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Contaminants of emerging concern (CECs) are widespread in the water cycle. Their levels in disinfected waters are usually low, as they may transform into CEC disinfection byproducts (DBPs) during disinfection processes or partially removed in previous water treatment steps. The occurrence of CEC DBPs in real waters has been scarcely addressed, although their presence may be of relevance in water circular economy scenarios, and thus deserves further study in water regeneration systems. In this work, a database of CEC DBPs (n=1338) after chlorination was generated and is ready to use in future screening studies to assess the relevance of these chemicals in contaminat mixtures. Moreover, the transformation of CECs during chlorination, their main reaction pathways with chlorine, and current knowledge gaps were critically reviewed. © 2021 The Author(s)

This paper describes the development and validation of a new method for the simultaneous determination of 148 substances in sewage sludge. The selected compounds belong to different classes of pharmaceuticals, including antibiotics, analgesic and/or anti-inflammatory drugs, antiepileptics, benzodiazepines, antipsychotics, and antidepressants, among others, and illicit drugs, including opiates, opioids, cocaine, amphetamines, cannabinoids, and their metabolites. As far as the authors are aware, this is the first method in the peer-reviewed literature covering such a large number of target drugs for determination in a complex matrix like sewage sludge. The method presented herein combines ultrasound-assisted extraction (USE) and liquid chromatography coupled to tandem mass spectrometry. Good analytical performance was achieved, with limit-of-detection values below 10 ng g−1 d.w. for 91 % of the analytes and absolute recovery in the range 50–110 % for more than 77 % of the studied compounds. A combination of methanol and acidified water, also containing EDTA, proved to be the optimum solvent mixture to perform the extractions. An extra solid-phase-extraction clean-up step was not required, substantially reducing sample-preparation time and solvent consumption. Finally, the developed method was applied to the analysis of different sewage-sludge samples from five wastewater treatment plants of Santorini Island (Greece). Out of the 148 target compounds, 36 were detected. Several compounds, including acetylsalicylic acid, citalopram, and ciprofloxacin among others, had maximum concentrations above 100 ng g−1 d.w. © 2015 Springer-Verlag Berlin Heidelberg

There is an increasing need for comparable and harmonized retention times (tR) 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).

The Partnership for Chemicals Risk Assessment (PARC) is currently under development as a joint research and innovation programme to strengthen the scientific basis for chemical risk assessment in the EU. The plan is to bring chemical risk assessors and managers together with scientists to accelerate method development and the production of necessary data and knowledge, and to facilitate the transition to next-generation evidence-based risk assessment, a non-toxic environment and the European Green Deal. The NORMAN Network is an independent, well-established and competent network of more than 80 organisations in the field of emerging substances and has enormous potential to contribute to the implementation of the PARC partnership. NORMAN stands ready to provide expert advice to PARC, drawing on its long experience in the development, harmonisation and testing of advanced tools in relation to chemicals of emerging concern and in support of a European Early Warning System to unravel the risks of contaminants of emerging concern (CECs) and close the gap between research and innovation and regulatory processes. In this commentary we highlight the tools developed by NORMAN that we consider most relevant to supporting the PARC initiative: (i) joint data space and cutting-edge research tools for risk assessment of contaminants of emerging concern; (ii) collaborative European framework to improve data quality and comparability; (iii) advanced data analysis tools for a European early warning system and (iv) support to national and European chemical risk assessment thanks to harnessing, combining and sharing evidence and expertise on CECs. By combining the extensive knowledge and experience of the NORMAN network with the financial and policy-related strengths of the PARC initiative, a large step towards the goal of a non-toxic environment can be taken. © 2020, The Author(s).

Contamination of soils with organic pollutants is an increasing global problem, so novel soil remediation techniques are urgently needed. One such technique is electrokinetic remediation, in which an electric field is applied over the soil to extract contaminants. Previous evaluations of the technique have been limited to a few specific compounds. In this study, we integrated the latest advances in high-resolution mass spectrometry (HRMS) to identify molecular fingerprints, and used the results to improve the mechanistic understanding necessary for successful remediation. A laboratory-scale 0.38 mA cm-2 electrodialytic treatment was applied for 21 days to a contaminated soil from a firefighter training facility in Sweden. Non-target analysis allowed generic evaluation of changes in the soil organic fraction by tentatively determining the elemental composition of compounds present. The results showed that smaller oxygen-rich molecules were significantly transported to the anode by electromigration, while larger hydrogen-saturated molecules were transported to the cathode by electroosmotic flow. Wide suspect screening with >3000 per- and polyfluoroalkyl substances (PFASs) tentatively identified seven new PFASs in the test soil, including perfluoroheptanesulfonic acid (PFHpS), and PFASs with butoxy, ethoxy, ethanol, and ethylcyclohexanesulfonate functional groups. © 2020 The Author(s).

This study presents the development and validation of a comprehensive quantitative target methodology for the analysis of 2316 emerging pollutants in water based on Ultra-Performance Liquid Chromatography Quadrupole-Time-Of-Flight Mass Spectrometry (UPLC-Q-ToF-HRMS/MS). Target compounds include pesticides, pharmaceuticals, drugs of abuse, industrial chemicals, doping compounds, surfactants and transformation products, among others. The method was validated for 195 analytes, chosen to be representative of the chemical space of the target list, enabling the assessment of the performance of the method. The method involves a generic sample preparation based on mixed mode solid phase extraction, a UPLC-QTOF-MS/MS screening method using Data Independent Acquisition (DIA) mode, which provides MS and MS/MS spectra simultaneously and an elaborate strong post-acquisition evaluation of the data. The processing method was optimized to provide a successful identification rate >95 % and to minimize the number of false positive results (< 5 %). Decision limit (CCα) and detection capability (CCβ) were also introduced in the validation scheme to provide more realistic metrics on the performance of a HRMS-based wide-scope screening method. A new system of identification points (IPs) based on the one described in the Commission Decision 2002/657/EC was applied to communicate the confidence level in the identification of the analytes. This system considers retention time, mass accuracy, isotopic fit and fragmentation; taking full advantage of the capacities of the HRMS instruments. Finally, 398 contaminants were detected and quantified in real wastewater. © 2019 Elsevier B.V.

Peak prioritization plays a key role in non-target analysis of complex samples in order to focus the elucidation efforts on potentially relevant substances. The present work shows the development of a computational workflow capable of detecting compounds that exhibit large variation in intensity over time. The developed approach is based on three open-source R packages (xcms, CAMERA and TIMECOURSE) and includes the use of the statistical test Multivariate Empirical Bayes Approach to rank the compounds based on the Hotelling T2 coefficient, which is an indicator of large concentration variations of unknown components. The approach was applied to replicate series of 24 h composite flow-proportional influent wastewater samples collected during 8 consecutive days. 60 events involving unknown substances with high fluctuation over time were successfully prioritized. 14 of those compounds were tentatively identified using HRMS/MS libraries, chemical databases, in-silico fragmentation tools, and retention time prediction models. Four compounds were confirmed with standards from which two never reported before in wastewater. © 2018 Elsevier B.V.

The economic crisis plaguing Greece was expected to impact consumption of pharmaceuticals and illicit drugs - a priori to an unknown extent. We quantified the change of use for various classes of licit and illicit drugs by monitoring Athens' wastewater from 2010 to 2014. A high increase in the use of psychoactive drugs was detected between 2010 and 2014, especially for antipsychotics (35-fold), benzodiazepines (19-fold), and antidepressants (11-fold). This directly reflects the perceived increase of incidences associated with mental illnesses in the population, as a consequence of severe socioeconomic changes. Other therapeutic classes, like antiepileptics, hypertensives, and gastric and ulcer drugs also showed an increase in use (from 2-fold increase for antiepileptics to 13-fold for hypertensives). In contrast, the overall use of antibiotics and NSAIDs decreased. For mefenamic acid, an almost 28-fold decrease was observed. This finding is likely related to the reduction in drug expenditure applied in public health. A 2-fold increase of methamphetamine use was detected, associated with a cheap street drug called ″sisa″ (related to marginal conducts), which is a health concern. MDMA (5-fold) and methadone (7-fold) use showed also an increase, while cocaine and cannabis estimates did not show a clear trend. © 2016 American Chemical Society.

Over the past decade, the application of liquid chromatography-high resolution mass spectroscopy (LC-HRMS) has been growing extensively due to its ability to analyze a wide range of suspected and unknown compounds in environmental samples. However, various criteria, such as mass accuracy and isotopic pattern of the precursor ion, MS/MS spectra evaluation, and retention time plausibility, should be met to reach a certain identification confidence. In this context, a comprehensive workflow based on computational tools was developed to understand the retention time behavior of a large number of compounds belonging to emerging contaminants. Two extensive data sets were built for two chromatographic systems, one for positive and one for negative electrospray ionization mode, containing information for the retention time of 528 and 298 compounds, respectively, to expand the applicability domain of the developed models. Then, the data sets were split into training and test set, employing k-nearest neighborhood clustering, to build and validate the models' internal and external prediction ability. The best subset of molecular descriptors was selected using genetic algorithms. Multiple linear regression, artificial neural networks, and support vector machines were used to correlate the selected descriptors with the experimental retention times. Several validation techniques were used, including Golbraikh-Tropsha acceptable model criteria, Euclidean based applicability domain, modified correlation coefficient (rm2), and concordance correlation coefficient values, to measure the accuracy and precision of the models. The best linear and nonlinear models for each data set were derived and used to predict the retention time of suspect compounds of a wide-scope survey, as the evaluation data set. For the efficient outlier detection and interpretation of the origin of the prediction error, a novel procedure and tool was developed and applied, enabling us to identify if the suspect compound was in the applicability domain or not. © 2016 American Chemical Society.

The existing target analytical methods described in the literature only cover a tiny fraction of the large number of compounds present in environmental samples. As a result, many potential chemical stressors are systematically omitted and there is an urgent need of analytical methodologies capable of detecting and identifying compounds using nontarget methods. In this regard, high resolution mass spectrometry coupled to liquid chromatography (LC-HRMS) has opened up new windows of opportunity for the detection of polar organic contaminants in complex samples. The objective of this chapter is to provide a critical overview of the state-of-the-art of the application of LC-HRMS to the nontarget analysis of organic contaminants in environmental samples. The existing methodologies and the different prioritisation strategies as well as workflows to characterise unknown organic pollutants are evaluated. © 2016 Elsevier B.V.

The occurrence and spatial distribution of 158 pharmaceuticals and drugs of abuse were studied in seawater of the EasternMediterranean Sea (Saronikos Gulf and Elefsis Bay in central Aegean Sea). This area is affected by various anthropogenic pressures as it receives the treated wastewater of the greatest Athens area and off-shore input fluxes. This study constitutes the largest one in terms of number of analytes in this environmental compartment. It provides the first evidence on the occurrence of several pharmaceuticals in marine environment including amoxicillin, lidocaine, citalopram or tramadol, among others. 22 sampleswere collected at three different depths in 9 sampling stations in order to assess the presence and the spatial distribution of the target compounds. A multi-residue method based on solid phase extraction and liquid chromatography coupled to tandem mass spectrometry was developed for the determination of the 158 target substances and validated for seawater sample analysis. 38 out of the 158 target compounds were detected, 15 of them with frequencies of detection equal to or higher than 50%. The highest detected values corresponded to amoxicillin, caffeine and salicylic acid, with concentrations in the range of b5.0-127.8 ng L-1; 5.2-78.2 ng L-1 and b0.4-53.3 ng L-1, respectively. Inputs fromthewastewater treatment plant(WWTP) of Athens revealed to be the main source of pollution in the Inner Saronikos Gulf, whereas, other anthropogenic pressures such as contamination fromshipping activity, industrial effluents, dredging and/or inputs fromland proved to be also relevant. The concentrations of some compounds varied significantly with depth suggesting that currents play an important role in the dilution of the target compounds. © 2015 Elsevier B.V.

Citalopram (CTR) is a worldwide highly consumed antidepressant which has demonstrated incomplete removal by conventional wastewater treatment. Despite its global ubiquitous presence in different environmental compartments, little is known about its behaviour and transformation processes during wastewater treatment. The present study aims to expand the knowledge on fate and transformation of CTR during the biological treatment process. For this purpose, batch reactors were set up to assess biotic, abiotic and sorption losses of this compound. One of the main objectives of the study was the identification of the formed transformation products (TPs) by applying suspect and non-target strategies based on liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS). The complementary use of reversed phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC) for the identification of polar TPs, and the application of in-house developed quantitative structure-retention relationship (QSRR) prediction models, in addition to the comprehensive evaluation of the obtained MS/MS spectra, provided valuable information to support identification. In total, fourteen TPs were detected and thirteen of them were tentatively identified. Four compounds were confirmed (N-desmethylCTR, CTR amide, CTR carboxylic acid and 3-oxo-CTR) through the purchase of the corresponding reference standard. Probable structures based on diagnostic evidence were proposed for the additional nine TPs. Eleven TPs are reported for the first time. A transformation pathway for the biotransformation of CTR was proposed. The presence of the identified TPs was assessed in real wastewater samples through retrospective analysis, resulting in the detection of five compounds. Finally, the potential ecotoxicological risk posed by CTR and its TPs to different trophic levels of aquatic organisms was evaluated by means of risk quotients. © 2016 Elsevier Ltd

The occurrence of eight organic UV filters (UV-Fs) was assessed in fish from four Iberian river basins. This group of compounds is extensively used in cosmetic products and other industrial goods to avoid the damaging effects of UV radiation, and has been found to be ubiquitous contaminants in the aquatic ecosystem. In particular, fish are considered by the scientific community to be the most feasible organism for contamination monitoring in aquatic ecosystems. Despite that, studies on the bioaccumulation of UV-F are scarce. In this study fish samples from four Iberian river basins under high anthropogenic pressure were analysed by liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Benzophenone-3 (BP3), ethylhexyl methoxycinnamate (EHMC), 4-methylbenzylidene camphor (4MBC) and octocrylene (OC) were the predominant pollutants in the fish samples, with concentrations in the range of ng/g. dry. weight (d.w.). The results indicated that most polluted area corresponded to Guadalquivir River basin, where maximum concentrations were found for EHMC (241.7. ng/g. d.w.). Sediments from this river basin were also analysed. Lower values were observed in relation to fish for OC and EHMC, ranging from below the limits of detection to 23. ng/g. d.w. Accumulation levels of UV-F in the fish were used to calculate biota-sediment accumulation factors (BSAFs). These values were always below 1, in the range of 0.04-0.3, indicating that the target UV-Fs are excreted by fish only to some extent. The fact that the highest concentrations were determined in predators suggests that biomagnification of UV-F may take place along the freshwater food web. © 2015.

Personal care products (PCPs) constitute a large group of emerging environmental pollutants, potentially hazardous compounds that have been receiving steadily growing attention over the last decade. Because of the lipophilic properties of these substances, it is expected that they can reach and accumulate in tissues of aquatic organisms in different trophic levels. Their continuous environmental input may lead to a high long-term concentration and promote continual but unnoticed adverse effects on aquatic and terrestrial organisms. This chapter summarizes the developed analytical procedures for the analysis of four important different families of PCPs: UV filters, synthetic musk fragrances, antimicrobials, and parabens. Sampling extraction and preparation, instrumental analysis, and method performance have been considered and discussed. The present work also summarizes the available data on the presence of these substances in biota samples, providing ranges of concentration for the different compounds in the species that have been evaluated in each study. © Springer-Verlag Berlin Heidelberg 2014.