Single injection LC-MS/MS analytical method for the quantification of diverse families of micropollutants, including PFAS and organotins, in Gammarus fossarum.

Since the last decades, light has been shed on the pollution of aquatic ecosystems. Considering apolar compounds in water, analysis of the dissolved phase is not sufficient due to their possible bioaccumulation. Additional analysis of sediments, biota, or sentinel species is necessary. Among sentinel species, Gammarus fossarum is a small shrimp of 30 mg that lives naturally in the river. Its ability to bioaccumulate makes it a good bioindicator of river pollution. Nevertheless, micropollutants are difficult to extract from gammarids due to their small size and their high level of lipids. Extracted interferences can lead to analytical difficulties. Targeted micropollutants in this work were organotins, personal and pharmaceutical care products (PPCPs), pesticides, flame retardants, and perfluorinated compounds. A sample preparation based on QuEChERS followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was developed: different salts (acetate and citrate) and purification (addition of hexane, dispersive SPE) were tested and validated. Targeted molecules used to be analyzed by LC-MS/MS, except organotins which are principally analyzed in gas chromatography. One of the main challenges was to quantify them also in LC-MS/MS to implement an original multi-residue method. The analysis of 40 compounds was finally validated according to ICH guidelines, with LOQs ranging from 0.04 ng.g-1 to 313.5 ng.g-1. Regarding Perfluorooctanesulfonic acid (PFOS) and the sum of hexabromocyclododecane, LOQs reached the environmental quality standards in biota which are respectively of 9.1 and 167 ng.g-1. Finally, the method was applied to 15 real samples. Many compounds were quantified: perfluorinated compounds, drugs such as ketoprofen, and even cosmetics products such as octocrylene. This is the first study to quantify as many emerging compounds, especially organotins, in a sentinel species such as G. fossarum.

Determination of groundwater origins and vulnerability based on multi-tracer investigations: New contributions from passive sampling and suspect screening approach.

Knowledge about groundwater origins and their interactions with surface water is fundamental to assess their vulnerability. In this context, hydrochemical and isotopic tracers are useful tools to investigate water origins and mixing. More recent studies examined the relevance of contaminants of emerging concern (CECs) as co-tracers to distinguish sources contributing to groundwater bodies. However, these studies focused on known and targeted CECs a priori selected regarding their origin and/or concentrations. This study aimed to improve these multi-tracer approaches using passive sampling and qualitative suspect screening by exploring a larger variety of historical and emerging concern contaminants in combination with hydrochemistry and water molecule isotopes. With this objective, an in-situ study was conducted in a drinking water catchment area located in an alluvial aquifer recharged by several water sources (both surface and groundwater sources). CECs determined by passive sampling and suspect screening allowed to provide in-depth chemical fingerprints of groundwater bodies by enabling the investigation of >2500 compounds with an increased analytical sensitivity. Obtained cocktails of CECs were discriminating enough to be used as chemical tracer in combination with hydrochemical and isotopic tracers. In addition, the occurrence and type of CECs contributed to a better understanding of groundwater-surface water interactions and highlighted short-time hydrological processes. Furthermore, the use of passive sampling with suspect screening analysis of CECs lead to a more realistic assessment and mapping of groundwater vulnerability.

Assessing the Potential Ecotoxicological Risk of Different Organic Amendments Used in Agriculture: Approach Using Acute Toxicity Tests on Plants and Earthworms.

In Europe, spreading organic wastes to fertilize soils is an alternative commonly used instead of chemical fertilizers. Through their contributions of nutrients and organic matter, these wastes promote plant growth and thus agricultural production. However, these organic amendments can also contain mineral and organic pollutants requiring chemical and ecotoxicological analyses to guarantee their harmlessness on soil and its organisms during spreading. The purpose of this study was to assess the potential toxicity of three organic amendments from different sources (sewage sludge, dairy cow manure, dairy cow slurry) by performing chemical analyses and acute toxicity tests on three types of organism: earthworms, plants, soil microbial communities. Chemical analysis revealed a higher content of certain pharmaceuticals, polycyclic aromatic hydrocarbons and metals in sewage sludge in comparison with the two other types of organic wastes. The ecotoxicological assessment showed a dose-dependent effect on soil organisms for the three organic amendments with higher toxic effects during the exposure tests with a soil amended with dairy cow slurry. However, at realistic spreading doses (10 and 20 g kg-1 dry weight of organic amendments) on a representative exposed soil, organic amendment did not show any toxicity in the three organisms studied and had positive effects such as increased earthworm biomass, increased plant root growth and earthworm behavior showing attraction for organic amendment. On the contrary, exposure assays carried out on a limited substrate like sandy soil showed increased toxicity of organic amendments on plant germination and root growth. Overall, the ecotoxicological analysis revealed greater toxicity for soil organisms during the amendment of cow slurry, contrary to the chemical analysis which showed the potential high risk of spreading sewage sludge due to the presence of a higher quantity of pollutants. The analysis of the chemical composition and use of acute toxicity tests is the first essential step for assessing the ecotoxicological risk of spreading organic amendments on soil organisms. In addition to standard tests, the study suggests using a representative soil in acute toxicity tests to avoid overestimating the toxic effects of these organic amendments.

Advantages of MS/MS/MS (MRM3) vs classic MRM quantification for complex environmental matrices: Analysis of beta-lactams in WWTP sludge.

When dealing with complex matrices such as wastewater treatment plant (WWTP) sludge or animal manure, usual MRM quantification may lack enough sensitivity or accuracy due to the presence of numerous interfering compounds co-extracted from the matrix. To circumvent the sensitivity and specificity loss, the method development can be focused on sample extraction, purification or/and optimisation of the detection. In this study, we propose an enhancement of a method for the analysis of five beta-lactams (Amoxicillin, Ampicillin, Cefapirin, Ceftiofur, and Cloxacillin) in WWTP, with the use of a hybrid triple quadrupole-Linear Ion Trap (LIT) spectrometer, enabling triple stage MS acquisition, namely MRM3, in place of the usual MS/MS detection. The adaptation of various parameters such as the secondary fragmentation energy, excitation, and accumulation times of the secondly generated ion are described. The method was then validated and enabled quantification limits between 0.8 and 14.7 ng g-1 associated with accurate quantification (between 98% and 113%). This method is the first to report the use of MRM3 acquisition in an environmental matrix as complex as sludge.

Ultrasound-assisted sample preparation for simultaneous extraction of anionic, cationic and non-ionic surfactants in sediment.

Despite their very wide use in various fields, knowledge concerning surfactants in environmental solid matrices is generally poor. One of the difficulties encountered in the analysis of surfactants is their very diverse physicochemical properties which require different extraction techniques. The objective of this work was therefore to develop an extraction method in sediments that allows the simultaneous analysis of anionic, cationic and non-ionic surfactants. Different extraction techniques (salting-out, ultrasound), solvents and additives were compared. The optimized method, followed by analysis by coupling liquid chromatography with tandem mass spectrometry, was then validated and applied to real samples in which the analytes were quantified by matrix matched calibration. Optimization of the extraction parameters showed different trends depending on the surfactant family. However, ultrasound assisted extraction with a 90/10 acetonitrile/water mixture at 1% acetic acid and 0.1 M EDTA showed the best results overall. The quantification limits obtained, between 6.4 µg/kg for linear alkylbenzene sulfonate (LAS) C10 and 158 µg/kg for 1-laureth sulfate, allow the analysis of traces in sediments. Eighteen of the 27 targeted surfactants were thus detected. The highest concentrations were found for LAS and quaternary ammoniums. Strong correlations between concentrations of different homologues of the same families of surfactants were observed.

SIPIBEL observatory: Data on usual pollutants (solids, organic matter, nutrients, ions) and micropollutants (pharmaceuticals, surfactants, metals), biological and ecotoxicity indicators in hospital and urban wastewater, in treated effluent and sludge from wastewater treatment plant, and in surface and groundwater.

The Bellecombe pilot site - SIPIBEL - was created in 2010 in order to study the characterisation, treatability and impacts of hospital effluents in an urban wastewater treatment plant. This pilot site is composed of: i) the Alpes Léman hospital (CHAL), opened in February 2012, ii) the Bellecombe wastewater treatment plant, with two separate treatment lines allowing to fully separate the hospital wastewater and the urban wastewater, and iii) the Arve River as the receiving water body and a tributary of the Rhône River and the Geneva aquifer. The database includes in total 48 439 values measured on 961 samples (raw and treated hospital and urban wastewater, activated sludge in aeration tanks, dried sludge after dewatering, river and groundwater, and a few additional campaigns in aerobic and anaerobic sewers) with 44 455 physico-chemistry values (including 15 pharmaceuticals and 14 related transformation products, biocides compounds, metals, organic micropollutants), 2 193 bioassay values (ecotoxicity), 1 679 microbiology values (including microorganisms and antibioresistance indicators) and 112 hydrobiology values.

Gentamicin at sub-inhibitory concentrations selects for antibiotic resistance in the environment.

Antibiotics released into the environment at low (sub-inhibitory) concentrations could select for antibiotic resistance that might disseminate to the human microbiome. In this case, low-level anthropogenic sources of antibiotics would have a significant impact on human health risk. In order to provide data necessary for the evaluation of this risk, we implemented river water microcosms at both sub-inhibitory and inhibitory concentrations of gentamicin as determined previously based on bacterial growth in enriched media. Using metagenomic sequencing and qPCR/RT-qPCR, we assessed the effects of gentamicin on water bacterial communities and their resistome. A change in the composition of total and active communities, as well as a gentamicin resistance gene selection identified via mobile genetic elements, was observed during a two-day exposure. We demonstrated the effects of sub-inhibitory concentrations of gentamicin on bacterial communities and their associated resistome in microcosms (simulating in situ conditions). In addition, we established relationships between antibiotic dose and the magnitude of the community response in the environment. The scope of resistance selection under sub-inhibitory concentrations of antibiotics and the mechanisms underlying this process might provide the basis for understanding resistance dispersion and associated risks in relatively low impacted ecosystems.

Improvement of the QuEChERS extraction step by matrix-dispersion effect and application on beta-lactams analysis in wastewater sludge by LC-MS/MS.

In the last decade, beta-lactams use in veterinary and human medicine increased to represent today about 15% of the overall consumption. Beta-lactams tend to degrade and metabolize in the environment. Therefore, analytical methods must be sensitive enough to quantify low concentrations of the parent molecules and also allow detection of metabolites. This study presents the development of a modified QuEChERS method for the extraction of seven beta-lactams and one degradation product (Amoxicillin, Ampicillin, Cefapirin, Cefoperazone, Cefquinome, Ceftiofur, Cloxacillin, and Amoxicillin-Diketopiperazine) from sewage treatment plant sludge and their analysis by liquid chromatography coupled with tandem mass spectrometry. Before the QuEChERS extraction, a dispersion step of the sample with EDTA-treated sand was optimized and added, allowing to facilitate the exchanges between the matrix and the extraction solvent. Then, to decrease the interferences present in the extract, a fast and efficient pass-through SPE was implemented. The optimized method was validated and showed satisfactory performances, in adequacy with the analysis of beta-lactams in solid environmental matrices. Limits of quantification lower than 20 ng.g-1 for all analytes, high accuracy (96%-114% quantification on spiked samples nominal concentration) and interday precision (2%-12% RSD) were obtained. This method was then applied to eight sludge samples. Cefapirin and amoxicillin-diketopiperazine were detected in four samples each, at concentrations of 10.2-53.3 ng.g-1 and 3.0-9.5 ng.g-1 respectively. Thus, the developed method is very effective for the extraction of beta-lactams from environmental solid matrices.

Distribution of pesticides and some of their transformation products in a small lentic waterbody: Fish, water, and sediment contamination in an agricultural watershed.

More than 20 years after the Water Framework Directive was adopted, there are still major gaps in the sanitary status of small rivers and waterbodies at the head of basins. These small streams supply water to a large number of wetlands that support a rich biodiversity. Many of these waterbodies are fishponds whose production is destined for human consumption or for the restocking of other aquatic environments. However, these ecosystems are exposed to contaminants, including pesticides and their transformation products. This work aims to provide information on the distribution, diversity, and concentrations of agricultural contaminants in abiotic and biotic compartments from a fishpond located at the head of watersheds. A total of 20 pesticides and 20 transformation products were analyzed by HPLC-ESI-MS/MS in water and sediment sampled monthly throughout a fish production cycle, and in three fish species at the beginning and end of the cycle. The highest mean concentrations were found for metazachlor-OXA (519.48 ± 56.52 ng.L-1) in water and benzamide (4.23 ± 0.17 ng g-1 dry wt.) in sediment. Up to 20 contaminants were detected per water sample and 26 per sediment sample. The transformation products of atrazine (banned in Europe since 2003 but still widely used in other parts of the world), flufenacet, imidacloprid (banned in France since 2018), metazachlor, and metolachlor were more concentrated than their parent compounds. Fewer contaminants were detected in fish and principally prosulfocarb accumulated in organisms during the cycle. Our work brings innovative data on the contamination of small waterbodies located at the head of a basin. The transformation products with the highest frequency of occurrence and concentrations should be prioritized for further environmental monitoring studies, and specific toxicity thresholds should be defined. Few contaminants were found in fish, but the results challenge the widely use of prosulfocarb.

Miniaturization of an extraction protocol for the monitoring of pesticides and polar transformation products in biotic matrices.

Monitoring pesticides in the environment requires the use of sensitive analytical methods. However, existing methods are generally not suitable for analyzing small organisms, as they require large matrix masses. This study explores the development of a miniaturized extraction protocol for the monitoring of small organisms, based on only 30 mg of matrix. The miniaturized sample preparation was developed using fish and macroinvertebrate matrices. It allowed the characterization of 41 pesticides and transformation products (log P from -1.9 to 4.8) in small samples with LC-MS/MS, based on European guidelines (European Commission DG-SANTE, 2019). Quantification limits ranged from 3 to 460 ng g-1 dry weight (dw) for fish and from 0.1 to 356 ng g-1 dw for invertebrates, with most below 60 ng g-1 dw. Extraction rates ranged from 70% to 120% for 35 molecules in fish. Recoveries ranged from 70% to 120% for 37 molecules in macroinvertebrates. Inter-day precision was below 30% for 32 molecules at quantification limits. The method was successfully applied to 17 fish and 19 macroinvertebrates collected from two ponds of the French region of Dombes in November and May 2018, respectively. Both sample matrices were nearly always contaminated with benzamide, imidacloprid-desnitro, and prosulfocarb at respective concentrations of 42-237, 3, and 30-165 ng g-1 dw in fish, and 62-438, 2-6, and 15-29 ng g-1 dw in macroinvertebrates. Results show that this method is an effective tool for characterizing polar pesticides in small biotic samples.

Aminoglycosides analysis optimization using ion pairing liquid chromatography coupled to tandem mass spectrometry and application on wastewater samples.

Aminoglycosides are mostly used as veterinary antibiotics. In France, their consumption accounts for about 10% of all prescribed animal medicine. Due to their high polarity nature (log Kow < -3), they require chromatographic separation by hydrophilic interaction liquid chromatography or ion-pairing chromatography. This study presents the development of an ion pairing liquid chromatography with alkanesulfonates coupled to tandem mass spectrometry for the analysis of 10 aminoglycosides (spectinomycin, streptomycin, dihydrostreptomycin, kanamycin, apramycin, gentamicin, neomycin and sisomicin) in wastewater samples. The novelty of this method lies in the addition of the ion paring salt directly and only into the sample vial and not in the mobile phase, lowering the amount of salt added and consequently reducing signal inhibition. The optimized method was validated and showed satisfactory resolution, performances suitable with the analysis of aminoglycosides in wastewater samples, with limits of quantifications less than 10 ng/mL for most of the compounds, low matrix effects, high accuracy (85%-115% recoveries) and reproducibility (2%-12%RSD). It was then applied successfully to raw and treated wastewater samples.

A multi-family offline SPE LC-MS/MS analytical method for anionic, cationic and non-ionic surfactants quantification in surface water.

Of the large number of emerging pollutants discharged from wastewaters into surface waters, surfactants are among those with the highest concentrations. However, few monitoring in river waters of these substances have already been performed and only on a few families, mostly anionic. This work aimed to develop a multi-family analytical strategy suitable for the quantification of low concentrations of surfactant in surface waters. Twelve families of surfactants, anionic, cationic and non-ionic were selected. Their quantification by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and their extraction by SPE were optimized by comparing different retention mechanisms. The best performances were obtained with a C18 grafted silica LC column and a hydrophilic-lipophilic balanced (HLB) polymeric SPE cartridge. The final analytical method was validated and applied for the quantification of surfactants in 36 river water samples. Method limits of quantification (LQ), intra and inter days precision and trueness were evaluated. With LQ between 15 and 485 ng/L, and trueness over 80%, this method was suitable for monitoring surfactants in surface water. Application on French river water samples revealed the presence of anionic, cationic and non-ionic surfactants with median concentrations from 24 ng/L for octylphenol ethoxylates (OPEO), up to 4.6 µg/L regarding linear alkylbenzene sulfonates (LAS).

Ecotoxicological risk assessment of contaminants of emerging concern identified by "suspect screening" from urban wastewater treatment plant effluents at a territorial scale.

Urban wastewater treatment plants (WWTP) are a major vector of highly ecotoxic contaminants of emerging concern (CECs) for urban and sub-urban streams. Ecotoxicological risk assessments (ERAs) provide essential information to public environmental authorities. Nevertheless, ERAs are mainly performed at very local scale (one or few WWTPs) and on pre-selected list of CECs. To cope with these limits, the present study aims to develop a territorial-scale ERA on CECs previously identified by a "suspect screening" analytical approach (LC-QToF-MS) and quantified in the effluents of 10 WWTPs of a highly urbanized territory during three periods of the year. Among CECs, this work focused on pharmaceutical residue and pesticides. ERA was conducted following two complementary methods: (1) a single substance approach, based on the calculation for each CEC of risk quotients (RQs) by the ratio of Predicted Environmental Concentration (PEC) and Predicted No Effect Concentration (PNEC), and (2) mixture risk assessment ("cocktail effect") based on a concentration addition model (CA), summing individual RQs. Chemical results led to an ERA for 41 CEC (37 pharmaceuticals and 4 pesticides) detected in treated effluents. Single substance ERA identified 19 CECs implicated in at least one significant risk for streams, with significant risks for DEET, diclofenac, lidocaine, atenolol, terbutryn, atorvastatin, methocarbamol, and venlafaxine (RQs reaching 39.84, 62.10, 125.58, 179.11, 348.24, 509.27, 1509.71 and 3097.37, respectively). Mixture ERA allowed the identification of a risk (RQmix > 1) for 9 of the 10 WWTPs studied. It was also remarked that CECs leading individually to a negligible risk could imply a significant risk in a mixture. Finally, the territorial ERA showed a diversity of risk situations, with the highest concerns for 3 WWTPs: the 2 biggest of the territory discharging into a large French river, the Rhône, and for the smallest WWTP that releases into a small intermittent stream.

Gentamicin Adsorption onto Soil Particles Prevents Overall Short-Term Effects on the Soil Microbiome and Resistome.

Antibiotics used in agriculture may reach the environment and stimulate the development and dissemination of antibiotic resistance in the soil microbiome. However, the scope of this phenomenon and the link to soil properties needs to be elucidated. This study compared the short-term effects of a range of gentamicin concentrations on the microbiome and resistome of bacterial enrichments and microcosms of an agricultural soil using a metagenomic approach. Gentamicin impact on bacterial biomass was roughly estimated by the number of 16SrRNA gene copies. In addition, the soil microbiome and resistome response to gentamicin pollution was evaluated by 16SrRNA gene and metagenomic sequencing, respectively. Finally, gentamicin bioavailability in soil was determined. While gentamicin pollution at the scale of µg/g strongly influenced the bacterial communities in soil enrichments, concentrations up to 1 mg/g were strongly adsorbed onto soil particles and did not cause significant changes in the microbiome and resistome of soil microcosms. This study demonstrates the differences between the response of bacterial communities to antibiotic pollution in enriched media and in their environmental matrix, and exposes the limitations of culture-based studies in antibiotic-resistance surveillance. Furthermore, establishing links between the effects of antibiotic pollution and soil properties is needed.

Spatio-temporal variations in chemical pollutants found among urban deposits match changes in thiopurine S-methyltransferase-harboring bacteria tracked by the tpm metabarcoding approach.

The bTPMT (bacterial thiopurine S-methyltransferase), encoded by the tpm gene, can detoxify metalloid-containing oxyanions and xenobiotics. The hypothesis of significant relationships between tpm distribution patterns and chemical pollutants found in urban deposits was investigated. The tpm gene was found conserved among eight bacterial phyla with no sign of horizontal gene transfers but a predominance among gammaproteobacteria. A DNA metabarcoding approach was designed for tracking tpm-harboring bacteria among polluted urban deposits and sediments recovered for more than six years in a detention basin (DB). This DB recovers runoff waters and sediments from a zone of high commercial activities. The PCR products from DB samples led to more than 540,000 tpm reads after DADA2 or MOTHUR bio-informatic manipulations that were allocated to more than 88 and less than 634 sequence variants per sample. The tpm community patterns were significantly different between the recent urban deposits and those that had accumulated for more than 2 years in the DB, and between those of the DB surface and the DB settling pit. These groups of samples had distinct mixture of priority pollutants. Significant relationships between tpm ordination patterns, sediment accumulation time periods and location, and concentrations in PAH, chlorpyrifos, and 4-nonylphenols (NP) were observed. These correlations matched the higher occurrences of, among others, Aeromonas, Pseudomonas, and Xanthomonas tpm-harboring bacteria in recent urban DB deposits more contaminated with chrysene and alkylphenol ethoxylates. Highly significant drops in tpm reads allocated to Aeromonas species were recorded in the oldest DB sediments accumulating naphthalene and metallic pollutants. Degraders of urban pollutants such as P. aeruginosa and P. putida showed conserved distribution patterns over time but P. syringae phytopathogens were more abundant in the oldest sediments. TPMT-harboring bacteria can be used to assess the incidence of high risk priority pollutants on environmental systems.

Development of a simple multiresidue extraction method for the quantification of a wide polarity range list of pesticides and transformation products in eggs by liquid chromatography and tandem mass spectrometry.

Waterfowl populations have been decreasing in Europe for the last years and pollution appears to be one of the main factors. This study was conducted to develop a single sensitive and robust analytical method for the monitoring of 2 fungicides, 15 herbicides, 3 insecticides and 24 transformation products in wild bird eggs. One of the major challenges addressed was the characterization of chemicals with large logP range (from -1.9 to 4.8). A total of 11 different extraction parameters were tested in triplicate to optimize the extraction protocol, on generic parameters, buffer addition and use of clean-up steps. Quantification was based on matrix-match approach with hen eggs as reference matrix (34 analytes with r²>0.99). Particular attention was payed to matrix effects (-28% on average), quantification limits (0.5 to 25 ng.g-1 dry mass / 0.2 to 7.5 ng.g-1 fresh mass) and extraction yields (46 to 87% with 25 analytes up to 70%) to ensure the relevance of the method and its compatibility with ultra-trace analysis. It led to a simple solid/liquid low temperature partitioning extraction method followed by LC-MS/MS. Analysis of 29 field samples from 3 waterfowl species revealed that eggs were slightly contaminated with pesticides as only one egg presented a contamination (terbutryn, herbicide, 0.7 ng.g-1) and confirmed the relevance of the method.

Emerging polar pollutants in groundwater: Potential impact of urban stormwater infiltration practices.

The quality of groundwater (GW) resources is decreasing partly due to chemical contaminations from a wide range of activities, such as industrial and agricultural enterprises and changes in land-use. In urban areas, one potential major pathway of GW contamination is associated with urban water management practices based on stormwater runoff infiltration systems (SIS). Data on the performance of the upper layer of soil and the unsaturated zone of infiltration basins to limit the contamination of GW by hydrophilic compounds are lacking. With this aim, the impact of infiltration practices on GW contamination was assessed for 12 pesticides and 4 pharmaceuticals selected according to their ecotoxicological relevance and their likelihood of being present in urban stormwater and GW. For this purpose, 3 campaigns were conducted at 4 SIS during storm events. For each campaign, passive samplers based on the use of Empore™ disk were deployed in GW wells upstream and downstream of SIS, as well as in the stormwater runoff entering the infiltration basins. Upstream and downstream GW contaminations were compared to evaluate the potential effect of SIS on GW contamination and possible relationships with stormwater runoff composition were examined. Our results showed two interesting opposite trends: (i) carbendazim, diuron, fluopyram, imidacloprid and lamotrigine had concentrations significantly increasing in GW impacted by infiltration, indicating a contribution of SIS to GW contamination, (ii) atrazine, simazine and 2 transformation products exhibited concentrations significantly decreasing with infiltration due to a probable dilution of historic GW contaminants with infiltrated stormwater runoff. The other 7 contaminants showed no general trend. This study demonstrates that passive samplers deployed in GW wells enabled the capture of emerging polar pollutants present at very low concentrations and allowed the assessment of infiltration practices on GW quality. New data on GW and urban stormwater are provided for poorly studied hazardous compounds.

Ecotoxicity and antibiotic resistance of wastewater during transport in an urban sewage network.

Urban wastewater (UWW) management usually entails biological and physicochemical monitoring due to its potential impact on the quality of the receiving environment. A major component of a sewage system is the pipe network leading the water to the treatment plant. Up to now, few studies have been conducted on the diverse phenomena that may affect the characteristics of the water during its transportation. In this study, ecotoxicity and potential antibiotic resistance were used in a global method to assess the change of UWW quality in a sewage system and determine if sewer pipes can act as a bioreactor spread. Three bioassays were conducted to assess the ecotoxicity of the samples and the concentration and relative abundance of two classes of integrons (as a proxy for antibiotic resistance) were measured. The results of the bioassay battery do not show a pattern, despite the fact that differences were noticeable between upstream and downstream samples. Antibiotic resistance appeared to decrease during transport in the pipe as the concentration and relative abundance of integrons decreased during several campaigns. This result should be confirmed in other sewer networks but already provides useful information for the management of urban sewage system.

Hospital discharges in urban sanitation systems: Long-term monitoring of wastewater resistome and microbiota in relationship to their eco-exposome.

Wastewaters (WW) are important sources for the dissemination of antimicrobial resistance (AMR) into the environment. Hospital WW (HWW) contain higher loads of micro-pollutants and AMR markers than urban WW (UWW). Little is known about the long-term dynamics of H and U WW and the impact of their joined treatment on the general burden of AMR. Here, we characterized the resistome, microbiota and eco-exposome signature of 126 H and U WW samples treated separately for three years, and then mixed, over one year. Multi-variate analysis and machine learning revealed a robust signature for each WW with no significant variation over time before mixing, and once mixed, both WW closely resembled Urban signatures. We demonstrated a significant impact of pharmaceuticals and surfactants on the resistome and microbiota of H and U WW. Our results present considerable targets for AMR related risk assessment of WW.