed to assess the use of SPMD and biological tests (Comet assay and Ames test) for air monitoring. For this purpose an occupational environment with expected polycyclic aromatic hydrocarbons (PAHs) contamination (coke plant) was selected for a case study. The SPMDs were deployed in five occupational contaminated sites and in a control site. The SPMD dialysates were chemically analysed and examined for in vitro DNA-damaging activity in human cells (Jurkat) by Comet assay and for mutagenicity with the Ames test (TA98 strain, w/o S9). Total suspended particulates were also collected and analysed (GC–MS). No biological effect of SPMD extract was revealed in the control site. On the other hand, air samples collected with SPMDs within the coke plant showed variable degrees of genotoxic and mutagenic activity. The highest effects were associated with the highest PAH level recovered in the SPMDs extracts and in particulate samples.Results obtained support the sensitivity of biological tests associated to SPMD sampling for evaluating the health risk of potentially contaminated work environments highlighting the usefulness of SPMDs for environmental air quality monitoring.     

Combining polar organic chemical integrative samplers (POCIS) with toxicity testing to evaluate pesticide mixture effects on natural phototrophic biofilms

Polar organic chemical integrative samplers (POCIS) are valuable tools in passive sampling methods for monitoring polar organic pesticides in freshwaters. Pesticides extracted from the environment using such methods can be used to toxicity tests. This study evaluated the acute effects of POCIS extracts on natural phototrophic biofilm communities. Our results demonstrate an effect of POCIS pesticide mixtures on chlorophyll a fluorescence, photosynthetic efficiency and community structure. Nevertheless, the range of biofilm responses differs according to origin of the biofilms tested, revealing spatial variations in the sensitivity of natural communities in the studied stream. Combining passive sampler extracts with community-level toxicity tests offers promising perspectives for ecological risk assessment.     

Accumulation of organochlorine pesticides by semipermeable membrane devices using composite complex

Semipermeable membrane devices (SPMDs) were developed for passive in situ monitoring of organochlorine pesticides (OCPs) in aqueous solution in both laboratory and field (Pearl River Delta, China) studies. The device consisted of a thin film of neutral lipid triolein, enclosed in thin-walled tubing made of composite cellulose acetate membrane (CA) supported by linear low density polyethylene (LLDPE) (CAPE). Results from the laboratory and field application indicated that triolein-CAPE (TCAPE) could quickly and efficiently accumulate hydrophobic OCPs in water and uptake equilibrium could reached within 20h in the laboratory. Some mathematical relationships of TCAPE-water partition coefficient (logK(sw)), triolein-water partition coefficient (logK(tw)) and octanol-water partition coefficient (logK(ow)) were developed under the laboratory conditions. A good correlation of accumulation in TCAPE with r(2) values ranging from 0.55 to 0.86 for individual OCPs (n=8) and an excellent correlation of logK(sw) and logK(ow) was also obtained under the field conditions. The average OCPs concentration in the surface water could be estimated by measuring OCPs concentration in the device under the field conditions.     

Comparison between the polar organic chemical integrative sampler and the solid-phase extraction for estimating herbicide time-weighted average concentrations during a microcosm experiment

Polar organic chemical integrative samplers (POCIS) were exposed for 9 days in two different microcosms that contained river waters spiked with deethylterbuthylazine, terbuthylazine and isoproturon. The experiment was performed with natural light and strong turbulence (flow velocities of about 15-50cms(-1)) for reproducing natural conditions. The concentrations were kept relatively constant in the first microcosm (2.6-3.6mugl(-1)) and were variable in the second microcosm (peak concentrations ranged from 15 to 24mugl(-1) during the 3 day pulse phase). The time-weighted average (TWA) concentrations were determined with both POCIS and repetitive grab sampling followed by solid-phase extraction. The results showed a systematic and significant overestimation of the TWA concentrations with the POCIS most probably due to the use of sampling rates derived under low flow scenario. The results showed also that peak concentrations of pollutants are fully integrated by this passive sampler. Even if the POCIS should not provide very accurate concentration estimates without the application of adequate sampling rate values or the use of performance reference compounds, it can be a really useful tool for detecting episodic or short-term pollution events (e.g. increased herbicide concentrations during a flood), which may be missed with classical and low frequency grab sampling.