Uptake rates of semipermeable membrane devices (SPMDs) for PCDDs, PCDFs and PCBs in water and sediment

Investigation of organic micropollutant pollution in İzmit Bay: a comparative study of passive sampling and instantaneous sampling techniques

In this study, we used a comprehensive array of sampling techniques to examine the pollution caused by organic micropollutants in İzmit Bay for the first time. Our methodology contains spot seawater sampling, semi-permeable membrane devices (SPMDs) passive samplers for time-weighted average (TWA), and sediment sampling for long-term pollution detection in İzmit Bay, together. Additionally, the analysis results obtained with these three sampling methods were compared in this study. Over the course of two seasons in 2020 and 2021, we deployed SPMDs for 21 days in the first season and for 30 days in the second season. This innovative approach allowed us to gather sea water samples and analyze them for the presence of polycyclic aromatic hydrocarbons (Σ15 PAHs), polychlorinated biphenyls (Σ7 PCBs), and organochlorine pesticides (Σ11 OCPs). Using SPMD-based passive sampling, we measured micropollutant concentrations: PAHs ranged from 1963 to 10342 pg/L in 2020 and 1338 to 6373 pg/L in 2021; PCBs from 17.46 to 61.90 pg/L in 2020 and 8.37 to 78.10 pg/L in 2021; and OCPs from 269.2 to 8868 pg/L in 2020 and 141.7 to 1662 pg/L in 2021. Our findings revealed parallels between the concentrations of PAHs, PCBs, and OCPs in both SPMDs and sediment samples, providing insights into the distribution patterns of these pollutants in the marine ecosystem. However, it is worth noting that due to limited data acquisition, the suitability of spot sampling in comparison to instantaneous sampling remains inconclusive, highlighting the need for further investigation and data collection.

Simultaneous passive sampling of hydrophilic and hydrophobic emerging organic contaminants in water

Passive sampling techniques have been considered robust tools for monitoring freely dissolved concentrations of contaminants in aquatic systems. However, few passive samplers are currently available for the simultaneous sampling of both hydrophilic and hydrophobic chemicals. In this study, we developed a novel passive sampler (a hydrophilic-lipophilic balance sorbent-embedded cellulose acetate membrane (HECAM)) for estimating the time-weighted average (TWA) concentrations of both hydrophilic and hydrophobic organic contaminants in water. In our laboratorial controlled dynamic experiments, the accumulation results of thirty-seven target chemicals (including organophosphorus flame retardants, phenols, estrogens, organophosphorus pesticides, and triazine herbicides) with a wide polarity range (1.44 < log K_ow < 9.49) in the HECAM followed first-order kinetics well, and the passive sampling parameters were estimated successfully. The estimated sampling rates for the target chemicals in the HECAM ranged from 0.14 to 6.90 L d^-1 in the laboratory experiment, and the log K_sw (equilibrium partition coefficient between the sampler and water) values ranged from 2.75 to 6.00. The HECAM exhibited high sampling rate for moderately hydrophilic and moderately hydrophobic chemicals. The field validation study in an urban river resulted in the detection of four target chemicals (tris(chloroisopropyl)phosphate, tris(1,3-dichloroisopropyl)phosphate, prometryn, and 4-tert-octylphenol) by the HECAM at estimated TWA concentrations of 10.9-179.5 ng L^-1, which were in agreement with the measured levels found in traditional grab samples by solid-phase extraction. In summary, both the laboratory tests and field deployment showed practicable results for the HECAM passive sampling, which suggests that it is an efficient approach for simultaneous monitoring of hydrophilic and hydrophobic organic contaminants in water.

Synthesis of Graphene-like Films by Electrochemical Reduction of Polyhalogenated Aromatic Compounds and their Electrochemical Capacitor Applications

Graphene is a promising two-dimensional nanomaterial for many applications due to its exciting properties. In the past decade, a variety of techniques-each with its own set of advantages and disadvantages-have been developed to prepare graphene, and there are ongoing efforts to improve these techniques and to reveal new approaches. Here, we describe a simple and low-cost process for the bottom-up synthesis of graphene-like films. This new methodology involves a two-step procedure: (i) formation of polyaromatic ring structures by the repeated covalent coupling of aryl radicals generated from electrochemical reduction of polyhalogenated aromatic compounds in aprotic solvent, and (ii) production of carbon networks by heating of polyaromatic surface films. Accordingly, polymeric films were prepared on the electrodes by electrochemical reduction of polyhalogenated compounds such as hexafluorobenzene (HFB), hexachlorobenzene (HCB), and hexabromobenzene (HBB), and then polymer films were annealed at 400 °C for 30 min. The structure and surface characteristics of electrodeposited carbon films under self- and thermal-annealing conditions were studied by spectroscopic and morphological techniques. Also, the capacitance performance of the films was evaluated by means of cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. Results indicate that graphene-like carbon films can be achieved by use of the electrochemical approach under mild conditions without expensive equipment, and also that these carbon materials are very promising for low-cost energy-storage devices.

Monitoring of organic pollutants in marine environment by semipermeable membrane devices and mussels: accumulation and biochemical responses

This study involves the monitoring of organic pollutants using transplanted mussels (Mytilus galloprovincialis) as bioindicator organisms and semipermeable membrane devices (SPMDs) as passive samplers. Mussels and SPMDs were deployed to marinas, shipyards and shipbreaking yards on the coastal area of Turkey and retrieved after 60 days. Polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB) and organochlorine pesticide (OCP) compounds were analysed with high-resolution GC-MS. Total PAH concentrations in SPMDs and mussels ranged from 200 to 4740 ng g sampler^-1 and from 7.0 to 1130 ng g^-1 in wet weight (ww). PCB and OCP concentrations in SPMDs changed between 0.04-200 and 4.0-26 ng g sampler^-1, respectively. The highest PCB (190 ng g^-1 ww) and OCP (200 ng g^-1 ww) concentrations in mussels were measured at shipyard stations. A strong correlation was observed between the PAH and PCB concentrations in SPMDs and mussels. Enzyme assays (acetylcholinesterase, ethoxyresorufin-O-deethylase, glutathione S-transferase, glutathion reductase and carboxylesterase activities) were performed as biomarkers to reveal the effects of pollution on the mussels. There was no clear relationship found between the enzyme levels and the pollutant concentrations in mussels. Integrated biomarker responses were calculated to interpret the overall effect of pollutants.

Using SPMDs for monitoring hydrophobic organic compounds in urban river water in Korea compared with using conventional water grab samples

We aimed to verify the effectiveness of semi-permeable membrane devices (SPMDs) for monitoring hydrophobic organic compounds, such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), that are not easy to detect using conventional grab samples (because of their low concentrations), in water. We used SPMDs and grab samples to monitor PCBs and PBDEs upstream and downstream of a sewage treatment plant (STP) in the Suyeong River in Busan, Korea. Concentrations in three different phases (freely dissolved, apparently dissolved, and particulate) were measured, to investigate the aquatic fate of PCBs and PBDEs. The freely dissolved (SPMD) concentrations were 2-3 times higher than the apparently dissolved and particulate phase (grab sample) concentrations. No meaningful relationships were found between the total PCB and PBDE concentrations of the grab sample and SPMD sample because of the different partitioning behaviors and detection frequencies of the individual chemicals. However, the summed concentrations of specific PCB and PBDE congeners (that were abundant in all samples) in the grab and SPMD samples correlated well (r(2)=0.7451 for PCBs 28+52+153, r(2)=0.9987 for PBDEs 28+47+99). The PBDE concentrations measured using SPMDs decreased with increasing distance from the STP, but no apparent dilution effect was found in the grab samples. Our results show that SPMDs could be used to support grab sampling for specific chemicals, or to trace chemical sources (such as STPs) to the aquatic environment.

Using SPMDs to monitor the seawater concentrations of PAHs and PCBs in marine protected areas (Western Mediterranean)

Aqueous concentrations of individual polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were determined in coastal sites of two marine protected areas (MPAs), that is, Asinara and the La Maddalena Archipelago, in Sardinia (Western Mediterranean Sea). The use of semi-permeable membrane devices (SPMDs) enabled the detection of dissolved PAHs and PCBs, even in very low concentrations of (pgL(-1)), in seawater. The results reveal significant differences between the two sampling areas relative to the concentration of the individual PAHs, which provide information concerning the pollution sources affecting relatively pristine environments. The PCBs were generally observed at levels below the detection limits of the utilised method.

Water concentrations of PAH, PCB and OCP by using semipermeable membrane devices and sediments

Water concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were estimated from semipermeable membrane devices (SPMDs) and from sediment pollutant concentrations. SPMDs were deployed in the Istanbul Strait and Marmara Sea and retrieved after 7 and 21 days. Performance reference compounds (PRCs) were used to determine the site-specific sampling rates of the compounds. Water concentrations (C(w)) of the analyzed compounds estimated by using two different calculation methods for SPMDs were found similar. C(w) of total PAHs estimated from SPMDs (C(w-spmd)) were found between 13 and 79 ng L⁻¹ and between 7.0 and 68 ng L⁻¹ for 7 and 21 days of deployments respectively. Water concentrations of PCBs using sediment data was found as between 0.001 and 11.0 ng L⁻¹. The highest value of C(w-spmd) for two deployments were 2.8 ng L⁻¹ for OCPs. C(w) estimated from sediment concentrations were generally higher than those estimated from SPMDs.

Overview of passive Chemcatcher sampling with SPE pretreatment suitable for the analysis of NPEOs and NPs

The European Union Water Framework Directive (WFD; 2000/60/EC) is an important piece of environmental legislation that protects rivers, lakes, coastal waters and groundwaters (EC 2000). The implementation of the WFD requires the establishment and use of novel and low-cost monitoring programmes, and several methods, e.g. passive sampling, have been developed to make the sampling process more representative compared to spot sampling. This review considers passive sampling methods focusing mainly on a passive sampler named Chemcatcher®, which has been used for monitoring several harmful compounds in aquatic environments. Also, the sample treatment and analysis of nonylphenol ethoxylates (NPEOs) and nonylphenol (NPs) from water using solid phase extraction (SPE) is briefly summarized. The procedure of Chemcatcher passive sampling is quite similar to that of the SPE extraction since it concentrates the studied compounds from water as well. After sampling, the accumulated substances are extracted from the receiving phase of the sampler. The concentrations of NPEOs and NPs are currently monitored by taking conventional spot samples; SPE can be successfully used as a pretreatment procedure. Chemcatcher® passive sampling technique is a simple and useful monitoring tool and can be applied to new chemicals, such as NPEOs and NPs in aquatic environments.

Incorporating contaminant bioavailability into sediment quality assessment frameworks

The recently adopted sediment quality assessment framework for evaluating bay and estuarine sediments in the state of California incorporates bulk sediment chemistry as a key line of evidence (LOE) but does not address the bioavailability of measured contaminants. Thus, the chemistry-based LOE likely does not provide an accurate depiction of organism exposure in all cases, nor is it particularly well suited for assessment of causality. In recent years, several methods for evaluating the bioavailability of sediment-associated contaminants have emerged, which, if optimized and validated, could be applied to improve the applicability and broaden the scope of sediment quality assessment. Such methods include equilibrium-based biomimetic extractions using either passive sampling devices (PSDs) or measures of rapidly desorbing contaminant pools, which provide information compatible with existing mechanistic approaches. Currently, these methods show promise in relating bioaccessible chemicals to effects endpoints, including bioaccumulation of hydrophobic organic compounds and/or toxicity due to metals. Using these methods, a bioavailability LOE for organics is proposed based on PSD and equilibrium partitioning theory that can be employed as an independent LOE or in assessing causality in tiered toxicity identification evaluations. Current and future research should be aimed at comparing the performance of PSDs and their relationships with effects concentrations, field validation of the most promising methods, addressing contaminant mixtures, further developing the parameterization of the proposed bioavailability LOE, and providing a better understanding of the underlying diagenetic cycling of metal contaminants that lead to exposure, affect bioavailability, and drive adverse outcomes.

Levels and distribution of dissolved hydrophobic organic contaminants in the Morava river in Zlín district, Czech Republic as derived from their accumulation in silicone rubber passive samplers

Dissolved waterborne polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were assessed over a period of one year at five sampling sites in a model industrial region in the Czech Republic using silicone rubber passive samplers. The spatial variability of POPs in the studied region in water was small and diffusive pollution sources predominate. Concentrations of the most volatile PAHs decreased with increasing water temperature in the whole region, which reflects the seasonality in atmospheric deposition. The dissolved concentrations of more hydrophobic PAHs, PCBs and OCPs in and downstream the industrial zone are related to desorption from suspended particles. Upstream the industrial area, a positive correlation of dissolved and particle-bound contamination was observed only for DDT metabolites and hexachlorobenzene. Calculated fugacities in water and bottom sediment indicated a fair degree of equilibrium between these compartments for OCPs and PCBs, whereas sediment represented a potential source of PAHs.

Bottom sediment as a source of organic contaminants in Lake Mead, Nevada, USA

Treated wastewater effluent from Las Vegas, Nevada and surrounding communities' flow through Las Vegas Wash (LVW) into the Lake Mead National Recreational Area at Las Vegas Bay (LVB). Lake sediment is a likely sink for many hydrophobic synthetic organic compounds (SOCs); however, partitioning between the sediment and the overlying water could result in the sediment acting as a secondary contaminant source. Locating the chemical plumes may be important to understanding possible chemical stressors to aquatic organisms. Passive sampling devices (SPMDs and POCIS) were suspended in LVB at depths of 3.0, 4.7, and 6.7 (lake bottom) meters in June of 2008 to determine the vertical distribution of SOCs in the water column. A custom sediment probe was used to also bury the samplers in the sediment at depths of 0-10, 10-20, and 20-30cm. The greatest number of detections in samplers buried in the sediment was at the 0-10cm depth. Concentrations of many hydrophobic SOCs were twice as high at the sediment-water interface than in the mid and upper water column. Many SOCs related to wastewater effluents, including fragrances, insect repellants, sun block agents, and phosphate flame retardants, were found at highest concentrations in the middle and upper water column. There was evidence to suggest that the water infiltrated into the sediment had a different chemical composition than the rest of the water column and could be a potential risk exposure to bottom-dwelling aquatic organisms.

Accumulation of polychlorinated dibenzo-p-dioxins and furans in Atlantic cod (Gadus morhua)--cage experiments in a Norwegian Fjord

Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) have been discharged to the Frierfjord (Eastern Norway) for 50 yr. The discharges, dominated by PCDF, were highest in the early 1970s and subsequently reduced 3-4 orders ofmagnitude to 1-2 g toxic equivalents (TEQ)/yr in 1992-2002. Atlantic cod (Gadus morhua) and semipermeable membrane devices (SPMD) were placed in cages for 6 wk in the Frierfjord and at two locations in the adjacent Langesundsfjord. The objective was to clarify the importance of PCDD/PCDF accumulation from the water directly compared to important food items. Little accumulation of PCDD and a significant accumulation of PCDF were observed in the SPMD. Accumulation of PCDF was observed in fish at Kastebukta, closest to the original source, but not at the other two stations. The PCDF concentrations detected in caged fish at Kastebukta were low compared to concentrations found in locally caught fish. Data indicate that it would take 4-55 yr to reach the PCDF-levels observed in locally caught cod if they were exposed only through water. Our results indicate that accumulation of PCDF/PCDD from prey is more important than accumulation from water.

Calibration of silicone rubber passive samplers: experimental and modeled relations between sampling rate and compound properties

Sampling rates (Rs) for silicone rubber (SR) passive samplers were measured under two different hydrodynamic conditions. Concentrations were maintained in the aqueous phase by continuous equilibration with SR sheets of a large total surface area which had been spiked with polycyclic aromatic hydrocarbons and/or polychlorinated biphenyls. Test sheets made of the same SR but of much smaller surface area were used to measure the uptake rate. Measured Rs values decreased with increasing passive sampler-water partition coefficient (Kpw) according to Rs approximately Kpw(-0.08) under both hydrodynamic conditions. This decrease is not significantly different from modeled values if the uncertainty of the diffusion coefficients in water is included. Modeling also confirmed that uptake of the test compounds under the experimental conditions was entirely controlled by diffusion in the water phase. A model using Rs approximately M(-0.47) is suggested for extrapolation of Rs estimated from the dissipation of performance reference compounds to target compounds in a higher hydrophobicity range.

Passive sampling as a tool for obtaining reliable analytical information in environmental quality monitoring

Passive sampling technology has been developing very quickly for the past 20 years, and is widely used for monitoring pollutants in different environments, for example air, water, and soil. It has many significant advantages, including simplicity, low cost, no need for expensive and complicated equipment, no power requirements, unattended operation, and the ability to produce accurate results. The present generation of passive samplers enables detection and analysis of bioavailable pollutants at low and very low concentrations and investigation of the environmental concentration of organic and inorganic pollutants not only on the local scale but also on continental and global scales. This review describes the current application of passive sampling techniques in environmental analysis and monitoring, under both equilibrium and non-equilibrium conditions.

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.

Using SPMDs to monitor water column concentrations of PCDDs, PCDFs and dioxin-like PCBs in Port Jackson (Sydney Harbour), Australia

Semipermeable membrane devices (SPMDs) were deployed on two occasions throughout Sydney Harbour, Australia, along a 25 km transect. They were used to measure spatial and temporal variation in the available concentrations of 7 polychlorinated dibenzo-p-dioxins (PCDDs) and 10 polychlorinated dibenzofurans (PCDFs) and 12 dioxin-like polychlorinated biphenyls (PCBs) in the water column. The relative percent difference (%RPD) among spatially replicated cages (within 0.13-0.41 km) ranged from less than 8% to greater than 66% across all congeners and was greater for WHO(05)-TEQ(DFP) (average=36%), PCDFs (average=34%) and PCDDs (average=33%) than PCBs (average=23%). Total PCDD (SigmaPCDDs) concentrations ranged between 2.7 and 84 pg L(-1), SigmaPCDF concentrations ranged from 0.15 to 7.2 pg L(-1), SigmaPCB concentrations ranged between 21 and 540 pg L(-1) and WHO(05)-TEQ(DFP) ranged from 0.069 to 1.85 pg L(-1). Highest concentrations were measured in SPMDs deployed in Homebush Bay and concentrations generally declined with distance from Homebush Bay. SPMDs detected changes in congener profiles downstream with OCDD, 2,3,7,8-TCDF and PCBs 189, 157, 167, and 126 increasing in proportion with distance from Homebush Bay. There was a large increase in the daily accumulation of the analytes from winter to summer resulting in an average 3.9-fold increase in the predicted concentration at one site with matched SPMDs.

Removal of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans by three coagulants in simulated coagulation processes for drinking water treatment

Surface water from Guangzhou to which standard polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were added was treated by coagulation with ferric chloride (FC), polyaluminium chloride (PAC), and aluminium sulfate (AS) at optimum removal dosages for nature organic matter (NOM) to assess the polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) removal efficiencies. PCDD/Fs in suspended particulate matter (SPM) and treated water (TW) after coagulation were analysed. Low residual levels of PCDD/Fs were found in treated water after coagulation: 0.8% for FC, 0.9% for PAC, and 3.1% for AS. The removal efficiency calculated using these results was >99% for FC and PAC and 97-98% for AS. Most PCDD/Fs congeners could be removed by the three coagulation processes; the removal efficiency of FC and PAC was similar, and slightly higher than that of AS. The results also demonstrate that coagulation with FC preferentially removed tetra- and penta-substituted PCDD/Fs from raw water.

Predicting bioavailability of PAHs in field-contaminated soils by passive sampling with triolein embedded cellulose acetate membranes

Triolein embedded cellulose acetate membrane (TECAM) was used for passive sampling of the fraction of naphthalene, phenanthrene, pyrene and benzo[a]pyrene in 18 field-contaminated soils. The sampling process of PAHs by TECAM fitted well with a first-order kinetics model and PAHs reached 95% of equilibrium in TECAM within 20 h. Concentrations of PAHs in TECAM (C(TECAM)) correlated well with the concentrations in soils (r(2)=0.693-0.962, p<0.001). Furthermore, concentrations of PAHs determined in the soil solution were very close to the values estimated by C(TECAM) and the partition coefficient between TECAM and water (K(TECAM-w)). After lipid normalization nearly 1:1 relationships were observed between PAH concentrations in TECAMs and earthworms exposed to the soils (r(2)=0.591-0.824, n=18, p<0.01). These results suggest that TECAM can be a useful tool to predict bioavailability of PAHs in field-contaminated soils.

Semipermeable membrane device (SPMD) for monitoring PCDD and PCDF levels from a paper mill effluent in the Androscoggin River, Maine, USA

Paper mill effluents may contain polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) that are normally generated due to chlorinated bleaching of pulp and paper. We used the semipermeable membrane device (SPMD) to monitor PCDD/F levels upstream and downstream of a paper mill on the Androscoggin River, in Jay (ME). Following the 36 day deployment, SPMD dialysis and cleanup, the samples were analyzed by HRGC/HRMS. Total concentrations of PCDD/Fs in SPMDs (sum of all tetra-through octachlorinated congeners) ranged from 4.71 pg g(-1) to 26.26 pg g(-1). Five out of the targeted 17 toxic congeners were detected, including: 2,3,7,8-TCDF; 1,2,3,7,8-PeCDF; 2,3,4,7,8-PeCDF; 1,2,3,4,6,7,8-HpCDD and OCDD. Permeability reference compounds (PRCs) were used for in situ calibration of the SPMD sampling rate (Rs). In all sites, water concentrations were the highest for OCDD (0.081-0.103 pg l(-1)), and the lowest for 1,2,3,7,8-PeCDF (0.005-0.009 pg l(-1)). There was not a consistent pattern of upstream-downstream gradient in the PCDD/F levels. This suggested that processes other than the mill in Jay (multiple sources, river dynamics) governed the flux of PCDD/Fs in the sampling locations. The SPMD results were validated by comparison to other studies on the Androscoggin River and elsewhere, confirming the potential of the device as a useful monitoring technique for PCDD/Fs in large river systems.

Field trial and modeling of uptake rates of in situ lipid-free polyethylene membrane passive sampler

Lipid-free polyethylene membrane tubing (LFT) has been further developed in response to a growing need for an inexpensive and simple time-integrative sampling device for dissolved hydrophobic contaminants in water. The LFT sampler is based on the diffusion of dissolved hydrophobic target compounds through the aqueous boundary layer and into the polyethylene membrane, mimicking uptake by organisms. We demonstrate through laboratory and field validation studies that LFT provided the same benefits as many other passive sampling devices, withoutthe potential of analytical interference from lipid impurities. A total of 370 LFTs and semipermeable membrane devices were deployed for 21 days in paired studies at highly urbanized, undeveloped, and two Superfund sites, representing several river conditions. A simple internal surrogate spiking method served as an in situ calibration indicator of the effects of environmental conditions on the uptake rates. A modified extraction method for the LFT increased recoveries while decreasing solvent use and labor compared to other organic extraction procedures. LFT sampling rates were estimated using ratios, in situ calibration and modeling for over 45 target analytes, including PAHs, PCBs, and pesticides.

Biomimetic accumulation of PAHs from soils by triolein-embedded cellulose acetate membranes (TECAMs) to estimate their bioavailability

A new passive sampling device (PSD), a triolein-embedded cellulose acetate membrane (TECAM), was used to biomimetically accumulate naphthalene, phenanthrene, pyrene and benzo[a]pyrene from ten spiked soils and a soil spiked with different concentrations of these polycyclic aromatic hydrocarbons (PAHs). TECAM exposure conditions were optimized. The quantities of PAHs accumulated by TECAMs were positively and linearly related to their concentrations in the soil. PAHs accumulated by TECAMs were negatively related to soil organic matter (SOM) and positively related to the dissolved organic carbon (DOC) according to the results obtained from ten spiked soils. Aging time (1-150 days) had a significant effect on accumulation of PAHs by TECAMs. A good linear relationship (R2=0.970-0.993) was observed between TECAM-accumulated PAHs and PAHs accumulated by earthworms (Eisenia andrei). The data indicate that TECAM represents a useful surrogate to estimate the bioavailability of PAHs and perhaps other hydrophobic organic contaminants (HOCs) in soils.

Occupational and indoor air exposure to persistent organic pollutants: a review of passive sampling techniques and needs

Exposure to persistent organic pollutants (POPs) and related compounds such as PCBs, brominated flame retardants, organochlorine pesticides and PAHs is regarded as an important environmental risk factor for humans. Recently concerns about POPs resulted in the international protocol called the Stockholm Convention on POPs. Air quality standards (indoor, outdoor and occupational) for PAHs and other POPs will also be applied in the EU in the future. This will bring requirements for monitoring, to check for compliance and to reduce human exposures to POPs. This can occur from point sources and in various microenvironments, indoors, outdoors and in workplaces. Monitoring can be undertaken either by an active (pumped) method or using a passive (diffusive) air sampling (PAS) device. To date, PAS for POPs have mainly been used as integrating (long-term) samplers for ambient (outdoor) air. However, there are several reasons to develop PAS for monitoring of POPs in occupational and indoor environments. We discuss the potential advantages, limitations and developments needed, so that PAS can be used reliably and routinely indoors and in occupational settings for POPs.

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 16g 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.

Estimation of the uptake rate constants for polycyclic aromatic hydrocarbons accumulated by semipermeable membrane devices and triolein-embedded cellulose acetate membranes

In this paper we report an extension of our previous work on the triolein-embedded cellulose acetate membrane (TECAM) as a passive sampling device (PSD) and describe the results from simultaneous exposure of TECAMs and triolein-containing semipermeable membrane devices (SPMDs) to PAHs in lake water for 16 days. The data obtained provided a comparison of the uptake rates of specific PAHs by the two PSDs. Using 16-day accumulation tests, similar PAH distribution patterns in TECAMs and in SPMDs (R2 = 0.89, p < 0.0001) were observed. However, it was noted that TECAMs could take up greater amounts of PAHs than SPMDs (735 ng/g of TECAM vs 630 ng/g of SPMD). Uptake rate constants of TECAMs and SPMDs for 16 priority pollutant (PP) PAHs, corrected for dissolved organic carbon, ranged from 0.28 to 2.94 L d(-1) and from 0.16 to 0.91 L d(-1), respectively. The elimination rate constants of TECAMs were 1.4-6.7 times greater than those observed for SPMDs, thereby indicating that PAHs required shorter times to achieve equilibrium in TECAMs than in SPMDs. Thus, the results of the present study suggest that TECAMs have significant potential as a good monitor to assess the pollution of hydrophobic pollutants in aquatic environments.

Ionic liquid-containing semipermeable membrane devices for monitoring the polycyclic aromatic hydrocarbons in water

Ionic liquid-containing semipermeable membrane devices (IL-SPMDs) were developed to monitor the polycyclic aromatic hydrocarbons in water. Uptake kinetics of naphthalene, 1-methylnaphthalene, phenanthrene, pyrene, chrysene by layflat low-density polyethylene tubing (15 cm x 2 cm) filled with 0.5 ml 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid were studied in a laboratory continuous-flow system for the duration of 16 days. The device concentration factors were in the range of 830-7800 for the studied PAHs. The kinetic parameters of IL/water partition coefficients, analytes uptake rate constants and sampling rates were estimated using mathematical models. These parameters were used in the field experiment to estimate the concentrations of the PAHs in Lanzhou section of Yellow River in China, with the result in comparison with that obtained by triolein-SPMD.

Review of passive accumulation devices for monitoring organic micropollutants in the aquatic environment

Over the past 15 years passive sampling devices have been developed that accumulate organic micropollutants and allow detection at ambient sub ng/l concentrations. Most passive accumulation devices (PADs) are designed for 1-4 weeks field deployment, where uptake is governed by linear first order kinetics providing a time weighted average of the exposure concentration. Semipermeable membrane devices (SPMDs) are the most comprehensively studied PADs, but other samplers may also be considered for aquatic monitoring purposes. The applicability of the PADs is reviewed with respect to commonly monitored aqueous matrices and compounds, the detection limits, and for use in quantitative monitoring related to requirements embedded in the EU Water Framework Directive, the US and EU Water Quality Criteria, and the Danish monitoring aquatic programme. The PADs may monitor >75% of the organic micropollutants of the programmes. Research is warranted regarding the uptake in PADs in low flow environments and for the development of samplers for polar organic compounds.

Electrochemical reduction of organohalogen compound by noble metal sintered electrode

1,2,3-Trichlorobenzene (1,2,3-TCB) was used as a model sample of persistent organic pollutants (POPs) which was dechlorinated by a closed electrochemical reduction system under an inert gas atmosphere. The effect of the electrode material was examined in the reaction. Dechlorination yields in different type of cathode electrodes using sintered RuO2 (major)/Pt/PdO, sintered Pt(major)/IrO2/RuO2, sintered RuO2, sintered PdO, sintered Pt, sintered PdO/Pt, sintered Pd/Pt and plain Pd plate were 91%, 81%, 59%, 96%, 53%, 97%, 82% and 70% respectively, at reaction times of 60 or 120 min. The reaction was exothermic after initially starting at room temperature. This electrochemical reduction system was friendly technology for environment using cation exchange membrane, supplying sodium ions from sodium hydroxide solution as anolyte. Trace amounts of dichlorobenzene, as products of stepwise dechlorination, were observed with different pathways, depending on the electrode material. Electrodes with Ru and Pd were selective mainly for meta-position dechlorination, while those with Pt groups selective mainly for ortho-position (o-position) dechlorination. A PdO sintered electrode had an especially high selectivity for meta-position (m-position) dechlorination. The results suggest that dechlorination is an electrocatalytic reduction in this cation supply system.

Efficiency assessment of wastewater treatment plant based on SPMD sampling

The efficiency of treatment processes forboth municipal and industrial wastewater (treatment plant-Ostrava, Czech Republic) focused on persistent organic pollutants (POPs) was assessed. Semipermeable membrane devices (SPMDs) as a sampling system were applied. Exposed SPMDs were analyzed both for chemical contaminants of POPs and toxicity response. The chemical analyses of PAHs were made by HPLC-FLD, PCDD/Fs and PCBs were analysed by GC/MS/MS on GCQ or PolarisQ (Thermoquest). Ecotoxicity data on chlorococcal alga Desmodesmus subspicatus (Scenedesmus subspicatus) and luminescent bacteria Vibrio fischeri are presented here. All toxicity data as effective volume Vtox are expressed. The results show good treatment ability of the treatment plant and proved used system as an appropriate tool for efficiency assessment of treatment and/or decontamination processes.

Bioavailability of sediment-associated PCDD/Fs and PCDEs: relative importance of contaminant and sediment characteristics and biological factors

Factors that determine accumulation of sediment-associated polychlorinated dibenzo-p-dioxins and furans and polychlorinated diphenyl ethers into semipermeable membrane devices (SPMDs) and benthic oligochaete worms (Lumbriculus variegatus) were examined. These factors included both physical-chemical and structural characteristics of the contaminants (water solubility, lipophilicity, dipole moment, molecular size, and conformation) and sediment characteristics (organic carbon content, particle size, aromaticity, and polarity of organic carbon). The results of partial least squares regression analysis indicated that lipophilicity alone is not a sufficient predictor for contaminant bioaccumulation potential, even though it is a significant contributor. It was shown that contaminant molecular size and conformation (specifically planarity/nonplanarity) as well as sediment characteristics also have a significant role. The studied factors contributed up to 63-88% of the variation in accumulation data for SPMDs and 50-65% for oligochaetes. Comparison of (bio)accumulation factors (BAF28d for oligochaetes and AF28d for SPMDs) revealed that accumulation of contaminants in oligochaetes is largely influenced by biological factors (e.g., feeding habits), while the physical-chemical nature of the process is emphasized for SPMDs.

Fish bioaccumulation and biomarkers in environmental risk assessment: a review

In this review, a wide array of bioaccumulation markers and biomarkers, used to demonstrate exposure to and effects of environmental contaminants, has been discussed in relation to their feasibility in environmental risk assessment (ERA). Fish bioaccumulation markers may be applied in order to elucidate the aquatic behavior of environmental contaminants, as bioconcentrators to identify certain substances with low water levels and to assess exposure of aquatic organisms. Since it is virtually impossible to predict the fate of xenobiotic substances with simple partitioning models, the complexity of bioaccumulation should be considered, including toxicokinetics, metabolism, biota-sediment accumulation factors (BSAFs), organ-specific bioaccumulation and bound residues. Since it remains hard to accurately predict bioaccumulation in fish, even with highly sophisticated models, analyses of tissue levels are required. The most promising fish bioaccumulation markers are body burdens of persistent organic pollutants, like PCBs and DDTs. Since PCDD and PCDF levels in fish tissues are very low as compared with the sediment levels, their value as bioaccumulation markers remains questionable. Easily biodegradable compounds, such as PAHs and chlorinated phenols, do not tend to accumulate in fish tissues in quantities that reflect the exposure. Semipermeable membrane devices (SPMDs) have been successfully used to mimic bioaccumulation of hydrophobic organic substances in aquatic organisms. In order to assess exposure to or effects of environmental pollutants on aquatic ecosystems, the following suite of fish biomarkers may be examined: biotransformation enzymes (phase I and II), oxidative stress parameters, biotransformation products, stress proteins, metallothioneins (MTs), MXR proteins, hematological parameters, immunological parameters, reproductive and endocrine parameters, genotoxic parameters, neuromuscular parameters, physiological, histological and morphological parameters. All fish biomarkers are evaluated for their potential use in ERA programs, based upon six criteria that have been proposed in the present paper. This evaluation demonstrates that phase I enzymes (e.g. hepatic EROD and CYP1A), biotransformation products (e.g. biliary PAH metabolites), reproductive parameters (e.g. plasma VTG) and genotoxic parameters (e.g. hepatic DNA adducts) are currently the most valuable fish biomarkers for ERA. The use of biomonitoring methods in the control strategies for chemical pollution has several advantages over chemical monitoring. Many of the biological measurements form the only way of integrating effects on a large number of individual and interactive processes in aquatic organisms. Moreover, biological and biochemical effects may link the bioavailability of the compounds of interest with their concentration at target organs and intrinsic toxicity. The limitations of biomonitoring, such as confounding factors that are not related to pollution, should be carefully considered when interpreting biomarker data. Based upon this overview there is little doubt that measurements of bioaccumulation and biomarker responses in fish from contaminated sites offer great promises for providing information that can contribute to environmental monitoring programs designed for various aspects of ERA.

Polycyclic aromatic hydrocarbons in a semiaquatic plant and semipermeable membrane devices exposed to air in Thailand

Semipermeable membrane devices (SPMDs) were deployed at six sites in the Bangkok region, Thailand, to investigate spatial variations in atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs). Sampling sites affected by various levels of traffic intensity were studied. In addition, PAH levels were determined in a common human food plant (water spinach) harvested from canals and ponds in the sampling areas. Significant differences in atmospheric PAH concentrations between sites were found, with 10 times higher PAH levels in the urban areas compared to the rural areas. Increasing concentrations of 1-methylphenanthrene relative to phenanthrene were found in the urban air close to the city center, indicating that traffic probably contributed to the higher PAH concentrations detected. Due to SPMD's passive sampling technique, their long-term operation and high ability to detect spatial differences, they proved to be suitable for semiquantitative field studies of PAHs. The PAH compounds sampled with SPMDs were mainly associated with gaseous PAHs, while both gas phase and particle-bound PAHs were detected in the plant samples. The relative abundance ratios of some PAHs in the plants were not well correlated with the ratios detected in the SPMDs, indicating that gas-phase exposure made low contribution to the PAH concentrations in the plants. However, similarities in the profiles of 3-ring PAHs between the SPMD and plant samples indicate that gas-phase exchange occurs between the atmosphere and the plants.

Review of the background and application of triolein-containing semipermeable membrane devices in aquatic environmental study

This paper briefly reviews research on passive in situ samplers for aquatic environments but focuses on the development and application of the triolein-containing semipermeable membrane device in aquatic environmental monitoring. Special attention is paid to the calibration of the devices, quality control issues, and its potential uses in environmental assessments of aquatic contaminants. Also, the suitability of the technique for incorporation with selected bioassays is examined.