High contamination of a sentinel vertebrate species by azoles in vineyards: a study of common blackbirds (Turdus merula) in multiple habitats in western France.

Azoles represent the most used family of organic fungicides worldwide and they are used in agriculture to circumvent the detrimental impact of fungi on yields. Although it is known that these triazoles can contaminate the air, the soil, and the water, field data are currently and dramatically lacking to assess if, and to what extent, the use of triazoles could contaminate non-target wild vertebrate species, notably in agroecosystems. In this study, we aimed to document for the first time the degree of blood contamination of a generalist wild bird species by multiple azoles which are used for plant protection and fungi pest control in various habitats. We deployed passive air samplers and captured 118 Common blackbirds (Turdus merula) in an agroecosystem (vineyard), a protected forest, and a city in western France. We collected blood and analyzed the plasma levels of 13 triazoles and 2 imidazoles. We found that a significant percentage of blackbirds living in vineyards have extremely high plasma levels of multiple azoles (means (pg.g-1); tebuconazole: 149.23, difenoconazole: 44.27, fenbuconazole: 239.38, tetraconazole: 1194.16), while contamination was very limited in the blackbirds from the protected forest and absent in urban blackbirds. Interestingly, we also report that the contamination of blackbirds living in vineyard was especially high at the end of Spring and the beginning of Summer and this matches perfectly with the results from the passive air samplers (i.e., high levels of azoles in the air of vineyards during June and July). However, we did not find any correlation between the levels of plasma contamination by azoles and two simple integrative biomarkers of health (feather density and body condition) in this sentinel species. Future experimental studies are now needed to assess the potential sub-lethal effects of such levels of contamination on the physiology of non-target vertebrate species.

Bioaccumulation of per- and polyfluoroalkyl substance in fish from an urban river: Occurrence, patterns and investigation of potential ecological drivers.

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in aquatic environments and a recent shift toward emerging PFAS is calling for new data on their occurrence and fate. In particular, understanding the determinants of their bioaccumulation is fundamental for risk assessment purposes. However, very few studies have addressed the combined influence of potential ecological drivers of PFAS bioaccumulation in fish such as age, sex or trophic ecology. Thus, this work aimed to fill these knowledge gaps by performing a field study in the Seine River basin (France). Composite sediment and fish (European chub, Squalius Cephalus) samples were collected from four sites along a longitudinal transect to investigate the occurrence of 36 PFAS. Sediment molecular patterns were dominated by fluorotelomer sulfonamidoalkyl betaines (i.e. 6:2 and 8:2 FTAB, 46% of ∑PFAS on average), highlighting the non-negligible contribution of PFAS of emerging concern. C9-C14 perfluoroalkyl carboxylic acids, perfluorooctane sulfonic acid (PFOS), perfluorooctane sulfonamide (FOSA) and 10:2 fluorotelomer sulfonate (10:2 FTSA) were detected in all fish samples. Conversely, 8:2 FTAB was detected in a few fish from the furthest downstream station only, suggesting the low bioaccessibility or the biotransformation of FTABs. ∑PFAS in fish was in the range 0.22-3.8 ng g-1 wet weight (ww) and 11-140 ng g-1 ww for muscle and liver, respectively. Fish collected upstream of Paris were significantly less contaminated than those collected downstream, pointing to urban and industrial inputs. The influence of trophic ecology and biometry on the interindividual variability of PFAS burden in fish was examined through analyses of covariance (ANCOVAs), with sampling site considered as a categorical variable. While the latter was highly significant, diet was also influential; carbon sources and trophic level (i.e. estimated using C and N stable isotope ratios, respectively) equally explained the variability of PFAS levels in fish.

Chlordecone-contaminated epilithic biofilms show increased adsorption capacities.

The rivers of Guadeloupe and Martinique (French West Indies) show high levels of chlordecone (CLD) contamination. This persistent molecule has a dramatic impact on both aquatic ecosystems and human health. In these rivers, epilithic biofilms are the main endogenous primary producers and represent a central food source for fish and crustaceans. Recently, their viscoelastic properties have been shown to be effective in bio-assessing pollution in tropical environments. As these properties are closely related to the biochemical composition of the biofilms, biochemical (fatty acids, pigments, extracellular polymeric substances (EPS) monosaccharides) and molecular markers (T-RFLP fingerprints of bacteria, archaea and eukaryotes) were investigated. Strong links between CLD pollution and both biofilm biochemistry and microbial community composition were found. In particular, high levels of CLD were linked with modified exo-polysaccharides corresponding to carbohydrates with enhanced adsorption and adhesion properties. The observed change probably resulted from a preferential interaction between CLD and sugars and/or a differential microbial secretion of EPS in response to the pollutant. These changes were expected to impact viscoelastic properties of epilithic biofilms highlighting the effect of CLD pollution on biofilm EPS matrix. They also suggested that microorganisms implement a CLD scavenging strategy, providing new insights on the role of EPS in the adaptation of microorganisms to CLD-polluted environments.

Refinement of an OECD test guideline for evaluating the effects of endocrine disrupting chemicals on aromatase gene expression and reproduction using novel transgenic cyp19a1a-eGFP zebrafish.

Transgenic fish are powerful models that can provide mechanistic information regarding the endocrine activity of test chemicals. In this study, our objective was to use a newly developed transgenic zebrafish line expressing eGFP under the control of the cyp19a1a promoter in the OECD Fish Short Term Reproduction Assay (TG 229) to provide additional mechanistic information on tested substances. For this purpose, we exposed adult transgenic zebrafish to a reference substance of the TG 229, i.e. prochloraz (PCZ; 1.7, 17.2 and 172.6 µg/L). In addition to "classical" endpoints used in the TG 229 (reproductive outputs, vitellogenin), the fluorescence intensity of the ovaries was monitored at 4 different times of exposure using in vivo imaging. Our data revealed that 172.6 µg/L PCZ significantly decreased the number of eggs laid per female per day and the concentrations of vitellogenin in females, reflecting the decreasing E2 synthesis due to the inhibition of the ovarian aromatase activities. At 7 and 14 days, GFP intensities in ovaries were similar over the treatment groups but significantly increased after 21 days at 17.2 and 172.6 µg/L. A similar profile was observed for the endogenous cyp19a1a expression measured by qPCR thereby confirming the reliability of the GFP measurement for assessing aromatase gene expression. The overexpression of the cyp19a1a gene likely reflects a compensatory response to the inhibitory action of PCZ on aromatase enzymatic activities. Overall, this study illustrates the feasibility of using the cyp19a1a-eGFP transgenic line for assessing the effect of PCZ in an OECD test guideline while providing complementary information on the time- and concentration-dependent effects of the compound, without disturbing reproduction of fish. The acquisition of this additional mechanistic information on a key target gene through in vivo fluorescence imaging of the ovaries was realized without increasing the number of individuals.

The influence of natural dissolved organic matter on herbicide toxicity to marine microalgae is species-dependent.

Microalgae, which are the foundation of aquatic food webs, may be the indirect target of herbicides used for agricultural and urban applications. Microalgae also interact with other compounds from their environment, such as natural dissolved organic matter (DOM), which can itself interact with herbicides. This study aimed to evaluate the influence of natural DOM on the toxicity of three herbicides (diuron, irgarol and S-metolachlor), singly and in ternary mixtures, to two marine microalgae, Chaetoceros calcitrans and Tetraselmis suecica, in monospecific, non-axenic cultures. Effects on growth, photosynthetic efficiency (Ф'M) and relative lipid content were evaluated. The chemical environment (herbicide and nutrient concentrations, dissolved organic carbon and DOM optical properties) was also monitored to assess any changes during the experiments. The results show that, without DOM, the highest irgarol concentration (I0.5: 0.5 mg.L-1) and the strongest mixture (M2: irgarol 0.5 µg.L-1 + diuron 0.5 µg.L-1 + S-metolachlor 5.0 µg.L-1) significantly decreased all parameters for both species. Similar impacts were induced by I0.5 and M2 in C. calcitrans (around -56% for growth, -50% for relative lipid content and -28% for Ф'M), but a significantly higher toxicity of M2 was observed in T. suecica (-56% and -62% with I0.5 and M2 for growth, respectively), suggesting a possible interaction between molecules. With DOM added to the culture media, a significant inhibition of these three parameters was also observed with I0.5 and M2 for both species. Furthermore, DOM modulated herbicide toxicity, which was decreased for C. calcitrans (-51% growth at I0.5 and M2) and increased for T. suecica (-64% and -75% growth at I0.5 and M2, respectively). In addition to the direct and/or indirect (via their associated bacteria) use of molecules present in natural DOM, the characterization of the chemical environment showed that the toxic effects observed on microalgae were accompanied by modifications of DOM composition and the quantity of dissolved organic carbon excreted and/or secreted by microorganisms. This toxicity modulation in presence of DOM could be explained by (i) the modification of herbicide bioavailability, (ii) a difference in cell wall composition between the two species, and/or (iii) a higher detoxification capacity of C. calcitrans by the use of molecules contained in DOM. This study therefore demonstrated, for the first time, the major modulating role of natural DOM on the toxicity of herbicides to marine microalgae.

Suspended solids moderate the degradation and sorption of waste water-derived pharmaceuticals in estuarine waters.

This study focuses on the fate of pharmaceuticals discharged into an estuarine environment, particularly into the Turbidity Maximum Zone (TMZ). Batch experiments were set up to investigate the factors regulating the degradation of 53 selected pharmaceuticals. Treated effluents from Bordeaux city (France) were mixed with water from the estuarine Garonne River during 4weeks under 6 characterized conditions in order to assess the influence of suspended particulates, sterilization, untreated wastewater input and dilution on the degradation kinetics. Of the 53 pharmaceuticals monitored, 43 were quantified at the initial time. Only 7 exhibited a persistent behavior (e.g. carbamazepine, meprobamate) while biotic degradation was shown to be the main attenuation process for 38 molecules (e.g. abacavir, ibuprofen highly degradable). Degradation was significantly enhanced by increasing concentrations of suspended solids. A persistence index based on the half-lives of the compounds has been calculated for each of the 43 pharmaceuticals to provide a practical estimate of their relative stability. The stability of pharmaceuticals in estuarine environments is likely to be highly variable and attenuated primarily by changes in suspended solid concentration.

Spatio-temporal dynamics of per and polyfluoroalkyl substances (PFASs) and transfer to periphytic biofilm in an urban river: case-study on the River Seine.

This study addresses the spatio-temporal dynamics of per and polyfluoroalkyl substances (PFASs) in a highly urbanized freshwater hydrosystem, the Seine River (NW France). The distribution of PFASs between water, sediment, and periphytic biofilm was investigated at three sampling sites along a longitudinal gradient upstream and downstream from the Paris urban area. Seasonal variability was assessed through four sampling campaigns performed under contrasting hydrological conditions. In the dissolved phase, ∑PFASs fluctuated between 2 and 9 ng L-1 upstream and 6-105 ng L-1 downstream from Paris. Negative correlations between dissolved PFAS levels and river flow rate were generally observed, corroborating the predominance of point-source PFAS inputs at these sites. 18/19 target PFASs were detected, with a predominance of PFHxS and PFOS (20% of ∑PFASs each), except for the farthest downstream site where 6:2 FTSA was prevalent (35 ± 8% of ∑PFASs), likely reflecting industrial and urban inputs. In biofilms, ∑PFASs fell in the 4-32 ng g-1 dw range, and substantial bioconcentration factors (BCFs) were reported for PFNA, PFDA, and PFOS (log BCF 2.1-4.3), higher than those of PFHxS or PFOA. BCFs varied inversely with dissolved PFAS levels, potentially pointing to concentration-dependent bioaccumulation. Biofilm community characteristics (C/N ratio) may also be an influential determinant of PFAS bioaccumulation. Graphical abstract ᅟ.

Photodegradation of novel oral anticoagulants under sunlight irradiation in aqueous matrices.

Kinetics of photodegradation of novel oral anticoagulants dabigatran, rivaroxaban, and apixaban were studied under simulated solar light irradiation in purified, mineral, and river waters. Dabigatran and rivaroxaban underwent direct photolysis with polychromatic quantum yields of 2.2 × 10-4 and 4.4 × 10-2, respectively. The direct photodegradation of apixaban was not observed after 19 h of irradiation. Kinetics of degradation of rivaroxaban was not impacted by the nature of the aqueous matrix while photosensitization from nitrate ions was observed for dabigatran and apixaban dissolved in a mineral water. The photosensitized reactions were limited in the tested river water (Isle River, Périgueux, France) certainly due to the hydroxyl radical scavenging effect of the dissolved organic matter. The study of photoproduct structures allowed to identify two compounds for dabigatran. One of them is the 4-aminobenzamidine while the second one is a cyclization product. In the case of rivaroxaban, as studied by very high field NMR, only one photoproduct was observed i.e. a photoisomer. Finally, seven photoproducts were clearly identified from the degradation of apixaban under simulated solar light.

Biomonitoring of fluoroalkylated substances in Antarctica seabird plasma: Development and validation of a fast and rugged method using on-line concentration liquid chromatography tandem mass spectrometry.

We report on a fast, accurate and rugged analytical procedure to determine a wide span of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in seabird plasma. The 26 investigated compounds included perfluoroalkyl carboxylates (C5-C14 PFCAs), perfluoroalkyl sulfonates (C4, C6, C7, C8, C10 PFSAs), perfluorooctane sulfonamide (FOSA) and N-alkyl derivatives (MeFOSA, EtFOSA), N-alkyl perfluorooctane sulfonamido acetic acids (MeFOSAA, EtFOSAA), fluorotelomer sulfonates (4:2 FTSA, 6:2 FTSA, 8:2 FTSA), polyfluoroalkyl phosphate diesters (diPAPs) and perfluorooctane sulfonamide phosphate diester (diSAmPAP). The method described herein requires a reduced sample amount (25µL) and involves rapid and simple sample preparation (protein precipitation with acetonitrile but without acidification) prior to analysis by on-line solid phase extraction (Oasis HLB sorbent) coupled to high performance liquid chromatography negative electrospray ionization tandem mass spectrometry. The optimization was conducted using experimental designs to account for potential interactions between variables. Out of the 26 target analytes, 23 compounds showed excellent accuracy (±25% of the expected values). Intermediate precision and matrix effects remained acceptable for most analytes thanks to efficient internal standardization. A human serum standard reference material (NIST SRM 1957) was included in the validation scheme to evaluate method trueness, which proved satisfactory (│Z-scores│<2 for most compounds). Notwithstanding the small initial sample intake, limits of detection as low as 0.003-0.1ngg-1 plasma were obtained. This allowed the determination of 11 target PFASs in Antarctic seabird plasma samples. ΣPFASs in Antarctic seabird plasma ranged from 0.37 to 19ngg-1, with a predominance of PFOS (>54% of ΣPFASs on average). The reduced plasma amount required implies that the present method could also be applied to the analysis of PFASs in the plasma of smaller biological models.

Occurrence survey and spatial distribution of perfluoroalkyl and polyfluoroalkyl surfactants in groundwater, surface water, and sediments from tropical environments.

The occurrence and spatial distribution of 22 selected perfluoroalkyl and polyfluoroalkyl substances (PFASs) in surface water (n=75), groundwater (n=80) and surficial sediment (n=15) were investigated for the first time in the tropical areas constituted by the French Overseas Territories (French Guiana, Guadeloupe, Martinique, Mayotte and Reunion). Descriptive statistics and correlations between PFASs were evaluated through the use of specific statistical treatments to handle left-censored data ("non-detects"). PFASs were ubiquitous in these samples and detection frequencies as high as 79% for perfluorooctane sulfonate (PFOS) and 65% for perfluorooctanoate (PFOA) were reported in surface waters. ∑PFASs was in the range

Quality survey of natural mineral water and spring water sold in France: Monitoring of hormones, pharmaceuticals, pesticides, perfluoroalkyl substances, phthalates, and alkylphenols at the ultra-trace level.

The aim of the present study, one of the most complete ever performed in France, was to carry out an extensive survey on the potential presence of a large amount of emerging contaminants in 40 French bottled waters, including parent compounds and metabolites. The studied samples represented 70% of the French bottled water market in volume. Six classes of compounds were investigated, most of them being unregulated in bottled waters: pesticides and their transformation products (118), pharmaceutical substances (172), hormones (11), alkylphenols (APs) (8), phthalates (11) and perfluoroalkyl substances (PFAS) (10). One of the objectives of this work was to achieve low and reliable limits of quantification (LOQs) (87% of the LOQs were below 10ng/L) using advanced analytical technologies and reliable sample preparation methodologies, including stringent quality controls. Among the 14,000 analyses performed, 99.7% of the results were below the LOQs. None of the hormones, pharmaceutical substances and phthalates were quantified. Nineteen compounds out of the 330 investigated were quantified in 11 samples. Eleven were pesticides including 7 metabolites, 6 were PFAS and 2 were APs. As regards pesticides, their sum was at least twice lower than the quality standards applicable for bottled waters in France. The presence of a majority of pesticide metabolites suggested a former use in the recharge areas of the exploited aquifers. The quantification of a few unregulated emerging compounds at the nano-trace level, such as PFAS, raised the issue of their potential sources, including long-range atmospheric transport and deposition. This study confirmed that the groundwater aquifers exploited for bottling were well-preserved from chemicals, as compared to less geologically protected groundwaters, and also underlined the need to pursue the protection policies implemented in recharge areas in order to limit the anthropogenic pressure.

The antidepressant venlafaxine may act as a neurodevelopmental toxicant in cuttlefish (Sepia officinalis).

The Serotonin/Norepinephrine Reuptake Inhibitor (SNRI) antidepressant venlafaxine (VEN, Effexor(®)) has become one of the most common antidepressants detected in North American and European streams. Mammalian research has established that VEN exposure is associated with a range of structural, neurochemical, and functional alterations of the brain in adults and newborns. However, the neurodevelopmental effects of VEN on non-target organisms have never been investigated. The aim of our research was to decrease this gap in knowledge by characterizing the effects of VEN exposure on a cephalopod mollusk, the common cuttlefish Sepia officinalis. This species inhabits VEN-contaminated waters and possesses an unusually sophisticated brain. These characteristics render it a unique invertebrate species for studying the neurodevelopmental effects of VEN. Cuttlefish were exposed to environmentally-relevant concentrations of VEN (Measured concentrations ≈5 and 100ngL(-)(1)) or to filtered natural seawater (control) in a closed-loop system with regular water changes during the first 20days after hatching. We evaluated brain maturation as well as neurochemical changes and behavioral performances during this critical period of development. Our results show that both VEN-exposed groups exhibited a decrease in norepinephrine levels, along with a reduction in the relative number of glutamate NMDA-like receptors binding sites in the group exposed to 5ngL(-1) of VEN after 20days of exposure. Brain regional changes in cellular proliferation were observed in VEN-exposed groups in the vertical lobe (i.e. a key structure involved in cognitive processes) and in the optic lobes (i.e. main visual processing centers) in the absence of significant change in their volume. Along with these neurodevelopmental changes, 20days of exposure to 100ngL(-1) of VEN was associated with a decrease in camouflage ability. Overall, our study suggests that VEN is a neurodevelopmental toxicant in non-target aquatic organisms at environmentally-relevant concentrations.

Combined effects of pollutants and salinity on embryo-larval development of the Pacific oyster, Crassostrea gigas.

For several years, low larval recruitment has been observed in Arcachon Bay, in southwest France. Exposure to pollutants could partly account for the reduction of early life stages of the Pacific oyster. This study evaluated the effects of copper and S-metolachlor in combination with salinity on the early life stages of Crassostrea gigas. Embryos were exposed to concentrations of copper (1, 10 and 50 µg L(-1)) or S-metolachlor (10, 100 and 1000 ng L(-1)) and six salinities (18, 21, 24, 27, 30 and 33 u.s.i). Embryotoxicity was measured by considering both the percentage of abnormalities and arrested development in D-shaped larvae. Embryo-larval development was only affected at salinities ≤24 u.s.i, which have never been observed during C. gigas reproduction period in Arcachon Bay. Both contaminants had an effect at environmental concentrations. Our results suggest that copper and metolachlor toxicity was enhanced with decreasing salinity.

Development and application of a multi-residue method for the determination of 53 pharmaceuticals in water, sediment, and suspended solids using liquid chromatography-tandem mass spectrometry.

Comprehensive source and fate studies of pharmaceuticals in the environment require analytical methods able to quantify a wide range of molecules over various therapeutic classes, in aqueous and solid matrices. Considering this need, the development of an analytical method to determine 53 pharmaceuticals in aqueous phase and in solid matrices using a combination of microwave-assisted extraction, solid phase extraction, and liquid chromatography coupled with tandem mass spectrometry is reported. Method was successfully validated regarding linearity, repeatability, and overall protocol recovery. Method detection limits (MDLs) do not exceed 1 ng L(-1) for 40 molecules in aqueous matrices (6 ng L(-1) for the 13 remaining), while subnanogram per gram MDLs were reached for 38 molecules in solid phase (29 ng g(-1) for the 15 remaining). Losses due to preparative steps were assessed for the 32 analytes associated to their labeled homologue, revealing an average loss of 40 % during reconcentration, the most altering step. Presence of analytes in wastewater treatment plant (WWTP) effluent aqueous phase and suspended solids (SS) as well as in river water, SS, and sediments was then investigated on a periurban river located in the suburbs of Bordeaux, France, revealing a major contribution of WWTP effluent to the river contamination. Sorption on river SS exceeded 5 % of total concentration for amitriptyline, fluoxetine, imipramine, ritonavir, sildenafil, and propranolol and appeared to be submitted to a seasonal influence. Sediment contamination was lower than the one of SS, organic carbon content, and sediment fine element proportion was accountable for the highest measured concentrations.

Identification of synthetic steroids in river water downstream from pharmaceutical manufacture discharges based on a bioanalytical approach and passive sampling.

A bioanalytical approach was used to identify chemical contaminants at river sites located downstream from a pharmaceutical factory, where reproductive alterations in wild fish have been previously observed. By using polar organic compound integrative samplers (POCIS) at upstream and downstream sites, biological activity profiles based on in vitro bioassays revealed the occurrence of xenobiotic and steroid-like activities, including very high glucocorticoid, antimineralocorticoid, progestogenic and pregnane X receptor (PXR)-like activities (µg standard-EQ/g of sorbent range), and weak estrogenic activity (ng E2-EQ/g of sorbent range). Chemical analyses detected up to 60 out of 118 targeted steroid and pharmaceutical compounds in the extracts. In vitro profiling of occurring individual chemicals revealed the ability of several ones to act as agonist and/or antagonist of different steroids receptors. Mass balance calculation identified dexamethasone, spironolactone, and 6-alpha-methylprednisolone as major contributors to corticosteroid activities and levonorgestrel as the main contributor to progestogenic activities. Finally, RP-HPLC based fractionation of POCIS extracts and testing activity of fractions confirmed identified compounds and further revealed the presence of other unknown active chemicals. This study is one of the first to report environmental contamination by such chemicals; their possible contribution to in situ effects on fish at the same site is suggested.

Comparative responses of sperm cells and embryos of Pacific oyster (Crassostrea gigas) to exposure to metolachlor and its degradation products.

Metolachlor is one of the most intensively used chloroacetanilide herbicides in agriculture. Consequently, it has been frequently detected in coastal waters as well as its major degradation products, metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid (MOA) which are encountered at higher concentrations than metolachlor. Although a few studies of metolachlor toxicity have been conducted on marine organisms, little is known about the environmental toxicity of metolachlor degradation products. In this study, the deleterious effects of metolachlor and its degradation products on spermatozoa and embryos of Crassostrea gigas have been compared using biomarkers of developmental defects, DNA damage and gene transcription levels. After 24h exposure, significant increases in the percentage of abnormal D-larvae and DNA damage were observed from 0.01 µg L(-1) for S-metolachlor and 0.1 µg L(-1) for MESA and MOA. Results showed that S-metolachlor was more embryotoxic and genotoxic than its degradation products. Oyster sperm was also very sensitive to metolachlor exposure and followed the pattern: metolachlor (0.01 µg L(-1))>MOA (0.1 µg L(-1))>MESA (1 µg L(-1)). Metolachlor and MESA mainly triggered variations in the transcription level of genes encoding proteins involved in oxidative stress responses (mitochondrial superoxide dismutase and catalase). Overall, no significant variation in transcription levels could be detected in C. gigas embryos exposed to MOA. This study demonstrates that metolachlor and its main degradation products have the potential to impact several steps of oyster development and therefore recruitment in coastal areas exposed to chronic inputs of pesticides.

Development of an adapted version of polar organic chemical integrative samplers (POCIS-Nylon).

POCIS (polar organic chemical integrative samplers) are increasingly used for sampling polar compounds. Although very efficient for a wide range of pollutants, the classic configuration of the device has a number of limitations, in particular for the sampling of highly polar analytes and hydrophobic compounds. This study presents a new version of the POCIS passive sampler which uses a highly porous Nylon membrane of 30 µm pore size, enabling the sampling of hydrophobic pollutants and improving the accumulation rate of other pollutants. This newly designed tool and the classic POCIS were both tested during a laboratory experiment to evaluate the accumulation kinetics of a selection of pesticides and pharmaceuticals. The observed results show unexpected accumulation kinetics for the new version of POCIS. To explain the data, the use of an intraparticulate diffusion model was required, which also enabled us to propose another explanation of the burst effect observed with the classic POCIS, primarily related to the potential wetting of the device as the first step in the accumulation of compounds.

Development of the performance reference compound approach for the calibration of "polar organic chemical integrative sampler" (POCIS).

The purpose of the Water Framework Directive is to ensure the quality of the natural water across Europe. In this context, passive samplers have shown interesting capacities for the monitoring of contaminants in aqueous ecosystems. They allow the measurement of time-weighted average concentrations, overcoming many drawbacks of the spot-sampling techniques known to be expensive and time consuming. However, application of passive samplers such as polar organic chemical integrative samplers (POCIS) for the monitoring of hydrophilic contaminants requires calibration to define compound sampling rates; key parameters to deduce the pollutant water concentrations from the amounts of pollutants accumulated by the device. Unfortunately, sampling rates are influenced by a range of environmental factors; in that respect, a question remains: is it not evident to know to what extent the sampling rates obtained in laboratory experiments can be used in field conditions? The problem can be solved for hydrophobic samplers by using performance reference compounds (PRCs), and an ongoing challenge for POCIS is focused on the improvement of the quantitative aspect of this family of samplers. In this study, potential PRCs have been selected during a specific experiment and their performance was tested in the laboratory under two hydrodynamic conditions. Results revealed a good proportionality between elimination rates of PRCs and sampling rates of chemicals. Afterwards, the application of the approach under environmental conditions was assessed by deploying POCIS in the Arcachon Bay (France) where POCIS-PRC-derived water concentrations appear to be close to the simultaneous grab-sampling results.