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Nontargeted screening (NTS) utilizing liquid chromatography electrospray ionization high-resolution mass spectrometry (LC/ESI/HRMS) is increasingly used to identify environmental contaminants. Major differences in the ionization efficiency of compounds in ESI/HRMS result in widely varying responses and complicate quantitative analysis. Despite an increasing number of methods for quantification without authentic standards in NTS, the approaches are evaluated on limited and diverse data sets with varying chemical coverage collected on different instruments, complicating an unbiased comparison. In this interlaboratory comparison, organized by the NORMAN Network, we evaluated the accuracy and performance variability of five quantification approaches across 41 NTS methods from 37 laboratories. Three approaches are based on surrogate standard quantification (parent-transformation product, structurally similar or close eluting) and two on predicted ionization efficiencies (RandFor- IE and MLR- IE ). Shortly, HPLC grade water, tap water, and surface water spiked with 45 compounds at 2 concentration levels were analyzed together with 41 calibrants at 6 known concentrations by the laboratories using in-house NTS workflows. The accuracy of the approaches was evaluated by comparing the estimated and spiked concentrations across quantification approaches, instrumentation, and laboratories. The RandFor- IE approach performed best with a reported mean prediction error of 15× and over 83% of compounds quantified within 10× error. Despite different instrumentation and workflows, the performance was stable across laboratories and did not depend on the complexity of water matrices.

Through the application of C-CF 3 -containing plant protection products (PPP) in agriculture, a substantial quantity of trifluoroacetate (TFA) can be formed and emitted. We here present estimations of TFA formation potentials from PPP across three important economical regions, namely Europe, the United States of America and China. PPP with TFA formation potential vary in type and use profile across those regions, but can be found throughout, with the estimated maximum TFA emissions ranging from 0 to 83 kg/km 2 per year. Therein, some PPP are only used for specific crops in specific regions, while others are used more widely. The importance of PPP as a TFA source is supported by the field data from a region in Germany, which revealed a significant increase in TFA groundwater concentrations with agriculture compared to other land uses. Substance-specific TFA formation rates and field studies are necessary to characterize the formation of TFA from precursors under environmental conditions and to rank and prioritize PPP of concern for potential (regulatory) action., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Generally, karst aquifers and springs are highly susceptible to contamination due to the high permeability and, therefore, groundwater flow velocities. The often thin soil cover, accompanied by dolines, can lead to fast infiltration of precipitation water loaded with mobilized contaminants such as pesticides and their transformation products. To date, continuous, temporally highly resolved in-situ monitoring to decipher concentration dynamics for a broad range of pesticides is missing. Therefore, a transportable HPLC-HRMS/MS system (MS 2 field) was positioned at two karst study sites in the Swiss Jura. Water samples were collected and analyzed for pesticides and their transformation products in-situ every 20 min for 6 weeks in 2021 and 8 weeks in 2022. During the spraying season in 2021, six rain events at site 1 and three at site 2 in 2022 were captured. Concurrently, the water quality parameters electrical conductivity, pH, nitrate, turbidity, and water level, were monitored continuously at high temporal resolution. Further, bacterial cell counts were monitored via online flow cytometry. In 2021, several pesticides and pesticide transformation products were detected in peak concentrations after rain events, of which metamitron showed the highest concentration of up to 1000 ng/L. In one rain event, the Swiss federal and EU drinking water limit of 100 ng/L was exceeded for up to 38 h. Compared with highly frequent MS 2 field samples collected every 20 min, 42-hours composite samples severely underestimated peak concentrations for all compounds, especially for labile ones. Therefore, it was demonstrated that exceedences of the regulatory limit would have been missed if just composite sampling would have been conducted. Peak concentrations of pesticides coincided with peaks in nitrate concentration and bacterial cell counts following rain events. The correlation analysis showed strong correlations between the three analyzed contaminants (pesticides, nitrate and bacteria), and the proxy parameters electrical conductivity, and pH. The investigation of a second spring revealed similar dynamics indicating that these can be expected in other karst aquifers as well., Competing Interests: Declaration of competing interest Juliane Hollender reports financial support was provided by Federal Office for the Environment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The rapid increase in the production and global use of chemicals and their mixtures has raised concerns about their potential impact on human and environmental health. With advances in analytical techniques, in particular, high-resolution mass spectrometry (HRMS), thousands of compounds and transformation products with potential adverse effects can now be detected in environmental samples. However, identifying and prioritizing the toxicity drivers among these compounds remain a significant challenge. Effect-directed analysis (EDA) emerged as an important tool to address this challenge, combining biotesting, sample fractionation, and chemical analysis to unravel toxicity drivers in complex mixtures. Traditional EDA workflows are labor-intensive and time-consuming, hindering large-scale applications. The concept of high-throughput (HT) EDA has recently gained traction as a means of accelerating these workflows. Key features of HT-EDA include the combination of microfractionation and downscaled bioassays, automation of sample preparation and biotesting, and efficient data processing workflows supported by novel computational tools. In addition to microplate-based fractionation, high-performance thin-layer chromatography (HPTLC) offers an interesting alternative to HPLC in HT-EDA. This review provides an updated perspective on the state-of-the-art in HT-EDA, and novel methods/tools that can be incorporated into HT-EDA workflows. It also discusses recent studies on HT-EDA, HT bioassays, and computational prioritization tools, along with considerations regarding HPTLC. By identifying current gaps in HT-EDA and proposing new approaches to overcome them, this review aims to bring HT-EDA a step closer to monitoring applications., (© 2024. The Author(s).)

Pharmaceuticals and their human metabolites are contaminants of emerging concern in the aquatic environment. Most monitoring studies focus on a limited set of parent compounds and even fewer metabolites. However, more than 50% of the most consumed pharmaceuticals are excreted in higher amounts as metabolites than as parents, as confirmed by a literature analysis within this study. Hence, we applied a wide-scope suspect screening approach to identify human pharmaceutical metabolites in wastewater influent from three Swiss treatment plants. Based on consumption amounts and human metabolism data, a suspect list comprising 268 parent compounds and over 1500 metabolites was compiled. Online solid phase extraction combined with liquid chromatography coupled to high-resolution tandem mass spectrometry was used to analyze the samples. Data processing, annotation, and structure elucidation were achieved with various tools, including molecular networking as well as SIRIUS/CSI:FingerID and MetFrag for MS2 spectra rationalization. We confirmed 37 metabolites with reference standards and 16 by human liver S9 incubation experiments. More than 25 metabolites were detected for the first time in influent wastewater. Semiquantification with MS2Quant showed that metabolite to parent concentration ratios were generally lower compared to literature expectations, probably due to further metabolite transformation in the sewer system or limitations in the metabolite detection. Nonetheless, metabolites pose a large fraction to the total pharmaceutical contribution in wastewater, highlighting the need for metabolite inclusion in chemical risk assessment.

Aquatic ecosystems continue to be threatened by chemical pollution. To what extent organisms are able to cope with chemical exposure depends on their ability to display mechanisms of defense across different organs. Among these mechanisms, biotransformation processes represent key physiological responses that facilitate detoxification and reduce the bioaccumulation potential of chemicals. Biotransformation does not only depend on the ability of different organs to display biotransformation enzymes but also on the affinity of chemicals towards these enzymes. In the present study, we explored the ability of different organs and of two freshwater fish to support biotransformation processes through the determination of in vitro phase I and II biotransformation enzyme activity, and their role in supporting intrinsic clearance and the formation of biotransformation products. Three environmentally relevant pollutants were evaluated: the polycyclic aromatic hydrocarbon (PAH) pyrene (as recommended by the OECD 319b test guideline), the fungicide azoxystrobin, and the pharmaceutical propranolol. Comparative studies using S9 sub-cellular fractions derived from the liver, intestine, gills, and brain of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) revealed significant phase I and II enzyme activity in all organs. However, organ- and species-specific differences were found. In brown trout, significant extrahepatic biotransformation was observed for pyrene but not for azoxystrobin and propranolol. In rainbow trout, the brain appeared to biotransform azoxystrobin. In this same species, propranolol appeared to be biotransformed by the intestine and gills. Biotransformation products could be detected only from hepatic biotransformation, and their profiles and formation rates displayed species-specific patterns and occurred at different magnitudes. Altogether, our findings further contribute to the current understanding of organ-specific biotransformation capacity, beyond the expression and activity of enzymes, and its dependence on specific enzyme-chemical interactions to support mechanisms of defense against exposure., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

When chemical pollutants enter the environment, they can undergo diverse transformation processes, forming a wide range of transformation products (TPs), some of them benign and others more harmful than their precursors. To date, the majority of TPs remain largely unrecognized and unregulated, particularly as TPs are generally not part of routine chemical risk or hazard assessment. Since many TPs formed from oxidative processes are more polar than their precursors, they may be especially relevant in the context of persistent, mobile, and toxic (PMT) and very persistent and very mobile (vPvM) substances, which are two new hazard classes that have recently been established on a European level. We highlight herein that as a result, TPs deserve more attention in research, chemicals regulation, and chemicals management. This perspective summarizes the main challenges preventing a better integration of TPs in these areas: (1) the lack of reliable high-throughput TP identification methods, (2) uncertainties in TP prediction, (3) inadequately considered TP formation during (advanced) water treatment, and (4) insufficient integration and harmonization of TPs in most regulatory frameworks. A way forward to tackle these challenges and integrate TPs into chemical management is proposed.

The chemical burden on the environment and human population is increasing. Consequently, regulatory risk assessment must keep pace to manage, reduce, and prevent adverse impacts on human and environmental health associated with hazardous chemicals. Surveillance of chemicals of known, emerging, or potential future concern, entering the environment-food-human continuum is needed to document the reality of risks posed by chemicals on ecosystem and human health from a one health perspective, feed into early warning systems and support public policies for exposure mitigation provisions and safe and sustainable by design strategies. The use of less-conventional sampling strategies and integration of full-scan, high-resolution mass spectrometry and effect-directed analysis in environmental and human monitoring programmes have the potential to enhance the screening and identification of a wider range of chemicals of known, emerging or potential future concern. Here, we outline the key needs and recommendations identified within the European Partnership for Assessment of Risks from Chemicals (PARC) project for leveraging these innovative methodologies to support the development of next-generation chemical risk assessment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Cationic surfactants are used in many industrial processes and in consumer products with concurrent release into the aquatic environment, where they may accumulate in aquatic organisms to regulatoryly relevant thresholds. Here, we aimed to better understand the bioconcentration behavior of three selected cationic surfactants, namely N,N -dimethyldecylamine (T10), N -methyldodecylamine (S12), and N,N,N -trimethyltetradecylammonium cation (Q14), in the cells of fish liver (RTL-W1) and gill (RTgill-W1) cell lines. We conducted full mass balances for bioconcentration tests with the cell cultures, in which the medium, the cell surface, the cells themselves, and the plastic compartment were sampled and quantified for each surfactant by HPLC MS/MS. Accumulation in/to cells correlated with the surfactants' alkyl chain lengths and their membrane lipid-water partitioning coefficient, D MLW . Cell-derived bioconcentration factors (BCF) of T10 and S12 were within a factor of 3.5 to in vivo BCF obtained from the literature, while the cell-derived BCF values for Q14 were >100 times higher than the in vivo BCF. From our experiments, rainbow trout cell lines appear as a suitable conservative in vitro screening method for bioconcentration assessment of cationic surfactants and are promising for further testing.

Environmental risk assessment of chemical contaminants requires prioritizing of substances taken up by biota as it is a starting point for potential adverse effects. Although knowledge about the occurrence of known chemical pollutants in aquatic organisms has significantly improved during the last decade, there is still a poor understanding for a broad range of more polar compounds. To tackle this issue, we proposed an approach that identifies bioaccumulative and biomagnifiable polar chemicals using liquid chromatography coupled with electrospray ionization to high resolution tandem mass spectrometry (LC-HRMS/MS) and combine it with trend analysis using hierarchical clustering. As a proof-of-concept, this approach was implemented on various organisms and compartments (sediment, litter leaves, periphytic biofilm, invertebrates and fish) collected from a small urban river. HRMS/MS data measured via data-independent acquisition mode were retrospectively analysed using two analytical strategies: (1) retrospective target and (2) suspect/non-target screening. In the retrospective target analysis, 56 of 361 substances spanning a broad range of contaminant classes were detected (i.e. 26 in fish, 18 in macroinvertebrates, 28 in leaves, 29 in periphyton and 32 in sediments, with only 7 common to all compartments), among which 49 could be quantified using reference standards. The suspect screening approach based on two suspect lists (in-house, Norman SusDat) led to the confirmation of 5 compounds with standards (three xenobiotics at level 1 and two lipids at level 2) and tentative identification of seven industrial or natural chemicals at level 2 and 3 through a mass spectra library match. Overall, this proof-of-concept study provided a more comprehensive picture of the exposure of biota to emerging contaminants (i.e., the internal chemical exposome) and potential bioaccumulation or biomagnification of polar compounds along the trophic chain., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Wastewater treatment plants (WWTPs) are a major source of micropollutants to surface waters. Currently, their chemical or biological monitoring is realized by using grab or composite samples, which provides only snapshots of the current wastewater composition. Especially in WWTPs with industrial input, the wastewater composition can be highly variable and a continuous assessment would be advantageous, but very labor and cost intensive. A promising concept are automated real-time biological early warning systems (BEWS), where living organisms are constantly exposed to the water and an alarm is triggered if the organism's responses exceed a harmful threshold of acute toxicity. Currently, BEWS are established for drinking water and surface water but are seldom applied to monitor wastewater. This study demonstrates that a battery of BEWS using algae (Chlorella vulgaris in the Algae Toximeter, bbe Moldaenke), water flea (Daphnia magna in the DaphTox II, bbe Moldaenke) and gammarids (Gammarus pulex in the Sensaguard, REMONDIS Aqua) can be adapted for wastewater surveillance. For continuous low-maintenance operation, a back-washable membrane filtration system is indispensable for adequate preparation of treated wastewater. Only minor deviations in the reaction of the organisms towards treated and filtered wastewater compared to surface waters were detected. After spiking treated wastewater with two concentrations of the model compounds diuron, chlorpyrifos methyl, and sertraline, the organisms in the different BEWS showed clear responses depending on the respective compound, concentration and mode of action. Immediate effects on photosynthetic activity of algae were detected for diuron exposure, and strong behavioral changes in water flea and gammarids after exposure to chlorpyrifos methyl or sertraline were observed, which triggered automated alarms. Different types of data analysis were applied to extract more information out of the specific behavioral traits, than only provided by the vendors algorithms. To investigate, whether behavioral movement changes can be linked to impact other endpoints, the effects on feeding activity of G. pulex were evaluated and results indicated significant differences between the exposures. Overall, these findings provide an important basis indicating that BEWS have the potential to act as alarm systems for pollution events in the wastewater sector., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Nontarget high-resolution mass spectrometry screening (NTS HRMS/MS) can detect thousands of organic substances in environmental samples. However, new strategies are needed to focus time-intensive identification efforts on features with the highest potential to cause adverse effects instead of the most abundant ones. To address this challenge, we developed MLinvitroTox, a machine learning framework that uses molecular fingerprints derived from fragmentation spectra (MS2) for a rapid classification of thousands of unidentified HRMS/MS features as toxic/nontoxic based on nearly 400 target-specific and over 100 cytotoxic endpoints from ToxCast/Tox21. Model development results demonstrated that using customized molecular fingerprints and models, over a quarter of toxic endpoints and the majority of the associated mechanistic targets could be accurately predicted with sensitivities exceeding 0.95. Notably, SIRIUS molecular fingerprints and xboost (Extreme Gradient Boosting) models with SMOTE (Synthetic Minority Oversampling Technique) for handling data imbalance were a universally successful and robust modeling configuration. Validation of MLinvitroTox on MassBank spectra showed that toxicity could be predicted from molecular fingerprints derived from MS2 with an average balanced accuracy of 0.75. By applying MLinvitroTox to environmental HRMS/MS data, we confirmed the experimental results obtained with target analysis and narrowed the analytical focus from tens of thousands of detected signals to 783 features linked to potential toxicity, including 109 spectral matches and 30 compounds with confirmed toxic activity.

A collaborative trial involving 16 participants from nine European countries was conducted within the NORMAN network in efforts to harmonise suspect and non-target screening of environmental contaminants in whole fish samples of bream (Abramis brama). Participants were provided with freeze-dried, homogenised fish samples from a contaminated and a reference site, extracts (spiked and non-spiked) and reference sample preparation protocols for liquid chromatography (LC) and gas chromatography (GC) coupled to high resolution mass spectrometry (HRMS). Participants extracted fish samples using their in-house sample preparation method and/or the protocol provided. Participants correctly identified 9-69 % of spiked compounds using LC-HRMS and 20-60 % of spiked compounds using GC-HRMS. From the contaminated site, suspect screening with participants' own suspect lists led to putative identification of on average ∼145 and ∼20 unique features per participant using LC-HRMS and GC-HRMS, respectively, while non-target screening identified on average ∼42 and ∼56 unique features per participant using LC-HRMS and GC-HRMS, respectively. Within the same sub-group of sample preparation method, only a few features were identified by at least two participants in suspect screening (16 features using LC-HRMS, 0 features using GC-HRMS) and non-target screening (0 features using LC-HRMS, 2 features using GC-HRMS). The compounds identified had log octanol/water partition coefficient (K OW ) values from -9.9 to 16 and mass-to-charge ratios (m/z) of 68 to 761 (LC-HRMS and GC-HRMS). A significant linear trend was found between log K OW and m/z for the GC-HRMS data. Overall, these findings indicate that differences in screening results are mainly due to the data analysis workflows used by different participants. Further work is needed to harmonise the results obtained when applying suspect and non-target screening approaches to environmental biota samples., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The application of mass spectrometry imaging (MSI) is a promising tool to analyze the spatial distribution of organic contaminants in organisms and thereby improve the understanding of toxicokinetic and toxicodynamic processes. MSI is a common method in medical research but has been rarely applied in environmental science. In the present study, the suitability of MSI to assess the spatial distribution of organic contaminants and their biotransformation products (BTPs) in the aquatic invertebrate key species Gammarus pulex was studied. Gammarids were exposed to a mixture of common organic contaminants (carbamazepine, citalopram, cyprodinil, efavirenz, fluopyram and terbutryn). The distribution of the parent compounds and their BTPs in the organisms was analyzed by two MSI methods (MALDI- and DESI-HRMSI) after cryo-sectioning, and by LC-HRMS/MS after dissection into different organ compartments. The spatial distribution of contaminats in gammarid tissue could be successfully analyzed by the different analytical methods. The intestinal system was identified as the main site of biotransformation, possibly due to the presence of biotransforming enzymes. LC-HRMS/MS was more sensitive and provided higher confidence in BTP identification due to chromatographic separation and MS/MS. DESI was found to be the more sensitive MSI method for the analyzed contaminants, whereas additional biomarkers were found using MALDI. The results demonstrate the suitability of MSI for investigations on the spatial distribution of accumulated organic contaminants. However, both MSI methods required high exposure concentrations. Further improvements of ionization methods would be needed to address environmentally relevant concentrations., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Persistent, mobile and toxic (PMT), and very persistent and very mobile (vPvM) substances pose a threat to the water cycle but are often not covered in conventional environmental monitoring programs. Within this realm of substances, one compound class of concern are pesticides and their transformation products as they are deliberately introduced into the environment. To detect very polar anionic substances, including many pesticide transformation products with log D OW values ranging between -7.4 and 2.2, an ion chromatography high-resolution mass spectrometry method was developed in this study. Since inorganic anions, such as chloride and sulfate, interfere with the analysis of organic species, their removal via precipitation with Ba/Ag/H cartridges was assessed. To improve LOQs, vacuum-assisted evaporative concentration (VEC) was evaluated. By using VEC and removing inorganic salt ions, the median LOQ improved from 100 ng/L in evian® water without sample treatment to 10 ng/L after enrichment and 30 ng/L in karst groundwater. Using this method, twelve out of 64 substances covered by the final method were found in karst groundwater in concentrations of up to 5600 ng/L, and seven exceeded 100 ng/L. To the authors' knowledge, the dimethenamid TP M31 and chlorothalonil TP SYN548008 were detected for the first time in groundwater samples. The coupling to a high-resolution mass spectrometer also allows for non-target screening and hence, this method presents a powerful tool to tackle PMT/vPvM substances., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Bioaccumulation of organic contaminants from contaminated food sources might pose an underestimated risk toward shredding invertebrates. This assumption is substantiated by monitoring studies observing discrepancies of predicted tissue concentrations determined from laboratory-based experiments compared with measured concentrations of systemic pesticides in gammarids. To elucidate the role of dietary uptake in bioaccumulation, gammarids were exposed to leaf material from trees treated with a systemic fungicide mixture (azoxystrobin, cyprodinil, fluopyram, and tebuconazole), simulating leaves entering surface waters in autumn. Leaf concentrations, spatial distribution, and leaching behavior of fungicides were characterized using liquid chromatography coupled with high-resolution tandem mass spectrometry (LC-HRMS/MS) and matrix-assisted laser desorption ionization-mass spectrometric imaging. The contribution of leached fungicides and fungicides taken up from feeding was assessed by assembling caged (no access) and uncaged (access to leaves) gammarids. The fungicide dynamics in the test system were analyzed using LC-HRMS/MS and toxicokinetic modeling. In addition, a summer scenario was simulated where water was the initial source of contamination and leaves contaminated by sorption. The uptake, translocation, and biotransformation of systemic fungicides by trees were compound-dependent. Internal fungicide concentrations of gammarids with access to leaves were much higher than in caged gammarids of the autumn scenario, but the difference was minimal in the summer scenario. In food choice and dissectioning experiments gammarids did not avoid contaminated leaves and efficiently assimilated contaminants from leaves, indicating the relevance of this exposure pathway in the field. The present study demonstrates the potential impact of dietary uptake on in situ bioaccumulation for shredders in autumn, outside the main application period. The toxicokinetic parameters obtained facilitate modeling of environmental exposure scenarios. The uncovered significance of dietary uptake for detritivores warrants further consideration from scientific as well as regulatory perspectives. Environ Toxicol Chem 2023;42:1993-2006. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC., (© 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.)

Delayed toxicity is a phenomenon observed for aquatic invertebrates exposed to nicotinic acetylcholine receptor (nAChR) agonists, such as neonicotinoids. Furthermore, recent studies have described an incomplete elimination of neonicotinoids by exposed amphipods. However, a mechanistic link between receptor binding and toxicokinetic modeling has not been demonstrated yet. The elimination of the neonicotinoid thiacloprid in the freshwater amphipod Gammarus pulex was studied in several toxicokinetic exposure experiments, complemented with in vitro and in vivo receptor-binding assays. Based on the results, a two-compartment model was developed to predict the uptake and elimination kinetics of thiacloprid in G. pulex . An incomplete elimination of thiacloprid, independent of elimination phase duration, exposure concentrations, and pulses, was observed. Additionally, the receptor-binding assays indicated irreversible binding of thiacloprid to the nAChRs. Accordingly, a toxicokinetic-receptor model consisting of a structural and a membrane protein (including nAChRs) compartment was developed. The model successfully predicted internal thiacloprid concentrations across various experiments. Our results help in understanding the delayed toxic and receptor-mediated effects toward arthropods caused by neonicotinoids. Furthermore, the results suggest that more awareness toward long-term toxic effects of irreversible receptor binding is needed in a regulatory context. The developed model supports the future toxicokinetic assessment of receptor-binding contaminants.

In order to protect European Union (EU) drinking water resources from chemical contamination, criteria for identifying persistent, mobile, and toxic (PMT) chemicals and very persistent and very mobile (vPvM) chemicals under the EU REACH Regulation were proposed by the German Environment Agency (Umweltbundesamt-UBA). Additionally, new hazard classes for PMT and vPvM substances in the revised EU classification, labeling, and packaging (CLP Regulation) are intended. Therefore, a reliable approach in the identification of potential drinking water resource contaminants is needed. The scientific basis of the property-based PMT/vPvM criteria, focusing on mobility, which dictates the migration of chemical drinking water sources, was evaluated, and a critical analysis of the deviation of sorption metrics from simple behavior was carried out. Based on our evaluation, a K oc may be used for nonionic substances on a screening level only, requiring a higher tier assessment. It is considered inappropriate for hydrophilic and ionizable chemicals, particularly for soils with low organic carbon contents. The nonextractable residue formation is complex and not well understood but remains significant in limiting the mobility of chemicals through soils and sediments. In order to inform the EU commission's work on the introduction of new hazard classes for PMT and vPvM substances into the European legislation, the derivation of a tiered approach is proposed, which utilizes the weight of evidence available, with adoption of appropriate higher tier models commensurate with the nature of the substance and the data available. Integr Environ Assess Manag 2023;19:775-791. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC)., (© 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).)

Permanent rainbow trout (Oncorhynchus mykiss) cell lines represent potential in vitro alternatives to experiments with fish. We here developed a method to assess the bioaccumulation potential of anionic organic compounds in fish, using the rainbow trout liver-derived RTL-W1 cell line. Based on the availability of high quality in vivo bioconcentration (BCF) and biomagnification (BMF) data and the substances' charge state at physiological pH, four anionic compounds were selected: pentachlorophenol (PCP), diclofenac (DCF), tecloftalam (TT) and benzotriazol-tert-butyl-hydroxyl-phenyl propanoic acid (BHPP). The fish cell line acute toxicity assay (OECD TG249) was used to derive effective concentrations 50 % and non-toxic exposure concentrations to determine exposure concentrations for bioaccumulation experiments. Bioaccumulation experiments were performed over 48 h with a total of six time points, at which cell, medium and plastic fractions were sampled and measured using high resolution tandem mass spectrometry after online solid phase extraction. Observed cell internal concentrations were over-predicted by K OW -derived predictions while pH-dependent octanol-water partitioning (D OW ) and membrane lipid-water partitioning (D MLW ) gave better predictions of cell internal concentrations. Measured medium and cell internal concentrations at steady state were used to calculate RTL-W1-based BCF, which were compared to D OW - or D MLW -based model approaches and in vivo data. With the exception of PCP, the cell-derived BCF best compared to D OW -based model predictions, which were higher than predictions based on D MLW . All methods predicted the in vivo BCF for diclofenac well. For PCP, the cell-derived BCF was lowest although all BCF predictions underestimated the in vivo BCF by ≥ 1 order of magnitude. The RTL-W1 cells, and all other prediction methods, largely overestimated in vivo BMF, which were available for PCP, TT and BHPP. We conclude that the RTL-W1 cell line can supplement BCF predictions for anionic compounds. For BMF estimations, however, in vitro-in vivo extrapolations need adaptation or a multiple cell line approach., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The acceleration of global climate change draws increasing attention towards interactive effects of temperature and organic contaminants. Many studies reported a higher sensitivity of aquatic invertebrates towards contaminant exposure with increasing or fluctuating temperatures. The hypothesis of this study was that the higher sensitivity of invertebrates is associated with the changes of toxicokinetic processes that determine internal concentrations of contaminants and consequently toxic effects. Therefore, the influence of temperature on toxicokinetic processes and the underlying mechanisms were studied in two key amphipod species (Gammarus pulex and Hyalella azteca). Bioconcentration experiments were carried out at four different temperatures with a mixture of 12 exposure relevant polar organic contaminants. Tissue and medium samples were taken in regular intervals and analysed by online solid-phase extraction liquid chromatography high-resolution tandem mass spectrometry. Subsequently, toxicokinetic rates were modelled and analysed in dependence of the exposure temperature using the Arrhenius equation. An exponential relationship between toxicokinetic rates versus temperature was observed and could be well depicted by applying the Arrhenius equation. Due to a similar Arrhenius temperature of uptake and elimination rates, the bioconcentration factors of the contaminants were generally constant across the temperature range. Furthermore, the Arrhenius temperature of the toxicokinetic rates and respiration was mostly similar. However, in some cases (citalopram, cyprodinil), the bioconcentration factor appeared to be temperature dependent, which could potentially be explained by the influence of temperature on active uptake mechanisms or biotransformation. The observed temperature effects on toxicokinetics may be particularly relevant in non-equilibrated systems, such as exposure peaks in summer as exemplified by the exposure modelling of a field measured pesticide peak where the internal concentrations increased by up to fourfold along the temperature gradient. The results provide novel insights into the mechanisms of chemical uptake, biotransformation and elimination in different climate scenarios and can improve environmental risk assessment., (© 2022 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)

Bioaccumulation and trophic transfer of persistent legacy contaminants have been intensively characterized, but little is known on the contaminants of emerging concern (CECs) in freshwater food webs. Herein, we comprehensively screened CECs with a focus on polar substances and further evaluated their trophic transfer behavior in selected items from the food web of Lake Templin, Germany. Weselected one plankton, two mussel, and nine fish samples covering three trophic levels. With an effective multi-residue sample preparation method and high-resolution mass spectrometry-based target, suspect, and non-target screening, we characterized 477 targets and further screened unknown features in complex biota matrices. Of the 477 targets, 145 were detected and quantified in at least one species (0.02-3640 ng/g, dry weight). Additionally, the suspect and non-target analysis with experimental mass spectra libraries and in silico techniques (MetFrag and SIRIUS4/CSI:FingerID) enabled further identification of 27 unknown compounds with 19 confirmed by reference standards. Overall, the detected compounds belong to a diverse group of chemicals, including 71 pharmaceuticals, 27 metabolites, 26 pesticides, 16 per- and polyfluoroalkyl substances (PFASs), 4 plasticizers, 3 flame retardants, 11 other industrial chemicals and 14 others. Moreover, we determined the trophic magnification factor (TMF) of 34 polar CECs with >80% detection frequency, among which 6 PFASs including perfluorooctane sulfonic acid (PFOS), perfluorodecanoic acid (PFDA), perfluorohexane sulfonic acid (PFHxS), perfluorotridecanoic acid (PFTrA), perfluorotetradecanoic acid (PFTeA), and perfluoroundecanoic acid (PFUnA), exhibited biomagnification potential (TMF =1.8 - 4.2, p < 0.05), whereas 5 pharmaceuticals (phenazone, progesterone, venlafaxine, levamisole, and lidocaine) and 1 personal care product metabolite (galaxolidone) showed biodilution potential (TMF = 0.4 - 0.6, p < 0.05)., (Copyright © 2022. Published by Elsevier Ltd.)

Surfactants are high-production-volume chemicals that are among the most abundant organic pollutants in municipal wastewater. In this study, sewage sludge samples of 36 Swiss wastewater treatment plants (WWTPs), serving 32% of the country's population, were analyzed for major surfactant classes by liquid chromatography mass spectrometry (LC-MS). The analyses required a variety of complementary approaches due to different analytical challenges, including matrix effects (which can affect adduct ion formation) and the lack of reference standards. The most abundant contaminants were linear alkylbenzene sulfonates (LAS; weighted mean [WM] concentration of 3700 μg g -1 dry weight), followed by secondary alkane sulfonates (SAS; 190 μg g -1 ). Alcohol polyethoxylates (AEO; 8.3 μg g -1 ), nonylphenol polyethoxylates (NPEO; 16 μg g -1 ), nonylphenol (NP; 3.1 μg g -1 ), nonylphenol ethoxy carboxylates (NPEC; 0.35 μg g -1 ) and tert-octylphenol (tert-OP, 1.8 μg g -1 ) were present at much lower concentrations. This concentration pattern agrees with the production volumes of the surfactants and their fates in WWTPs. Branched AEO homologues dominated over linear homologues, probably due to higher persistence. Sludge concentrations of LAS, SAS, and NP were positively correlated with the residence time in the anaerobic digester. Derivation of the per capita loads successfully revealed potential industrial/commercial emission sources. Comparison of recent versus historic data showed a decrease in NPEO and NP levels by one or two orders of magnitude since their ban in the 1980s. By contrast, LAS still exhibit similar concentrations compared to 30 years ago., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: The NORMAN Association (https://www.norman-network.com/) initiated the NORMAN Suspect List Exchange (NORMAN-SLE; https://www.norman-network.com/nds/SLE/) in 2015, following the NORMAN collaborative trial on non-target screening of environmental water samples by mass spectrometry. Since then, this exchange of information on chemicals that are expected to occur in the environment, along with the accompanying expert knowledge and references, has become a valuable knowledge base for "suspect screening" lists. The NORMAN-SLE now serves as a FAIR (Findable, Accessible, Interoperable, Reusable) chemical information resource worldwide., Results: The NORMAN-SLE contains 99 separate suspect list collections (as of May 2022) from over 70 contributors around the world, totalling over 100,000 unique substances. The substance classes include per- and polyfluoroalkyl substances (PFAS), pharmaceuticals, pesticides, natural toxins, high production volume substances covered under the European REACH regulation (EC: 1272/2008), priority contaminants of emerging concern (CECs) and regulatory lists from NORMAN partners. Several lists focus on transformation products (TPs) and complex features detected in the environment with various levels of provenance and structural information. Each list is available for separate download. The merged, curated collection is also available as the NORMAN Substance Database (NORMAN SusDat). Both the NORMAN-SLE and NORMAN SusDat are integrated within the NORMAN Database System (NDS). The individual NORMAN-SLE lists receive digital object identifiers (DOIs) and traceable versioning via a Zenodo community (https://zenodo.org/communities/norman-sle), with a total of > 40,000 unique views, > 50,000 unique downloads and 40 citations (May 2022). NORMAN-SLE content is progressively integrated into large open chemical databases such as PubChem (https://pubchem.ncbi.nlm.nih.gov/) and the US EPA's CompTox Chemicals Dashboard (https://comptox.epa.gov/dashboard/), enabling further access to these lists, along with the additional functionality and calculated properties these resources offer. PubChem has also integrated significant annotation content from the NORMAN-SLE, including a classification browser (https://pubchem.ncbi.nlm.nih.gov/classification/#hid=101)., Conclusions: The NORMAN-SLE offers a specialized service for hosting suspect screening lists of relevance for the environmental community in an open, FAIR manner that allows integration with other major chemical resources. These efforts foster the exchange of information between scientists and regulators, supporting the paradigm shift to the "one substance, one assessment" approach. New submissions are welcome via the contacts provided on the NORMAN-SLE website (https://www.norman-network.com/nds/SLE/)., Supplementary Information: The online version contains supplementary material available at 10.1186/s12302-022-00680-6., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2022.)

The chemical pollution crisis severely threatens human and environmental health globally. To tackle this challenge the establishment of an overarching international science-policy body has recently been suggested. We strongly support this initiative based on the awareness that humanity has already likely left the safe operating space within planetary boundaries for novel entities including chemical pollution. Immediate action is essential and needs to be informed by sound scientific knowledge and data compiled and critically evaluated by an overarching science-policy interface body. Major challenges for such a body are (i) to foster global knowledge production on exposure, impacts and governance going beyond data-rich regions (e.g., Europe and North America), (ii) to cover the entirety of hazardous chemicals, mixtures and wastes, (iii) to follow a one-health perspective considering the risks posed by chemicals and waste on ecosystem and human health, and (iv) to strive for solution-oriented assessments based on systems thinking. Based on multiple evidence on urgent action on a global scale, we call scientists and practitioners to mobilize their scientific networks and to intensify science-policy interaction with national governments to support the negotiations on the establishment of an intergovernmental body based on scientific knowledge explaining the anticipated benefit for human and environmental health., Competing Interests: Competing interestsThe authors declare that they have no competing interests. HH is Editor-in-Chief of this Journal., (© The Author(s) 2022.)

Pesticides used in agriculture can end up in nearby streams and can have a negative impact on nontarget organisms such as aquatic invertebrates. During registration, bioaccumulation potential is often investigated using laboratory tests only. Recent studies showed that the magnitude of bioaccumulation in the field substantially differs from laboratory conditions. To investigate this discrepancy, we conducted a field bioaccumulation study in a stream known to receive pollutant loadings from agriculture. Our work incorporates measurements of stream pesticide concentrations at high temporal resolution (every 20 min), as well as sediment, leaves, and caged gammarid analyses (every 2-24 h) over several weeks. Of 49 investigated pesticides, 14 were detected in gammarids with highly variable concentrations of up to 140 ± 28 ng/g ww . Toxicokinetic modeling using laboratory-derived uptake and depuration rate constants for azoxystrobin, cyprodinil, and fluopyram showed that despite the highly resolved water concentrations measured, the pesticide burden on gammarids remains underestimated by a factor of 1.9 ± 0.1 to 31 ± 3.0, with the highest underestimations occurring after rain events. Including dietary uptake from polluted detritus leaves and sediment in the model explained this underestimation only to a minor proportion. However, suspended solids analyzed during rain events had high pesticide concentrations, and uptake from them could partially explain the underestimation after rain events. Additional comparison between the measured and modeled data showed that the pesticide depuration in gammarids is slower in the field. This observation suggests that several unknown mechanisms may play a role, including lowered enzyme expression and mixture effects. Thus, it is important to conduct such retrospective risk assessments based on field investigations and adapt the registration accordingly., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Toxic plant secondary metabolites (PSMs), so-called phytotoxins, occur widely in plant species. Many of these phytotoxins have similar mobility, persistence, and toxicity properties in the environment as anthropogenic micropollutants, which increasingly contaminate surface waters. Although recent case studies have shown the aquatic relevance of phytotoxins, the overall exposure remains unknown. Therefore, we performed a detailed occurrence analysis covering 134 phytotoxins from 27 PSM classes. Water samples from seven small Swiss streams with catchment areas from 1.7 to 23 km 2 and varying land uses were gathered over several months to investigate seasonal impacts. They were complemented with samples from different biogeographical regions to cover variations in vegetation. A broad SPE-LC-HRMS/MS method was applied with limits of detection below 5 ng/L for over 80% of the 134 included phytotoxins. In total, we confirmed 39 phytotoxins belonging to 13 PSM classes, which corresponds to almost 30% of all included phytotoxins. Several alkaloids were regularly detected in the low ng/L-range, with average detection frequencies of 21%. This is consistent with the previously estimated persistence and mobility properties that indicated a high contamination potential. Coumarins were previously predicted to be unstable, however, detection frequencies were around 89%, and maximal concentrations up to 90 ng/L were measured for fraxetin produced by various trees. Overall, rainy weather conditions at full vegetation led to the highest total phytotoxin concentrations, which might potentially be most critical for aquatic organisms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

There is an increasing need for comparable and harmonized retention times ( t R ) in liquid chromatography (LC) among different laboratories, to provide supplementary evidence for the identity of compounds in high-resolution mass spectrometry (HRMS)-based suspect and nontarget screening investigations. In this study, a rigorously tested, flexible, and less system-dependent unified retention time index (RTI) approach for LC is presented, based on the calibration of the elution pattern. Two sets of 18 calibrants were selected for each of ESI+ and ESI-based on the maximum overlap with the retention times and chemical similarity indices from a total set of 2123 compounds. The resulting calibration set, with RTI set to range between 1 and 1000, was proposed as the most appropriate RTI system after rigorous evaluation, coordinated by the NORMAN network. The validation of the proposed RTI system was done externally on different instrumentation and LC conditions. The RTI can also be used to check the reproducibility and quality of LC conditions. Two quantitative structure-retention relationship (QSRR)-based models were built based on the developed RTI systems, which assist in the removal of false-positive annotations. The applicability domains of the QSRR models allowed completing the identification process with higher confidence for substances within the domain, while indicating those substances for which results should be treated with caution. The proposed RTI system was used to improve confidence in suspect and nontarget screening and increase the comparability between laboratories as demonstrated for two examples. All RTI-related calculations can be performed online at http://rti.chem.uoa.gr/.

Non-target analysis (NTA) employing high-resolution mass spectrometry is a commonly applied approach for the detection of novel chemicals of emerging concern in complex environmental samples. NTA typically results in large and information-rich datasets that require computer aided (ideally automated) strategies for their processing and interpretation. Such strategies do however raise the challenge of reproducibility between and within different processing workflows. An effective strategy to mitigate such problems is the implementation of inter-laboratory studies (ILS) with the aim to evaluate different workflows and agree on harmonized/standardized quality control procedures. Here we present the data generated during such an ILS. This study was organized through the Norman Network and included 21 participants from 11 countries. A set of samples based on the passive sampling of drinking water pre and post treatment was shipped to all the participating laboratories for analysis, using one pre-defined method and one locally (i.e. in-house) developed method. The data generated represents a valuable resource (i.e. benchmark) for future developments of algorithms and workflows for NTA experiments., (© 2021. The Author(s).)

Natural estrogens are present in high concentrations in livestock slurries, which are often applied to agricultural fields in large quantities. As such, the export of slurry-derived natural estrogens from tile-drained fields is a potential source for estrogenic pollution in surface waters. Yet despite the abundance of tile-drained fields in Central Europe, export of natural estrogens from agricultural fields receiving livestock slurries is rarely studied in this region. In an effort to fill this knowledge gap, here we applied natural estrogens to Swiss experimental fields in the form of cattle slurry, pig slurry or dissolved in water, and quantified them in flow-proportionally collected drainage water over 18 months. After pig and cattle slurry applications, concentration maxima in drainage water of 73, 8, 37, and 60 ng L -1 for 17α-estradiol (E2α), 17β-estradiol (E2β), estrone (E1), and estriol (E3), respectively, were observed shortly after rain events. The exported fractions of individual natural estrogens to tile drains were on average 0.26% (ranging from 0.08 to 0.41%) after cattle, and 0.18% (0.03-0.40%) after pig slurry applications. Such numbers were higher than expected from the leaching potential based on substance properties, and comparable to those of more mobile micropollutants previously studied on the same fields. Natural estrogens were mainly exported to tile drains through preferential flow. Exported fractions were lower when applied in aqueous solution than when applied in slurry, pointing to particle-facilitated transport to tile drains when applied in slurry. In Switzerland, the estimated 6.3, 0.6, 7.4, and 7.7 g of E2α, E2β, E1, and E3, respectively, exported through the tile-drained agricultural area per year contribute little to the total natural estrogen load received by surface waters. However, after slurry applications in highly drained catchments, natural estrogen emissions to tile drains can cause short term (i.e. less than 1 week) estrogenic exposure in nearby streams., Competing Interests: Declaration of competing interest The authors declare no competing financial interest or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Advanced treatment is increasingly being applied to improve abatement of micropollutants in wastewater effluent and reduce their load to surface waters. In this study, non-target screening of high-resolution mass spectrometry (HRMS) data, collected at three Swiss wastewater treatment plants (WWTPs), was used to evaluate different advanced wastewater treatment setups, including (1) granular activated carbon (GAC) filtration alone, (2) pre-ozonation followed by GAC filtration, and (3) pre-ozonation followed by powdered activated carbon (PAC) dosed onto a sand filter. Samples were collected at each treatment step of the WWTP and analyzed with reverse-phase liquid chromatography coupled to HRMS. Each WWTP received a portion of industrial wastewater and a prioritization method was applied to select non-target features potentially resulting from industrial activities. Approximately 37,000 non-target features were found in the influents of the WWTPs. A number of non-target features (1207) were prioritized as likely of industrial origin and 54 were identified through database spectral matching. The fates of all detected non-target features were assessed through a novel automated trend assignment method. A trend was assigned to each non-target feature based on the normalized intensity profile for each sampling date. Results showed that 73±4% of influent non-target features and the majority of industrial features (89%) were well-removed (i.e., >80% intensity reduction) during biological treatment in all three WWTPs. Advanced treatment removed, on average, an additional 11% of influent non-target features, with no significant differences observed among the different advanced treatment settings. In contrast, when considering a subset of 66 known micropollutants, advanced treatment was necessary to adequately abate these compounds and higher abatement was observed in fresh GAC (7,000-8,000 bed volumes (BVs)) compared to older GAC (18,000-48,000 BVs) (80% vs 56% of micropollutants were well-removed, respectively). Approximately half of the features detected in the WWTP effluents were features newly formed during the various treatment steps. In ozonation, between 1108-3579 features were classified as potential non-target ozonation transformation products (OTPs). No difference could be observed for their removal in GAC filters at the BVs investigated (70% of OTPs were well-removed on average). Similar amounts (67%) was observed with PAC (7.7-13.6 mg/L) dosed onto a sand filter, demonstrating that a post-treatment with activated carbon is efficient for the removal of OTPs., (Copyright © 2021. Published by Elsevier Ltd.)

The exposure of ecologically critical invertebrate species to biologically active pharmaceuticals poses a serious risk to the aquatic ecosystem. Yet, the fate and toxic effects of pharmaceuticals on these nontarget aquatic invertebrates and the underlying mechanisms are poorly studied. Herein, we investigated the toxicokinetic (TK) processes (i.e., uptake, biotransformation, and elimination) of the pharmaceutical diclofenac and its biotransformation in the freshwater invertebrate Hyalella azteca . We further employed mass spectrometry-based metabolomics to assess the toxic effects of diclofenac on the metabolic functions of H . azteca exposed to environmentally relevant concentrations (10 and 100 μg/L). The TK results showed a quick uptake of diclofenac by H . azteca (maximum internal concentration of 1.9 μmol/kg) and rapid formation of the conjugate diclofenac taurine (maximum internal concentration of 80.6 μmol/kg), indicating over 40 times higher accumulation of diclofenac taurine than that of diclofenac in H . azteca . Depuration kinetics demonstrated that the elimination of diclofenac taurine was 64 times slower than diclofenac in H . azteca . Metabolomics results suggested that diclofenac inhibited prostaglandin synthesis and affected the carnitine shuttle pathway at environmentally relevant concentrations. These findings shed light on the significance of the TK process of diclofenac, especially the formation of diclofenac taurine, as well as the sublethal effects of diclofenac on the bulk metabolome of H . azteca . Combining the TK processes and metabolomics provides complementary insights and thus a better mechanistic understanding of the effects of diclofenac in aquatic invertebrates.

Groundwater is a major drinking water resource but its quality with regard to organic micropollutants (MPs) is insufficiently assessed. Therefore, we aimed to investigate Swiss groundwater more comprehensively using liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS). First, samples from 60 sites were classified as having high or low urban or agricultural influence based on 498 target compounds associated with either urban or agricultural sources. Second, all LC-HRMS signals were related to their potential origin (urban, urban and agricultural, agricultural, or not classifiable) based on their occurrence and intensity in the classified samples. A considerable fraction of estimated concentrations associated with urban and/or agricultural sources could not be explained by the 139 detected targets. The most intense nontarget signals were automatically annotated with structure proposals using MetFrag and SIRIUS4/CSI:FingerID with a list of >988,000 compounds. Additionally, suspect screening was performed for 1162 compounds with predicted high groundwater mobility from primarily urban sources. Finally, 12 nontargets and 11 suspects were identified unequivocally (Level 1), while 17 further compounds were tentatively identified (Level 2a/3). amongst these were 13 pollutants thus far not reported in groundwater, such as: the industrial chemicals 2,5-dichlorobenzenesulfonic acid (19 detections, up to 100 ng L -1 ), phenylphosponic acid (10 detections, up to 50 ng L -1 ), triisopropanolamine borate (2 detections, up to 40 ng L -1 ), O-des[2-aminoethyl]-O-carboxymethyl dehydroamlodipine, a transformation product (TP) of the blood pressure regulator amlodipine (17 detections), and the TP SYN542490 of the herbicide metolachlor (Level 3, 33 detections, estimated concentrations up to 100-500 ng L -1 ). One monitoring site was far more contaminated than other sites based on estimated total concentrations of potential MPs, which was supported by the elucidation of site-specific nontarget signals such as the carcinogen chlorendic acid, and various naphthalenedisulfonic acids. Many compounds remained unknown, but overall, source related prioritisation proved an effective approach to support identification of compounds in groundwater., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

A wide range of micropollutants can be monitored with non-targeted screening; however, the quantification of the newly discovered compounds is challenging. Transformation products (TPs) are especially problematic because analytical standards are rarely available. Here, we compared three quantification approaches for non-target compounds that do not require the availability of analytical standards. The comparison is based on a unique set of concentration data for 341 compounds, mainly pesticides, pharmaceuticals, and their TPs in 31 groundwater samples from Switzerland. The best accuracy was observed with the predicted ionization efficiency-based quantification, the mean error of concentration prediction for the groundwater samples was a factor of 1.8, and all of the 74 micropollutants detected in the groundwater were quantified with an error less than a factor of 10. The quantification of TPs with the parent compounds had significantly lower accuracy (mean error of a factor of 3.8) and could only be applied to a fraction of the detected compounds, while the mean performance (mean error of a factor of 3.2) of the closest eluting standard approach was similar to the parent compound approach.

Synthetic water-soluble polymeric materials are widely employed in e.g. cleaning detergents, personal care products, paints or textiles. Accordingly, these compounds reach sewage treatment plants and may enter receiving waters and the aquatic environment. Characteristically, these molecules show a polydisperse molecular weight distribution, comprising multiple repeating units, i.e. a homologous series (HS). Their analysis in environmentally relevant samples has received some attention over the last two decades, however, the majority of previous studies focused on surfactants and a molecular weight range <1000 Da. To capture a wider range on the mass versus polarity plane and extend towards less polar contaminants, a workflow was established using three different ionization strategies, namely conventional electrospray ionization, atmospheric pressure photoionization and atmospheric pressure chemical ionization. The data evaluation consisted of suspect screening of ca. 1200 suspect entries and a non-target screening of HS with pre-defined accurate mass differences using ca. 400 molecular formulas of repeating units of HS as input and repeating retention time shifts as HS indicator. To study the fate of these water-soluble polymeric substances in the wastewater treatment process, the different stages, i.e. after primary and secondary clarifier, and after ozonation followed by sand filtration, were sampled at a Swiss wastewater treatment plant. Remaining with two different ionization interfaces, ESI and APPI, in both polarities, a non-targeted screening approach led to a total number of 146 HS (each with a minimum number of 4 members), with a molecular mass of up to 1200 detected in the final effluent. Of the 146 HS, ca 15% could be associated with suspect hits and approximately 25% with transformation products of suspects. Tentative characterization or probable chemical structure could be assigned to almost half of the findings. In positive ionization mode various sugar derivatives with differing side chains, for negative mode structures with sulfonic acids, could be characterized. The number of detected HS decreased significantly over the three treatment stages. For HS detectable also in the biological and oxidative treatment stages, a change in HS distribution towards to lower mass range was often observed., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier Ltd.)

Pyrrolizidine alkaloids (PAs) are found to be toxic pollutants emitted into the environment by numerous plant species, resulting in contamination. In this article, we investigate the occurrence of PAs in the aquatic environment of small Swiss streams combining two different approaches. Pyrrolizidine alkaloids (PAs) are toxic secondary metabolites produced by numerous plant species. Although they were classified as persistent and mobile and found to be emitted into the environment, their occurrence in surface waters is largely unknown. Therefore, we performed a retrospective data analysis of two extensive HRMS campaigns each covering five small streams in Switzerland over the growing season. All sites were contaminated with up to 12 individual PAs and temporal detection frequencies between 36 and 87%. Individual PAs were in the low ng/L range, but rain-induced maximal total PA concentrations reached almost 100 ng/L in late spring and summer. Through PA patterns in water and plants, several species were tentatively identified as the source of contamination, with Senecio spp . and Echium vulgare being the most important. Additionally, two streams were monitored, and PAs were quantified with a newly developed, faster, and more sensitive LC-MS/MS method to distinguish different plant-based and indirect human PA sources. A distinctly different PA fingerprint in aqueous plant extracts pointed to invasive Senecio inaequidens as the main source of the surface water contamination at these sites. Results indicate that PA loads may increase if invasive species are sufficiently abundant.

Pesticide contamination of agricultural streams has widely been analysed in regions of high intensity agriculture such as in Western Europe or North America. The situation of streams subject to low intensity agriculture relying on human and animal labour, as in parts of Romania, remains unknown. To close this gap, we determined concentrations of 244 pesticides and metabolites at 19 low-order streams, covering sites from low to high intensity agriculture in a region of Romania. Pesticides were sampled with two passive sampling methods (styrene-divinylbenzene (SDB) disks and polydimethylsiloxane (PDMS) sheets) during three rainfall events and at base flow. Using the toxic unit approach, we assessed the toxicity towards algae and invertebrates. Up to 50 pesticides were detected simultaneously, resulting in sum concentrations between 0.02 and 37 µg L -1 . Both, the sum concentration as well as the toxicities were in a similar range as in high intensity agricultural streams of Western Europe. Different proxies of agricultural intensity did not relate to in-stream pesticide toxicity, contradicting the assumption of previous studies. The toxicity towards invertebrates was positively related to large scale variables such as the catchment size and the agricultural land use in the upstream catchment and small scale variables including riparian plant height, whereas the toxicity to algae showed no relationship to any of the variables. Our results suggest that streams in low intensity agriculture, despite a minor reported use of agrochemicals, exhibit similar levels of pesticide pollution as in regions of high intensity agriculture., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Natural estrogens such as 17α-estradiol (E2α), 17β-estradiol (E2β), estrone (E1), and estriol (E3), released to surface waters from both urban and agricultural sources, are endocrine disrupting for fish. Here, we assess the prevalence of livestock farming derived natural estrogens in tributaries and ponds in the agriculturally dominated catchment of Lake Baldegg, Switzerland. Passive samplers were deployed in the main tributary and daily time-proportional water samples were collected in five tributaries for 30 days at the beginning of the vegetation period. Furthermore, we took grab samples of 12 ponds in the catchment. Aqueous samples were liquid-liquid extracted, derivatized, and analysed with LC-MS/MS and stream water samples additionally with ERα-CALUX, a bioassay for assessing total estrogenic activity. Natural estrogens were regularly detected, with mean concentrations ranging from below the limit of detection to 0.55 ng L -1 for E2β and E1, respectively, and passive sampling and bioassay results largely confirmed these findings. Monte Carlo simulated mean natural estrogen concentrations underestimated measured ones by a factor of three to 11. An agricultural area's hydrological contribution and connectivity to surface waters seemed to be more important for the development of estrogen concentrations in streams than livestock densities in a catchment or the actual loads of slurry applied. Pond water occasionally contained natural estrogens in concentrations up to 8.6 ng L -1 for E2α. The environmental quality standards of the European Union (0.4 ng L -1 for E2β and 3.6 ng L -1 for E1) were never exceeded for longer than a day in tributaries, but E1 reached critical concentrations for aquatic organisms in ponds.

An approach to identifying persistent organic contaminants in the environment was developed and executed for Switzerland as an example of an industrialized country. First, samples were screened with an in-house list using liquid chromatography high-resolution mass spectrometry (LC-HRMS/MS) and gas chromatography tandem mass spectrometry (GC-MS/MS) in 13 samples from the Swiss National Soil Monitoring Network and three sediment cores of an urban and agricultural contaminated lake. To capture a broader range of organic contaminants, the analysis was extended with a suspect screening analysis by LC-HRMS/MS of >500 halogenated compounds obtained from a Swiss database that includes industrial and household chemicals identified, by means of fugacity modeling, as persistent substances in the selected matrices. In total, the confirmation of 96 compounds with an overlap of 34 in soil and sediment was achieved. The identified compounds consist generally of esters, tertiary amines, trifluoromethyls, organophosphates, azoles and aromatic azines, with azoles and triazines being the most common groups. Newly identified compounds include transformation products, pharmaceuticals such as the flukicide niclofolan, the antimicrobial cloflucarban, and the fungicide mandipropamid. The results indicate that agricultural and urban soils as well as sediments impacted by agriculture and wastewater treatment plants (WWTPs) are the most contaminated sites. The plausibility of this outcome confirms the combination of chemical inventory, modeling of partitioning and persistence, and HRMS-based screening as a successful approach to shed light on less frequently or not yet investigated environmental contaminants and emphasizes the need for more soil and sediment monitoring in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Exposure assessment of pesticides has substantially improved over time, with methods that now include a combination of advanced analytical techniques and fate/transport models to evaluate their spatiotemporal distribution. However, the current regulatory environmental risk assessment considers thresholds from laboratory studies completed under standardized conditions that do not reflect environmental dynamics. Using the General Unified Threshold model for Survival (GUTS) model framework, we predicted the impact of time-varying pesticide exposures on the survival of gammarids in a small agricultural stream. The LP 50 values were used as an additional metric for assessing risks (defined in GUTS as a multiplication factor applied to the concentration time series to induce 50% mortality by the end of exposure). Although real-case exposures to individual pesticides were predicted to produce little to no impact on survival, the LP 50 values indicate acute (LP 50 ≤ 100) and/or chronic (LP 50 ≤ 10) toxicities for azoxystrobin, chlorpyrifos, diazinon, and imidacloprid, while risk to propiconazole exposure was considered very low (LP 50 ≫ 100). Finally, the model was extended to reflect mixture toxicity via concentration addition. It predicted risks under acute and chronic exposures to organophosphates and neonicotinoids. Given that gammarids are simultaneously exposed to multiple chemicals and other stressors throughout their lifetime, a decline in survival probabilities due to chemical stress can likely influence their overall fitness. We recognize that some assumptions require validation, but our work included a level of realism that can assist risk managers when evaluating the cumulative consequences of chemical exposure.

Chlorothalonil, a fungicide applied for decades worldwide, has recently been banned in the European Union (EU) and Switzerland due to its carcinogenicity and the presence of potentially toxic transformation products (TPs) in groundwater. The spread and concentration range of chlorothalonil TPs in different drinking water resources was examined (73 groundwater and four surface water samples mainly from Switzerland). The chlorothalonil sulfonic acid TPs (R471811, R419492, R417888) occurred more frequently and at higher concentrations (detected in 65-100% of the samples, ≤2200 ngL -1 ) than the phenolic TPs (SYN507900, SYN548580, R611968; detected in 10-30% of the samples, ≤130 ngL -1 ). The TP R471811 was found in all samples and even in 52% of the samples above 100 ngL -1 , the drinking water standard in Switzerland and other European countries. Therefore, the abatement of chlorothalonil TPs was investigated in laboratory and pilot-scale experiments and along the treatment train of various water works, comprising aquifer recharge, UV disinfection, ozonation, advanced oxidation processes (AOPs), activated carbon treatment, and reverse osmosis. The phenolic TPs can be abated during ozonation (second order rate constant k O3 ∼10 4  M -1 s -1 ) and by reaction with hydroxyl radicals (OH) in AOPs (k OH ∼10 9  M -1 s -1 ). In contrast, the sulfonic acid TPs, which occurred in higher concentrations in drinking water resources, react only very slowly with ozone (k O3 <0.04 M -1 s -1 ) and OH (k OH  <5.0 × 10 7  M -1 s -1 ) and therefore persist in ozonation and OH-based AOPs. Activated carbon retained the very polar TP R471811 only up to a specific throughput of 25 m 3 kg -1 (20% breakthrough), similarly to the X-ray contrast agent diatrizoic acid. Reverse osmosis was capable of removing all chlorothalonil TPs by ≥98%., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Bioaccumulation assessment predominantly relies on the bioconcentration factor (BCF) as the sole decisive metric. The test guideline 305 by the Organisation for Economic Co-operation and Development (OECD) provides the standard procedure for deriving this in vivo fish BCF, which is not only expensive and labor-intensive, but also requires many animals. Accordingly, there is a great need for and interest in alternative methods that can help to reduce, replace, and refine vertebrate tests, as described in the 3R principles. Two alternative approaches have been developed: the bioconcentration test with the freshwater amphipod Hyalella azteca and the OECD test guideline 319 which provides a method to determine experimentally derived in vitro metabolism rates that can then be incorporated into in silico prediction models for rainbow trout BCF calculation. In the present study both alternative methods were applied to 5 substances of different physicochemical characteristics. The results were compared with literature values of fish in vivo BCFs and additional BCFs obtained with the alternative methods, if available. Potential differences between the results of the test methods are discussed utilizing information such as in vivo metabolism rates. The currently available data set suggests that these 2 alternative methods pose promising alternatives to predict bioaccumulation in fish, although defined applicability domains have yet to be determined. Environ Toxicol Chem 2020;39:1813-1825. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC., (© 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.)

Preventing and remedying fresh waters from chemical pollution is a fundamental societal and scientific challenge. With other nonchemical stressors potentially co-occurring, assessing the ecological consequences of reducing chemical loads in the environment is arduous. In this case study, we comparatively assessed the community structure, functions, and tolerance of stream biofilms to micropollutant mixtures extracted from deployed passive samplers at wastewater treatment plant effluents. These biofilms were growing up- and downstream of one upgraded and two nonupgraded wastewater treatment plants before being sampled for analyses. Our results showed a substantial decrease in micropollutant concentrations by 85%, as the result of upgrading the wastewater treatment plant at one of the sampling sites with activated carbon filtration. This decrease was positively correlated with a loss of community tolerance to micropollutants and the recovery of the community structure downstream of the effluent. On the other hand, downstream biofilms at the nonupgraded sites displayed higher tolerance to the extracts than the upstream biofilms. The observed higher tolerance was positively linked to micropollutant levels both in stream water and in biofilm samples, and to shifts in the community structure. Although more investigations of upgraded sites are needed, our findings point toward the suitability of using community tolerance for the retrospective assessment of the risks posed by micropollutants, to assess community recovery, and to relate effects to causes in complex environmental conditions.

Sertraline is one of the most commonly prescribed antidepressants in the last few years. Therefore, it is not surprising that it is regularly detected in wastewaters, surface waters, sediments, biosolids and biota. Effluents from wastewater treatment plants are the main contributors to its presence in the environment. The presented study aims to elucidate the processes involved in its removal, concentrating mainly on sorption and biodegradation during wastewater treatment. We performed our laboratory scale experiments in two sets of experiments: 1) batch biodegradation and sorption experiments and 2) flow-through laboratory scale pilot wastewater treatment bioreactors. The batch experiments revealed that sorption to activated sludge was the leading removal process, eliminating up to 90% of sertraline present in the batches. Biodegradation was however the secondary removal process, influenced by the presence of alternative easily biodegradable carbon sources. We postulated chemical structures of ten detected biotransformation products. Among these, we propose the previously recognized metabolite norsertraline, sertraline ketone and hydroxy-sertraline. All the remaining biotransformation products are herein reported for the first time. The removal efficiency of approximately 94% was determined after the treatment in the flow-through bioreactors. To support our findings, we sampled influents and effluents from two wastewater treatment plants and untreated wastewater from a psychiatric hospital. Removal efficiencies of 81% and 77% were determined, and along with the parent compound sertraline, the presence of eight transformation products was confirmed in the actual wastewaters., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Many organic contaminants entering the aquatic environment feature stereogenic structural elements that give rise to enantiomerism. While abiotic processes usually act identical on enantiomers, biotic processes, such as biodegradation often result in enantiomeric fractionation (EFr), i.e., the change of the relative abundance of enantiomers. Therefore, EFr offers the opportunity to differentiate biodegradation in complex environmental systems from abiotic processes. In this study, an achiral-chiral two-dimensional liquid chromatographic method for the enantioseparation of selected pharmaceuticals was developed. This method was then applied to determine the enantiomeric compositions of eight chiral pharmaceuticals in 20 water-sediment test flumes and test EFr as an indicator of biodegradation. While all eight substances were attenuated by at least 60%, five (atenolol, metoprolol, celiprolol, propranolol, and flecainide) displayed EFr. No EFr was observed for citalopram, fluoxetine, and venlafaxine despite almost complete attenuation (80 to 100%). Celiprolol, a barely studied β-blocker, revealed the most distinct EFr among all investigated substances; however, EFr varied considerably with biodiversity. Celiprolol-H2 was identified as a biological transformation product possibly formed by reduction of the celiprolol keto group through a highly regio- and enantioselective carbonyl reductase. While celiprolol-H2 was observed across all flumes, as expected, its formation was faster in flumes with high bacterial diversity where also EFr was highest. Overall, EFr and transformation product formation together served as good indicators of biological processes; however, the strong dependence of EFr on biodiversity limits its usefulness in complex environmental systems.

Environmental risk assessment associated with aquatic and terrestrial contamination is mostly based on predicted or measured environmental concentrations of a limited list of chemicals in a restricted number of environmental compartments. High resolution mass spectrometry (HRMS) can provide a more comprehensive picture of exposure to harmful chemicals, particularly through the retrospective analysis of digitally stored HRMS data. Using this methodology, our study characterized the contamination of various environmental compartments including 154 surface water, 46 urban effluent, 67 sediment, 15 soil, 34 groundwater, 24 biofilm, 41 gammarid and 49 fish samples at 95 sites widely distributed over the Swiss Plateau. As a proof-of-concept, we focused our investigation on antifungal azoles, a class of chemicals of emerging concern due to their endocrine disrupting effects on aquatic organisms and humans. Our results demonstrated the occurrence of antifungal azoles and some of their (bio)transformation products in all the analyzed compartments (0.1-100 ng/L or ng/g d.w.). Comparison of actual and predicted concentrations showed the partial suitability of level 1 fugacity modelling in predicting the exposure to azoles. Risk quotient calculations additionally revealed risk of exposure especially if some of the investigated rivers and streams are used for drinking water production. The case study clearly shows that the retrospective analysis of HRMS/MS data can improve the current knowledge on exposure and the related risks to chemicals of emerging concern and can be effectively employed in the future for such purposes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Natural estrogens act as endocrine disruptors. However, the fate of livestock farming derived natural estrogens (17α-estradiol, 17β-estradiol, estrone, and estriol) in slurry is not well understood. In this study, we assessed the effects of on farm-storage on natural estrogen concentrations in slurry. Furthermore, we monitored pig and cattle slurry pits from major agricultural areas in Switzerland and determined natural estrogen concentrations therein. They were relatively stable over time, and mean concentrations ranged from 138 to 861 and 54 to 244 ng/L for cattle and pig slurries, respectively. 17α-Estradiol and estriol were the most prevalent estrogens in cattle and pig slurries, respectively. Based on livestock numbers, agricultural area, and estrogen concentrations in slurry, the estimated annual load of total natural estrogens applied on agricultural area amounted to 36 mg/ha. Our results indicate that slurry application is a relevant source of natural estrogens in the environment.