Two-dimensional gas chromatography coupled to triple quadrupole mass spectrometry for the unambiguous determination of atropisomeric polychlorinated biphenyls in environmental samples

Chiral signatures of polychlorinated biphenyls in serum from e-waste workers and their correlation with hydroxylated metabolites

Elevated concentrations of polychlorinated biphenyls (PCBs) found in environmental media and biota from typical e-waste dismantling sites have raised concerns regarding their human body burden and potential negative health effects. In the present study, the enantiomeric compositions of three typical chiral congeners (PCB-95, PCB-132, and PCB-149) were measured in 24 serum samples from e-waste workers by using gas chromatography coupled to triple quadrupole tandem mass spectrometry. The mean enantiomer fractions (EFs) of chiral congeners in serum from the workers were 0.655 ± 0.103, 0.679 ± 0.164, and 0.548 ± 0.095 for PCB-95, PCB-132, and PCB-149, respectively. The (+) enantiomers of PCB-95, PCB-132, and PCB-149 were enantioselectively enriched in serum. Significant positive correlations were observed between the EF of the chiral congener PCB-95 and the total concentration of OH-PCBs, suggesting that EF values of chiral PCBs could be used to indicate the extent of biological metabolism. In addition, the EF of PCB-95 in serum samples increased with increasing work duration of the e-waste workers, thus demonstrating the usefulness of EF values of chiral PCBs as tracers of human exposure to PCBs. Because of the enantioselective enrichment of (+) enantiomers of PCB-95, PCB-132, and PCB-149, further studies are needed to explore the metabolism and toxicity of chiral contaminants in humans.

Atropselective Oxidation of 2,2',3,3',4,6'-Hexachlorobiphenyl (PCB 132) to Hydroxylated Metabolites by Human Liver Microsomes and Its Implications for PCB 132 Neurotoxicity

Polychlorinated biphenyls (PCBs) have been associated with neurodevelopmental disorders. Several neurotoxic congeners display axial chirality and atropselectively affect cellular targets implicated in PCB neurotoxicity. Only limited information is available regarding the atropselective metabolism of these congeners in humans and their atropselective effects on neurotoxic outcomes. Here we investigate the hypothesis that the oxidation of 2,2',3,3',4,6'-hexachlorobiphenyl (PCB 132) by human liver microsomes (HLMs) and their effects on dopaminergic cells in culture are atropselective. Racemic PCB 132 was incubated with pooled or single donor HLMs, and levels and enantiomeric fractions of PCB 132 and its metabolites were determined gas chromatographically. The major metabolite was either 2,2',3,4,4',6'-hexachlorobiphenyl-3'-ol (3'-140), a 1,2-shift product, or 2,2',3,3',4,6'-hexachlorobiphenyl-5'-ol (5'-132). The PCB 132 metabolite profiles displayed inter-individual differences and depended on the PCB 132 atropisomer. Computational studies suggested that 3'-140 is formed via a 3,4-arene oxide intermediate. The second eluting atropisomer of PCB 132, first eluting atropisomer of 3'-140, and second eluting atropisomer of 5'-132 were enriched in all HLM incubations. Enantiomeric fractions of the PCB 132 metabolites differed only slightly between the single donor HLM preparations investigated. Reactive oxygen species and levels of dopamine and its metabolites were not significantly altered after a 24 h exposure of dopaminergic cells to pure PCB 132 atropisomers. These findings suggest that there are inter-individual differences in the atropselective biotransformation of PCB 132 to its metabolites in humans; however, the resulting atropisomeric enrichment of PCB 132 is unlikely to affect neurotoxic outcomes associated with the endpoints investigated in the study.

Gas chromatographic analysis of polychlorinated biphenyls in compost samples from different origin

Depending on the origin, the compost produced may contain not only nutrients but also pollutants, such as heavy metals and persistent organic pollutants. It is very important to determine them in soil-improving substances, because persistent organic pollutants show environmental toxic, cancerogenic, mutagenic effects and do not decompose for a long time. The aim of this study was to determine seven polychlorinated biphenyls concentrations in different kinds of composts produced in Lithuania and to evaluate the appliance of these composts in agricultural land. First, before routine analysis was done a gas chromatography with electron-capture detector method was developed. In this study 145 samples of green waste, sewage sludge, cattle manure, food waste, mixed municipal waste, digestate and composts made from mixed municipal waste after mechanical-biological treatment were analysed. Obtained results show that 28% of investigated cattle manure composts (CMCs) and 10.5% of food waste composts (FWCs) were free from polychlorinated biphenyls. Other kinds of composts investigated in this study (green waste compost (GWC), sewage sludge compost (SSC), mixed municipal waste compost (MMWC), mixed municipal waste compost after mechanical biological treatment (MMWCABMT) and digestate (DIG)) were contaminated 100% with polychlorinated biphenyls. Despite the fact that polychlorinated biphenyls were forbidden 25 years ago, their concentration varied from 2.70 to 163.7 µg kg^-1 in different kinds of composts produced in Lithuania. According to get an increasing average amount of Σ7 polychlorinated biphenyls, Lithuanian composts were distributed as follows CMC > GWC > DIG > FWC > SSC > MMWCABMT > MMWC.

Enantioselectivity in biotransformation and bioaccumulation processes of typical chiral contaminants

Chirality is a critical topic in the medicinal and agrochemical fields. One quarter of all agrochemicals was chiral in 1996, and this proportion has increased remarkably with the introduction of new compounds over time. Despite scientists have made great efforts to probe the enantiomeric selectivity of chiral chemicals in the environment since early 1990s, the different behaviours of individual enantiomers in biologically mediated processes are still unclear. In the present review, we highlight state-of-the-knowledge on the stereoselective biotransformation and accumulation of chiral contaminants in organisms ranging from invertebrates to humans. Chiral insecticides, fungicides, and herbicides, polychlorinated biphenyls (PCBs), pharmaceuticals, flame retardants hexabromocyclododecane (HBCD), and perfluorooctane sulfonate (PFOS) are all included in the target compounds. Key findings included: a) Changes in the enantiomeric fractions in vitro and in vivo models revealed that enantioselectivity commonly occurs in biotransformation and bioaccumulation. b) Emerging contaminants have become more important in the field of enantioselectivity together with their metabolites in biological transformation process. c) Chiral signatures have also been regarded as powerful tools for tracking pollution sources when the contribution of precursor is unknown. Future studies are needed in order to understand not only preliminary enrichment results but also detailed molecular mechanisms in diverse models to comprehensively understand the behaviours of chiral compounds.

Enantioseparation and identification for the rationalization of the environmental impact of 4 polychlorinated biphenyls

Polychlorinated biphenyls (PCBs) are harmful and persistent organic pollutants that have long been used in industrial manufacturing. Their persistence leads to accumulation in the food chain causing potential toxic effects. As 19 out of 78 of the chiral congeners have stable atropisomers at ambient temperature, we studied some typical enantiomers: PCB45, PCB95, PCB136, and PCB149. The chiral stationary phases OD-H and OJ-H were used for separation in analytic high-performance liquid chromatography (HPLC), as well as for collection in semi-preparative HPLC. The resolution was optimized with respect to n-hexane-based mobile phases, temperature, and flow rate. All pure enantiomers were recovered from semi-preparative HPLC within 15 minutes for practical purpose. Characterization of the absolute configurations were conducted with a combination of theoretical and experimental electronic circular dichroism measurements. The enantiomers of PCB45, PCB95, PCB136, and PCB149 proved to be eluted as R > S, S > R, R > S, and S > R, respectively. Molecular structures (eg, substituent groups) and properties (eg, bond lengths, bond angles, and dipole moments) were quantitatively analyzed to understand the toxicity effect of PCBs. In summary, we have developed a well-established methodology of collection and configuration identification for analogous PCB derivatives.

Enantioselectivity of 2,2',3,5',6-Pentachlorobiphenyl (PCB 95) Atropisomers toward Ryanodine Receptors (RyRs) and Their Influences on Hippocampal Neuronal Networks

Nineteen ortho-substituted PCBs are chiral and found enantioselectively enriched in ecosystems. Their differential actions on biological targets are not understood. PCB 95 (2,2',3,5',6-pentachlorobiphenyl), a chiral PCB of current environmental relevance, is among the most potent toward modifying ryanodine receptors (RyR) function and Ca²⁺ signaling. PCB 95 enantiomers are separated and assigned aR- and aS-PCB 95 using three chiral-column HPLC and circular dichroism spectroscopy. Studies of RyR1-enriched microsomes show aR-PCB 95 with >4× greater potency (EC₅₀ = 0.20 ± 0.05 μM), ∼ 1.3× higher efficacy (B_max = 3.74 ± 0.07 μM) in [³H]Ryanodine-binding and >3× greater rates (R = 7.72 ± 0.31 nmol/sec/mg) of Ca²⁺ efflux compared with aS-PCB 95, whereas racemate has intermediate activity. aR-PCB 95 has modest selectivity for RyR2, and lower potency than racemate toward the RyR isoform mixture in brain membranes. Chronic exposure of hippocampal neuronal networks to nanomolar PCB 95 during a critical developmental period shows divergent influences on synchronous Ca²⁺ oscillation (SCO): rac-PCB 95 increasing and aR-PCB 95 decreasing SCO frequency at 50 nM, although the latter's effects are nonmonotonic at higher concentration. aS-PCB95 shows the greatest influence on inhibiting responses to 20 Hz electrical pulse trains. Considering persistence of PCB 95 in the environment, stereoselectivity toward RyRs and developing neuronal networks may clarify health risks associated with enantioisomeric enrichment of PCBs.

Polychlorinated Biphenyls (PCBs) in Human Hair and Serum from E-Waste Recycling Workers in Southern China: Concentrations, Chiral Signatures, Correlations, and Source Identification

Hair is increasingly used as a biomarker for human exposure to persistent organic pollutants (POPs). However, the internal and external sources of hair POPs remain a controversial issue. This study analyzed polychlorinated biphenyls (PCBs) in human hair and serum from electronic waste recycling workers. The median concentrations were 894 ng/g and 2868 ng/g lipid in hair and serum, respectively. The PCB concentrations in male and female serum were similar, while concentrations in male hair were significantly lower than in female hair. Significant correlations between the hair and serum PCB levels and congener profiles suggest that air is the predominant PCB source in hair and that hair and blood PCB levels are largely dependent on recent accumulation. The PCB95, 132, and 183 chiral signatures in serum were significantly nonracemic, with mean enantiomer fractions (EFs) of 0.440-0.693. Nevertheless, the hair EFs were essentially racemic (mean EFs = 0.495-0.503). Source apportionment using the Chemical Mass Balance model also indicated primary external PCB sources in human hair from the study area. Air, blood, and indoor dust are responsible for, on average, 64.2%, 27.2%, and 8.79% of the hair PCBs, respectively. This study evidenced that hair is a reliable matrix for monitoring human POP exposure.

Toxicokinetics of chiral polychlorinated biphenyls across different species--a review

Nineteen polychlorinated biphenyls (chiral or C-PCBs) exist as two stable rotational isomers (atropisomers) that are non-superimposable mirror images of each other. C-PCBs are released into the environment as racemic (i.e., equal) mixtures of both atropisomers and undergo atropisomeric enrichment due to biological, but not abiotic, processes. In particular, toxicokinetic studies provide important initial insights into atropselective processes involved in the disposition (i.e., absorption, distribution, biotransformation, and excretion) of C-PCBs. The toxicokinetic of C-PCBs is highly congener and species dependent. In particular, at lower trophic levels, abiotic processes play a predominant role in C-PCB toxicokinetics. Biotransformation plays an important role in the elimination of C-PCBs in mammals. The elimination of C-PCB follows the approximate order mammals > birds > amphibians > fish, mostly due to a corresponding decrease in metabolic capacity. A few studies have shown differences in the toxicokinetics of C-PCB atropisomers; however, more work is needed to understand the toxicokinetics of C-PCBs and the underlying biological processes. Such studies will not only contribute to our understanding of the fate of C-PCBs in aquatic and terrestrial food webs but also facilitate our understanding of human exposures to C-PCBs.

Determination of polychlorinated biphenyls by liquid chromatography-atmospheric pressure photoionization-mass spectrometry

This study presents the atmospheric pressure photoionization (APPI) of high-chlorinated (five or more chlorine atoms) polychlorinated biphenyls (PCBs) using toluene as dopant, after liquid chromatographic separation. Mass spectra of PCB 101, 118, 138, 153, 180, 199, 206 and 209 were recorded by using liquid chromatography-APPI-tandem mass spectrometry (LC-APPI-MS/MS) in negative ion full scan mode. Intense peaks appeared at m/z that correspond to [M - Cl + O](-) ions, where M is the analyte molecule. Furthermore, a detailed strategy, which includes designs of experiments, for the development and optimization of LC-APPI-MS/MS methods is described. Following this strategy, a sensitive and accurate method with low instrumental limits of detection, ranging from 0.29 pg for PCB 209 to 8.3 pg for PCB 101 on column, was developed. For the separation of the analytes, a Waters XSELECT HSS T3 (100 mm × 2.1 mm, 2.5 µm) column was used with methanol/water as elution system. This method was applied for the determination of the above PCBs in water samples (surface water, tap water and treated wastewater). For the extraction of PCBs from water samples, a simple liquid-liquid extraction with dichloromethane was used. Method limits of quantification, ranged from 4.8 ng l(-1), for PCB 199, to 9.4 ng l(-1), for PCB 180, and the recoveries ranged from 73%, for PCB 101, to 96%, for PCB 199. The estimated analytical figures were appropriate for trace analysis of high-chlorinated PCBs in real samples.

Chiral chemicals as tracers of atmospheric sources and fate processes in a world of changing climate

Elimination of persistent organic pollutants (POPs) under national and international regulations reduces "primary" emissions, but "secondary" emissions continue from residues deposited in soil, water, ice and vegetation during former years of usage. In a future, secondary source controlled world, POPs will follow the carbon cycle and biogeochemical processes will determine their transport, accumulation and fate. Climate change is likely to affect mobilisation of POPs through e.g., increased temperature, altered precipitation and wind patterns, flooding, loss of ice cover in polar regions, melting glaciers, and changes in soil and water microbiology which affect degradation and transformation. Chiral compounds offer advantages for following transport and fate pathways because of their ability to distinguish racemic (newly released or protected from microbial attack) and nonracemic (microbially degraded) sources. This paper discusses the rationale for this approach and suggests applications where chiral POPs could aid investigation of climate-mediated exchange and degradation processes. Multiyear measurements of two chiral POPs, trans-chlordane and α-HCH, at a Canadian Arctic air monitoring station show enantiomer compositions which cycle seasonally, suggesting varying source contributions which may be under climatic control. Large-scale shifts in the enantioselective metabolism of chiral POPs in soil and water might influence the enantiomer composition of atmospheric residues, and it would be advantageous to include enantiospecific analysis in POPs monitoring programs.

Polychlorinated biphenyls in human hair at an e-waste site in China: composition profiles and chiral signatures in comparison to dust

We analyzed the polychlorinated biphenyls (PCBs) in human hair collected from an electronic waste (e-waste) recycling area in southern China and compared their composition profiles and chiral signatures to those of workplace and domestic dust. The PCB concentrations showed significant age dependence in dismantling workers' hair but not in residents' hair. Among residents, PCB concentrations decreased in the following order: elderly people>students>pre-school children>adults. The PCB homologue and congener profiles of the workers' hair were similar to those of the workplace dust. However, the PCB homologue profile of the residents' hair was clearly different from that of the domestic dust. The chiral congener CB95 generally exhibited a racemic or near-racemic composition in both hair and dust, with enantiomer fractions (EFs) ranging from 0.485 to 0.525 in hair and from 0.479 to 0.504 in dust. The EFs of CB132 in dust (0.477-0.513) were closer to a racemic chiral signature than those in hair (0.378-0.521), but this difference was not significant. Our results suggest that the chiral signature of PCBs may be a better tool than the PCB composition profile for identifying the external and internal sources of organic contaminants in human hair. Further measurements of chiral PCB signatures in hair and blood from the same individuals are needed to identify the external and internal sources of PCBs in human hair.

Tracking chiral polychlorinated biphenyl sources near a hazardous waste incinerator: fresh emissions or weathered revolatilization?

The Swan Hills Treatment Centre (SHTC), located in central Alberta, is the primary facility in Canada for incinerating polychlorinated biphenyls (PCBs). Past studies have shown significant contamination by PCBs and other pollutants of the immediate surrounding region. However, it is unclear whether the major source of contamination to the region's atmosphere is historical release incidents or long-term emissions. To answer this question, concentrations of PCBs and enantiomer fractions of several PCB congeners were determined in soil and air, via polyurethane foam passive samplers, over several seasons between 2005 and 2008. Concentrations in both media were highest for samples collected closest to the SHTC, demonstrating a concentration profile typical of a point source. Enantiomer analysis revealed racemic profiles in air for all congeners, while soil was significantly nonracemic for PCB 95, indicating significant microbial degradation of this congener. However, the primary source of this congener, and likely others, in the surrounding atmosphere is recent and continual releases from the SHTC, rather than the release of weathered PCBs previously deposited to local soils. In addition, enantiomer compositions for PCBs 95 and 149 yielded minimum biotransformation half-lives of 25 and 97 years, respectively, suggesting an expected gradual decline in the region's PCB load once fresh inputs cease.

Recent advances in flow-controlled multidimensional gas chromatography

The continued development of flow-controlled two-dimensional gas chromatography (2-D GC) is reviewed, with a special emphasis on results published from 2001 through 2011. Heart-cutting 2-D GC continues to be used for isolating selected components in complex mixtures. The programmable and highly precise flows and temperatures produced by modern gas chromatographs have made it easier to selectively transfer analytes to the secondary column and to backflush unwanted components from the primary column. Several new Deans switch interfaces for performing heart-cutting 2-D GC have been introduced, with most attention given to devices that integrate the flow connections into a single unit. Heart-cutting 2-D GC has been used to isolate analytes in a wide variety of complex mixtures including fuels, industrial feedstocks, fragrances, and environmental extracts. Valve-based comprehensive 2-D GC (GC×GC) was also actively developed in the past decade. Valve-based modulation is a simple way to generate GC×GC separations without using cryogenic fluids. More than ten new valve-based modulators were introduced. Diaphragm valves fitted with sample loops are the most common low duty cycle modulators, whereas fluidic modulators that employ differential flow conditions are the most common high duty cycle modulators. Applications of valve-based GC×GC include analysis of hydrocarbon mixtures, essential oils, and environmental samples.

Has the burden and distribution of PCBs and PBDEs changed in European background soils between 1998 and 2008? Implications for sources and processes

Background soils were collected from 70 locations on a latitudinal transect in the United Kingdom and Norway in 2008, ten years after they had first been sampled in 1998. The soils were analyzed for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCs), to see whether there had been any change in the loadings or distributions of these persistent organic pollutants (POPs). The same transect has also been used to sample air between the mid-1990s and the present, so the air and soil spatial and temporal trends provide information on air-soil transfers, source-receptor relationships, long-range atmospheric transport (LRAT), and recycling phenomena. Comparisons of the 2008 and 1998 data sets show a general decline for PBDEs in surface soil, and a smaller averaged net decline of PCBs. Changes between the years were observed for total POP concentrations in soil and also for correlations with site and sample characteristics assumed to affect those concentrations. POP concentrations were correlated to distance and strength of possible sources, a relationship that became weaker in the 2008 data. Fractionation, a commonly discussed process for the global cycling of POPs was also lost in the 2008 data. As in 1998, soil organic matter content continues to have a strong influence on the loadings of POPs in surface soils, but changes in the PCB loads were noted. These factors indicate an approach to air-surface soil equilibrium and a lessening of the influence of primary sources on POP concentrations in soil between 1998 and 2008.

Chiral polychlorinated biphenyl transport, metabolism, and distribution: a review

Chirality can be exploited to gain insight into enantioselective fate processes that may otherwise remain undetected because only biological, but not physical and chemical transport and transformation processes in an achiral environment will change enantiomer compositions. This review provides an in-depth overview of the application of chirality to the study of chiral polychlorinated biphenyls (PCBs), an important group of legacy pollutants. Like other chiral compounds, individual PCB enantiomers may interact enantioselectively (or enantiospecifically) with chiral macromolecules, such as cytochrome P-450 enzymes or ryanodine receptors, leading to differences in their toxicological effects and the enantioselective formation of chiral biotransformation products. Species and congener-specific enantiomer enrichment has been demonstrated in environmental compartments, wildlife, and mammals, including humans, typically due to a complex combination of biotransformation processes and uptake via the diet by passive diffusion. Changes in the enantiomer composition of chiral PCBs in the environment have been used to understand complex aerobic and anaerobic microbial transformation pathways, to delineate and quantify PCB sources and transport in the environment, to gain insight into the biotransformation of PCBs in aquatic food webs, and to investigate the enantioselective disposition of PCBs and their methylsulfonyl PCBs metabolites in rodents. Overall, changes in chiral signatures are powerful, but currently underutilized tools for studies of environmental and biological processes of PCBs.

Influence of activated charcoal amendment to contaminated soil on dieldrin and nutrient uptake by cucumbers

Activated charcoal (AC) amendments have been suggested as a promising, cost-effective method to immobilize organic contaminants in soil. We performed pot experiments over two years with cucumber (Cucumis sativus L.) grown in agricultural soil with 0.07 mg kg(-1) of weathered dieldrin and 0, 200, 400, and 800 mg AC per kg soil. Dieldrin fresh weight concentrations in cucumber fruits were significantly reduced from 0.012 to an average of 0.004 mg kg(-1), and total uptake from 2 to 1 microg in the 800 mg kg(-1) AC treatment compared to the untreated soil. The treatment effects differed considerably between the two years, due to different meteorological conditions. AC soil treatments did neither affect the availability of nutrients to the cucumber plants nor their yield (total fruit wet weight per pot). Thus, some important prerequisites for the successful application of AC amendments to immobilize organic pollutants in agricultural soils can be considered fulfilled.

Assessing the phytoavailability of dieldrin residues in charcoal-amended soil using tenax extraction

Consecutive and single Tenax extractions were applied to characterize the effectiveness of activated charcoal (AC) amendments to reduce the phytoavailability of dieldrin in a natively contaminated horticultural soil. Dieldrin desorption from untreated and 800 mg(AC) kg(-1) soil was well described by a model with three dieldrin fractions of different kinetics: a rapidly (F(rap)), slowly (F(slow)), and very slowly (F(v.slow)) desorbing fraction. The AC amendment resulted in a transfer of dieldrin from the F(slow) to the F(v.slow) fraction. The F(v.slow) increased by nearly 10% compared to the control soil. Dieldrin extractability by Tenax from AC amended soils was not influenced by the cultivation of cucumber plants indicating the stability of this remediation technique. Dieldrin extractability by Tenax at the beginning of plant growth correlated only weakly with the dieldrin content of the cucumbers at harvest. Therefore, the potential of Tenax extractions to predict the uptake of dieldrin by cucumbers appears to be limited.

Can physicochemical and microbial soil properties explain enantiomeric shifts of chiral organochlorines?

Enantiomeric fractions (EF) of PCB 95, 132, 149, and 174, alpha-HCH, o,p'-DDD, and o,p'-DDT were analyzed in 112 soil samples using two-dimensional gas chromatography and triple-quadrupole mass spectrometry. To assess the soil conditions that facilitate enantioselective fractionation of chiral compounds, EF values of selected PCBs were further correlated with a wide range of physicochemical and microbial soil parameters in an attempt to identify the influential factors and their mutual relations. It was evident that soils where nonracemic ratios of investigated compounds were found were more carbon rich but they also contained significantly more humic and fulvic acids and total nitrogen. These specific physicochemical properties were accompanied by significantly increased values of all key biotic variables, the amount of microbial biomass, and its respiration activity (both basal and substrate-induced). Therefore, the shifts from racemic ratios appeared to be associated with more sustainable and active soil microflora. Among other abiotic characteristics, most significant differences were detected in the soil texture. Soil samples with significant shifts contained increased amount of clay component and correspondingly decreased proportion of sand fraction. These differences can also be associated with more intensive microbial activity, because clay content and texture with an increased amount of microaggregates are known to be favorable for soil microflora and its viability.

Chiral source apportionment of polychlorinated biphenyls to the Hudson River estuary atmosphere and food web

The New York/New Jersey Harbor Estuary is subject to significant contamination of polychlorinated biphenyls (PCBs) from numerous sources, including the historically contaminated Upper Hudson River, stormwater runoff and sewer overflows, and atmospheric deposition from PCBs originating from the surrounding urban area. However, the relative importance of these sources to the estuary's food web is not fully understood. Sources of PCBs to the estuary were apportioned using chiral signatures of PCBs in air, water, total suspended matter, phytoplankton, and sediment. PCBs 91, 95, 136, and 149 were racemic in the atmosphere of the estuary. However, the other phases contained nonracemic PCB 95 and to a lesser extent PCB 149. Thus, the predominant atmospheric source of these congeners is likely unweathered local pollution and not volatilization from the estuary. The similarity in chiral signatures in the other phases is consistent with dynamic contaminant exchange among them. Chiral signatures in the dissolved phase and total suspended matter were correlated with Upper Hudson discharge, suggesting thatthe delivery of nonracemic contaminated sediment from the Upper Hudson, not the atmosphere, controls phytoplankton uptake of some PCBs. Thus, measures to control PCB contamination in the Upper Hudson should be effective in reducing loadings to the estuary's aquatic ecosystem.

Fate of PCBs, PAHs and their source characteristic ratios during composting and digestion of source-separated organic waste in full-scale plants

Composting and digestion are important waste management strategies. However, the resulting products can contain significant amounts of organic pollutants such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). In this study we followed the concentration changes of PCBs and PAHs during composting and digestion on field-scale for the first time. Concentrations of low-chlorinated PCBs increased during composting (about 30%), whereas a slight decrease was observed for the higher chlorinated congeners (about 10%). Enantiomeric fractions of atropisomeric PCBs were essentially racemic and stable over time. Levels of low-molecular-weight PAHs declined during composting (50-90% reduction), whereas high-molecular-weight compounds were stable. The PCBs and PAHs concentrations did not seem to vary during digestion. Source apportionment by applying characteristic PAH ratios and molecular markers in input material did not give any clear results. Some of these parameters changed considerably during composting. Hence, their diagnostic potential for finished compost must be questioned.

Concentrations and chiral signatures of polychlorinated biphenyls in outdoor and indoor air and soil in a major U.K. conurbation

Concentrations and chiral signatures of polychlorinated biphenyls (PCBs) were measured in outdoor air (using polyurethane foam (PUF)--disk passive samplers) and surface soil samples taken at approximately monthly intervals over 1 year at 10 locations on a rural-urban transect across the West Midlands of the U.K. In both air and soil, concentrations clearly decrease with increasing distance from the city center, supporting the existence of an urban "pulse", that indicate the West Midlands conurbation to be a source of PCBs to the wider environment. Concentrations of PCBs in outdoor air samples in this study are well below those reported previously for indoor air in the West Midlands. This, combined with comparison of chiral signatures in outdoor air and soil with those in samples of indoor air taken in the West Midlands, suggest strongly that the principal contemporary source of PCBs in this conurbation is ventilation of indoor air and not volatilization from soil. Future reductions in PCB concentrations in outdoor air and ultimately human exposure appear best achieved by action to remove remaining sources of PCBs from existing structures.

Determination of priority organic micro-pollutants in water by gas chromatography coupled to triple quadrupole mass spectrometry

A multiclass method has been developed for screening, quantification and confirmation of organic micro-pollutants in water by gas chromatography coupled to mass spectrometry with a triple quadrupole analyzer. The work has been focused on the determination of more than 50 compounds belonging to different chemical families: 19 organochlorine and organophosphorus insecticides, 6 herbicides, 7 polychlorinated biphenyls, 16 polycyclic aromatics hydrocarbons, 2 brominated diphenyl ethers, and 3 octyl/nonyl phenols and pentachlorobenzene. Most of these analytes are included in the list of priority substances in the framework on European Water Policy. Analyte extraction was performed by solid phase extraction using C18 cartridges, and five isotopically labeled standards were added before extraction as surrogates. Analyses were performed by gas chromatography with tandem mass spectrometry (MS/MS) in electron impact mode. Accuracy and precision were evaluated by means of recovery experiments using water samples fortified at two concentration levels (25 and 250 ng L(-1)), with satisfactory results for most of analytes. The excellent selectivity and sensitivity reached in selected reaction monitoring mode allowed us satisfactory quantification and confirmation at levels as low as 25 ng L(-1). Two MS/MS transitions were acquired for each analyte, using the Q/q intensity ratio as a confirmatory parameter. The method developed was applied to the analysis of surface, ground and wastewater samples collected from the Valencia Region (Spain). Analytical methodology using negative chemical ionization mode was also validated for the organochlorine compounds selected, showing a superior sensitivity and lower detection limits.

Current literature in mass spectrometry

In order to keep subscribers up‐to‐date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of mass spectrometry. Each bibliography is divided into 11 sections: 1 Books, Reviews & Symposia; 2 Instrumental Techniques & Methods; 3 Gas Phase Ion Chemistry; 4 Biology/Biochemistry: Amino Acids, Peptides & Proteins; Carbohydrates; Lipids; Nucleic Acids; 5 Pharmacology/Toxicology; 6 Natural Products; 7 Analysis of Organic Compounds; 8 Analysis of Inorganics/Organometallics; 9 Surface Analysis; 10 Environmental Analysis; 11 Elemental Analysis. Within each section, articles are listed in alphabetical order with respect to author (6 Weeks journals ‐ Search completed at 4th. Oct. 2006)

Organic pollutants in compost and digestate. : Part 1. Polychlorinated biphenyls, polycyclic aromatic hydrocarbons and molecular markers

In Europe, 9.3 x 10(6) t(dry weight (dw)) of compost and digestate are produced per year. Most of this is applied to agricultural land, which can lead to considerable inputs of organic pollutants, such as polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH) to soil. This paper presents an inventory of the pollutant situation in source-separated composts, digestates and presswater in Switzerland by a detailed analysis of over 70 samples. PCB concentrations ( summation PCB 28, 52, 101, 118, 138, 153, 180) were significantly higher in urban (median: 30 microg kg(-1)dw, n = 52) than in rural samples (median: 14 microg kg(-1)dw, n = 16). Together with low concentrations in general, this points to aerial deposition on compost input material as the major contamination pathway. Enantiomeric fractions of atropisometric PCB were close to racemic. Median PAH concentration was 3010 microg kg(-1)dw( summation 15PAH, n = 69), and one quarter of the samples exhibited concentrations above the relevant Swiss guide value for compost (4000 microg kg(-1)dw). The levels were influenced by the treatment process (digestate > compost), the season of input material collection (spring-summer > winter > autumn), the particle size (coarse-grained > fine-grained), and maturity (mature > less mature). The main source of PAH in compost was pyrogenic, probably influenced mainly by liquid fossil fuel combustion and some asphalt abrasion, as suggested by multiple linear regression. This study, together with a companion paper reporting on other organic contaminates including emerging compound classes, provides a starting point for a better risk-benefit estimation of the application of compost and digestate to agricultural soil in Switzerland.