Wastewater treatment plant (WWTP) effluents release complex mixtures of organic and inorganic micropollutants, including endocrine disrupting compounds, into receiving water bodies. These substances may cause adverse effects in aquatic communities as well as in ecosystem functions they provide. The aim of this study was to determine the potential impact of secondary treated wastewater released into a small Swiss stream on leaf litter decomposition based on feeding rates of the amphipod shredder Gammarus fossarum measured in situ. Additionally, endocrine disrupting effects downstream of the WWTP were investigated by measuring vitellogenin (vg) induction in male gammarids exposed in situ, as well as estrogen receptor activation using the Yeast Estrogen Screen (YES) involving passive sampler and grab water sample extracts. Extracts were also analysed for 424 organic micropollutants and selected transformation products. Gammarid feeding rate was significantly reduced 100, 200 and 400 m downstream of the WWTP effluent relative to the upstream site. While YES results showed significantly elevated estrogenicity at downstream sites, vg production in male gammarids was not induced. A laboratory experiment, in which gammarids were exposed to WWTP effluent, supported this observation. These results, hence, suggest that treated wastewater released into aquatic ecosystems impairs the ecosystem function of leaf litter decomposition. Vg levels in male gammarids measured by UPLC-MS/MS did, however, not alter.

Wastewater treatment plant effluents are important point sources of micropollutants. To assess how the discharge of treated wastewater affects the ecotoxicity of small to medium-sized streams we collected water samples up- and downstream of 24 wastewater treatment plants across the Swiss Plateau and the Jura regions of Switzerland. We investigated estrogenicity, inhibition of algal photosynthetic activity (photosystem II, PSII) and growth, and acetylcholinesterase (AChE) inhibition. At four sites, we measured feeding activity of amphipods (Gammarus fossarum) in situ as well as water flea (Ceriodaphnia dubia) reproduction in water samples. Ecotoxicological endpoints were compared with results from analyses of general water quality parameters as well as a target screening of a wide range of organic micropollutants with a focus on pesticides and pharmaceuticals using liquid chromatography high-resolution tandem mass spectrometry. Measured ecotoxicological effects in stream water varied substantially among sites: 17β-estradiol equivalent concentrations (EEQ_bio, indicating the degree of estrogenicity) were relatively low and ranged from 0.04 to 0.85 ng/L, never exceeding a proposed effect-based trigger (EBT) value of 0.88 ng/L. Diuron equivalent (DEQ_bio) concentrations (indicating the degree of photosystem II inhibition in algae) ranged from 2.4 to 1576 ng/L and exceeded the EBT value (70 ng/L) in one third of the rivers studied, sometimes even upstream of the WWTP. Parathion equivalent (PtEQ_bio) concentrations (indicating the degree of AChE inhibition) reached relatively high values (37 to 1278 ng/L) mostly exceeding the corresponding EBT (196 ng/L PtEQ_bio). Decreased feeding activity by amphipods or decreased water flea reproduction downstream compared to the upstream site was observed at one of four investigated sites only. Results of the combined algae assay (PSII inhibition) correlated best with results of chemical analysis for PSII inhibiting herbicides. Estrogenicity was partly and AChE inhibition strongly underestimated based on measured steroidal estrogens respectively organophosphate and carbamate insecticides. An impact of dissolved organic carbon on results of the AChE inhibition assay was obvious. For this assay more work is required to further explore the missing correlation of bioassay data with chemical analytical data. Overall, the discharge of WWTP effluent led to increased estrogenicity, PSII and AChE inhibition downstream, irrespective of upstream land use.

Effect-based methods including cell-based bioassays, reporter gene assays and whole-organism assays have been applied for decades in water quality monitoring and testing of enriched solid-phase extracts. There is no common EU-wide agreement on what level of bioassay response in water extracts is acceptable. At present, bioassay results are only benchmarked against each other but not against a consented measure of chemical water quality. The EU environmental quality standards (EQS) differentiate between acceptable and unacceptable surface water concentrations for individual chemicals but cannot capture the thousands of chemicals in water and their biological action as mixtures. We developed a method that reads across from existing EQS and includes additional mixture considerations with the goal that the derived effect-based trigger values (EBT) indicate acceptable risk for complex mixtures as they occur in surface water. Advantages and limitations of various approaches to read across from EQS are discussed and distilled to an algorithm that translates EQS into their corresponding bioanalytical equivalent concentrations (BEQ). The proposed EBT derivation method was applied to 48 in vitro bioassays with 32 of them having sufficient information to yield preliminary EBTs. To assess the practicability and robustness of the proposed approach, we compared the tentative EBTs with observed environmental effects. The proposed method only gives guidance on how to derive EBTs but does not propose final EBTs for implementation. The EBTs for some bioassays such as those for estrogenicity are already mature and could be implemented into regulation in the near future, while for others it will still take a few iterations until we can be confident of the power of the proposed EBTs to differentiate good from poor water quality with respect to chemical contamination.

Background: The European Commission Implementing Decision EU 2015/495 included three steroidal estrogens, namely 17α-ethinyl estradiol, 17β-estradiol, and estrone, in the so-called "watch list" of the EU Water Framework Directive (WFD). The monitoring of these compounds is difficult because the detection limits of the majority of the available analytical methods cannot achieve the very low target concentrations required to meet proposed environmental quality criteria. In 2014, a combined Science-Policy Interface/Chemical Monitoring of Emerging Pollutants project was launched to meet this monitoring challenge. The project involved 24 research organizations and environmental agencies from 12 different countries.
Methods: Sixteen surface water (SW) and 17 wastewater (WW) samples were collected across Europe and analysed using five in vitro effect-based and three chemical analytical methods. A general description of the project and data evaluation is provided by Könemann and colleagues in the companion publication 2018. In our study, we compared bioanalytical and chemical analytical results with regard to their application for aquatic status assessment. Therefore we considered the potential to predict population-relevant risks for aquatic organisms and the specificity and sensitivity of the various methods used in both approaches. Finally, we tested and discussed the applicability and relevance of previously suggested effect-based trigger values (EBT).
Results and discussion: Results of the risk assessment based on chemical analytical data correlated highly with estrogenic activities (expressed as 17β-estradiol equivalents (EEQ) determined using effect-based methods), demonstrating the ability of the bioassays to predict the mixture risk caused by steroidal estrogens. For about 15% of SW and 40% of WW samples detection limits of chemical-analytical methods were too high to allow a status assessment, while detection limits of all effect-based methods were below proposed EBT. This demonstrates that effect-based methods are suitable for status assessment of surface waters. The in vitro effect-based methods were quite specific for steroidal estrogens and highly sensitive, meaning they have a low probability to detect false positive or negative results. After testing of three alternative EBT proposals, we concluded to use preliminary 400 pg/L EEQ as screening EBT corresponding to the AA-EQS of E2. Further test specific refinements in the application of this value are not excluded.
Conclusions: We conclude that water quality assessment can progress from a purely analytical approach to effect-based monitoring, from single substance to known and unknown mixture assessment and from in vitro screening to population-relevant risk assessment. Despite a few limitations, effect-based in vitro methods are recommendable for monitoring steroidal estrogens under the WFD because they, a) are able to sensitively quantify the activity of steroidal estrogens in all surface and wastewater samples, b) are able to detect the combined effect of estrogen mixtures including unknown chemicals with estrogen receptor activating properties, c) allow an ecotoxicological status assessment using EBT to calculate risk quotients. This approach is similar to the risk ratio used in regulatory environmental risk assessments, but allows for an integrated mixture assessment.

Eine Beurteilung der Wasserqualität mit Biotests kann besonders dann sinnvoll sein, wenn biologisch aktive Stoffe und Stoffgemische vorhanden sind, die mit chemischer Analytik nur unvollständig erfasst werden können. Nun wurde im Rahmen des Modul-Stufen-Konzepts (MSK) ein Konzept zur Grobbeurteilung von abwasserbelasteten Fliessgewässern mit ökotoxikologischen Biotests entwickelt. Das Konzept stellt einen ersten Schritt zur integrativen Beurteilung der Wasserqualität dar.

The numbers of potential neurotoxicants in the environment are raising and pose a great risk for humans and the environment. Currently neurotoxicity assessment is mostly performed to predict and prevent harm to human populations. Despite all the efforts invested in the last years in developing novel in vitro or in silico test systems, in vivo tests with rodents are still the only accepted test for neurotoxicity risk assessment in Europe. Despite an increasing number of reports of species showing altered behaviour, neurotoxicity assessment for species in the environment is not required and therefore mostly not performed. Considering the increasing numbers of environmental contaminants with potential neurotoxic potential, eco-neurotoxicity should be also considered in risk assessment. In order to do so novel test systems are needed that can cope with species differences within ecosystems. In the field, online-biomonitoring systems using behavioural information could be used to detect neurotoxic effects and effect-directed analyses could be applied to identify the neurotoxicants causing the effect. Additionally, toxic pressure calculations in combination with mixture modelling could use environmental chemical monitoring data to predict adverse effects and prioritize pollutants for laboratory testing. Cheminformatics based on computational toxicological data from in vitro and in vivo studies could help to identify potential neurotoxicants. An array of in vitro assays covering different modes of action could be applied to screen compounds for neurotoxicity. The selection of in vitro assays could be guided by AOPs relevant for eco-neurotoxicity. In order to be able to perform risk assessment for eco-neurotoxicity, methods need to focus on the most sensitive species in an ecosystem. A test battery using species from different trophic levels might be the best approach. To implement eco-neurotoxicity assessment into European risk assessment, cheminformatics and in vitro screening tests could be used as first approach to identify eco-neurotoxic pollutants. In a second step, a small species test battery could be applied to assess the risks of ecosystems.

The efficiency of ozone-based processes under various conditions was studied for the treatment of a surface water (Lake Zürich water, Switzerland) spiked with 19 micropollutants (pharmaceuticals, pesticides, industrial chemical, X-ray contrast medium, sweetener) each at 1 μg L⁻¹. Two pilot-scale ozonation reactors (4–5 m³ h⁻¹), a 4-chamber reactor and a tubular reactor were investigated by either conventional ozonation and/or the advanced oxidation process (AOP) O₃/H₂O₂. The effects of selected operational parameters, such as ozone dose (0.5–3 mg L⁻¹) and H₂O₂ dose (O₃:H₂O₂ = 1:3–3:1 (mass ratio)), and selected water quality parameters, such as pH (6.5–8.5) and initial bromide concentration (15–200 μg L⁻¹), on micropollutant abatement and bromate formation were investigated. Under the studied conditions, compounds with high second-order rate constant k_O3>10⁴ M⁻¹ s⁻¹ for their reaction with ozone were well abated (>90%) even for the lowest ozone dose of 0.5 mg/L. Conversely, the abatement efficiency of sucralose, which only reacts with hydroxyl radicals (·OH), varied between 19 and 90%. Generally, the abatement efficiency increased with higher ozone doses and higher pH and lower bromide concentrations. H₂O₂ addition accelerated the ozone conversion to radical ·OH, which enables a faster abatement of ozone-resistant micropollutants. Interestingly, the abatement of micropollutants decreased with higher bromide concentrations during conventional ozonation due to competitive ozone-consuming reactions, except for lamotrigine, due to the suspected reaction of HOBr/OBr⁻ with the primary amine moieties. In addition to the abatement of micropollutants, the evolution of the two main transformation products (TPs) of hydrochlorothiazide (HCTZ) and tramadol (TRA), chlorothiazide (CTZ) and tramadol N-oxide (TRA-NOX) respectively, was assessed by chemical analysis and kinetic modelling. Both selected TPs were quickly formed initially to reach a maximum concentration followed by a decrease of their concentrations for longer contact times. For the studied conditions, the TP's concentrations at the outlet of the reactors ranged from 0 to 61% of the initial parent compound concentration, CTZ being a more persistent TP than TRA-NOX. Finally, it was demonstrated in both reactors that the formation of bromate (BrO₃−), a potentially carcinogenic oxidation by-product, could be controlled by H₂O₂ addition with a general improvement on micropollutant abatement. Post-treatment by granular activated carbon (GAC) filtration enabled the reduction of micropollutants and TPs concentrations but no changes in bromate were observed. The combined algae assays showed that water quality was significantly improved after oxidation and GAC post-treatment, driven by the abatement of the spiked pesticides (diuron and atrazine).

Der vorliegende Bericht fasst die Ergebnisse des Forschungsprojektes "Biologische Nachbehandlung von kommunalem Abwasser nach Ozonung", kurz "ReTREAT", zusammen. Das Projekt wurde durch das Bundesamtes für Umwelt (BAFU) im Rahmen der Umwelttechnologieförderung (UTF) finanziert. Zudem wurde das Projekt durch hohe Eigen- und Cash-Leistungen der Industriepartner finanziell und technisch unterstützt.
Ziel des Projektes war es Untersuchungen zur Leistungsfähigkeit und Effizienz verschiedener Verfahren der biologischen Nachbehandlung zur Reduktion der ökotoxikologischen Wirkung und zur Reduktion von Transformationsprodukten von ozonten, kommunalem Abwassers durchzuführen.

Im Rahmen des Projekts ReTREAT wurden verschiedene Verfahren auf deren Eignung als biologische Nachbehandlung nach einer Ozonung getestet. Der Fokus lag dabei – neben allgemeinen Reinigungseffekten – insbesondere auf dem Abbau von labilen Reaktionsprodukten sowie deren ökotoxikologischen Wirkungen.

Das Wichtigste in Kürze:

• Die Ozonung reduziert ökotoxikologische Effekte deutlich und verbessert die Abwasserqualität signifikant.
• Unmittelbar nach der Ozonung sind nur in Einzelfällen geringe „Auffälligkeiten“ aufgetreten (z.B. Mutagenität). Das ist nicht erstaunlich, da es sich bei der ARA Neugut um ein Abwasser handelt, das für eine Ozonung geeignet ist (d.h. durch die Ozonbehandlung wird grundsätzlich eine Verbesserung der Abwasserqualität erreicht, und es werden keine oder kaum problematische Oxidationsnebenprodukte gebildet).
• Die Abwasserqualität ist durch die Nachbehandlung nach Ozonung in nur wenigen Fällen noch weiter verbessert worden
• Da durch die Ozonung keine deutlichen messbaren toxischen Effekte (Toxizitätszunahme) aufgetreten sind, ist ein Vergleich der Nachbehandlungsverfahren anhand der verwendeten Biotests schwierig.
• Auf Grund der zusätzlichen Elimination von organischen Spurenstoffen (Kombination einer „vollen“ Ozonung mit einer Aktivkohlebehandlung) hat der Filter mit neuer granulierter Aktivkohle etwas besser abgeschnitten. Bezüglich der Elimination von toxischen labilen Reaktionsprodukten – die Hauptaufgabe einer Nachbehandlungsstufe – hat sich dieser GAK-Filter nicht von den anderen Nachbehandlungsverfahren unterschieden.

In vitro estrogen receptor transactivation assays (ERTAs) are increasingly used to measure the overall estrogenic activity of environmental water samples, which may serve as an indicator of exposure of fish or other aquatic organisms to (xeno)estrogens. Another potential area of application of ERTAs is to assist the monitoring of the potent steroids 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) under the Water Framework Directive (WFD) watch-list mechanism. Chemical analysis of E2 and EE2 is currently hampered by limits of quantification being mostly above the proposed annual average Environmental Quality Standards (AA-EQS) of 0.4 and 0.035 ng/L, respectively. Sensitive ERTAs could circumvent current detection challenges by measuring total estrogenic activity expressed as E2-equivalent (EEQ) concentrations.
However, the use of different ERTAs results in different EEQ concentrations for the same sample. Reasons for these differences are known, but it remains unclear how to use and interpret bioassay results in a harmonised way. The aim of this study was to compare the intra- and inter-day variability of EEQ measurements using five different ERTAs (YES, ERα-CALUX, MELN, T47D-KBluc and GeneBLAzer-ERα) with regard to their applicability as effect-based tools in environmental monitoring.
Environmentally relevant artificial mixtures of (xeno)estrogens were prepared to represent samples with higher (i.e. multiple times the AA-EQS for E2) or lower pollution levels (i.e. around the AA-EQS for E2). Mixtures were tested either directly or following solid phase extraction (SPE). The SPE step was included, as environmental samples typically require enrichment before analysis. Samples were analysed repeatedly to test intra-day and inter-day variability. Estrogenicity was quantified using the 10% effect level (PC10) of the positive control (E2) and expressed as EEQ concentrations.
The average coefficient of variation (CV) of EEQ concentrations for the five ERTAs and all samples was 32%. CV was lower for intra-day experiments (30%) compared to inter-day experiments (37%). Sample extraction using SPE did not lead to additional variability; the intra-day CV for SPE extracted samples was 28%. Of the five ERTAs, ERα-CALUX had the best precision and repeatability (overall CV of 13%).

Surface waters can contain a range of micropollutants from point sources, such as wastewater effluent, and diffuse sources, such as agriculture. Characterizing the source of micropollutants is important for reducing their burden and thus mitigating adverse effects on aquatic ecosystems. In this study, chemical analysis and bioanalysis were applied to assess the micropollutant burden during low flow conditions upstream and downstream of three wastewater treatment plants (WWTPs) discharging into small streams in the Swiss Plateau. The upstream sites had no input of wastewater effluent, allowing a direct comparison of the observed effects with and without the contribution of wastewater. Four hundred and five chemicals were analyzed, while the applied bioassays included activation of the aryl hydrocarbon receptor, activation of the androgen receptor, activation of the estrogen receptor, photosystem II inhibition, acetylcholinesterase inhibition and adaptive stress responses for oxidative stress, genotoxicity and inflammation, as well as assays indicative of estrogenic activity and developmental toxicity in zebrafish embryos. Chemical analysis and bioanalysis showed higher chemical concentrations and effects for the effluent samples, with the lowest chemical concentrations and effects in most assays for the upstream sites. Mixture toxicity modeling was applied to assess the contribution of detected chemicals to the observed effect. For most bioassays, very little of the observed effects could be explained by the detected chemicals, with the exception of photosystem II inhibition, where herbicides explained the majority of the effect. This emphasizes the importance of combining bioanalysis with chemical analysis to provide a more complete picture of the micropollutant burden. While the wastewater effluents had a significant contribution to micropollutant burden downstream, both chemical analysis and bioanalysis showed a relevant contribution of diffuse sources from upstream during low flow conditions, suggesting that upgrading WWTPs will not completely reduce the micropollutant burden, but further source control measures will be required.

Im Projekt EcoImpact wurden die ökotoxikologischen und ökologischen Effekte von Mikroverunreinigungen aus Kläranlagen auf aquatische Lebensgemeinschaften untersucht. Chemische und biologische Untersuchungen oberhalb und unterhalb von Kläranlagen deuten auf Effekte dieser Stoffe hin, die von physiologischen Antworten der Organismen bis hin zu veränderten Ökosystemfunktionen wie z. B. dem Laubabbau reichen. Gezielte Rinnenexperimente mit kontrollierter Wasserqualität unterstützen diese Befunde.

The overarching aim of this field study was to examine causal links between in-situ exposure to complex mixtures of micropollutants from wastewater treatment plants and effects on freshwater microbial communities in the receiving streams. To reach this goal, we assessed the toxicity of serial dilutions of micropollutant mixtures, extracted from deployed passive samplers at the discharge sites of four Swiss wastewater treatment plants, to in situ periphyton from upstream and downstream of the effluents. On the one hand, comparison of the sensitivities of upstream and downstream periphyton to the micropollutant mixtures indicated that algal and bacterial communities composing the periphyton displayed higher tolerance towards these micropollutants downstream than upstream. On the other hand, molecular analyses of the algal and bacterial structure showed a clear separation between upstream and downstream periphyton across the sites. This finding provides an additional line of evidence that micropollutants from the wastewater discharges were directly responsible for the change in the community structure at the sampling sites by eliminating the micropollutant-sensitive species and favouring the tolerant ones. What is more, the fold increase of algal and bacterial tolerance from upstream to downstream locations was variable among sampling sites and was strongly correlated to the intensity of contamination by micropollutants at the respective sites. Overall, our study highlights the sensitivity of the proposed approach to disentangle effects of micropollutant mixtures from other environmental factors occurring in the field and, thus, establishing a causal link between exposure and the observed ecological effects on freshwater microbial communities.

Endocrine-disrupting chemicals (EDCs) are man-made compounds interfering with hormone signaling. Omnipresent in the environment, they can cause adverse effects in a wide range of wildlife. Accordingly, Endocrine Disruption is one focal area of ecotoxicology. Because EDCs induce complex response patterns in vivo via a wide range of mechanisms of action, in vitro techniques have been developed to reduce and understand endocrine toxicity. In this review we revisit the evidence for endocrine disruption in diverse species and the underlying molecular mechanisms. Based on this, we examine the battery of in vitro bioassays currently in use in ecotoxicological research and discuss the following key questions. Why do we use in vitro techniques? What endpoints are we looking at? Which applications are we using in vitro bioassays for? How can we put in vitro data into a broader context? And finally, what is the practical relevance of in vitro data? In critically examining these questions, we review the current state-of-the-art of in vitro (eco)toxicology, highlight important limitations and challenges, and discuss emerging trends and future research needs.

The efficiency of wastewater ozonation for the abatement of three nitrogen-containing pharmaceuticals, two antihistamine drugs, cetirizine (CTR) and fexofenadine (FXF), and the diuretic drug, hydrochlorothiazide (HCTZ), was investigated. Species-specific second-order rate constants for the reactions of the molecular, protonated (CTR, FXF) or deprotonated (HCTZ) forms of these compounds with ozone were determined. All three compounds are very reactive with ozone (apparent second order rate constants at pH 7: k_O3,pH7 = 1.7·10⁵ M⁻¹s⁻¹, 8.5·10⁴ M⁻¹s⁻¹ and 9.0·10³ M⁻¹s⁻¹ for CTR, HCTZ and FXF, respectively). Transformation product (TP) structures were elucidated using liquid chromatography coupled with high-resolution tandem mass spectrometry, including isotope-labeled standards. For cetirizine and hydrochlorothiazide 8 TPs each and for fexofenadine 7 TPs were identified. The main TPs of cetirizine and fexofenadine are their respective N-oxides, whereas chlorothiazide forms to almost 100% from hydrochlorothiazide. In the bacteria bioluminescence assay the toxicity was slightly increased only during the ozonation of cetirizine at very high cetirizine concentrations. The main TPs detected in bench-scale experiments were also detected in full-scale ozonation of a municipal wastewater, for >90% elimination of the parent compounds.

Die Ozonung ist ein etabliertes Behandlungsverfahren, um Mikroverunreinigungen aus Abwasser zu entfernen. Da bei der Ozonung jedoch labile toxische Reaktionsprodukte entstehen können, ist eine biologische Nachbehandlung notwendig. Mithilfe von Biotests hat das Oekotoxzentrum verglichen, wie gut die Ozonung in Kombination mit verschiedenen Nachbehandlungsverfahren ökotoxikologische Effekte verringern kann.

La qualité des eaux est habituellement évaluée sur la base d'analyses chimiques en comparant les concentrations mesurées à des critères de qualité individuels déterminés en fonction des effets des substances isolées. Cette méthode ne peut cependant s'appliquer qu'aux polluants connus pour lesquels des données sont disponibles en qualité et en quantité suffisantes. Pour aller au-delà de cette limite, l'appréciation doit recourir à des méthodes intégratives comme les bioessais écotoxicologiques. Ces derniers permettent de déterminer la toxicité générale de l'eau ou de l'effluent ou de mesurer les effets de groupes de substances apparentées. Dans ce cadre, la qualité de l’eau de la Versoix concernant les perturbateurs endocriniens de type oestrogène a été évaluée en appliquant le bioessai ER-CALUX®. C’est un bioessai utilisant des cellules humaines très sensibles. En plus, la qualité d’eau concernant des inhibiteurs du photosystème II a été évalué par un teste algues combiné. Les concentrations des substances d’activité oestrogénique et des inhibiteurs du photosystème II ont été déterminées dans des échantillons de la rivière Versoix, ainsi que dans des échantil-lons de l’effluent de la STEP de Divonne. La qualité de l’eau a ensuite été jugée par un système en cinq classes. L'étude de l'activité oestrogénique et de l'inhibition du photosystème II a permis de mettre en évidence une influence de la STEP de Divonne sur la Versoix, le cours d'eau récepteur. En aval du point de rejet de l’effluent, les teneurs en équivalents 17β-oestradiol (EEQ) et en équivalents diuron (DEQ) mesurées avec les bioessais étaient en général plus élevées qu'en amont. Mais, cette augmentation était faible. Dans l'ensemble, la pollution par les substances d’activité oestrogénique et par les inhibiteurs du photosystème II peut être jugée peu significative en termes d'impacts. Les teneurs en EEQ et en DEQ dans la Versoix ne dépassaient jamais la valeur de 0.4 ng/L fixée pour le critère de qualité « chronique » (CQC) du 17β-oestradiol et la valeur de 20 ng/L fixée pour le CQC du diu-ron.

This report provides a brief review of the 20th annual meeting of the German Language Branch of the Society of Environmental Toxicology and Chemistry (SETAC GLB) held from September 7th to 10th 2015 at ETH (Swiss Technical University) in Zurich, Switzerland. The event was chaired by Inge Werner, Director of the Swiss Centre for Applied Ecotoxicology (Ecotox Centre) Eawag-EPFL, and organized by a team from Ecotox Centre, Eawag, Federal Office of the Environment, Federal Office of Agriculture, and Mesocosm GmbH (Germany). Over 200 delegates from academia, public agencies and private industry of Germany, Switzerland and Austria attended and discussed the current state of science and its application presented in 75 talks and 83 posters. In addition, three invited keynote speakers provided new insights into scientific knowledge 'brokering', and—as it was the International Year of Soil—the important role of healthy soil ecosystems. Awards were presented to young scientists for best oral and poster presentations, and for best 2014 master and doctoral theses. Program and abstracts of the meeting (mostly in German) are provided as Additional file 1.

The current deliverable summarizes the work conducted on the implementation of in vitro bioassays as new screening systems in water quality monitoring, starting with a description of the relatively broad bioassay panel as it was selected before evaluation of the water treatment technologies in the case studies. The case studies were conducted together with work area 1-3 partners. The case studies had a twofold aim: 1. To assess the performance of the novel water treatment technologies with bioassays, mainly focussing on removal of bioactivity. 2. Further assessment of the optimal application domain of the bioassays, selecting subpanels suitable for particular applications. This was done in a final evaluation using case study results as a main guidance. Finally, we placed these bioassays in an innovative novel testing framework as designed by Waternet (called SIMONI) to further promote dissemination and practical application of the DEMEAU bioassay panel in water utilities.

Auf der ARA Basel der ProRheno AG, die hauptsächlich kommunales Abwasser reinigt, wird aufgrund ihrer Grösse eine zusätzliche Stufe zur Elimination von Mikroverunreinigungen nötig sein. Während mehreren Monaten wurde in einer Pilotanlage untersucht, ob sich die Verfahren Zugabe von Pulveraktivkohle (PAK) und Ozonung grundsätzlich auf der ARA Basel eignen. Zusätzlich wurde die Reinigungsleistung der weitergehenden Abwasserbehandlung für kommunales Abwasser der ARA Basel getestet, das einen gewissen Anteil biologisch gereinigtes Industrieabwasser enthielt.

Introduction: Within the framework of the “Modular Stepwise Procedure” (MSP), standardized methods are being developed to evaluate and assess the status of rivers in Switzerland. It encompasses various aspects that influence habitat quality, including riverine structure, hydrology, biology, water chemistry and ecotoxicology. The MSP provides information which will form the basis for potential management measures to reduce impairments. The goal of the Ecotoxicology module is to develop a robust approach for routine assessment of water quality based on ecotoxicological bioassays. The concept includes sampling, sample processing, bioassays, and interpretation of results. The selected bioassays should be sensitive, effect-specific, easy to perform, cost-effective and easily interpretable. The present report describes an approach for a first tier evaluation (“Grobbeurteilung”) of water quality in wastewaterimpacted rivers based on ecotoxicological bioassays. Sampling and sample processing: It is recommended to collect composite samples over a minimum of 24 h or (if former is not possible) grab samples. These must be transported and stored at 0-5°C. Samples are generally processed using solid phase extraction (SPE). Bioassays for measuring water quality: This first tier evaluation is focused on two relevant substance groups: photosystem II (PSII) inhibiting and estrogenic substances. The biological effects of these two substance groups can be assessed using bioassays. An evaluation of water quality regarding PSII-inhibiting substances can be done using the combined algae assay with single-celled green algae (Pseudokirchneriella subcapitata). The photosystem II plays a central role in algae photosynthesis. If it is inhibited, the algae cannot grow. This assay is easy to perform and cost-effective, and it has provided accurate and robust results in numerous previous studies. Due to its robustness, the Yeast Estrogen Screen (YES), a bioassay using genetically modified yeast (Saccharomyces cerevisae), is well suited to assess estrogenicity in wastewater. For this assay, there are several versions, for which protocol drafts are submitted for standardisation by the International Organization for Standardization (ISO). At this time, for both assays, a definitive recommendation for a specific test cannot be given due to the pending ISO certification. We therefore describe versions of these tests, which have been validated and can be applied for a first tier evaluation. The combined algae assay can be conducted with native as well as SPE concentrated samples. Samples to be tested by YES usually have to be SPE concentrated, as the estrogen concentrations in wastewater are often too low to be detectable in native samples. Water quality assessment: An evaluation of the measured values is performed by applying a class based evaluation system based on the MSP methods. For this purpose, available suggestions for chronic environmental quality standards of estrogenic and PSII-inhibiting substances are used. Conclusions: The approach presented here is intended for the evaluation of wastewater impacted surface waters and represents a first step towards an integrated water quality assessment. The suggested bioassays complement the generally used methods, which are based on single substance assessment, and make it possible to assess a broad spectrum of organic trace substances in an integrative way.

The assessment of water quality based on ecotoxicological bioassays requires the availability of sensitive, robust, standardized and preferably cost-effective methods. As part of the module ecotoxicology within the framework of the Swiss modular stepwise procedure, we conducted an extensive literature search, consulted a group of experts and conducted an expert workshop to identify bioassays with such characteristics. Our aim was the identification of the most relevant biological modes of action of environmental pollutants, and of bioassays to measure such effects. This report summarizes the results and provides recommendations for those bioassays well suited to evaluate water quality, but also shows were further action is required. The literature search showed that, so far, mainly in vivo bioassays have been applied in regulation for the assessment of general toxicity. Application of in vitro bioassays to detect specific effects is scarce. Only one in vitro bioassay for the detection of genotoxicity has been included in the German legislation. In Sweden, an in vitro bioassay to detect estrogenic activity is used. In contrast, a multitude of in vitro, in vivo, and in situ bioassays are used in research to evaluate wastewater effluents or surface waters.

Toxizitätstests auf der Basis von Zellkulturen oder Organismen eignen sich, um die Reinigungsleistung einer Kläranlage in Bezug auf Mikroverunreinigungen zu überprüfen. Damit lassen sich im Routineeinsatz nicht nur Einzelstoffe, sondern auch Gemische ökotoxikologisch beurteilen, wie im Rahmen des Projektes «Strategie Micropoll» des Bundesamtes für Umwelt gezeigt werden konnte.

In the context of the European Water Framework Directive (WFD) it is fully recognized that pharmaceuticals can represent a relevant issue for the achievement of the good chemical and ecological status of European surface water bodies. The recent European Directive on the review of priority substances in surface water bodies has included three pharmaceuticals of widespread use (diclofenac, 17α-ethinylestradiol (EE2), 17β-estradiol (E2)) in the European monitoring list, the so-called watch list. Endocrine active pharmaceuticals such as EE2 and E2 (also occurring as natural hormone) can cause adverse effects on aquatic ecosystems at very low levels. However, monitoring of these pharmaceuticals within the watch list mechanism of the WFD and national monitoring programs can be difficult because of detection problems of most routine analytical methods. With proposed annual average Environmental Quality Standards (AA-EQS) of 0.035 ng/L and 0.4 ng/L, respectively, the estrogenic pharmaceutical EE2 and the natural hormone E2 are among those substances. Sensitive in vitro bioassays could reduce the current detection problems by measuring the estrogenic activity of environmental samples. In a short review article the application of this approach to screen and assess the risks of endocrine active pharmaceuticals with a focus on estrogenic pharmaceuticals in environmental waters is discussed.

Oxidative treatment is one of the options to eliminate emerging pollutants (EPs) from drinking water or wastewater. For drinking water treatment, the ozonation technology is already implemented at many sites all around the world, so far mostly for disinfection purposes. However, in some countries such as the Netherlands surface water contains relatively high bromide concentrations, which leads upon reaction with ozone to the formation of bromate, a suspe cted carcinogen. In such a case, UV/H₂O₂ treatment is considered a useful alternative, despite the fact that energy requirements are substantially higher compared to treatment with ozone or O₃ /H₂O₂. Only in recent years, the oxidative treatment of wastewat er has been investigated to not only protect our water resources, but also the ecosystem from pollution with chemicals used in our daily life. In Switzerland, the first permanent full scale plant with ozonat ion, WWTP Neugut in Dübendorf, is running since March 2014 . Its performance was investigated i n detail in the DEMEAU project. The goal of this paper is to present a decision basis for the implementation of oxidation technologies to eliminate EPs. Depending on the composition of the water in different European regions, one or the other treatment is recommended. The different parameters that influence the efficiency of oxidation and the formation of by - products are discussed. A decision tool is presented to decide if oxidative treatment of wastewater is rec ommended and under which circumstances the treatment of drinking water with ozone, O₃/H₂O₂ , or UV/H₂O₂ may be the treatment of choice.

Bioanalytical tools hold great promise in being introduced and integrated in current water monitoring strategies which mainly utilize chemical analytics at present. The latter focuses mainly on compound identification irrespective of the biological effect. Bioassays are suitable to assess hazards even of complex mixtures of pollutants with limited possibilities of chemical identification and are therefore expected to be highly complementary to modern chemical analytical methods. Smart combinations of chemical- and biological analytics therefore can lead to reduced uncertainty in safety assessments at lower costs. This document is aimed at the selection of a minimal panel of in vitro bioassays for cost effective comprehensive toxicity screening for the evaluation of drinking water quality. After determination of selection criteria for such assays and the most relevant toxicological effects of concern, the appropriate bioassay panel is identified to detect human health effects of emerging (micro)pollutants. The project has started with identifying the most relevant toxicological endpoints or modes of action that will be used as a starting point for the effect-based assessment of water quality, in particular for human health. A set of selection criteria has been defined to assess the effect-based assays whether they are suitable to detect activity towards the selected endpoints. Using the selection criteria we established a state-of-the art bioassay panel for comprehensive screening of the water cycle and including drinking water safety assessment.

The Water Framework Directive (WFD), 2000/60/EC, requires an integrated approach to the monitoring and assessment of the quality of surface water bodies. The chemical status assessment is based on compliance with legally binding Environmental Quality Standards (EQSs) for selected chemical pollutants (priority substances) of EU-wide concern. In the context of the mandate for the period 2010 to 2012 of the subgroup Chemical Monitoring and Emerging Pollutants (CMEP) under the Common Implementation Strategy (CIS) for the WFD, a specific task was established for the elaboration of a technical report on aquatic effect-based monitoring tools. The activity was chaired by Sweden and co-chaired by Italy and progressively involved several Member States and stakeholders in an EU-wide drafting group. The main aim of this technical report was to identify potential effect-based tools (e.g. biomarkers and bioassays) that could be used in the context of the different monitoring programmes (surveillance, operational and investigative) linking chemical and ecological status assessment. The present paper summarizes the major technical contents and findings of the report.

This project report summarizes work conducted in work package 11. Along with the deliverable 11.1 and milestone report 11 it covers the tasks from work package 11 as formulated in the Description of Work (DoW). The content of the different sections is interrelated, but each section is organized as an independent part. Title of this report differs from DoW because recommendations for optimum design and operation will be handled in the deliverable 12.2. The sections in this report cover various topics and each section can be found as a stand-alone report in the DEMEAU tool box (http://demeaufp7. eu/toolbox/) for download. Detailed summaries can be found for each section separately.

In vitro bioassays are techniques that promise great steps forward in drinking water security. The technique is based on engineered cells that show a reaction if the sample they are exposed to contains toxins. A wide range of in vitro bioassays has been applied for water quality assessment.

To protect façade renders from growth of bacteria, fungi and algae, biocides can be added to a render before it is applied onto a façade. A comprehensive protection can be achieved by combining several biocides. During rain events and over time, biocides will gradually leach out and thus have the potential to affect soil or aquatic ecosystems. In this project the leaching behaviour of biocides from three render formulations was evaluated: one render containing free, another render containing encapsulated biocides (Terbutryn, OIT, DCOIT) and a control render without biocides. The renders were applied onto extruded polystyrene panels and water samples were generated over nine immersion cycles of the panels in accordance with standard EN 16105. Concentrations of the biocides were measured using LC-MS. The toxicity of the first and ninth immersion samples was determined using bioassays. Toxicity to aquatic organisms was evaluated by assessing inhibition of photosynthesis and algal growth rate, inhibition of bacterial luminescence and inhibition of daphnid population growth. Toxicity to soil organism was assessed by determining avoidance behaviour of worms and reproductive output in springtails. For aquatic effects, the toxic potential of a sample was expressed as a 50% effect concentration (EC50) based on sample dilution factors (DF; the sample volume and volume of culture medium used for dilution divided by the sample volume). Encapsulation reduced the leaching of Terbutryn, OIT, and DCOIT 4-, 17-, and 25-fold compared to free biocides used in the same amounts in the render. Generally, the toxicity of water from render containing encapsulated biocides was always lower than that of render with free biocides and toxicity was considerably lower for the ninth immersion day compared to the first immersion day sample for both free and encapsulated samples. Thus, on the first immersion day, the free biocide sample had a DF EC50 of 630, and the encapsulated biocides sample a DF EC50 of 130. On the ninth immersion cycle, the free biocide sample had a DF EC50 of 120 and encapsulated biocide sample a DF EC50 of 30. Toxicity therefore decreased 4- to 5-fold over the nine immersion cycles for both free and encapsulated samples. For the aquatic organisms, inhibition of photosynthesis was the most sensitive endpoint, followed by algal growth rate, bacterial bioluminescence and daphnid reproduction. At all tested sample concentrations, none of the samples with biocides caused effects on soil organisms. No toxicity was observed in control immersion samples without biocides in render although TOC (total organic carbon) reached up 250 mg/L. Results from bioassays matched quite well with expected bioassay responses based on chemical analysis and the toxicity of the individual biocides. It could be concluded, that the toxicity of given concentrations on algae is explained by Terbutryn whereas the toxicity on bacteria and daphnids is caused by DCOIT and OIT. The results thus indicated that other components in the render did not add to the toxicity of the individual biocides. Furthermore, the good agreement between the chemical analysis and the expected and observed biological effects indicates that the data are robust and that an assessment of the biological effect data using DF EC50 is a suitable evaluation tool for e.g. biocides released from treated articles or substances from construction products. Overall, the approach combining a standard leaching test with standard bioassays is very promising to evaluate the ecotoxicity of biocides leached out from façade renders.

Erweiterte Behandlungsmethoden in Abwasserreinigungsanlagen (ARA) können mit Hilfe von Biotests bewertet werden – dies haben Untersuchungen im Projekt „Strategie Micropoll“ des Schweizerischen Bundesamtes für Umwelt (BAFU) gezeigt. Im Rahmen einer Pilotstudie der ProRheno AG wurde untersucht ob sich auf der ARA Basel eine Behandlung mit Pulverak-tivkohle oder eine Ozonung gefolgt von einer biologischen Behandlungsstufe (Wirbelbett) besser als zusätzliche Reinigungsstufe eignet. Beide Methoden können schädliche Mikroverunreinigungen, die durch die biologische Reinigung nicht komplett entfernt wurden, weiter reduzieren.

Purpose. In order to assess possible adverse effects originating from pulp deposits in a Swiss lake, a sediment quality triad approach was applied with chemical, ecotoxicological and ecological assessment methods.
Materials and methods. To obtain an integrative picture of the potential ecotoxicological effects on organisms of different trophic levels, four test procedures were applied. The acute effects of pulp deposit pore water on a decomposer, the amphipod Gammarus fossarum, were monitored. Chronic toxicity of the pore water was evaluated on primary producers via a growth inhibition test with unicellular green algae (Pseudokirchneriella subcapitata) and on secondary consumers in a reproduction test with the water flea Ceriodaphnia dubia. To evaluate the effects of the pulp deposit on sediment inhabitants, a whole-life-cycle test with the non-biting midge Chironomus riparius was undertaken. Chemical assessment included dissolved organic carbon, extractable organic halogenic compounds, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and heavy metals. The composition of the macrozoobenthos community was analysed in order to assess the ecological effects.
Results and discussion. G. fossarum displayed increased locomotor activity at 12.5% but not at 25% sample concentration during a short-time exposure of 20 h. Chronic effects compromised the reproduction and growth of C. dubia (lowest observed effect concentration, 12.5% sample concentration) with zero population growth in 100% pulp deposit pore water. In 100% pulp deposit, C. riparius exhibited increased mortality at 10 and 17 days after oviposition. Pulp deposits of 50% and 100% concentration caused a significantly lower emergence compared with the reference treatments (lake sediment and quartz sand). Additionally, the locomotor activity of chironomids decreased significantly in 25–100% pulp deposit. No chronic effects of pulp deposit pore water on algae photosynthesis and growth could be detected. The bioassay results were in accordance with an elevated content of PAHs, PCBs and metals in the pulp deposit. Significantly more organisms known to be tolerant to organic pollution were present within the macrozoobenthos community
Conclusions. In general, for sediment inhabitants such as chironomids, the pulp deposit has to be classified toxic. In the present test setup, the toxicity of the pulp deposit was reflected better by the chronic test systems applied than by the acute ones. The applied testing framework could be a suitable tool to assess the risk of contaminated sites, and this information will help decide whether risk mitigation measures should be taken. In addition, with a similar approach, the success of any mitigation measures taken can be assessed.

Many organic micropollutants present in wastewater, such as pharmaceuticals and pesticides, are poorly removed in conventional wastewater treatment plants (WWTPs). To reduce the release of these substances into the aquatic environment, advanced wastewater treatments are necessary. In this context, two large-scale pilot advanced treatments were tested in parallel over more than one year at the municipal WWTP of Lausanne, Switzerland. The treatments were: i) oxidation by ozone followed by sand filtration (SF) and ii) powdered activated carbon (PAC) adsorption followed by either ultrafiltration (UF) or sand filtration. More than 70 potentially problematic substances (pharmaceuticals, pesticides, endocrine disruptors, drug metabolites and other common chemicals) were regularly measured at different stages of treatment. Additionally, several ecotoxicological tests such as the Yeast Estrogen Screen, a combined algae bioassay and a fish early life stage test were performed to evaluate effluent toxicity. Both treatments significantly improved the effluent quality. Micropollutants were removed on average over 80% compared with raw wastewater, with an average ozone dose of 5.7 mg O₃ l⁻¹ or a PAC dose between 10 and 20 mg l⁻¹. Depending on the chemical properties of the substances (presence of electron-rich moieties, charge and hydrophobicity), either ozone or PAC performed better. Both advanced treatments led to a clear reduction in toxicity of the effluents, with PAC-UF performing slightly better overall. As both treatments had, on average, relatively similar efficiency, further criteria relevant to their implementation were considered, including local constraints (e.g., safety, sludge disposal, disinfection), operational feasibility and cost. For sensitive receiving waters (drinking water resources or recreational waters), the PAC-UF treatment, despite its current higher cost, was considered to be the most suitable option, enabling good removal of most micropollutants and macropollutants without forming problematic by-products, the strongest decrease in toxicity and a total disinfection of the effluent.

Einleitung: In der Schweiz werden im Rahmen der Aktivitäten der Koordinierten Beobachtung Oberflächengewässer (KBO) sowie des Vorgängerprojektes Modulstufenkonzept (MSK), standardisierte Methoden für die Untersuchung und Bewertung des Zustandes der Fliessgewässer erarbeitet, um so strukturelle, hydrologische, biologische, chemische sowie ökotoxikologische Aspekte der Wasserqualität zu erfassen und gegebenenfalls Massnahmen zur Verminderung dieser Belastung ergreifen zu können. Zielsetzung des Moduls Ökotoxikologie innerhalb des MSK bzw. der KBO ist die Entwicklung eines, auf ökotoxikologischen Biotests basierenden, Konzeptes zur routinemässigen Beurteilung der Wasserqualität anhand von Biotests, bestehend aus Probenahme, Probenaufbereitung, Biotests und Beurteilung der Effekte. Die Biotests sollen sensitiv, wirkungsbasiert, einfach durchführbar, kostengünstig und gut interpretierbar sein. In dem vorliegenden Bericht werden ausgewählte Testsysteme zur Detektion und Quantifizierung von Östrogenität in Wasserproben für eine Anwendung durch Vollzugsbehörden und private Labore evaluiert.

Hormonaktive Stoffe, die vor allem über das Abwasser in Oberflächengewässer gelangen, können die Gesundheit von Wassertieren beeinträchtigen. Ökotoxikologische Testmethoden verbessern die Messbarkeit und Bewertung dieser Substanzen. Sie liefern wichtige Entscheidungshilfen für Massnahmen zur Verminderung des Eintrags der Stoffe. So lässt sich mit ihnen die Wirkung zusätzlicher Reinigungsstufen in den Kläranlagen evaluieren.

Östrogen wirksame Substanzen werden mit gereinigtem Abwasser in Fliessgewässer und Seen eingetragen. Im Auftrag des Kanton St. Gallen wurden 44 Abwasser- und 3 Gewässerproben mit dem YES (Yeast Estrogen Screen; Anhang 1) untersucht. In den nächsten Absätzen werden die methodischen Schritte zusammengefasst und die Resultate in einer Tabelle aufgeführt. In einem letzten Absatz werden YES-Werte aus der Literatur kurz beleuchtet.

Endocrine-disrupting compounds, which enter surface waters mainly via wastewater discharges, can have adverse effects on aquatic organisms. Ecotoxicological test methods improve the measurement of these substances and the assessment of water quality, providing valuable decision support for reduction measures. For example, these methods can be used to evaluate additional treatment steps at wastewater treatment plants.

Hormonaktive Stoffe, die vor allem über das Abwasser in Oberflächengewässer gelangen, können die Gesundheit von Wassertieren beeinträchtigen. Ökotoxikologische Testmethoden verbessern die Messung und Bewertung dieser Substanzen. Sie liefern wichtige Entscheidungshilfen für Massnahmen zur Verminderung. So lässt sich mit ihnen die Wirkung zusätzlicher Reinigungsstufen in den Kläranlagen evaluieren.

The goal of the FOEN project “Strategy Micropoll“ was to develop a strategy regarding micropollutants originating from wastewater. Besides an analysis of water quality in Switzerland and other aspects, this included the evaluation of the efficiency of complementary wastewater treatments such as ozonation followed by sand filtration (ozonation-SF) and different processes including powdered activated carbon addition (PAC) in eliminating micropollutants from wastewater treatment effluent. Two large-scale pilot studies were conducted at the wastewater treatment plants (WWTP) Wüeri in Regensdorf (ozonation followed by sand-filtration) and Vidy in Lausanne (ozonation followed by sandfiltration and PAC followed by ultrafiltration). The studies were done in close collaboration with experts from research, practice and with personnel and financial support of cantonal water protection agencies (Gewässerschutzfachstellen) and the operators of the WWTPs. In both studies, samples before and after various treatment steps were analysed for micropollutants and ecotoxicological effects, in order to get insight into the efficiency of the different treatment steps. The focus laid on studying the effects of the advanced treatment technologies, ozonation and PAC, on the removal efficiency for polar, persistent and bioactive substances as well as possible side products and their biological effects. This report focuses on the study performed at the WWTP Vidy in Lausanne from April 2009 to July 2010 with four major measurement campaigns being conducted. Detailed information on the Regensdorf study can be found in Abegglen et al. (2009). The Lausanne study is described in Margot et al. (2011). Results at the WWTP Vidy showed that both ozonation-SF and PAC-UF treatments are useful measures to reduce the concentration and biological effects of micropollutants in treated wastewater and therefore in surface water bodies. Total elimination efficiency with regard to the measured specific effects was generally above 80 %. Similarly, advanced treatment led to lowered risk quotients, i.e. the relationship between measured concentrations and environmental quality standards, as well as reduced toxicity in bioassays, and thus lowered risk of adverse effects. There was no evidence of toxic effects due to the formation of stable by-products during ozonation (i.e. by-products still present after the final filtration step). A final filtration step with biological activity (such as a sand filter) after ozonation is recommended, in order to minimize the risk of reactive and potentially toxic ozonation by-products being released in waterbodies. Overall, the application of bioassays for comparing the performance of advanced wastewater treatment methods has proven to be relevant and useful. In general, in vitro bioassays were deemed most promising for the routine monitoring of the performance of advanced treatment in WWTPs, however only specific cellular effects are assessed in those tests. Certain in vivo bioassays also showed the beneficial effects of ozonation-SF and PACUF treatment such as the fish early life stage test with Oncorhynchus mykiss.

The evaluation of the toxicity of chemical agent mixtures poses important challenges for authorities, research and industry. In November 2010, the Ecotoxicology Centre, in collaboration with the SCAHT held a workshop with the aim of introducing the issue of chemical agent mixtures in the environment and in people and of providing an overview of the assessment of mixture toxicity based on various models. For this purpose, not only mixtures of various chemicals were examined, but also the interactions of chemicals with other abiotic stressors. The participants discussed the resulting regulatory challenges, the requirements for different sectors and formulated the need for action for the future.

The SETAC Europe Student Advisory Council (SAC) represents student members (master, diploma or Ph.D.) throughout every level of SETAC since 2006 and provides additional advice, recommendations, and new initiatives to the SETAC Europe Council. During this year’s SETAC Europe annual meeting in Gothenburg, Sweden, the SAC organized three student-oriented activities.

Micropollutants (MP) from municipal wastewater are frequently detected in surface waters and occur in ecotoxicological relevant concentrations. Therefore a broadly accepted method for the assessment of MP is needed. Here, we propose a procedure for the assessment of MP from municipal wastewater. The suggested method comprises (1) a substance list with relevant MP, (2) toxicologically based quality criteria, (3) an approach for the identification of potentially polluted sites, (4) a sampling strategy that considers the input-dynamics of chemicals and (5) a scheme to rate the water quality concerning MP. In the proposed concept the assessment of continuous entering substances is focused.

The effects of chemicals on biotic interactions, such as competition and predation, have rarely been investigated in aquatic ecotoxicology. This study presents a new approach for the investigation of predator–prey interactions between zebrafish (Danio rerio) and midge larvae (Chironomus riparius) impaired by chlorpyrifos (CHP), a neurotoxic insecticide. With a simple experimental design including four different treatments: (1) control, (2) predator exposed, (3) prey exposed and (4) both, predator and prey, exposed, we were able to detect by visual observation an increase in the feeding rate of zebrafish preying on exposed chironomids after acute (2 h) exposure to 6 μg/l CHP. Previously, a decrease in the burrowing behaviour of exposed chironomid larvae was observed. However, when pre-exposing simultaneously both predators and prey, no significant differences in the feeding rate of zebrafish were observed. This suggests an impairment in prey recognition of the exposed zebrafish. At a lower CHP concentration (1 μg/l), no differences in feeding rate of zebrafish were observed. We therefore propose the use of trophic interactions as parameters in higher tier studies for chemical testing and evaluation of ecotoxicological risk assessment.

Silber und Nanosilber werden in vielen Produkten des täglichen Lebens als antimikrobieller Wirkstoff eingesetzt. So wird auch eine Farbprodukt für die Anwendung auf Gebäudefassa-den gegen den Befall von Mikroorganismen mit Nanosilber ausgerüstet. Dies kann durch Verwitterungsprozesse ausgewaschen werden. Zusammen mit den Abteilungen Siedlungs-wasserwirtschaft und Verfahrenstechnik der Eawag und der Abteilung Bautechnologien der Empa wurde die Auswaschung der Silberpartikel aus einer marktüblichen Fassadenfarbe untersucht. Das Ökotoxzentrum hat dabei den Fassadenablauf auf dessen ökotoxikologi-sches Potential hin untersucht. Es wurden unterschiedliche Biotests angewendet. Nebst in vivo Tests mit Gammarus fossarum und Ceriodaphnia dubia wurden Tests in Mikrotiterplat-ten durchgeführt, der Leuchtbakterientest mit Vibrio fischeri und der kombinierte Algentest mit Pseudokirchneriella subcapitata. Es wurden Beregungsversuche mit Prüfkörpern durchgeführt, von denen einer mit einer na-nosilberhaltigen Farbe (nAg) und einer mit derselben Farbe, jedoch ohne Nanosilber (Refe-renz) beschichtet waren. Die, in einer ersten, simulierten Bewitterung gezogenen Proben zeigten lediglich im Ablauf des nAg-Prüfkörpers toxische Effekte. Mittels des Leuchtbakteri-entests nachgewiesene Effekte auf Vibrio fischeri zeigten sich deutlich in den ersten 2 L des nAg-Ablaufs. Der Freilandversuch zeigte, dass sowohl aus der Beschichtung des Referenz- als auch aus dem nAg-Prüfkörper ökotoxisch wirksame Substanzen ausgewaschen und in die Umwelt getragen werden. Von den angewendeten Biotests konnten mit dem chronischen Toxizitäts-test mit Ceriodaphnia dubia stark toxische Effekte und mit dem Leuchtbakterientest wie auch dem Algentest leichte, toxische Effekte detektiert werden. Der Algentest zeigte ledig-lich eine leichte Hemmung des Wachstums, die Photosynthese wurde nicht inhibiert, was darauf hindeutet, dass keine herbiziden Substanzen aus den Fassadenbeschichtungen frei-gesetzt werden. Der Gammarustest zeigte im Ablauf des nAg-Prüfkörper nach 24 h Exposi-tion Effekte auf das Verhalten der Gammariden, sowohl auf die Bewegung als auch auf die Ventilation.

The 1st Young Environmental Scientists (YES) Meeting took place in March (16–18) 2009 at the Institute for Environmental Sciences at the University of Koblenz-Landau, Landau Campus, Germany. This special students-only conference was organised under the umbrella of Society of Environmental Toxicology and Chemistry (SETAC) Europe by its Student Advisory Council (SAC). The SAC represents student members (master, diploma or Ph.D.) throughout every level of SETAC and provides additional advice, recommendations and new initiatives to the SETAC Europe Council.

Zur ökotoxikologischen Beurteilung des Sickerwassers einer Deponie wurden drei Testsysteme angewandt. Um die Toxizität des Sickerwassers auf einzellige Grünalgen (planktonische Primärproduzenten) zu beurteilen, wurde ein kombinierter Algentest mit der Art Pseudokirchnerellia subcapitata durchgeführt. Ein akuter Toxizitätstest mit Bachflohkrebsen (Gammarus spp.), die als Zerkleinerer und Verwerter organischer Substanz (Destruenten) und als Beuteorganismus für Fische eine Schlüsselfunktion in Fliessgewässerökosystemen haben, diente zur Evaluation der Auswirkungen des Sickerwassers auf diese Organismen. Abschliessend wurden die chronischen Auswirkungen des Sickerwassers auf die Reproduktion und Mortalität der Cladocere Ceriodaphnia dubia untersucht, die als planktonischer Primärkonsument (u.a. von Grünalgen) und als wichtiger Beuteorganismus für Fische und andere Wasserlebewesen eine wichtige Rolle im stehenden Gewässerökosystem spielt. Das Sickerwasser wies weder akut noch chronisch eine Toxizität gegenüber den Testorganismen auf.

Zur ökotoxikologischen Beurteilung der mit Epoxidharzen belasteten Trinkwasserproben wurden fünf Testsysteme angewandt: 1) Zur Beurteilung der Gesamttoxizität: Durchgeführt wurden ein akuter Daphnientest über die Dauer von 48 h mit dem Bachflohkrebs Daphnia magna, einem Standardtestorganismus in aquatischer Ökotoxikologie, und ein akuter Test mit dem Bachflohkrebs Gammarus fossarum über die Dauer von 7 d in Ergänzung. Diese rasch durchführbaren Screeningtests auf der Gesamtorganismusebene (Überleben, Verhalten) zeigen die integrierte Gesamttoxizität der Probe an, d.h. integrieren mehrere Wirkmechanismen. Endpunkte waren hierbei die Hemmung der Mobilität (D. magna) bzw. die Änderung der Bewegungs- und Ventilationsaktivität und die Mortalität (G. fossarum). 2) Um eine mögliche östrogene Wirkung der Proben abzuklären wurde mit einer Auswahl von Proben der ER-Calux-Test mit von menschlichen Zelllinien abgeleiteten Reportergen- Zellen durchgeführt. 3) Um eine evtl. auftretende Zytotoxizität abzuschätzen erfolgte mit der gleichen Auswahl an Proben das Zytotoxizitäts-Test-Kit PAN 1, in dem Auswirkungen der untersuchten Proben auf verschiedene Vitalitätsparameter von Säugetierzellen (Mäusefibroblasten) untersucht wurden. 4) Zur Abklärung einer möglichen mutagenen Wirkung der Proben wurde mit ausgewählten Proben ein Mutagenitätstest nach Ames mit dem Bakterium Salmonella typhimurium (Maron and Ames 1983) durchgeführt.

In Zusammenarbeit mit den Abteilungen SWW (Siedlungswasserwirtschaft) und Verfahrenstechnik der Eawag wurde das Abwasser einer Wäscherei untersucht. Die Wäscherei gibt dem Waschmittel Nanosilber in Form von Silberchlorid zu, um sich die antimikrobiellen Eigenschaften von Silber zu Nutze zu machen. Die Abteilung SWW und Verfahrenstechnik ermitteln dabei u. a. die Austragungsmenge und das Verhalten von Nanosilber im Abwasser. Das Oekotoxzentrum untersuchte anhand von unterschiedlichen Biotests die Toxizität des komplexen Abwassers. Im kombinierten Algentest mit der einzelligen Grünalge Pseudokirchneriella subcapitata wurden die Inhibition der Photosynthese und des Wachstums untersucht. Der Leuchtbakterientest mit dem marinen Bakterium Vibrio fischeri zeigte durch eine Hemmung der Lichtemission eine allgemeine Toxizität an. Des Weiteren wurde ein in vivo Test mit dem Bachflohkrebs Gammarus fossarum durchgeführt, bei dem Auswirkungen des Abwassers auf Verhalten und Mortalität untersucht wurden. Die Rohabwasserproben wurden auf unterschiedliche Weise aufbereitet und getestet. Sie wurden grob filtriert, steril filtriert, ultrazentrifugiert, mit DL-Cystein versetzt und ultrazentrifugiert kombiniert mit DL-Cystein-Zugabe. Die Ultrazentrifugation diente der Entfernung der Nanopartikel und DL-Cystein wurde zugegeben, um freie Silberionen zu komplexieren. Die Kombination von Ultrazentrifugation und Zugabe von DL-Cystein wurde durchgeführt, um eine Referenzprobe des Abwassers ohne Silber, weder partikuläres noch ionisches, zu erhalten. Zudem wurde eine Testreihe mit Silbernitrat durchgeführt. Beim Test mit Silbernitrat (1.5 μM, 255 μg·L-1) in einer 1:2 Verdünnungsreihe zeigte G. fossarum bereits nach 3 h eine erhöhte Mortalität, nach 24 h waren in allen Ansätzen alle Tiere tot. Die dem Algentest angepassten Effekt-Konzentrationen des Silbernitrats zeigten beim Leuchtbakterientest keine Effekte. V. fischeri ist demnach, im Vergleich zu P. subcapitata und G. fossarum deutlich weniger sensitiv gegenüber freien Silberionen. Am sensitivsten reagierte G. fossarum mit einer signifikant verringerten Bewegungsaktivität auf die Exposition gegenüber dem Rohabwasser. Es konnten bis zur 1:100 Verdünnung Effekte auf das Verhalten der Bachflohkrebse detektiert werden, wohingegen beim Algentest nur bis zur 1:16 Verdünnung und beim Leuchtbakterientest bis zur 1:64 Verdünnung Effekte auftraten. Die Ultrazentrifugation und/oder Zugabe von DL-Cystein verringerte die Toxizität des Abwassers bei allen Tests mehr oder weniger stark. Die hemmenden Effekte beim Algen- und Leuchtbakterientest verringerten sich durch Eliminierung von Silber signifikant um bis zu 10 %. Diese Abnahme der Toxizität durch das Entfernen des Silbers war beim Gammarus-Test viel deutlicher. Signifikante Verhaltensänderungen im Vergleich zur Kontrolle konnten bei den aufbereiteten Proben erst bei 1:20 verdünntem Abwasser detektiert werden, und nicht wie beim lediglich grob filtrierten Abwasser bereits ab 1:100 verdünntem Wäscherei-Abwasser. Vor allem der Algen- und der Leuchtbakterientest, aber auch der in vivo Test mit Gammarus fossarum zeigten, dass das Abwasser auch nach der vollständiger Entfernung des Silbers noch sehr toxisch ist. Die detektierten toxischen Effekte sind also nur z. T. auf das im Abwasser vorhandene Silber zurückzuführen.