Ongoing Laboratory Performance Study on Chemical Analysis of Hydrophobic and Hydrophilic Compounds in Three Aquatic Passive Samplers.

The quality of chemical analysis is an important aspect of passive sampling-based environmental assessments. The present study reports on a proficiency testing program for the chemical analysis of hydrophobic organic compounds in silicone and low-density polyethylene (LDPE) passive samplers and hydrophilic compounds in polar organic chemical integrative samplers. The median between-laboratory coefficients of variation (CVs) of hydrophobic compound concentrations in the polymer phase were 33% (silicone) and 38% (LDPE), similar to the CVs obtained in four earlier rounds of this program. The median CV over all rounds was 32%. Much higher variabilities were observed for hydrophilic compound concentrations in the sorbent: 50% for the untransformed data and a factor of 1.6 after log transformation. Limiting the data to the best performing laboratories did not result in less variability. Data quality for hydrophilic compounds was only weakly related to the use of structurally identical internal standards and was unrelated to the choice of extraction solvent and extraction time. Standard deviations of the aqueous concentration estimates for hydrophobic compound sampling by the best performing laboratories were 0.21 log units for silicone and 0.27 log units for LDPE (factors of 1.6 to 1.9). The implications are that proficiency testing programs may give more realistic estimates of uncertainties in chemical analysis than within-laboratory quality control programs and that these high uncertainties should be taken into account in environmental assessments.

Wild fish from a highly urbanized river (Orge, France) as vectors of culturable Enterobacterales resistant to antibiotics.

This study shows how wild fishes from urbanized rivers could be involved in the spread of antibiotic-resistant Enterobacterales. Antibiotic resistance profiles and molecular detection of clinical integron (IntI1) were carried out on 105 Enterobacterales isolated from 89 wildfish (skin or gut) belonging to 8 species. The proportion of isolates resistant to at least one antibiotic was independent of fish species and reached 28.3% within the Escherichia coli (E. coli) population and 84.7% in the non-E.coli Enterobacterales. Bacteria involved in nosocomial infections were isolated, such as E. coli, Klebsiella, and Enterobacter, as well as the environmental bacteria (Lelliottia, Butiauxella, and Kluyvera).

Fish from urban rivers and with high pollutant levels have shorter telomeres.

Environmental pressures, such as urbanization and exposure to pollutants may jeopardize survival of free-living animals. Yet, much remains to be known about physiological and ecological responses to currently-released pollutants, especially in wild vertebrate ectotherms. We tested the effect of urbanization and pollution (phthalates, organochlorine and pyrethroid pesticides, polychlorobiphenyls, polybromodiphenylethers, polycyclic aromatic hydrocarbons, and some of their metabolites) on telomere length, a suggested biomarker of life expectancy, in the European chub, Squalius cephalus, from urban and agricultural rivers of the Marne hydrographic network, France. We showed that telomere length was reduced in chub from urban rivers. Moreover, among the wide range of anthropogenic contaminants investigated, high levels of phthalate metabolites in liver were associated with shorter telomeres. This study suggests that urbanization and chemical pollution may compromise survival of wild fish, by accelerating telomere attrition.

Urbanization Constrains Skin Bacterial Phylogenetic Diversity in Wild Fish Populations and Correlates with the Proliferation of Aeromonads.

Changes in the state of rivers resulting from the activity and expansion of urban areas are likely to affect aquatic populations by increasing stress and disease, with the microbiota playing a potentially important intermediary role. Unraveling the dynamics of microbial flora is therefore essential to better apprehend the impact of anthropogenic disturbances on the health of host populations and the ecological integrity of hydrosystems. In this context, the present study simultaneously examined changes in the microbial communities associated with mucosal skin and gut tissues of eight fish species along an urbanization gradient in the Orge River (France). 16S rRNA gene metabarcoding revealed that the structure and composition of the skin microbiota varied substantially along the disturbance gradient and to a lesser extent according to fish taxonomy. Sequences affiliated with the Gammaproteobacteria, in particular the genus Aeromonas, prevailed on fish caught in the most urbanized areas, whereas they were nearly absent upstream. This rise of opportunistic taxa was concomitant with a decline in phylogenetic diversity, suggesting more constraining environmental pressures. In comparison, fish gut microbiota varied much more moderately with the degree of urbanization, possibly because this niche might be less directly exposed to environmental stressors. Co-occurrence networks further identified pairs of associated bacterial taxa, co-existing more or less often than expected at random. Few correlations could be identified between skin and gut bacterial taxa, supporting the assumption that these two microbial niches are disconnected and do not suffer from the same vulnerability to anthropic pressures.

Parasitism reduces oxidative stress of fish host experimentally exposed to PAHs.

Some parasites are known to bioaccumulate some environmental pollutants within their host. We hypothesized that these parasites may be beneficial for their hosts in polluted environments. We experimentally increased long-term (five weeks) exposure to polycyclic aromatic hydrocarbons (PAHs, three levels: 0.1X, 1X, 10X environmental exposure) in European chubs (Squalius cephalus) that were naturally infected or uninfected with acanthocephalan parasites. We monitored PAHs levels in fish tissues, as well as oxidative stress, telomere length and condition indices. Although parasite infection did not significantly reduce the levels of PAHs and PAH metabolites in host tissues, host oxidative status was explained by parasitism and pollution levels. Oxidative damage increased with parasitism in fish exposed to low PAH levels (0.1X) but decreased in infected fish at higher PAH exposure (10X), thus corroborating our hypothesis. Meanwhile, antioxidant capacity did not differ in response to parasite infection nor PAHs exposure. Despite this imbalance in oxidative status, experimental increase in PAH levels did not compromise telomere length, body condition, or survival in infected and uninfected fish. This study provides the first experimental evidence that the outcome of host-parasite interactions can shift from negative to positive as pollutant exposure increases.

Effects of DEHP on the ecdysteroid pathway, sexual behavior and offspring of the moth Spodoptera littoralis.

Bis(2-ethylhexyl) phthalate (DEHP) is a widely produced plasticizer that is considered to act as an endocrine-disrupting chemical in vertebrates and invertebrates. Indeed, many studies have shown that DEHP alters hormonal levels, reproduction and behavior in vertebrates. Few studies have focused on the effects of DEHP on insects, although DEHP is found almost everywhere in their natural habitats, particularly in soils and plants. Here, we investigated the effects of DEHP on the sexual behavior and physiology of a pest insect, the noctuid moth Spodoptera littoralis. In this nocturnal species, olfaction is crucial for sexual behavior, and ecdysteroids at the antennal level have been shown to modulate sex pheromone detection by males. In the present study, larvae were fed food containing different DEHP concentrations, and DEHP concentrations were then measured in the adults (males and females). Hemolymphatic ecdysteroid concentrations, the antennal expression of genes involved in the ecdysteroid pathway (nuclear receptors EcR, USP, E75, and E78 and calmodulin) and sexual behavior were then investigated in adult males. The success and latency of mating as well as the hatching success were also studied in pairs consisting of one DEHP male and one uncontaminated female or one DEHP female and one uncontaminated male. We also studied the offspring produced from pairs involving contaminated females to test the transgenerational effect of DEHP. Our results showed the general downregulation of nuclear receptors and calmodulin gene expression associated with the higher concentrations of DEHP, suggesting peripheral olfactory disruption. We found some effects on male behavior but without an alteration of the mating rate. Effects on offspring mortality and developmental rates in the N + 1 generation were also found at the higher doses of DEHP. Taken together, the results of the study show for the first time that larval exposure to DEHP can induce delayed endocrine-disruptive effects in the adults of a terrestrial insect as well as effects on the next generation. To date, our study is also the first description of an impact of endocrine disrupter on olfaction in insects.

Potential Benefits of Acanthocephalan Parasites for Chub Hosts in Polluted Environments.

Some parasites are expected to have beneficial impacts on wild populations in polluted environments because of their bioaccumulation potential of pollutants from their hosts. The fate of organic micropollutants in host-parasite systems and the combined effect of parasitism and pollution were investigated in chub Squalius cephalus, a freshwater fish, infected (n = 73) or uninfected (n = 45) by acanthocephalan parasites Pomphorhynchus sp. from differently contaminated riverine sites. Several ubiquitous pollutants (polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl-ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), phthalates, insecticides, pyrethroids, and N,N-diethyl-meta-toluamide (DEET)) and some of their metabolites were characterized for the first time in parasites and various fish matrices (muscle, liver, and stomach content). Most organic pollutants reached higher levels in parasites than in chub matrices. In contrast, metabolite levels were lower in parasite tissues compared to fish matrices. Infected and uninfected chub exhibited no significant differences in their pollutant load. Body condition, organo-somatic indices, and immunity were not affected by parasitism, and few correlations were found with chemical pollution. Interestingly, infected chub exhibited lower oxidative damage compared to uninfected fish, irrespective of their pollutant load. In light of these results, this correlative study supports the hypothesis that acanthocephalan parasites could bring benefits to their hosts to cope with organic pollution.

Trophic Transfer of Micropollutants and Their Metabolites in an Urban Riverine Food Web.

Trophic magnification factors (TMFs, i.e., the average change in the log-concentration of a pollutant per trophic level) have been extensively assessed for the so-called persistent organic pollutants, especially organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), which are biomagnified along the food web. In contrast, trophic dilution was documented for pollutants with a high metabolic conversion rate, such as phthalate plasticizers and polycyclic aromatic hydrocarbons (PAHs). However, the fate of their metabolites across the food web has been rarely investigated. In this comparative study, the trophodynamics of 104 micropollutants and 25 of their metabolites were investigated in a freshwater food web from the urban Orge River, France. Trophic levels were determined using stable isotopes. Pyrethroid pesticides and their metabolites were not detected. As predicted, PCBs and OCPs biomagnified (TMF >1), while all chlorinated paraffins (CPs), PAHs, and phthalates underwent a trophic dilution (TMF <1). TMFs significantly decreased with a metabolic transformation rate and increased with hydrophobicity. The levels of PAH or phthalate metabolites were not significantly correlated with trophic levels or underwent a trophic dilution. This study highlighted that the relative contribution of metabolite levels in TMF values calculated for both parent compound and its metabolite(s) is weak compared to TMF values of the parent compound only in a riverine food web.

Polychlorinated biphenyls, polybrominated diphenyl ethers, and phthalates in roach from the Seine River basin (France): impact of densely urbanized areas.

Endocrine disruptors (EDs) from three chemical classes-polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and phthalates-were investigated in the Seine River and one tributary, the Orge River, upstream and downstream of urban areas. The impact of urban areas was characterized by a concentration increase of all compounds in the Seine River and for phthalates and PBDEs in the Orge River. In the Seine River, from upstream (Marnay) to downstream (Triel) of urban areas, water concentration increases were greater for diethylhexyl phthalate (DEHP) (6 times, p < 0.05) and ∑tri-hexa BDE (5 times [p < 0.05]) than for ∑7PCBi (2.6 times). Simultaneously, sediments displayed a strong accumulation of contaminants downstream and compared with upstream values, their concentrations increased greatly: 202-fold for DEHP, 69-fold for BDE209, 25-fold for ∑tri-hexa-BDE, and 11-fold for ∑7PCBi. Variations of fish ED concentrations gave an indication of their habitat contamination increase observed downstream of densely urbanized areas of the Seine River, especially for PBDEs (∑tri-hexa-PBDEs = 14-fold increase ≤15.7 ± 6.9 ng g(-1) dry weight [dw; p < 0.001]) and for PCBs (∑7PCBi eightfold increase ≤211 ± 55 ng g(-1) dw [p < 0.01]). PCA results highlighted relationships between the different ED classes. A correlation (p < 0.05) was observed between PCB and PBDE fish concentrations, suggesting common sources and similar absorption mechanisms. For PCBs, which were poorly biodegraded, the bioaccumulation factor was strongly correlated (p < 0.001) to molecular hydrophobicity, whereas for PBDEs a negative correlation (p < 0.05) was observed related active debromination processes. This multichemical study investigates for the first time the occurrence of a wide range of EDs in roach, which was chosen as a sentinel species for this survey of surface water contamination.

Pesticide concentrations in a threatened freshwater turtle (Emys orbicularis): Seasonal and annual variation in the Camargue wetland, France.

Wetlands are among the most threatened ecosystems on the planet and pollution is a major factor causing the decline of wetland biodiversity. Despite the increasing use of pesticides, their fate and effects on freshwater reptiles remain largely unknown. We studied the European pond turtle (Emys orbicularis), a long-lived species at risk with a high exposure potential to pesticides. Between 2018 and 2020, we measured 29 pesticides and metabolites in 408 blood samples of turtles from two populations in the Camargue wetland (France). We were able to quantify 24 compounds and at least one pesticide or one degradation product in 62.5% of samples. Pesticide occurrences and concentrations were low, except for a herbicide widely used in rice cultivation and locally detected in water: bentazone that reached high blood concentrations in E. orbicularis. The occurrence and the concentration of pesticides in E. orbicularis blood depended mainly on the site and the sampling date in relation to pesticide application. Individual characteristics (sex, age, body condition) did not explain the occurrence or the concentration of pesticides found in turtle blood. Assessing the exposure of aquatic wildlife to a cocktail of currently-used pesticides is a first and crucial step before studying their effects at the individual and population levels.

Contrasted Antibiotics and Pesticides Occurrence in Fish Exposed In Situ to Urban Effluents: A 20-Day Caging Experiment.

Urban freshwater ecosystems receive a wide array of organic pollutants through wastewater-treatment plant (WWTP) discharges and agricultural runoff. Evaluating the fate and effects of antibiotics and pesticides can be a challenging task, especially the effects on freshwater vertebrates because of their abilities to metabolize and excrete these chemicals and because of their high mobility and escape behavior when exposed to stressful environmental conditions. In the present study, 37 wild gudgeons (Gobio gobio) were caged for a period of up to 20 days, upstream and downstream of a WWTP effluent discharge in the Orge River (a tributary of the Seine River, France). Levels of pesticides and antibiotics in fish muscles were monitored weekly and compared with environmental contamination (water and sediments). Our results highlighted a slight bioaccumulation of pesticides in the gudgeon muscles at the downstream site after 20 days of exposure. Concerning antibiotics, ofloxacin was the most detected compound in fish muscles (85% of occurrence) and ranged from undetectable to 8 ng g-1 dry weight. Antibiotic levels in fish muscle were not higher at the downstream site and did not increase with exposure duration, despite high levels in the water (up to 29 times greater than upstream). Potential ecotoxicological effects were also evaluated: Body condition did not differ between the caging location and exposure time. Three oxidative status markers in the fish livers showed significant shifts after 14 days of caging. Our results suggest a high clearance rate of antibiotics and, to a lesser extent, of pesticides in wild gudgeons, which could be explained by changes in xenobiotic metabolism with pollutant exposure. Environ Toxicol Chem 2024;43:701-711. © 2023 SETAC.

Occurrence of polybrominated diphenyl ethers, polychlorinated biphenyls, and phthalates in freshwater fish from the Orge river (Ile-de France).

Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and phthalates were investigated from July 2009 to April 2010 in three fish species from the Orge river, which flows in a densely populated area of Ile-de-France. In two Cyprinidae (roach and chub) and one Percidae (perch), muscle contents in increasing order ranged as follows: 12-18 ng g(-1) dw for PBDEs (Σtri-hepta), 120-170 ng g(-1) dw for PCBs (Σ7), and 2,250-5,125 ng g(-1) dw for phthalates (Σ7). No variation was observed between contaminant contents and lipid levels. No biomagnification was found according to the trophic level for PBDEs and PCBs, whereas for phthalates the highest contents were found in perch. Seasonal variations were observed with the lowest PBDE and PCB contents occurring in July after spawning in roach and perch (p < 0.001). PBDE content followed a decreasing trend-gonad > liver > muscle-whatever the period. For PCBs, gonad and liver contents remained greater than that of muscle (p < 0.05). Our results indicate a preferential accumulation of halogenated compounds in gonad and liver outside the reproduction period. Bioaccumulation factors for PCBs in muscle were significantly correlated to their chlorination degree in perch (p < 0.01) and roach (p < 0.01). In roach, that correlation slope was by decreasing importance order as follows: gonad > liver > muscle. The biota-sediment accumulation factors varied from 0.1 to 29.2, from 1.6 to 4.8, and from 1 to 123.5 for PBDEs, PCBs, and phthalates, respectively. These results contribute to document the use of freshwater fish as bioindicators of river quality.

Influence of hydrological parameters on organohalogenated micropollutant (polybrominated diphenyl ethers and polychlorinated biphenyls) behaviour in the Seine (France).

The temporal dynamics of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were investigated in a heavily urbanized river (Seine River, Paris, France) from November 2009 to May 2010. Pollutant concentrations were in the range of 0.2 to 3.8 ng l(-1) (median 1.1) and 0.4 to 3.6 ng l(-1) (median 1.1) for ∑ tri-deca BDEs and ∑ 7PCBs, respectively. In addition, for both PBDEs and PCBs, the partitioning between the particulate and dissolved phases was investigated. Due to their low water solubility, PBDEs were mainly (>70%) bound to particles. In contrast, only 54% of ∑ 7PCBs occurred in the particulate phase, and their partitioning was influenced by the degree of chlorination. During the sampling period, PBDE/PCB fluxes were quite similar and ranged from 3 to 128 and from 6 to 125 g day(-1), respectively. The annual mass flow of PBDEs and PCBs was estimated to 10 kg for both. Contrary to PCBs and BDE-209, the temporal evolution of ∑ tri-hepta BDEs was related to particulate organic matter content, which is controlled by river flow variations. This suggests that they exhibit different sources or behavior in the Seine River.

Trace organic contaminants within solid matrices along an anthropized watercourse: Organo-mineral controls on their spatial distribution.

Although numerous studies have determined significant contamination in terms of trace organic contaminant (TrOC) diversity and concentration, the occurrence of TrOCs within solid matrices as suspended solids and sediments flies under the radar. In this study, the occurrence of 35 TrOCs of various classes (i.e. pharmaceutical products and pesticides) was investigated in three compartments, namely dissolved phase, suspended particulate matter (SPM) and sediments, within an anthropized river in France. The sampling was performed to assess the spatial contamination dynamics and the impact of a major wastewater treatment plant (WWTP), under two contrasted hydrological conditions, i.e. base level and flood conditions. Solid samples were finely characterized (XRD, grainsize, TOC) in order to assess the impact of organic and mineral composition on the sorption extent of TrOCs. The study reveals that the clear spatial pattern of contamination in water samples, mostly generated by the effluent discharge of WWTPs, is less clear in solid matrices as the variability of the organo-mineral composition of such samples strongly impacts their favourability for sorption. Moreover, the flood event strongly impacted the sedimentary compartment, remobilizing fine and TrOC contaminated particles that were further found in suspended particulate matter. Lastly, the representativeness of contaminant diversity and concentration within the solid matrices displayed more favourable insights for SPM.

Evidence of environmental transfer of tebuconazole to the eggs in the house sparrow (Passer domesticus): An experimental study.

Triazole compounds are among the most widely used fungicides in agroecosystems to protect crops from potential fungal diseases. Many farmland birds spend a significant part of their life cycle in agroecosystems, which may chronically expose them to pesticides. We experimentally tested whether exposure to environmental concentrations of tebuconazole could induce a contamination of the eggs in an agroecosystem sentinel species, the house sparrow (Passer domesticus). Wild-caught adult sparrows were maintained in captivity and exposed (exposed group) or not (control group) for seven months to tebuconazole through drinking water. Eggs were opportunistically collected for the determination of tebuconazole concentration by Liquid Chromatography coupled to tandem Mass Spectrometry in eggs. We found that eggs from exposed parents all contained tebuconazole with a mean concentration of 1.52 ng g-1 dry weight. In eggs from control parents, the tebuconazole concentration was below the limit of quantification (0.23 ng g-1 dry weight) for 11 out of 13 eggs. Thus, our study demonstrates for the first time that environmental exposure of female birds to tebuconazole can translate into egg contamination by this fungicide.

Dysbiosis of fish gut microbiota is associated with helminths parasitism rather than exposure to PAHs at environmentally relevant concentrations.

Although parasite infection and pollution are common threats facing wild populations, the response of the gut microbiota to the joint impact of these stressors remains largely understudied. Here, we experimentally investigated the effects of exposure to Polycyclic Aromatic Hydrocarbons (PAHs) and infection by a common acanthocephalan intestinal parasite (Pomphorhynchus sp.) on the gut microbial flora of a freshwater fish, the European chub (Squalius cephalus). Naturally infected or uninfected individuals were exposed to PAHs at environmentally realistic concentrations over a five-week period. Characterization of the gut bacterial community through 16S rRNA gene amplicon sequencing revealed that parasitic infection was a more structuring factor of bacterial diversity and composition than PAH exposure. Specifically, chub infected by Pomphorhynchus sp. harbored significantly less evenly represented gut bacterial communities than the uninfected ones. In addition, substantial changes in sequence abundance were observed within the main bacterial phyla, including the Firmicutes, Fusobacteriota, Actinobacteriota, and Proteobacteria. Again, these compositional changes correlated with host infection with Pomphorhynchus sp., confirming its pivotal role in gut microbial assemblage. Overall, these results highlight the importance of defining the parasitic status of individuals when conducting microbial ecotoxicological analyses at the digestive tract level, as this should lead to better understanding of microbiota modulations and help to identify microbial markers specifically associated with chemicals.

Record of trace organic contaminants in a river sediment core: From historical wastewater management to historical use.

Some trace organic contaminants (TrOCs) can be considered as ubiquitous contaminants since the 1950s, and the study of their historical distribution within river sediments allows us to better understand the temporal variation of the chemical quality of sediments, and make assumptions about the most insightful forcings impacting these distributions. In this study, the occurrence of 41 TrOCs of various classes (i.e. pharmaceutical products and pesticides) was studied in a sedimentary core sampled in a disused dock along the Seine River, France. This core covers a 60 year-long period between 1944 and 2003, and 23 TrOCs were detected at least once. Their concentrations mainly ranged between 1 and 10 ng g-1 within the core, except for tetracycline that exhibited higher concentrations (~hundreds of ng·g-1). The dating of the core, based on previous studies, enabled the characterization of the changes since 1945, potentially impacted by (i) the sewer connectivity, (ii) the upgrading of wastewater treatment technologies, (iii) historical modifications in the use of each TrOC, and (iv) the sedimentary composition. In every case the deepest occurrence of each TrOC in the core matched its market authorization date, indicating the potential of TrOC to be used as chronomarkers. This study also reveals that the recent upgrading of wastewater treatment technologies within the watershed decreased the concentrations of each TrOC, despite an increase in TrOC diversity in the most recent years.

Determinants of Legacy Persistent Organic Pollutant Levels in the European Pond Turtle (Emys orbicularis) in the Camargue Wetland, France.

Many banned persistent organic pollutants (POPs) remain for decades in the aquatic environment and can have harmful effects on long-lived predators because of their high bioaccumulation and biomagnification potentials. We investigated the occurrence and levels of 18 polychlorinated biphenyls (PCBs) and 16 organochlorine pesticides in European pond turtles (n = 174) from April to July 2018 in the Camargue wetland, France. Although the Camargue was highly contaminated in previous decades, plasma occurrence and levels of POPs were very low: we were able to quantify only 3 of the 34 compounds we analyzed in >10% of the turtles. The burdens from POPs did not differ between males and females and were uncorrelated with sampling date and body mass. We observed differences in POP burdens between turtles from the 2 sampling sites. One possible explanation is that the sampling sites were in different agricultural hydraulic systems: plasma occurrence and levels were higher for PCB-52 and hexachlorobenzene in turtles captured in drainage channels and for PCB-153 at the site that receives irrigation. Finally, the occurrence and levels of PCB-153 in turtles increased with age, likely because of bioaccumulation and much higher exposure 20 to 30 yr ago than now. Environ Toxicol Chem 2021;40:2261-2268. © 2021 SETAC.

Development of analytical procedures for trace-level determination of polybrominated diphenyl ethers and tetrabromobisphenol A in river water and sediment.

The aim of this work was to develop procedures for the simultaneous determination of selected brominated flame retardants (BFRs) in river water and in river bed sediment. The target analytes were polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBPA). To determine dissolved BFRs, a novel mixed-mode solid-phase extraction procedure was developed by combining a hydrophobic sorbent (C(18)) with a silica-based anion exchange sorbent, so as to overcome the negative artefact induced by dissolved organic carbon. Extraction recoveries exceeded 73% for most analytes, except for BDE-183 and BDE-209 (57%). As regards suspended sediment and river bed sediment, extraction was carried out by means of ultrasonication (recoveries: 73-94%). These procedures, combined to gas chromatography coupled to negative chemical ionisation mass spectrometry (GC-NCI-MS), enabled the determination of BFRs at trace level: 3-160 pg L(-1) in river water, 5-145 pg g(-1) in bed sediment. These methods were applied to the determination of PBDEs and TBBPA in a suburban river (near Paris, France). PBDEs were systematically detected in the water column (SigmaBDEs, 2,300-4,300 pg L(-1)); they partitioned between the dissolved and particulate phases and BDE-209 was the dominant congener, followed by BDE-99 and BDE-47. TBBPA was detected in the dissolved phase only (<35-68 pg L(-1)). All selected BFRs were ubiquitous in bed sediments and levels ranged from 3,100 to 15,100 pg g(-1) and from 70 to 280 pg g(-1) (dry weight), for SigmaBDEs and TBBPA, respectively.

Rapid SPE - LC MS/MS analysis for atrazine, its by-products, simazine and S metolachlor in groundwater samples.

A rapid analysis of pesticides using on-line Solid phase extraction LC MS/MS (Agilent Technology) was performed using only 2-mL water samples. SPE cartridge PLRP-s was used for the pre-concentration sample with methanol elution in back flush. Sensitive transitions and mass spectrometry conditions were optimized by direct infusion of individual standard solutions in a positive electrospray mode. Water samples were spiked with internal standards to compensate the matrix effect. The limit of quantification was calculated to be 20 ng L-1 using the standard deviation of blank analysis injected ten times and uncertainties were estimated at less than 20% on concentrations. This method was validated to study leaching water samples for which only small quantities of water were available.•Only 2 mL water sample was used.•Samples were filtered at 0.2 µm and spiked with individual standard.•Compounds were separated in an 18.5-min elution time using the dynamic MRM program.