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Veröffentlichung How TK-TD and population models for aquatic macrophytes could support the risk assessment for plant protection products(2016) Hommen, Udo; Schmitt, Walter; Heine, Simon; Duquesne, Sabine; Brock, Theo CM; Manson, Phil; Meregalli, Giovanna; Ochoa-Acuna, Hugo; van Vliet, Peter; Arts, Gertie H.P.Veröffentlichung Fatal neurotoxicosis in dogs associated with tychoplanktic, anatoxin-a producing tychonema sp. in mesotrophic Lake Tegel, Berlin(2018) Beulker, Camilla; Chorus, Ingrid; Fastner, JuttaIn May 2017, at least 12 dogs showed signs of acute neurotoxicosis after swimming in or drinking from Lake Tegel, a mesotrophic lake in Berlin, Germany, and several of the affected dogs died shortly afterwards despite intensive veterinary treatment. Cyanobacterial blooms were not visible at the water surface or the shorelines. However, detached and floating water moss (Fontinalis antipyretica) with high amounts of Tychonema sp., a potential anatoxin-a (ATX) producing cyanobacterium, was found near the beaches where the dogs had been swimming and playing. Necropsies of two of the dogs revealed no specific lesions beside the anamnestic neurotoxicosis. ATX was detected in concentrations up to 8700 Ìg Lâ Ì1 in the stomach contents, while other (neuro)toxic substances were not found. In the aqueous fraction of Fontinalis/Tychonema clumps sampled after the casualties, ATX was found in concentrations up to 1870 Ìg Lâ Ì1. This is the first report of a dense population of Tychonema sp. in stands of Fontinalis resulting in high ATX contents. This case emphasizes the need for further investigation of potentially toxic, non-bloom forming cyanobacteria in less eutrophic water bodies and underlines the novel challenge of developing appropriate surveillance schemes for respective bathing sites. Quelle: https://www.mdpi.comVeröffentlichung Plants in aquatic ecosystems: current trends and future directions(2018) O'Hare, Matthew T.; Aguiar, Francisca C.; Asaeda, Takashi; Mohr, SilviaAquatic plants fulfil a wide range of ecological roles, and make a substantial contribution to the structure, function and service provision of aquatic ecosystems. Given their well-documented importance in aquatic ecosystems, research into aquatic plants continues to blossom. The 14th International Symposium on Aquatic Plants, held in Edinburgh in September 2015, brought together 120 delegates from 28 countries and six continents. This special issue of Hydrobiologia includes a select number of papers on aspects of aquatic plants, covering a wide range of species, systems and issues. In this paper, we present an overview of current trends and future directions in aquatic plant research in the early twenty first century. Our understanding of aquatic plant biology, the range of scientific issues being addressed and the range of techniques available to researchers have all arguably never been greater; however, substantial challenges exist to the conservation and management of both aquatic plants and the ecosystems in which they are found. The range of countries and continents represented by conference delegates and authors of papers in the special issue illustrates the global relevance of aquatic plant research in the early twenty first century but also the many challenges that this burgeoning scientific discipline must address. © Springer International Publishing Switzerland 2017Veröffentlichung Mass occurrence of anatoxin-a- and dihydroanatoxin-a-producing tychonema sp. in mesotrophic reservoir mandichosee (River Lech, Germany) as a cause of neurotoxicosis in dogs(2020) Bauer, Franziska; Bartha-Dima, Bernadett; Fastner, JuttaIn August 2019, three dogs died after bathing in or drinking from Mandichosee, a mesotrophic reservoir of the River Lech (Germany). The dogs showed symptoms of neurotoxic poisoning and intoxication with cyanotoxins was considered. Surface blooms were not visible at the time of the incidents. Benthic Tychonema sp., a potential anatoxin-a (ATX)-producing cyanobacterium, was detected in mats growing on the banks, as biofilm on macrophytes and later as aggregations floating on the lake surface. The dogsâ€Ì pathological examinations showed lung and liver lesions. ATX and dihydroanatoxin-a (dhATX) were detected by LC-MS/MS in the stomachs of two dogs and reached concentrations of 563 and 1207 Ìg/L, respectively. Anatoxins (sum of ATX and dhATX, ATXs) concentrations in field samples from Mandichosee ranged from 0.1 Ìg/L in the open water to 68,000 Ìg/L in samples containing a large amount of mat material. Other (neuro)toxic substances were not found. A molecular approach was used to detect toxin genes by PCR and to reveal the cyanobacterial community composition by sequencing. Upstream of Mandichosee, random samples were taken from other Lech reservoirs, uncovering Tychonema and ATXs at several sampling sites. Similar recent findings emphasize the importance of focusing on the investigation of benthic toxic cyanobacteria and applying appropriate monitoring strategies in the future. © 2020 by the authorsVeröffentlichung Decades needed for ecosystem components to respond to a sharp and drastic phosphorus load reduction(2020) Beulker, Camilla; Köhler, Antje; Chorus, Ingrid; Fastner, JuttaLake Tegel is an extreme case of restoration: inflow treatment reduced its main external phosphorus (TP) load 40-fold, sharply focused in time, and low-P water flushed the lake volume ~ 4 times per year. We analysed 35 years of data for the time TP concentrations took to decline from ~ 700 to 20-30 (my)g/l, biota to respond and cyanobacteria to become negligible. The internal load proved of minor relevance. After 10 years, TP reached 35-40 (my)g/l, phytoplankton biomass abruptly declined by 50% and cyanobacteria no longer dominated; yet 10 years later at TP < 20-30 (my)g/l they were below quantifiable levels. 20-25 years after load reduction, the lake was stably mesotrophic, macrophytes had returned down to 6-8 m, and vivianite now forms, binding P insolubly in the sediment. Bottom-up control of phytoplankton through TP proved decisive. Five intermittent years with a higher external P load caused some 're-eutrophication', delaying recovery by 5 years. While some restoration responses required undercutting thresholds, particularly that of phytoplankton biomass to TP, resilience and hysteresis proved irrelevant. Future research needs to focus on the littoral zone, and for predicting time spans for recovery more generally, meta-analyses should address P load reduction in combination with flushing rates. The Author(s) 2020Veröffentlichung Fate, bioaccumulation and toxic effects of triclosan on a freshwater community - a mesocosm study(2021) Berghahn, Rüdiger; Contardo-Jara, Valeska; Feibicke, Michael; Meinecke, Stefan; Mohr, Silvia; Schmidt, RalfThe antibacterial agent triclosan (TCS) is added to many daily-used consumer products and can therefore reach the aquatic environment via treated wastewater and potentially harm aquatic ecosystems. A 120 days pond mesocosm study was conducted in order to investigate the fate of TCS in water and sediment, its bioaccumulative potential in different biota as well as the effects of TCS and its main transformation product methyl-triclosan (M-TCS) on plankton, periphyton, macrophytes, and benthos communities. TCS was dosed once each in six pond mesocosms (nominal concentrations: 0.12, 0.6, 3.5, 21, 130 and 778 (micro)g/L TCS, respectively) while two ponds served as controls. A concentration-dependent increase in the DT50 values from 5.0 to 15.0 and 7.5 to 16.3 days was observed for TCS in water and the whole pond system (water, sediment, biota), respectively. Consequently, the substance should be categorized as non-persistent. For TCS, the bioaccumulation factors (non steady-state conditions, BAFnssc) in Lymnaea stagnalis, Myriophyllum spicatum and periphyton were below the critical limit of 2000, above which a substance is classified as bioaccumulative. In contrast, a BAFnssc value of >10,000 was found for M-TCS in L. stagnalis, denoting that M-TCS definitely falls under this classification. Although strong effects on freshwater communities could only be observed in the highest TCS treatments, some periphyton species, such as Oedogonium spp., reacted very sensitive to TCS with an EC50 (time weighted average, 28 d) of 0.3 (micro)g/L TCS. Considering the high bioaccumulative potential of M-TCS in combination with the observed effects of TCS at low doses suggests that the use of TCS, and therefore its release into the environment, should cease. © 2021 The AuthorsVeröffentlichung The auxin herbicide mecoprop-P in new light: Filling the data gap for dicotyledonous macrophytes(2021) Feibicke, Michael; Gergs, René; Sahm, René; Hönemann, Linda; Kusebauch, Björn; Mohr, Silvia; Périllon, CécileMecoprop-P (MCPP-P) is an auxin herbicide which has been used against dicotyledonous weed plants since the 1980s. While fate and monitoring data of MCPP-P in the aquatic environment revealing concentrations up to 103 ÎÌg/L in freshwaters are well documented, only very few toxicity data and no studies with dicotyledonous macrophytes have been published in open literature so far. To fill up this essential data gap, a microcosm study was conducted in order to test the sensitivity of nine dicotyledonous and one Ceratophyllales macrophyte species. The plant species were exposed to seven MCPP-P concentrations ranging from 8 to 512 (micro)g/L for 21/22 days in one microcosm per concentration, and two further microcosms served as controls. Plant preparation was adapted to each species and endpoints were measured to calculate growth rates. Data were generated to obtain effect concentrations (ECX) which then were used to construct species sensitivity distribution curves (SSD). Eight species proved to be sensitive to MCPP-P in the tested concentration range with EC50 values ranging from 46.9 (micro)g/L for Ranunculus aquatilis to 656.4 (micro)g/L MCPP-P for Ludwigia repens. Taking the EC50 values of this study and published data for autotrophic organisms into account, a hazard concentration (HC5) of 2.7 (micro)g/L was derived from the SSD curve, while an SSD curve without dicotyledonous macrophytes resulted in an about 100 times higher HC5 (360.8 (micro)g/L MCCP-P). This confirms that a re-evaluation for old auxin herbicides by including dicotyledonous test species into the environmental risk assessment may be indicated. Furthermore, the use of MCPP-P in bitumen felts as protection against rooting by plants is not in the focus of any risk regulation so far. This application, however, can lead to high run-off concentrations that can enter surface waters easily, exceeding the new regulatory acceptable concentration values. © 2021 The AuthorsVeröffentlichung Cyanotoxins associated with macrophytes in Berlin (Germany) water bodies - occurrence and risk assessment(2023) Fastner, Jutta; Teikari, Jonna; Hoffmann, AnjaFatal dog poisoning after uptake of neurotoxic cyanobacteria associated with aquatic macrophytes in Tegeler See (Berlin, Germany) raised concerns about critical exposure of humans, especially children, to cyanotoxins produced by macrophyte associated cyanobacteria during recreational activity. From 2017 to 2021 a total of 398 samples of macrophytes washed ashore at bathing sites located at 19 Berlin lakes were analysed for anatoxins, microcystins, and cylindrospermopsins, as were 463 water samples taken in direct proximity to macrophyte accumulations. Cyanotoxins were detected in 66 % of macrophyte samples and 50 % of water samples, with anatoxins being the most frequently detected toxin group in macrophyte samples (58 %) and cylindrospermopsins in water samples (41 %). Microcoleus sp. associated with the water moss Fontinalis antipyretica was identified as anatoxin producing cyanobacterium in isolated strains as well as in field samples from Tegeler See. Anatoxin contents in macrophyte samples rarely exceeded 1 (micro)g/g macrophyte fresh weight and peaked at 9. 2 (micro)g/g f.w. Based on established toxicological points of departure, a critical anatoxin content of macrophyte samples of 3 (micro)g/g f.w. is proposed. Five samples, all taken in Tegeler See and all associated with the water moss Fontinalis antipyretica, exceeded this value. Contents and concentrations of microcystins and cylindrospermopsins did not reach critical levels. The potential exposure risks to anatoxins for children and dogs are assessed and recommendations are given. © 2022 The AuthorsVeröffentlichung Effects of a realistic pesticide spraying sequence for apple crop on stream communities in mesocosms: negligible or notable?(2023) Duquesne, Sabine; Feibicke, Michael; Frische, Tobias; Gergs, René; Meinecke, Stefan; Sahm, René; Mohr, SilviaBackground Several large-scale studies revealed impacts and risks for aquatic communities of small rural lakes and streams due to pesticides in agricultural landscapes. It appears that pesticide risk assessment based on single products does not offer sufficient protection for non-target organisms, which are exposed repeatedly to pesticide mixtures in the environment. Therefore, a comprehensive stream mesocosm study was conducted in order to investigate the potential effects of a realistic spraying sequence for conventional orchard farmed apples on a stream community using pesticides at their regulatory acceptable concentrations (RACs). Eight 74-m-long stream mesocosms were established with water, sand, sediment, macrophytes, plankton and benthic macroinvertebrates. In total, nine fungicidal, four herbicidal and four insecticidal pesticides were applied in four of the eight stream mesocosms on 19 spraying event days in the period from April to July while the remaining four stream mesocosms served as controls. The community composition, the abundance of benthos, periphyton and macrophytes, the emergence of insects, physico-chemical water parameters, and drift measurements of aquatic invertebrates were measured. Results The pesticide spraying sequence induced significant effects on invertebrates, periphyton, and macrophytes as well as on the water ion composition especially in the second half of the experiment. It was not possible to relate the observed effects on the community to specific pesticides applied at certain time points and their associated toxic pressure using the toxic unit approach. The most striking result was the statistically significant increase in variation of population response parameters of some taxa in the treated mesocosms compared to the controls. This inter-individual variation can be seen as a general disturbance measure for the ecosystem. Conclusions The pesticide spraying sequence simulated by using RAC values had notable effects on the aquatic stream community in the conducted mesocosm study. The results indicate that the current risk assessment for pesticides may not ensure a sufficient level of protection to the field communities facing multiple pesticide entries due to spraying sequences and other combined stress. Hence, there is still room for improvement regarding the prospective risk assessment of pesticides to further reduce negative effects on the environment. © 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