Evaluation and in situ assessment of photodegradation of polyaromatic hydrocarbons in semipermeable membrane devices deployed in ocean water

Semipermeable membrane devices (SPMDs) were deployed in water using four different methods: a typical SPMD cage with and without a mesh cover, a bowl chamber and without any protection. In addition to routinely used performance reference compounds (PRCs), perdeuterated dibenz[a,h]anthracene was added. Due to its high sampler to water partition coefficient no measurable clearance due to diffusion was expected during the deployment period, hence any observed loss could be attributed to photodegradation. The loss of PRCs was measured and SPMD-based water concentrations determined. Results showed that a typical SPMD deployment cage covered with mesh provided the best protection from photodegradation. Samplers which had undergone the highest photodegradation underestimated PAH water concentrations by up to a factor of 5 compared to the most protected SPMDs. This study demonstrates that the potential for photodegradation needs to be addressed when samplers are deployed in water of low turbidity.     

Spiking of performance reference compounds in low density polyethylene and silicone passive water samplers

A method for spiking performance reference compounds (PRCs) into low density polyethylene (LDPE) and silicone polymers is described. This method is based on equilibration of the polymers in aqueous/methanolic solutions of PRCs. Equilibration times range from minutes to hours for perdeuterated polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) with a hydrophobicity in the range 3.9 < logKow < 7.7. Best results were obtained for methanol-water ratios of 80/20 (v/v). The method allows for the use of PRCs for in situ calibration of the uptake kinetics of these solvent-free sampling phases in a similar way as for semipermeable membrane devices (SPMDs).     

Polycyclic aromatic hydrocarbon sampling in wastewaters using semipermeable membrane devices: accuracy of time-weighted average concentration estimations of truly dissolved compounds

Semipermeable membrane devices (SPMDs) previously spiked with performance reference compounds were exposed in wastewater. After 6 days of exposure, 13 polycyclic aromatic hydrocarbons (PAHs) were quantified in SPMDs. Exchange rate constants and time-weighted average (TWA) concentrations of SPMD-available PAHs in water were calculated. The bias of using SPMDs to estimate an actual TWA concentration if the concentration in water fluctuates, as can be expected in wastewater, was studied with numerical simulations. The bias increased with the exchange rate constant. However, most exchange rate constants evaluated in SPMDs exposed in wastewater were small enough for SPMDs to estimate a TWA concentration of PAHs even when the water concentration varied. TWA-SPMD-available concentrations were always below total dissolved (operationally defined as 0.7 microm) concentrations, indicating that part of the dissolved PAHs was not available for sampling. In situ partitioning coefficients K(DOC) were computed and found to be slightly higher than data from the literature. This confirms that only truly dissolved PAHs should be sampled by SPMDs in wastewater.     

Field use of semipermeable membrane devices (SPMDs) for passive air sampling of polycyclic aromatic hydrocarbons: Opportunities and limitations

Semipermeable membrane devices (SPMDs) were used for measurements in air of twelve polycyclic aromatic hydrocarbons (PAHs) in two Genoa locations, both on building roofs, distant 300 m from each other. The first, site A, was in front a dismissing steel complex and the second, site B, was in an urban area overlooking a busy thoroughfare. SPMDs were deployed contemporary at the two sites, in nine monthly samplings, from April 2007 to May 2008. The amount of sequestered PAHs, in sites A and B, ranged between 61–267 ng SPMD^?1 d^?1 and 50–535 ng SPMD^?1 d^?1, respectively.PAHs profiles highlighted seasonal differences and suggested the possible role of different PAHs sources in the two areas. In particular, the contribution of remediation works of the steel complex was observed in site A. Moreover, a naphthalene leak from a tank, into the former industrial area, and a fire broke out near site A, were registered by time-integrated measurements of SPMDs.However, the strong dependence between amount of sequestered PAHs and air temperature needs further studies to distinguish between uptake rate variability and seasonal contribution of different sources. Finally, to measure air concentrations with reasonable accuracy, it should be very important to have certified sampling rates for all individual PAHs.     

Levels of persistent organic pollutants in the Neretva River (Bosnia and Herzegovina) determined by deployment of semipermeable membrane devices (SPMD)

The main objective of this study was to determine levels of certain persistent organic pollutants (POPs) in Neretva River, Bosnia and Herzegovina (BiH), which is currently facing implementation of the Stockholm Convention on persistent organic pollutants (POPs) and environmental protection strategies. This is the very first report on the deployment of semipermeable membrane devices (SPMDs) in BiH. SPMDs were used for continuous 3-weeks sampling of POPs at three locations, covering 220 km long stream of the Neretva River. Water concentrations of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polybrominated diphenylethers (PBDEs) were calculated using performance reference compounds (PRCs). The total OCP concentrations ranged from 40 to 140 pg L^?1 and most of compounds were detected only in lower course of the river. Total PAH ranged from 160 to 4000 pg L^?1 and show a clear spatial variation. Dominant PAHs were phenanthrene, fluoranthene, fluorene and acenaphthene. Total PCB ranged from undetectable to 120 pg L^?1. From the group of 15 PBDE congeners investigated, only PBDE-47 and PBDE-99 were detected. Since the concentrations of broad spectrum of POPs found in the Neretva River are quite low, future actions should be focused on preservation rather than on sanitation measures. Regular monitoring should anyhow be established.     

Use of semipermeable membrane devices (SPMDs)

Triolein-containing semipermeable membrane devices (SPMDs) were employed as passive samplers to provide data on the bioavailable fraction of organic, waterborne, organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polynuclear aromatic hydrocarbons (PAHs) in streams flowing through a highly polluted industrial area of Bitterfeld in Saxony-Anhalt, Germany. The contamination of the region with organic pollutants originates in wastewater effluents from the chemical industry, from over one-hundred years of lignite exploitation, and from chemical waste dumps. The main objective was to characterise time-integrated levels of dissolved contaminants, to use them for identification of spatial trends of contamination, and their relationship to potential pollution sources. SPMDs were deployed for 43 days in the summer of 1998 at four sampling sites. The total concentration of pollutants at sampling sites was found to range from a low of 0.8 microgram/SPMD to 25 micrograms/SPMD for PAHs, and from 0.4 microgram/SPMD to 22 micrograms/SPMD for OCPs, respectively. None of the selected PCB congeners was present at quantifiable levels at any sampling site. A point source of water pollution with OCPs and PAHs was identified in the river system considering the total contaminant concentrations and the distribution of individual compounds accumulated by SPMDs at different sampling sites. SPMD-data was also used to estimate average ambient water concentrations of the contaminants at each field site and compared with concentrations measured in bulk water extracts. The truly dissolved or bioavailable portion of contaminants at different sampling sites ranged from 4% to 86% for the PAHs, and from 8% to 18% for the OCPs included in the estimation. The fraction of individual compounds found in the freely dissolved form can be attributed to the range of their hydrophobicity. In comparison with liquid/liquid extraction of water samples, the SPMD method is more suitable for an assessment of the background concentrations of hydrophobic organic contaminants because of substantially lower method quantification limits. Moreover, contaminant residues sequestered by the SPMDs represent an estimation of the dissolved or readily bioavailable concentration of hydrophobic contaminants in water, which is not provided by most analytical approaches.     

PAHs and nitrated PAHs in air of five European countries determined using SPMDs as passive samplers

The gas phase polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs in the atmosphere of five European countries (Austria, the Czech Republic, Poland, Slovakia and Sweden) were measured simultaneously during two 21-day passive sampling campaigns using semipermeable membrane devices (SPMDs). SPMD samplers, consisting of a pair of SPMDs covered by a metal umbrella, were deployed at 40 locations ranging from remote and rural to urban and industrial, at a similar time during each of the two sampling campaigns (autumn 1999, except in Poland, winter 1999, and summer 2000). The total amounts of PAHs and nitro-PAHs found in the SPMDs ranged between 5.0–1.2×10³ and 1.1×10⁻³–4.0 ng SPMD⁻¹ day⁻¹, respectively. The measured environmental sampling conditions were similar between sites and, thus, the variations in the SPMD data reflected the spatial differences in gas phase concentrations of nitro-PAHs and PAHs within and between countries. The gas phase concentrations of nitro-PAHs and PAHs found in East Europe (Slovakia, the Czech Republic and Poland 1999) were 10 times higher than those measured in Sweden, Austria and Poland in 2000. In each country, the levels of PAHs and nitro-PAHs differed by one–three orders of magnitudes amongst sampling sites. The highest within-country spatial differences were found in Poland where levels of PAHs and nitro-PAHs were about one and two orders of magnitudes, respectively, higher in winter 1999 than in summer 2000, probably due to increasing emissions of coal combustion for residential heating. Differences in PAH-patterns between sites were visualized by the multivariate projection method, principal component analysis (PCA). However, no specific source patterns were found, probably since imissions rather than emissions were measured, so the PAHs detected at many sites originated from multiple sources.     

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.     

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.     

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.     

Acute toxicity and genotoxicity of aquatic hydrophobic pollutants sampled with semipermeable membrane devices

Triolein-filled semipermeable membrane devices (SPMDs) were deployed for 4 weeks in polluted water sources in Lithuania. The mixtures of pollutants sampled by the SPMDs were fractionated by size-exclusion chromatography (SEC). The fraction containing average molecular weight compounds such as polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides was screened by gas chromatography and mass spectrometry. The whole (non-fractionated) samples and their SEC fractions were tested in bioassays including Microtox, Mutatox, Daphnia pulex immobilization assay and the sister chromatid exchange (SCE) in human lymphocytes in vitro test. The Microtox test was most sensitive with the estimated EC(50) values in the range of milligrams or even micrograms per milliliter based on the amount of the SPMD triolein. Part of the observed toxicity was caused by elemental sulfur co-sampled by the SPMDs from sediments. The sum of toxicity equivalents of the SEC fractions was smaller than the relative toxicity of the whole samples indicating the presence of synergistic interactions in the complex mixtures of chemical pollutants. The toxic or genotoxic response induced by the chemical mixtures and their fractions was smaller in the D. pulex, Mutatox and SCE tests. In Mutatox, a positive response was only detected without the S9 metabolic activation which indicates the presence of mainly direct-acting mutagens in the samples. Interpretation of the Mutatox data was difficult due to the complexity of dose-response and time-response relationships. The study has demonstrated the potential as well as some limitations of SPMDs in the monitoring of biological effects of bioavailable organic pollutants in the aquatic environment.     

Uptake rates of alkylphenols, PAHs and carbazoles in semipermeable membrane devices (SPMDs) and polar organic chemical integrative samplers (POCIS)

Passive sampling devices provide a useful contribution to the monitoring of contaminants in the aquatic environment. However, calibration data needed for the calculation of water concentrations from sampler accumulations are restricted to a limited number of compound classes. Thus uptake of a range of alkylated phenols (AP), polycyclic aromatic hydrocarbons (PAH) and carbazoles was determined for semipermeable membrane devices (SPMDs) and polar organic chemical integrative samplers (POCIS) using a flow through exposure system. Sampling rates ranged from 0.02 to 0.26 l d(-1) for POCIS and 0.02 to 13.83 l d(-1) for SPMDs. Observed SPMD uptake was also compared to that predicted by an empirical model including the use of performance reference compounds (PRCs). Predicted sampling rates did not differ by more than a factor of 1.3 from experimental values for PAH, providing further evidence that the PRC approach can be successfully used to determine in situ sampling rates for these compounds. Experimental sampling rates for AP in SPMDs were, however, much lower than predicted. This discrepancy was too large to be explained by small uncertainties in the calibration system or in the calculations. Based on these data we conclude that while hydrophobic AP are accumulated by SPMDs their partitioning cannot be predicted from their logK(ow) using current methods. Due to this lower than expected uptake, sampling rates were only higher in SPMDs than POCIS in the range of logK(ow)>5.0. Simultaneous deployment of both sampler types allows the study of compounds with a broad range of physicochemical properties.     

Application of semipermeable membrane device for assessing toxicity in drinking water

Semipermeable membrane devices (SPMDs) mimic passive diffusive transport of bioavailable hydrophobic organic compounds through biological membranes and their partitioning between lipids and environmental levels. Our study was developed on a surface water treatment plant based in Turin, Northern Italy. The investigated plant treats Po River surface water and it supplies about 20% of the drinking water required by Turin city (about one million inhabitants). Surface water (input) and drinking water (output) were monitored with SPMDs from October 2001 to January 2004, over a period of 30 days. The contaminant residues, monthly extracted from SPMDs by dialysis in organic solvent, were tested with the Microtox^TM acute toxic test and with the Ames mutagenicity test. Same extracts were also analyzed with gaschromatography—mass spectrometry technique in order to characterise the organic pollutants sampled, especially Polycyclic Aromatic Hydrocarbons (PAHs).

Although the PAHs mean concentration is about one hundred times lower in the output samples, the mean toxic units are similar in drinking and surface water.

Our data indicate that the SPMD is a suitable tool to assess the possible toxicity in drinking water.     

Lipid-Filled semipermeable membrane devices and mussels as samplers of organochlorine compounds in lake water

Semipermeable membrane sampling devices (SPMDs) and caged lake mussels (Anodonta piscinalis) were simultaneously deployed at four lake watercourse sites in Central Finland four weeks in August 1992. This study was part of the regular annual monitoring of the organochlorine compounds (OCC) in pulp-mill recipient watercourses of Finland with bivalves. Chlorohydrocarbons (CHCs), chlorophenol compounds (PCPs), chloroanisoles (PCAs) and chloroveratroles (PCVs) were analyzed from lipid extract of mussels and from the synthetic triolein lipid of the SPMDs. Hexane-diethyl ether (9:1, v/v) dialysis using polyethylene membrane was applied in dean up of the SPMD lipids and, for comparison, to six sets of the mussel fat. Dialysis recovered CHCs but not PCPs from the mussel fat. CHCs, PCPs, PCAs and PCVs were all recovered in dialysis of the SPMD lipid. Handling of SPMDs in the transport and deployment operations caused significant OCC contamination for the blank SPMDs. Similar trends were revealed in the OCC profiles for mussels ans SPMDs. An exception was the lack of PCPs appearing in SPMDs that did appear in mussels and in a complementary manner the appearance of the PCAs and PCVs in SPMDs.     

Influence of solar UV radiation on the nitrogen metabolism in needles of Scots pine (Pinus sylvestris L.)

Needles of 20-year-old Scots pine (Pinus sylvestris L.) saplings were studied in an ultraviolet (UV) exclusion field experiment (from 2000 to 2002) in northern Finland (67 °N). The chambers held filters that excluded both UV-B and UV-A, excluded UV-B only, transmitted all UV (control), or lacked filters (ambient). UV-B/UV-A exclusion decreased nitrate reductase (NR) activity of 1-year-old needles of Scots pines compared to the controls. The proportion of free amino acids varied in the range 1.08-1.94% of total proteins, and was significantly higher in needles of saplings grown under UV-B/UV-A exclusion compared to the controls or UV-B exclusion. NR activity correlated with air temperature, indicating a “chamber effect”. The study showed that both UV irradiance and increasing temperature are significant modulators of nitrogen (N) metabolism in Scots pine needles.     

Feasibility of a simple laboratory approach for determining temperature influence on SPMD–air partition coefficients of selected compounds

Semipermeable membrane devices (SPMDs) are a widely used passive sampling methodology for both waterborne and airborne hydrophobic organic contaminants. The exchange kinetics and partition coefficients of an analyte in a SPMD are mediated by its physicochemical properties and certain environmental conditions. Controlled laboratory experiments are used for determining the SPMD–air (K_sa's) partition coefficients and the exchange kinetics of organic vapors. This study focused on determining a simple approach for measuring equilibrium K_sa's for naphthalene (Naph), o-chlorophenol (o-CPh) and p-dichlorobenzene (p-DCB) over a wide range of temperatures. SPMDs were exposed to test chemical vapors in small, gas-tight chambers at four different temperatures (−16, −4, 22 and 40 °C). The exposure times ranged from 6 h to 28 d depending on test temperature. K_sa's or non-equilibrium concentrations in SPMDs were determined for all compounds, temperatures and exposure periods with the exception of Naph, which could not be quantified in SPMDs until 4 weeks at the −16 °C temperature. To perform this study the assumption of constant and saturated atmospheric concentrations in test chambers was made. It could influence the results, which suggest that flow through experimental system and performance reference compounds should be used for SPMD calibration.     

A comparison of mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) for monitoring chlorinated trace organic contaminants in Hong Kong coastal waters.

A comparison of mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) was carried out at five sites, representing a gradient of contaminant concentrations, in Hong Kong coastal waters. Mussels, originally collected from a “clean” location, were deployed along with SPMDs at each site for 30 days. Analyses for chlorinated pesticides and polychlorinated biphenyls (PCBs) indicated that SPMDs have potential as monitoring tools, and to some extent can overcome the problems associated with mussels, such as natural variability, differing age, sex, and physical condition. However, in most cases, SPMDs failed to rank the sites in the same order as mussels in terms of contaminant concentrations. Nonetheless, in localities where mussels cannot survive – as shown at Kwun Tong in the present experiment – SPMDs may be valuable in providing an indication of potentially bio-available lipophilic pollutants.     

A comparison of polycyclic aromatic hydrocarbon and petroleum hydrocarbon uptake by mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) in Hong Kong coastal waters

The ability of mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) to accumulate polycyclic aromatic hydrocarbons (PAHs) and petroleum hydrocarbons (PHCs) from five sites in Hong Kong's coastal waters was compared. Mussels consistently had higher levels of contaminants, but their utility was limited at one highly polluted site due to mortality. Mussels and SPMDs ranked sites differently in terms of individual contaminant levels. Although SPMDs overcome many of the disadvantages of using living organisms to measure contaminants in marine waters, they cannot be used as "mimics" due to different PAH and PHC accumulation patterns.     

Polychlorinated biphenyls and hexachlorobenzene in atmosphere, sea-surface microlayer, and water measured with semi-permeable membrane devices (SPMDs).

The time evolution of polychlorinated biphenyl (PCB) levels and hexachlorobenzene (HCB) levels in air, seawater, and at the sea-air boundary layer was examined during autumn and winter at a near-shore location in the Western Wadden Sea (Netherlands), using semi-permeable membrane devices (SPMDs). Performance reference compounds (PRCs) were added to the SPMDs prior to exposure for measuring the in situ exchange kinetics. For PCBs, a fair degree of equilibrium between atmosphere and water was found. HCB concentrations in the atmosphere were about eight times higher than the equilibrium concentration. PCB concentrations in seawater and atmosphere fell by a factor of 2-10, respectively, during the sampling period. HCB concentrations in water increased by a factor of 2. Atmospheric concentrations of HCB showed a decrease by a factor of about 10. Results for the sea-surface microlayer (SSM) deployment showed that the chemical activities at the air-water interface did not differ from those in deeper water layers. This means that the SSM was of no special toxicological significance in this study as far as PCBs and HCB are concerned.     

A comparison of mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) for monitoring chlorinated trace organic contaminants in Hong Kong coastal waters

A comparison of mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) was carried out at five sites, representing a gradient of contaminant concentrations, in Hong Kong coastal waters. Mussels, originally collected from a “clean” location, were deployed along with SPMDs at each site for 30 days. Analyses for chlorinated pesticides and polychlorinated biphenyls (PCBs) indicated that SPMDs have potential as monitoring tools, and to some extent can overcome the problems associated with mussels, such as natural variability, differing age, sex, and physical condition. However, in most cases, SPMDs failed to rank the sites in the same order as mussels in terms of contaminant concentrations. Nonetheless, in localities where mussels cannot survive – as shown at Kwun Tong in the present experiment – SPMDs may be valuable in providing an indication of potentially bio-available lipophilic pollutants.