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Due to the fast urbanization and climate change, urban aquifers are considered as a strategic source of potable water. However, a potential limitation is the presence of contaminants, such as pharmaceuticals, which might deteriorate groundwater quality. This work investigated the occurrence of pharmaceuticals and evaluated their human health risk in an alluvial urban aquifer recharged by a polluted river that receives discharges from wastewater treatment plants (WWTPs). To this end, river and groundwater samples were collected from February to May 2021 for the analysis of 92 pharmaceuticals using a solid-phase extraction and a highpressure liquid chromatography coupled to a high resolution mass spectrometric methodology (HPLC-HRMS). Results showed that 35 pharmaceuticals, including 6 transformation products (TPs), were detected in all groundwater samples and the range of concentrations was from the low ng L-1 to 44.5 μg L-1. Moreover, the concentrations of some substances decreased along the flow path during bank filtration, suggesting the occurrence of natural attenuation processes (e.g., adsorption or oxidation-reduction). Finally, most of the measured substances did not pose a risk to human health since estimated risk quotients were low., This research has been supported by the Ministerio de Ciencia e Innovación (grant no. CEX2018-000794-S). We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).

A simple data-based advection-reaction (reactive transport) model applicable to both rivers and aquifers monitoring networks is proposed. It is built on (a) available monitoring data, and (b) graph-theoretical concepts, specifically making use of the Laplacian matrix to capture the network topology and the advection process. The method yields useful information regarding the dynamic spatial behavior of the variables monitored, expressed in terms of quantitative parameters like characteristic length, entropy, first-order decay constants, synchronization between sites, and the external inputs/outputs to the system. The model was tested in an unconfined shallow aquifer located in the lower Besòs River (Spain), in which 37 pharmaceutical compounds were monitored at 7 sites, alongside two campaigns (February and May 2021). Characteristic lengths were, on average, of the same order (24.5 m) as the mean distance between consecutive monitoring sites (33.6 m), thus reflecting an adequate monitoring network design. From an estimated mean advection velocity (0.24 m·h-1), first-order decay constants were calculated for each compound and campaign, with mean values of 0.025 h-1 (February) and 0.005 h-1 (May). Whereas entropy was generally slightly larger values in February than in May (mean values of 1.02 and 0.9 entropy units respectively), synchronization showed the opposite trend (mean values of 62.4% and 68.8% respectively). The input/output profiles were generally site-dependent, regardless of the compound, and campaign considered. • A new advection-reaction modeling approach directly based on experimental data obtained from monitoring campaigns together with the network topology is proposed. • The method yields new quantitative information regarding the dynamic behavior of the variables monitored, useful for both research and management purposes., This research has been supported through the grant CEX2018-000794-S funded by MCIN/AEI/ 10.13039/501100011033.

Wastewater-based epidemiology (WBE) is a new complementary alternative to traditional epidemiological surveillance approaches for community health surveys. It provides objective, flexible, and comprehensive data on diseases, exposure to toxicants and pathogens, social habits, and lifestyle. Wastewater is regarded as an integrated pooled sample of the entire population served by a certain wastewater system, thus providing an average picture of its health status. WBE relies on the extraction, analysis, and subsequent interpretation of appropriate health status indicators, including both chemical and biological components, either exogenous or endogenous, altogether constituting the exposome. Instrumental development, especially mass spectrometry (MS) for the chemical analysis of small and large molecules, has been critical to the success achieved through WBE. Whereas all previous studies have been restricted to small molecules, the use of proteomics in WBE is an obvious extension of the intensive ongoing pursuit of biomarkers for community surveillance of diseases and health status. The relevance of human proteins present in wastewater as potential WBE indicators of population-prevalent diseases has been previously postulated, although no real examples to demonstrate their feasibility have been available until recently. These findings provide new insights into the characterization of wastewater proteomics useful for practical purposes related not only to WBE applications but also to environmental monitoring and wastewater treatment plant management.

Sustaining healthy living conditions in urban areas is a tremendous challenge in the European Union, and central to this mission is the supplying of freshwater resources. However, rapid urban growth and climate change will negatively impact water resources. Therefore, water shortage is encouraging research into potential alternative freshwater resources such as urban groundwater. Sometimes, urban groundwater is pumped to prevent damage to underground structures. This is the case of the underground parking lot of Sant Adrià del Besòs (Barcelona, NE Spain), where large amounts of urban groundwater are pumped to avoid seepage problems, which are directly poured to the sewage system. This consideration ponders if this urban groundwater might be used as safe drinking-water because urban aquifers contain a vast array of pollutants such as pharmaceuticals.This work investigated the occurrence and fate of more than 100 pharmaceuticals in the shallow aquifer of the Besòs Delta River, which main contamination source is a polluted river that receives discharges from wastewater treatment plants. To this end, river and groundwater samples were collected from February to May 2021 for the analysis of pharmaceuticals using a solid-phase extraction and high pressure liquid chromatography coupled to high resolution mass spectrometric methodology (HPLC-HRMS). Preliminary results showed that, in more than 70% of the samples, several pharmaceuticals such as anticonvulsants, antihypertensives, antibiotics, and antivirals were detected. More precisely, 38 substances were detected in all river samples and 15 were ubiquitous in groundwater samples. The range of concentrations for all the compounds was between 2 ng/L and up to 880 ng/L. Moreover, the behavior of the compounds along the bank filtration until reach the pumping site, close to the parking lot, suggested that the natural attenuation of the pharmaceuticals likely to adsorption or oxidation-reduction processes occurred, as groundwater sampling points located close to the river presented the highest concentrations for the detected substances. This observation allows inferring that the pumped urban groundwater could be used for different purposes including drinking water but further studies are required to quantify the coupled processes that control their fate in urban aquifers.

In this work, the Regions of Interest-Multivariate Curve Resolution (ROIMCR) method is proposed for the analysis of non-target metabolomics data. Samples from marine mussels (Mytilus galloprovincialis) exposed to a sublethal concentration (10 μg/L) of sulfamethoxazole (SMX) during 4 days in different seasonal conditions (summer and winter) were analyzed by High-Performance Liquid Chromatography - High-Resolution Mass Spectrometry (HPLC-HRMS) to study the effect of their exposure to SMX and the different seasonal conditions. The Regions of Interest (ROI) procedure has been applied for data filtering, compression, preprocessing and storage steps. Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) is then applied to the previously MS ROI preprocessed data sets to resolve the elution profiles and spectral fingerprints of the chemical constituents of the analyzed samples. The peak areas of the elution profiles of the chemical constituents resolved by the combined ROIMCR procedure were analyzed by Principal Component Analysis (PCA) and samples were clustered according to their experimental seasonal and SMX exposure. The effects of the two investigated factors and of their interaction on the concentrations of the metabolites were statistically assessed by ANOVA simultaneous component analysis (ASCA). Both types of analyses, PCA clustering and ASCA, confirmed that the seasonal conditions (summer versus winter) produced larger effects than those produced by the exposure to SMX and by the interaction of these two factors. The concentration changes of 16 identified endogenous metabolites were validated individually using a Wilcoxon statistical test, which confirmed the presence of significant disturbances in the levels of some of these metabolites (free fatty acids, amino acids and nucleic acids), and indicated the possible alteration of six different biological pathways, affected by the investigated seasonal and SMX exposure factors., This work has been supported by the grant CEX2018-000794-S funded by MCIN/AEI/10.13039/501100011033 (Project ID2019 -105732 GB/AEI/10.13039/501100011033 and project PLAS-MED (CTM2017-89701-C3-2-R)). Carlos Pérez-López acknowledges the predoctoral scholarship FPI 2019–090182 included in the Grant CEX2018-000794-S funded by MCIN/AEI/10.13039/501100011033.

This research presents the occurrence and fate of 121 contaminants of emerging concern (CECs) in an urban aquifer polluted by river recharge through a data-base modelling. Afterwards, risk quotients (RQs) are computed to determine the risk posed by CECs to human health. To this end, groundwater and river water samples were collected in four campaigns conducted from February to May 2021. Results show that 46 CECs are ubiquitous in groundwater and their concentrations vary several orders of magnitude, ranging from below the limit of quantification to 44.5·103 ng/L for iopamidol. Transformation products (TPs) are usually detected at lower concentrations than those of the parent substances but there are some exceptions (i.e., fipronil sulphide, fipronil sulfone and O-desmethylvenlafaxine). River concentrations are higher than those detected in groundwater for some CECs, indicating the occurrence of natural attenuation processes when river water infiltrates the aquifer. A data-based advection-reaction modelling is proposed and tested for ca. 40 substances with detection frequencies higher than 90%. It provides useful quantitative information regarding the dynamic behaviour of the variables monitored, expressed in terms of characteristic length, entropy and synchronized state contribution. Finally, risk quotients (RQs) are used to assess the human health risk posed by the ubiquitous CECs in groundwater. Most CECs do not pose any risk to the different life stages considered, as the RQs evaluated are lower than 0.01. However, the pharmaceuticals valsartan and its TP valsartan acid show RQs higher than 1, indicating that these substances might be harmful to human beings., This research has been supported through the grant CEX2018-000794-S funded by MCIN/AEI/10.13039/501100011033 and the UrbanWat project (JPI-JC-2018_16) from the “Agencia Estatal de Investigación” from the Spanish Ministry of Science and Innovation.

As a key component of mountain ecosystems, high-mountain lakes are recognized indicators of global change. In the analysis of the effects induced by local or global human activities, microplastic (MP) pollution is of critical environmental concern for mountain ecosystem compartments and for high-mountain lakes in particular. This minireview reports on current knowledge of MP occurrence, source, distribution, and characteristics in high-mountain lake ecosystems. The literature search returned only nine studies mainly from the Tibet plateau (China). Generally, the two most often investigated compartments were water and sediment, followed by snow and fish. Plastic particles were found as fragments and fibers of polypropylene and polyethylene, which are primarily utilized in food packaging and supplies brought by tourists and then discarded on site. Tourism and atmospheric long-range transport from lowlands were identified as the main sources of MP pollution. Precipitation events (snow and rain) were reported as key events in MP deposition and fallout. Further studies are needed to better understand the effects of MP pollution on aquatic food webs and ecosystem resources (e.g., drinking water) in these key ecosystems.

The longitudinal structure of the environmental and phytoplankton variables was investigated in the Ebro River (NE Spain), which is heavily affected by water abstraction and regulation. A first exploration indicated that the phytoplankton community did not resist the impact of reservoirs and barely recovered downstream of them. The spatial analysis showed that the responses of the phytoplankton and environmental variables were not uniform. The two set of variables revealed spatial variability discontinuities and river fragmentation upstream and downstream from the reservoirs. Reservoirs caused the replacement of spatially heterogeneous habitats by homogeneous spatially distributed water bodies, these new environmental conditions downstream benefiting the opportunist and cosmopolitan algal taxa. The application of a spatial auto-regression model to algal biomass (chlorophyll-a) permitted to capture the relevance and contribution of extra-local influences in the river ecosystem.

Temporary rivers become dependent on wastewater effluent for base flows, which severely impacts river ecosystems through exposure to elevated levels of nutrients, dissolved organic matter, and organic micropollutants. However, biodegradation processes occurring in these rivers can be enhanced by wastewater bacteria/biofilms. Here, we evaluated the attenuation of pharmaceuticals and their human metabolites performing retrospective analysis of 120 compounds (drugs, their metabolites and transformation products) in mesocosm channels loaded with wastewater effluents twice a week for a period of 31 days. Eighteen human metabolites and seven biotransformation products were identified with high level of confidence. Compounds were classified into five categories. Type-A: recalcitrant drugs and metabolites (diclofenac, carbamazepine and venlafaxine); Type-B: degradable drugs forming transformation products (TPs) (atenolol, sitagliptin, and valsartan); Type-C: drugs for which no known human metabolites or TPs were detected (atorvastatin, azithromycin, citalopram, clarithromycin, diltiazem, eprosartan, fluconazole, ketoprofen, lamotrigine, lormetazepam, metformin, telmisartan, and trimethoprim); Type-D: recalcitrant drug metabolites (4-hydroxy omeprazole sulfide, erythro/threo-hydrobupropion, and zolpidem carboxylic acid); Type-E: unstable metabolites whose parent drug was not detectable (norcocaine, benzolylecgonine, and erythromycin A enol ether). Noteworthy was the valsartan acid formation from valsartan with transient formation of TP-336., This study has been financially supported by the EU through the PRIMA project (INWAT 201980E121). This work was supported by the Spanish Ministry of Science and Innovation (Project CEX2018-000794-S). The authors also acknowledge SCIEX for providing the loan instrument LC/HRMS QTOF X500R. The EU is not liable for any use that may be made of the information contained therein.

There is a worldwide growing use of chemicals by our developed, industrialized, and technological society. More than 100,000 chemical substances are thus commonly used both by industry and households. Depending on the amount produced, physical-chemical properties, and mode of use, many of them may reach the environment and, notably, the aquatic receiving systems. This may result in undesirable and harmful side-effects on both the human and the ecosystem's health. Mediterranean rivers are largely different from Northern and Central European rivers in terms of hydrological regime, climate conditions (e.g. air temperature, solar irradiation, precipitation), and socio-economics (e.g. land use, tourism, crop types, etc.), with all these factors leading to differences in the relative importance of the environmental stressors, in the classes and levels of the pollutants found and their environmental fate. Furthermore, water scarcity might be critical in affecting water pollution because of the lowered dilution capacity of chemicals. This work provides raw chemical data from different families of microcontaminants identified in three selected Mediterranean rivers (the Sava, Evrotas, and Adige) collected during two sampling campaigns conducted in 2014 and 2015 in three different matrices, namely, water, sediments, and biota (fish). More than 200 organic micropollutants were analyzed, including relevant groups like pharmaceuticals, personal care products, perfluorinated compounds, pesticides, pyrethroid insecticides, flame retardants, and persistent organic pollutants. Data obtained were summarized with some basic statistics for all compound families and matrices analyzed. Observed occurrence and spatial patterns were interpreted both in terms of compound physical-chemical properties and local environmental pressures. Finally, their spatial distribution was examined and their ecotoxicological risk in the water phase was assessed. This allowed locating, at each basin, the most polluted sites (“hot spots”) and identifying the respective river basin specific pollutants (RBSPs), prioritizing them in terms of the potential ecotoxicological risk posed to the aquatic ecosystems., This work has been supported by the European Communities EU 7th Framework Programme Funding under Grant agreement no. 603629-ENV-2013-6.2.1-Globaqua and partly by the Generalitat de Catalunya (Consolidate Research Group 2017-SGR-01404) and by the Spanish Ministry of Science, Innovation and Universities (Projects CEX2018-000794-S and IBERAQUA-NET RED2018-102737-T). Special thanks are due to all partners of the GLOBAQUA consortium and the peer review panel for ensuring quality results and a fruitful collaboration within the frame of the project.

The management of the anthropogenic water cycle must ensure the preservation of the quality and quantity of water resources and their careful allocation to the different uses. Protection of water resources requires the control of pollution sources that may deteriorate them. This is a challenging task in multi-stressed catchments. This work presents an approach that combines pesticide occurrence patterns and stable isotope analyses of nitrogen (δ15N-NO3−, δ15N-NH4+), oxygen (δ18O-NO3−), and boron (δ11B) to discriminate the origin of pesticides and nitrogen-pollution to tackle this challenge. The approach has been applied to a Mediterranean sub-catchment subject to a variety of natural and anthropogenic pressures. Combining the results from both analytical approaches in selected locations of the basin, the urban/industrial activity was identified as the main pressure on the quality of the surface water resources, and to a large extent also on the groundwater resources, although agriculture may play also an important role, mainly in terms of nitrate and ammonium pollution. Total pesticide concentrations in surface waters were one order of magnitude higher than in groundwaters and believed to originate mainly from soil and/or sediments desorption processes and urban and industrial use, as they were mainly associated with treated wastewaters. These findings were supported by the stable isotope results that pointed to an organic origin of nitrate in surface waters and most groundwater samples. Ammonium pollution observed in some aquifer locations is probably generated by nitrate reduction. Overall, no significant attenuation processes could be inferred for nitrate pollution. The approach presented here exemplifies the investigative monitoring envisioned in the Water Framework Directive., This work has received funding from the EU Horizon 2020 Research and Innovation Programme through the WaterProtect project (grant agreement No. 727450), the Spanish Ministry of Science and Innovation (Project CEX2018-000794-S), and the Generalitat de Catalunya (Consolidated Research Group 2017 SGR 01404-Water and Soil Quality Unit).

s applied to the results of ROIMCR and PLS-DA, compared with the results obtained considering only the unprocessed ROI data. Finally, when ROIMCR and PLS-DA results were analyzed using Proteome Discoverer, 281, 314, and 58 peptides were respectively identified at the three sampling sites in the case of ROIMCR, and 137, 123, and 31 peptides in the case of PLS-DA. From these peptides, a total number of 38 proteins are postulated to be present in the WWTP analyzed samples., This work has been supported by the Spanish Ministry of Science and Innovation (MICINN, Spain) (Projects CEX2018-000794-S, PID2019-105732GB and IBERAQUA-NET RED2018-102737-T). Carlos Pérez acknowledges the predoctoral Severo Ochoa FPI 2019-090182 scholarship from MICINN.

Wastewater discharges from cities and industries, especially megacities, and intensive livestock can be considered as main sources of pollution of our rivers and groundwater. Water pollution, therefore, constitutes a major threat to both aquatic ecosystems and human health. Here we address the influence of chemical pollution in waste- and drinking water, their associated potential toxicological effects, as well as, the available technologies for their removal. This opinion paper provides illustrative selected examples covering a broad range for both drinking water and wastewater treatment processes, for which a battery of toxicity tests is applied for their risk assessment. The examples are classified based on five hot topics: (i) Bioassays for toxicity evaluation, (ii) Toxicity of municipal wastewaters, (iii) Toxicity of pharmaceutical residues and hospital wastewaters, (iv) Toxicity of other non-urban effluent examples, and (v) Drinking water treatment processes and toxicity evaluation. 'Chemical analysis combined with batteries of bioassays covering a broad range of endpoints: cytotoxicity, endocrine disruption, genotoxicity, and other types seem to be good way to assess performance/efficiency of the water treatment processes when removing chemical contaminants.. Altogether, while recognizing that water treatment is a cornerstone for water pollution reduction, providing safe water for both human use and its return back to the aquatic environment will be undoubtedly enhanced with the use of ecotoxicity biomonitoring., This work has been financially supported by the Generalitat de Catalunya (Consolidated Research Group “2017 SGR 1404 - Water and Soil Quality Unit”) and by the Spanish Ministry of Science and Innovation (Project CEX2018-000794-S). The authors would like to thank the reviewers whose valuable comments helped us to improve the manuscript.

According to the European Union, half of the human population will live in cities, one of the main water spend zones and focus of pollutants it is expected by 2050. Considering the growing pressure on water resources whole world, a better knowledge for its management is needed to face this situation.URBANWAT is a project funded by the EU Commission under the call “Closing the Water Cycle Gap” of the Water JPI Strategic Research and Innovation Agenda. The goal of this project is to come up with an improvement of tools and criteria for groundwater management in urban areas to guarantee the urban water resources sustainability, identify their potential uses and their risks related to groundwater use from both environmental and human health perspectives by an integral approach developing novel technologies and methodologies.The project will involve a multidisciplinary approach integrating the research of the natural state of the hydrological cycle and pollutants identification (general chemistry, pollutants of emerging concern (CECs) and microorganisms, with emphasis in viruses).To achieve that goal, URBANWAT proposes to use innovative approaches based on liquid chromatography high resolution mass spectrometry (HLC-RMS) to: (1) detect differences in degradation in different anoxic conditions employing CECs as indicators of contamination and their transformation products (TPs) as indicators of degradability; (i2) analyse fate and transport of chosen contaminants in the soil-plant as a remediation system utilizing picked infrastructures; (3) understand the contaminants movement applying encapsulated DNA nanoparticles; (4) scout the presence of new and emergent viruses in groundwater samples employing viral metagenomics. Viral concentration methods from water samples will be also optimized in this research. To do so, column experiments will be carried out.URBANWAT project will focus on Barcelona city. In parallel, several studies will be carried out at full-scale in the demonstration facility called ‘WaterStreet’ at TUDelft. The expected results will help to provide novel and cost-efficient technologies for urban groundwater management with beneficial environmental, economic and societal impacts for the European Union (EU) facilitating their application worldwide.

The presence of pharmaceutically active compounds (PhACs) in the environment has gained increasing attention the past two decades. After administration, PhACs are excreted and thus delivered with wastewater to the wastewater treatment plants (WWTPs). WWTP effluents are usually discharged into receiving environment and, therefore, a high proportion of pollutants (including pharmaceuticals) can enter water bodies (surface or sea water), but also soils and eventually groundwater. The risk that pharmaceuticals can pose to the environment depends not only on compound concentration but also on its toxicity. In this chapter, different existing risk assessment approaches are presented, applied to the effluents from conventional WWTPs but also from alternative and advance wastewater treatment processes. Environmental Risk assessment (ERA) can also be applied as a tool to evaluate the removal efficiency of a wastewater treatment. Moreover, special focus is paid to assess the risk of pharmaceuticals in water reclamation practices such as crop irrigation. Finally, some research lines or topics that demand greater attention related to ERA in wastewater treatment are addressed such as toxicogenomics, antibiotic resistance, and evaluation of impact of chemical mixtures.

The topic of this book is dedicated to the analysis, fate, metabolism, effects, and remediation of pharmaceutically active compounds in water-soil-biota systems. While the majority of readers are likely to already have a broad understanding of potential entry points, flows, transformation pathways, and temporary and permanent sinks of drugs in the environment, the objectives of this first chapter are fourfold: (a) to provide a concise overview of the journey a drug takes from its inception at the laboratory bench to the desk of the reviewer at the regulatory agency; (b) to understand the biological and physiological processes a drug undergoes from administration to humans – or to the animal in case of veterinary medicines – to their excretion and ultimately discharge into wastes; (c) to describe the physico-chemical space small-molecule drugs reside in as this characteristic largely governs their later environmental fate; (d) to review their presence, fate, and metabolism in crops and plants determined using innovative analytical methods; as well as (e) to evaluate the effects and remediation of drugs in crops and biota.

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Degradation of solid polymers in the aquatic environment encompasses a variety of biotic and abiotic processes giving rise to heterogeneous patterns across the surface of the material, which cannot be investigated using conventional Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) that only renders an "average" picture of the sample. In that context, MALDI-TOF MS Imaging (MALDI MSI) provides a rapid and efficient tool to study 2D spatial changes occurred in the chemical composition of the polymer surface.Commercial polycaprolactone diol (average molecular weight of 1250 Da) was selected as test material because it had been previously known to be amenable to biological degradation. The test oligomer probe was incubated under aerobic and denitrifying conditions using synthetic water and denitrifying mixed liquor obtained from a wastewater treatment plant respectively. After ca. seven days of exposure the mass spectra obtained by MALDI MSI showed the occurrence of chemical modifications in the sample surface. Observed heterogeneity across the probe's surface indicated significant degradation and suggested the contribution of biotic processes. The results were investigated using different image processing tools. Major changes on the oligomer surface were observed when exposed to denitrifying conditions. © 2016., This study has been financially supported by the EU through the FP7 project GLOBAQUA (Grant agreement No 603629 ), and by the Generalitat de Catalunya (Consolidated Research Groups “2014 SGR 418—Water and Soil Quality Unit” and "2014 SGR 291—ICRA"). It reflects only the author's views. The Community is not liable for any use that may be made of the information contained therein. The authors are thankful to Dr. P. Eichhorn for his critical reading of the manuscript and the valuable comments provided and to Maria Casellas (Experimental Streams Facility, Catalan Institute for Water Research, Girona, Spain) for her technical help in the operation of the artificial stream. Appendix A

To meet the United Nations (UN) sustainable development goals and the European Union (EU) strategy for a non-toxic environment, water resources and ecosystems management require cost-efficient solutions for prevailing complex contamination and multiple stressor exposures. For the protection of water resources under global change conditions, specific research needs for prediction, monitoring, assessment and abatement of multiple stressors emerge with respect to maintaining human needs, biodiversity, and ecosystem services. Collaborative European research seems an ideal instrument to mobilize the required transdisciplinary scientific support and tackle the large-scale dimension and develop options required for implementation of European policies. Calls for research on minimizing society’s chemical footprints in the water–food–energy–security nexus are required. European research should be complemented with targeted national scientific funding to address specific transformation pathways and support the evaluation, demonstration and implementation of novel approaches on regional scales. The foreseeable pressure developments due to demographic, economic and climate changes require solution-oriented thinking, focusing on the assessment of sustainable abatement options and transformation pathways rather than on status evaluation. Stakeholder involvement is a key success factor in collaborative projects as it allows capturing added value, to address other levels of complexity, and find smarter solutions by synthesizing scientific evidence, integrating governance issues, and addressing transition pathways. This increases the chances of closing the value chain by implementing novel solutions. For the water quality topic, the interacting European collaborative projects SOLUTIONS, MARS and GLOBAQUA and the NORMAN network provide best practice examples for successful applied collaborative research including multi-stakeholder involvement. They provided innovative conceptual, modelling and instrumental options for future monitoring and management of chemical mixtures and multiple stressors in European water resources. Advancement of EU water framework directive-related policies has therefore become an option. © 2019, The Author(s)., Funding text #1 This article has been prepared as an outcome of the projects SOLUTIONS (European Union’s Seventh Framework Programme for research, technological development and demonstration under Grant Agreement No. 603437), GLOBAQUA (European Union’s Seventh Framework Programme for research, technological development and demonstration under Grant Agreement No. 603629) and MARS (European Union’s Seventh Framework Programme for research, technological development and demonstration under Grant Agreement No. 603378). Funding text #2 The authors declare that they have no competing interests. CIS Common Implementation Strategy DG Directorate General DPSIR Drivers–Pressure–State–Impacts–Response ECHA European Chemical Agency EEA European Environmental Agency EFSA European Food Safety Authority EU European Union ICPDR International Commission for the Protection of the Danube River ICPR International Commission for the Protection of the Rhine NGO Non-Governmental Organisation SDG sustainable development goals UN United Nations WFD Water Framework Directive

Environmental water quality monitoring aims to provide the data required for safeguarding the environment against adverse biological effects from multiple chemical contamination arising from anthropogenic diffuse emissions and point sources. Here, we integrate the experience of the international EU-funded project SOLUTIONS to shift the focus of water monitoring from a few legacy chemicals to complex chemical mixtures, and to identify relevant drivers of toxic effects. Monitoring serves a range of purposes, from control of chemical and ecological status compliance to safeguarding specific water uses, such as drinking water abstraction. Various water sampling techniques, chemical target, suspect and non-target analyses as well as an array of in vitro, in vivo and in situ bioanalytical methods were advanced to improve monitoring of water contamination. Major improvements for broader applicability include tailored sampling techniques, screening and identification techniques for a broader and more diverse set of chemicals, higher detection sensitivity, standardized protocols for chemical, toxicological, and ecological assessments combined with systematic evidence evaluation techniques. No single method or combination of methods is able to meet all divergent monitoring purposes. Current monitoring approaches tend to emphasize either targeted exposure or effect detection. Here, we argue that, irrespective of the specific purpose, assessment of monitoring results would benefit substantially from obtaining and linking information on the occurrence of both chemicals and potentially adverse biological effects. In this paper, we specify the information required to: (1) identify relevant contaminants, (2) assess the impact of contamination in aquatic ecosystems, or (3) quantify cause–effect relationships between contaminants and adverse effects. Specific strategies to link chemical and bioanalytical information are outlined for each of these distinct goals. These strategies have been developed and explored using case studies in the Danube and Rhine river basins as well as for rivers of the Iberian Peninsula. Current water quality assessment suffers from biases resulting from differences in approaches and associated uncertainty analyses. While exposure approaches tend to ignore data gaps (i.e., missing contaminants), effect-based approaches penalize data gaps with increased uncertainty factors. This integrated work suggests systematic ways to deal with mixture exposures and combined effects in a more balanced way, and thus provides guidance for future tailored environmental monitoring. © 2019, The Author(s)., Funding text #1 1 UFZ‑Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany. 2 Institute for Environmental Research, RWTH Aachen University, 52074 Aachen, Germany. 3 Office of Research and Development, Atlantic Ecology Division, United States Environmental Protection Agency, Narragansett, RI, USA. 4 Center for Applied Geoscience, Eberhard Karls Uni‑ versity Tübingen, 72074 Tübingen, Germany. 5 Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen, The Netherlands. 6 Environment and Climate Change Canada, Burlington, ON, Canada. 7 Sophus Bauditz Vej 19 B, 2800 Kgs. Lyngby, Denmark. 8 Water and Soil Quality Research Group, Institute of Environmental Assessment and Water Research (IDAEA‑ CSIC), Jordi Girona 18‑26, 08034 Barcelona, Spain. 9 Unité d’Ecotoxicologie Funding text #2 The SOLUTIONS Project is supported by the Seventh Framework Programme (FP7‑ENV‑2013) of the European Union under Grant Agreement No. 603437. G.A. Umbuzeiro thanks FAPESP Projects 2013/16956‑6 and 2015/24758‑5. We like to thank all partners for their continued efforts in making this project a success story. Funding text #3 The SOLUTIONS Project is supported by the Seventh Framework Programme (FP7‑ENV‑704 2013) of the European Union under Grant Agreement No. 603437. G.A. Umbuzeiro thanks 705 FAPESP Projects 2013/16956‑6 and 2015/24758‑5.

Urban wastewater inputs are a relevant pollution source to rivers, contributing a complex mixture of nutrients, organic matter and organic microcontaminants to these systems. Depending on their composition, WWTP effluents might perform either as enhancers (subsidizers) or inhibitors (stressors) of biological activities. In this study, we evaluated in which manner biofilms were affected by treated urban WWTP effluent, and how much they recovered after exposure was terminated. We used indoor artificial streams in a replicated regression design, which were operated for a total period of 56 days. During the first 33 days, artificial streams were fed with increasing concentration of treated effluents starting with non-contaminated water and ending with undiluted effluent. During the recovery phase, the artificial streams were fed with unpolluted water. Sewage effluents contained high concentrations of personal care products, pharmaceuticals, nutrients, and dissolved organic matter. Changes in community structure, biomass, and biofilm function were most pronounced in those biofilms exposed to 58% to 100% of WWTP effluent, moving from linear to quadratic or cubic response patterns. The return to initial conditions did not allow for complete biofilm recovery, but biofilms from the former medium diluted treatments were the most benefited (enhanced response), while those from the undiluted treatments showed higher stress (inhibited response). Our results indicated that the effects caused by WWTP effluent discharge on biofilm structure and function respond to the chemical pressure only in part, and that the biofilm dynamics (changes in community composition, increase in thickness) imprint particular response pathways over time. © 2019 Elsevier B.V., This study has been financially supported by the EU FP7 project GLOBAQUA [Grant Agreement No. 603629] and by the Generalitat de Catalunya [Consolidated Research Groups: 2017 SGR 01404−Water and Soil Quality Unit]. NM thanks SCIEX for generously providing the loaned instrument. Authors are grateful to Vicenç Acuña, Maria Casellas, Ferran Romero and Olatz Pereda for their support and advice during the experiment, and to Peter Eichhorn for his critical reading of the manuscript.

Current prioritisation procedures under the EU Water Framework Directive (WFD) do not account for risks from chemical mixtures. SOLUTIONS proposes a multiple-lines-of-evidence approach to tackle the problem effectively. The approach merges all available evidence from co-exposure modelling, chemical monitoring, effect-based monitoring, and ecological monitoring. Full implementation of the proposed methodology requires changes in the legal text in adaptation to scientific progress., The research leading to this Policy Brief was part of the SOLUTIONS project which received funding from the European Union Seventh Framework Programme (FP7-ENV-2013) under Grant Agreement No. 603437.

Recently, the Guardian published an article entitled “EU clean water laws under attack from industry lobbyists” by Arthur Neslen (https://www.theguardian.com/environment/2019/may/15/eu-clean-water-laws-under-attack-from-industry-lobbyists) expressing concerns regarding a roll back in European clean water regulations. As principal investigators of the large EU-funded project “SOLUTIONS for present and future emerging pollutants in land and water resources management”, we appreciate such an open debate on water quality protection in Europe, which we would like to enrich with conclusions from 5 years of extensive research and stakeholder dialogue within SOLUTIONS and other large EU projects., This article has been prepared as an outcome of the SOLUTIONS project (European Union’s Seventh Framework Programme for research, technological development and demonstration under Grant Agreement No. 603437).

Summary We studied the relative importance of environmental factors (river flow, nutrients, dissolved organic matter) and organic micro-pollutants [herbicides, insecticides, industrial organic compounds, personal care products, antibiotics and pharmaceuticals, (PhCs)] to the structure and function of epilithic biofilms under various hydrological conditions and land uses. Biofilms from four river basins in the Iberian Peninsula (Llobregat, Ebro, Jucar and Guadalquivir) were analysed in summer–autumn during a wet period and base-flow conditions. The sites experienced different levels of pollution. We used variance partitioning (Redundancy Detrended Analysis, RDA) to link environmental stressors to the structure and function of biofilms, which were assessed as diatom community composition, algal biomass, photosynthetic activity, bacterial density and extracellular phosphatase activity. RDAs showed that industrial organic compounds, herbicides and PhC products were the pollutants most strongly associated with measures of biofilm structure and function, whereas dissolved inorganic nitrogen, dissolved organic carbon and hydrological variability were the environmental factors most strongly associated with biofilm responses. Thicker biofilms developing during base flow were most affected by pollutants and nutrients. In contrast, thinner biofilms developing during periods of high river flow were less affected by chemicals.

Water scarcity is a serious environmental problem in many European regions, and will likely increase in the near future as a consequence of increased abstraction and climate change. Water scarcity exacerbates the effects of multiple stressors, and thus results in decreased water quality. It impacts river ecosystems, threatens the services they provide, and it will force managers and policy-makers to change their current practices. The EU-FP7 project GLOBAQUA aims at identifying the prevalence, interaction and linkages between stressors, and to assess their effects on the chemical and ecological status of freshwater ecosystems in order to improve water management practice and policies. GLOBAQUA assembles a multidisciplinary team of 21 European plus 2 non-European scientific institutions, as well as water authorities and river basin managers. The project includes experts in hydrology, chemistry, biology, geomorphology, modelling, socio-economics, governance science, knowledge brokerage, and policy advocacy. GLOBAQUA studies six river basins (Ebro, Adige, Sava, Evrotas, Anglian and Souss Massa) affected by water scarcity, and aims to answer the following questions: how does water scarcity interact with other existing stressors in the study river basins? How will these interactions change according to the different scenarios of future global change? Which will be the foreseeable consequences for river ecosystems? How will these in turn affect the services the ecosystems provide? How should management and policies be adapted to minimise the ecological, economic and societal consequences? These questions will be approached by combining data-mining, field- and laboratory-based research, and modelling. Here, we outline the general structure of the project and the activities to be conducted within the fourteen work-packages of GLOBAQUA., This work has been supported by the European Communities 7th Framework Programme Funding under Grant agreement no. 603629- ENV-2013-6.2.1-Globaqua and by the Generalitat de Catalunya (Consolidated Research Groups “2014 SGR 418 - Water and Soil Quality Unit” and 2014 SGR 291 - ICRA). Damià Barceló acknowledges support from the Visiting Professor Program of King Saud University. Special thanks are due to all partners of the GLOBAQUA consortium and the peer review panel for ensuring quality results and fruitful collaboration within the project.

Pollutants' dynamics in rivers flowing through industrial areas is linked to the entrainment and transport of contaminants attached to solid particles. The transport of sediment is mainly associated to high discharges and flood episodes, and these events constitute one of the main factors causing fluxes of buried pollutants in rivers. We performed a field study in the lower River Cinca (Ebro basin, Northeast Spain) to quantify the mobilization and transfer of several contaminants present in the river bed sediments. We focused on contaminants previously identified (PCBs, DDXs, PBDEs, HBCDs and PFRs) to occur in the river. River bed sediment samples were collected during low flows and a subsequent sampling campaign was used to capture sediment borne contaminants during a flood event. Water samples were taken at the same locations as the static sediment samples and used to determine the suspended sediment concentrations and the contaminants content (i.e. mass of contaminant per sediment mass unit) during the event. We estimated mass fluxes for both sediment and pollutants, and determined that sediment transport followed a clockwise hysteresis. This is typically observed in high flow events after dry summer periods. With sediments there was a large mobilization of PFRs (36 kg in 48 h in one of the main tributaries) and PCBs not previously observed in the static sediment. Observed contaminant load ranges during the two-day sampling campaign were: PCB (34–152 g), DDT (12–213 g), PBDE (50–1740 g), HBCD (0–2.2 g) and PFR (2410–35,895 g). An environmental risk assessment was carried out by comparing the pollutant concentrations found in the sediments with the Canadian quality guidelines (ISQC), showing a significant noncompliance for PCBs in dynamic sediments. Our results point out to the need of a regular assessment of the downstream transfer of the sediment-borne pollutants in drainage basins historically affected by intense industrial activities and associated contamination. The authors are grateful to the reviewers, whose valuable suggestion contributed to improving the present manuscript. This work was funded by the EU through the FP7 Project GLOBAQUA (grant agreement 603629) and the Redes de Excelencia project NET-SCARCE (CTM2015-69780-REDC). Authors acknowledge the support from the Economy and Knowledge Department of the Catalan Government through Consolidated Research Groups ICRA-ENV 2017 SGR 1124 and 2017 SGR 459 Fluvial Dynamics Research Group (RIUS). Authors thank Efren Muñoz who helped during the sampling campaign and provided turbidity data.

River ecosystems are subject to multiple stressors that affect their structure and functioning. Ecosystem structure refers to characteristics such as channel form, water quality or the composition of biological communities, whereas ecosystem functioning refers to processes such as metabolism, organic matter decomposition or secondary production. Structure and functioning respond in contrasting and complementary ways to environmental stressors. Moreover, assessing the response of ecosystem functioning to stressors is critical to understand the effects on the ecosystem services that produce direct benefits to humans. Yet, there is more information on structural than on functional parameters, and despite the many approaches available to measure river ecosystem processes, structural approaches are more widely used, especially in management. One reason for this discrepancy is the lack of synthetic studies analyzing river ecosystem functioning in a way that is useful for both scientists and managers. Here, we present a synthesis of key river ecosystem processes, which provides a description of the main characteristics of each process, including criteria guiding their measurement as well as their respective sensitivity to stressors. We also discuss the current limitations, potential improvements and future steps that the use of functional measures in rivers needs to face. © 2017 The Author(s), This work has been supported by the EU 7th Framework Programme Funding under Grant agreement no. 603629-ENV-2013-6.2.1-Globaqua. Additional financial support has been provided by the Basque Government under Grant agreement no. IT951-16. We also acknowledge financial support in terms of pre-doctoral and post-doctoral grants from the University of the Basque Country (O. Pereda, L. Solagaistua, I. Aristi, M. Arroita, A. Martínez) and from the Spanish Ministry of Economy and Competitiveness (S. Monroy).

Polymers are used in high amounts in a wide range of applications from biomedicine to industry. Because of the growing awareness of the increasing amounts of plastic wastes in the aquatic environment during recent years, the evaluation of their biodegradability deserves special attention. In the past, most efforts were dedicated to studying the biodegradation of polyesters in soil and compost, while very little research has been conducted on their fate in wastewater. Here, we assessed the ability of bacterial communities residing in the aerobic and denitrification tank from a wastewater treatment plant (WWTP) to degrade the polymeric ester polycaprolactone diol (PCLD; average molecular weight of 1250 Da). Following the incubation of the solid polymer in WWTP tanks, matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) was used to provide evidence for hydrolytic reactions and to study differences in the spatial degradation on the PCLD surface. It was demonstrated that regardless of the wastewater type, the chemical structure on the PCLD surface underwent modifications after 7 days of exposure. Apart from the parent PCLD peak series in MALDI-MSI mass spectra, the presence of a second oligomer series with mass peaks spaced by m/z 114 (as in PCLD) was observed. It was proposed to correspond to polycaprolactone (PCL) originating from the hydrolytic cleavage of the diethylene glycol from PCLD. Their ion masses were detected at m/z 104 below the PCLD peaks and their structures were proposed as PCL cyclized oligomers. Differences in the spatial distribution of low MW ions (, This study has been financially supported by the EU through the FP7 project GLOBAQUA (Grant Agreement No 603629), and by the Generalitat de Catalunya (Consolidated Research Groups “2014 SGR 418—Water and Soil Quality Unit” and 2014 SGR 291—ICRA). It reflects only the author’s views. The Community is not liable for any use that may be made of the information contained therein.

Human Health Risk Assessment (HHRA) and Environmental Risk Assessment (ERA) are well-established regulatory and scientific research fields that support regulatory decision-making in the European Union (EU) and are undergoing constant development. HHRA and ERA are crucial steps for reaching the objectives of Europe 2020, a strategy put forward by the Commission that sets out a vision of Europe’s social market economy for the twenty-first century. This chapter aims to describe the basic principles, the evolution and the future challenges of HHRA and ERA.

We used the trait composition of macroinvertebrate communities to identify the effects of pesticides and multiple stressors associated with urban land use at different sites of four rivers in Spain. Several physical and chemical stressors (high metal pollution, nutrients, elevated temperature and flow alterations) affected the urban sites. The occurrence of multiple stressors influenced aquatic assemblages at 50% of the sites. We hypothesized that the trait composition of macroinvertebrate assemblages would reflect the strategies that the assemblages used to cope with the respective environmental stressors. We used RLQ and fourth corner analysis to address the relationship between stressors and the trait composition of benthic macroinvertebrates. We found a statistically significant relationship between the trait composition and the exposure of assemblages to environmental stressors. The first RLQ dimension, which explained most of the variability, clearly separated sites according to the stressors. Urban-related stressors selected taxa that were mainly plurivoltine and fed on deposits. In contrast, pesticide impacted sites selected taxa with high levels of egg protection (better egg survival), indicating a potentially higher risk for egg mortality. Moreover, the trait diversity of assemblages at urban sites was low compared to that observed in pesticide impacted sites, suggesting the homogenization of assemblages in urban areas.

In the present work, a new method is proposed for the analysis of linear (lVMS) and cyclic methylsiloxanes (cVMS) in waters and sediments. The method is based on liquid-liquid extraction followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) using a triple quadrupole analyser (QqQ) working in selected reaction monitoring (SRM) mode. The instrumental parameters were optimized taking into account the interaction between different parameters and not only individual effects of variables. The method was validated yielding to convenient linearity and precision (RSD%16%), and limits of quantification in the low ng/L and ng/g orders for wastewaters and river sediments, respectively. To the author's knowledge it is the first time that GC-MS/MS is used for analyzing methylsiloxanes in waters and sediments. The method was applied to the analysis of surface water and river sediments from the Llobregat River and Riera de Rubí (Catalonia, NE of Spain) and the influents and effluents of 17 wastewater treatment plants (WWTPs). The main results of this study showed that methylsiloxanes were present in all the analyzed wastewater samples, with cVMS being found at higher concentrations. Decamethylcyclopentasiloxane (D5) was the predominant compound, the maximum concentration was 8915 ng/L in influent wastewater and treated effluents, and the median concentration was 273 ng/L. Although these samples were collected primarily for method development purposes and have limited statistical value for characterizing spatial and temporal patterns, they represent a significant contribution to dataset needed to verify exposure calculations in environmental risk assessment studies, for a significantly wide range of dimethylsiloxane analytes.

The occurrence of 73 representative pharmacologically active compounds (PhACs) was assessed in a sewage-impacted section of the Llobregat River (NE Catalonia, Spain). This Mediterranean river is characterized by flow rate fluctuations strongly influenced by seasonal rainfall. River flow variations increase the potential environmental risk posed by organic micro-pollutants as their concentrations may increase substantially under low flow conditions. Little is known about the transport behavior of emerging contaminants in surface waters once they are discharged from waste water treatment plants (WWTP) into rivers. This research aimed to study the presence and fate of emerging contaminants under different hydrological conditions by sampling two different sites along the river in different seasons. The highest levels of pharmaceuticals were determined during cold and dry periods. The impact of the flow changes on the concentration of the pharmaceuticals in the river was assessed with the relative sensitive coefficients. Due to expected dilution effects, the response of pharmaceuticals to river flow was negative. Only in a few cases, positive relationships between drug concentrations and flow were detected, suggesting an important role of other hydrological phenomena like sediment re-suspension as well as the source of pollutants. To evaluate the role of other factors influencing PhAC concentrations, a plug-flow model was applied to obtain disappearance constants "k" for a set of selected compounds. Erythromycin presented k values of -0.15 h(-1) in both sites being the compound more efficiently removed from the water column. The k values for ibuprofen, furosemide, enrofloxacin, enalapril, acetaminophen, diclofenac and Ketoprofen were between -0.04 and -0.10 h(-1) showing less disappearance than erythromycin in the water column. However, other compounds presented k values0.06, which suggested conservative behavior of these compounds in the water column. This study supports the reliability of the calculated k values for the disappearance of compounds in river waters.

Data from four Spanish basin management authorities were analysed. Chemical and biological data from four Spanish basin management authorities were analysed, focusing on three consecutive years. Aims were to i) determine the chemicals most likely responsible for the environmental toxicological risk in the four Spanish basins and ii) investigate the relationships between toxicological risk and biological status in these catchments. The toxicological risk of chemicals was evaluated using the toxic unit (TU) concept. With these data we considered if the potential risk properly reflects the risk to the community or, alternatively, if new criteria should be developed to improve risk assessment. Data study revealed inadequacies in processing and monitoring that should be improved (e.g., site coincidence for chemical and biological sampling). Analysis of the chemical data revealed high potential toxicological risk in the majority of sampling points, to which metals were the main contributors to this risk. However, clear relationships between biological quality and chemical risk were found only in one river. Further investigation of metal toxicity may be necessary, and future analyses are necessary to accurately estimate the risk to the environment., The present work was funded by the Spanish Ministry of Economics and Competitiveness through the Consolider-Ingenio 2010 Program (project Scarce CSD2009-00065). The authors would like to acknowledge the Confederacion Hidrografica del Ebro (C. Duran and V. Sanchez-Tello), Confederacion Hidrografica del Guadalquivir (V. Cifuentes), Agenda Andaluza del Agua, Agenda Catalana de l'Aigua (A Munne, L Tirapu) and Confederacion Hidrografica del Jucar (MA Pinon) which kindly provided the monitoring data. Nuria De Castro-Catala holds a predoctoral grant from the University of Barcelona. We would like to thank two anonymous reviewers for their suggestions which have improved this manuscript.

This review examines information generated over the past decade on the pollution of rivers in regions with a mediterranean-type climate (med-climate). Pollution has clearly increased in the last 100 years and is correlated with the development of industry, agriculture and human population. Important efforts have been made in some med-climate countries in order to characterise the chemical status of rivers. In addition, the number of chemical substances detectable in mediterranean-climate rivers (med-rivers), as well as the limits of detection, have improved from the development of better analytical methods. New substances detected in rivers are gaining attention. We discuss available knowledge regarding real and potential effects of pollutants on the biota and ecosystems in med-rivers, taking into account natural environmental characteristics of these rivers. The extreme seasonal conditions in med-rivers add to the potential risk because these characteristics can enhance pollutant effects. Efforts and policies to prevent or reduce pollution effects on med-rivers are linked to the knowledge about pollution pressures associated with the degree of economic development. Aquatic communities in med-rivers are more sensitive to pollutants because they are exposed to strong natural and human stressors.

Ecotoxicological risk assessment of chemical pollution in four Iberian river basins (Llobregat, Ebro, Júcar and Guadalquivir) was performed. The data set included more than 200 emerging and priority compounds measured at 77 sampling sites along four river basins studied. The toxic units (TU) approach was used to assess the risk of individual compounds and the concentration addition model (CA) to assess the site specific risk. Link between chemical pollution and aquatic macroinvertebrate communities in situ was examined by using four biological indexes; SPEAR ("Species at Risk Index") as the indicator of decline of sensitive species in relation to general organic (SPEARorganic) and pesticides (SPEARpesticides) pollution; and Shannon and Margalef biodiversity indexes. The results of the study suggested that organic chemicals posed the risk of acute effects at 42% of the sampling sites and the risk of chronic effects at all the sites. Metals posed the acute risk at 44% of the sites. The main drivers of the risk were mainly pesticides and metals. However, several emerging contaminants (e.g. the antidepressant drug sertraline and the disinfectant triclosan) were contributing to the chronic effects risk. When risk associated with metals and organic chemicals was compared, the latter dominated in 2010, mainly due to the presence of highly toxic pesticides, while metals did in 2011. Compounds that are not regulated on the European level were posing the risk of chronic effects at 23% of the sites. The decline of sensitive macroinvertebrate taxa expressed in terms of SPEAR index was correlated with the increase of toxic stress related to organic compounds Biodiversity indexes were negatively correlated with the metals and the urban land use type in the catchment This study has been financially supported by the EU through the FP7 project GLOBAQUA (Grant Agreement No. 603629), by the Spanish Ministry of Economy and Competitiveness [project Consolider-Ingenio 2010 SCARCE CSD2009-00065] and by the Generalitat de Catalunya (Consolidated Research Groups: 2014 SGR 418 – Water and Soil Quality Unit and 2014 SGR 291-ICRA)

Mediterranean rivers are characterized by a high flow variability, which is strongly influenced by the seasonal rainfall. When water scarcity periods occur, water flow, and dilution capacity of the river is reduced, increasing the potential environmental risk of pollutants. On the other hand, floods contribute to remobilization of pollutants from sediments. Contamination levels in Mediterranean rivers are frequently higher than in other European river basins, including pollution by pharmaceutical residues. Little attention has been paid to the transport behavior of emerging contaminants in surface waters once they are discharged from WWTP into a river. In this context, this work aimed to relate presence and fate of emerging contaminants with hydrological conditions of a typical Mediterranean River (Llobregat, NE Spain). River fresh water samples were collected twice a week over a period of 5 weeks at three sampling points. Sixty-six pharmaceutical compounds belonging to different therapeutical classes were analyzed by LC-MS/MS. Positive and negative correlations between the concentrations of the target analytes and hydrological variables like river flow and dissolved organic matter were observed pointing out the relevance of different hydrological phenomena like dilution effects or sediment re-suspension. Sensitivity calculations showed that the majority of compounds were sensitive to flow variations

Contamination of surface waters by pesticides continues to be the focus of concern for water authorities due to the growing evidence of their deleterious effects on aquatic life. In this context, the present work investigates the occurrence of 16 selected pesticides belonging to the classes of triazines, phenylureas, organophosphates, chloroacetanilides and thiocarbamates in surface waters from the Llobregat River (NE Spain) and some of its tributaries (Anoia and Rubí) and assesses their potential impact on the aquatic organisms by applying a recently developed index, the Short-term Pesticide Risk Index for the Surface Water System (PRISW-1), which takes into account the pesticides concentrations and their overall toxicity against three aquatic organisms (algae, Daphnia, and fish). Chemical analysis, performed by means of a fully automated method based on isotope dilution on-line solid phase extraction–liquid chromatography– electrospray–tandem mass spectrometry (on-line SPE–LC–ESI–MS/MS), revealed diuron and diazinon as the most ubiquitous and abundant compounds with levels up to 818 and 132 ng L 1, respectively. Total pesticide concentrations, which in only 1 out of 66 samples surpassed 500 ng L 1, were higher in the tributaries than in the river but their contribution in terms of mass-loads to the overall pesticide pollution of the Llobregat River was relatively small. Contamination increased downstream of the river and was clearly influenced by rainfall and hence river flow. Application of the PRISW-1 index indicated that, although pesticides levels fulfilled the European Union Environmental Quality Standards (EQS) for surface waters, the existing pesticide contamination poses a low to high ecotoxicological risk for aquatic organisms, that algae and macro-invertebrates are at higher risk than fish, and that the organophosphates diazinon and malathion and the phenylurea diuron are the major contributors to the overall toxicity and therefore the most problematic compounds.

In compliance with the requirements of the EU Water Framework Directive, monitoring of the ecological and chemical status of Catalan river basins (NE Spain) is carried out by the Catalan Water Agency. The large amount of data collected and the complex relationships among the environmental variables monitored often mislead data interpretation in terms of toxic impact, especially considering that even pollutants at very low concentrations might contribute to the total toxicity. The total dataset of chemical monitoring carried out between 2007 and 2008 (232 sampling stations and 60 pollutants) has been analyzed using sequential advanced modeling techniques. Data on concentrations of contaminants in water were pre-treated in order to calculate the bioavailable fraction, depending on substance properties and local environmental conditions. The resulting values were used to predict the potential impact of toxic substances in complex mixtures on aquatic biota and to identify hot spots. Exposure assessment with Species Sensitivity Distribution (SSD) and mixture toxicity rules were used to compute the multi-substances Potentially Affected Fraction (msPAF). The combined toxicity of the pollutants analyzed in the Catalan surface waters might potentially impact more than 50% of the species in 10% of the sites. In order to understand and visualize the spatial distribution of the toxic risk, Self Organising Map (SOM), based on the Kohonen's Artificial Neural Network (ANN) algorithm, was applied on the output data of these models. Principal Component Analysis (PCA) was performed on top of Neural Network results in order to identify main influential variables which account for the pollution trends. Finally, predicted toxic impacts on biota have been linked and correlated to field data on biological quality indexes using macroinvertebrate and diatom communities (IBMWP and IPS). The methodology presented could represent a suitable tool for water managers in environmental risk assessment and management.