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Veröffentlichung Is there synergistic interaction between fungicides inhibiting different enzymes in the ergosterol biosynthesis pathway in toxicity tests with the green alga Raphidocelis subcapitata?(2018) Coors, Anja; Vollmar, Pia; Kehrer, Anja; Sacher, FrankProducts used for plant protection or as biocides often contain more than one active substance together with numerous formulation additives. The environmental risk assessment for such commercial mixtures applies as default the concept of concentration addition. There is remaining regulatory concern, however, that underestimation of risks can occur if components in the mixture interact synergistically, i.e., elicit effects greater than those predicted by concentration addition. While cases of true synergism appear to be rare, the combination of substances targeting different steps in the same biosynthesis pathway was pointed out as one potential case of synergistic interaction although mechanistic explanations are lacking. The present study aimed to verify this hypothesis using the green alga Raphidocelis subcapitata as the regulatory standard test organism for which such synergism had been indicated earlier. Algal growth inhibition tests were conducted with mixtures of ergosterol biosynthesis inhibitors (tebuconazole, fenpropidin, and fenpropimorph). The fungicides were first tested individually to derive reliable data for a mixture toxicity prediction. The here determined toxicity estimates for two of the fungicides were considerably lower than the endpoints in the regulatory dossiers, which had been used for earlier mixture toxicity predictions. Experimentally observed toxicity estimates for the mixtures deviated <2.6-fold from the predicted values. Hence, the hypothesis of synergistic interaction between fungicides targeting different enzymes in the ergosterol biosynthesis was clearly not confirmed for the green alga R. subcapitata. Overall, the present study demonstrates the importance of reliable and correct input data for mixture toxicity predictions in order to avoid erroneous conclusions on non-additive (synergistic) interactions. © Springer Science+Business Media, LLC, part of Springer Nature 2018Veröffentlichung Hazard grouping of nanomaterials for daphnia and algae toxicity: lessons learned from scientific projects for regulatory applicability(2019) Schwirn, Kathrin; Völker, DorisGiven the numerous manufactured nanomaterials already on the market and expected in future, the effort for the individual investigation of hazard and risk would be enormous. To overcome this challenge, grouping of nanomaterials has been identified as one critical issue by the European Commission as well as the Organisation for Economic Co-operation and Development (OECD). In that context, several research projects have been carried out to deliver scientific input and develop approaches. This publication discusses experiences from several cases of two scientific projects with the aims to develop and review analogy hypotheses for grouping of different nanoforms of same substances for endpoints related to aquatic ecotoxicity from a regulatory point of view. Furthermore, by presenting examples of grouping attempts, it outlines the need for considerations of further aspects beside key physicalâ€Ìchemical parameters for grouping nanomaterials regarding environmental endpoints. The results substantiate previous educated guesses with strategically collected experimental data on issues that needs to be considered for grouping nanomaterials in regulatory context. Still, grouping of nanomaterials for the aim of joint assessment of ecotoxicity of nanoforms in a regulatory context is in its infants compared to grouping approaches of nanoforms for human health assessment. This publication features important aspects on possibilities and challenges of grouping nanomaterials for environmental hazard assessment. Quelle: https://enveurope.springeropen.comVeröffentlichung Impacts of autochthonous particulate organic matter on redox-conditions and elimination of trace organic chemicals in managed aquifer recharge(2023) Filter, Josefine; Ermisch, Till; Jekel, Martin; Ruhl, Aki SebastianAutochthonous carbon fxation by algae and subsequent deposition of particulate organic matter can have signifcant efects on redox conditions and elimination of trace organic chemicals (TOrCs) in managed aquifer recharge (MAR). This study investigated the impacts of diferent algae loadings (0-160 g/m2) and infltration rates (0.06-0.37 m/d) on overall oxygen consumption and elimination of selected TOrCs (diclofenac, formylaminoantipyrine, gabapentin, and sulfamethoxazole) in adapted laboratory sand columns. An infltration rate of 0.37 m/d in conjunction with an algae load of 80 g/m2 (dry weight) sustained oxic conditions in the sand bed and did not afect the degradation of TOrCs. Thus, the availability of easily degradable organic carbon from algae did not infuence the removal of TOrCs at an infuent concentration of 1 Ìg/L. In contrast, a lower infltration rate of 0.20 m/d in combination with a higher algae loading of 160 g/m2 caused anoxic conditions for 30 days and signifcantly impeded the degradation of formylaminoantipyrine, gabapentin, sulfamethoxazole, and diclofenac. Especially the elimination of gabapentin did not fully recover within 130 days after pulsed algae deposition. Hence, measures like micro-sieving or nutrient control are required at bank fltration or soil aquifer treatment sites with low infltration rates. © The Author(s) 2023Veröffentlichung A critical examination of the protection level for primary producers in the first tier of the aquatic risk assessment for plant protection products(2023) Brendel, Stephan; Duquesne, Sabine; Hönemann, Linda; Konschak, Marco; Pieper, Silvia; Solé, Magali; Wogram, JörnBackground The aim of environmental risk assessment (ERA) for pesticides is to protect ecosystems by ensuring that specific protection goals (SPGs) are met. The ERA follows a prospective tiered approach, starting with the most conservative and simple step in risk assessment (RA) (so-called tier 1) using the lowest available appropriate endpoint derived from ecotoxicological tests. In 2015, for the tier 1 RA of aquatic primary producers, the recommendation was changed from using the lowest of the 50% inhibition (EC50) values based on biomass (area under the curve-EbC50), increase in biomass (yield- EyC50) or growth rate (ErC50) to only using the growth rate inhibition endpoint (ErC50) because it is independent of the test design and thus more robust. This study examines the implications of this such on the level of conservatism provided by the tier 1 RA and evaluates whether it ensures a suitable minimum protection level. Results Our analysis shows that replacing the lowest endpoint with the growth rate inhibition endpoint while maintaining the assessment factor (AF) of 10 significantly reduces the conservatism in the tier 1 RA. Comparing protection levels achieved with different endpoints reveals that the current assessment is less protective. To maintain the previous level of protection, and since the protection goals have not changed, we recommend to multiply the default AF of 10 by an extra factor of minimum 2.4 in the tier 1 RA based on ErC50. Independently of the endpoint selected in tier 1 RA, several issues in the general RA of pesticides contribute to uncertainties when assessing the protection levels, e.g., lack of appropriate comparison of the higher tier experimental studies (i.e., best achievable approximation of field situation, so-called surrogate reference tier) with field conditions or the regulatory framework's failure to consider realistic conditions in agricultural landscapes with multiple stressors and pesticide mixtures. Conclusions We advise to consider adjusting the risk assessment in order to reach at least the previous protection level for aquatic primary producers. Indeed continuing using an endpoint with a higher value and without adjustment of the assessment factor is likely to jeopardize the need of halting biodiversity loss in surface waters. © The Author(s) 2023