Bisphenol A induces superfeminization in the Ramshorn snail Marisa cornuarietis (Gastropoda: Prosobranchia) at environmentally relevant concentrations

Previous investigations have shown that bisphenol A (BPA) induces a superfeminization syndrome in the freshwater snail Marisa cornuarietis at concentrations as low as 1 μg/L. Superfemales are characterized by the formation of additional female organs, enlarged accessory sex glands, gross malformations of the pallial oviduct, and a stimulation of egg and clutch production, resulting in increased female mortality. However, these studies were challenged on the basis of incomplete experimentation. Therefore, the objective of the current approach was to bridge several gaps in knowledge by conducting additional experiments. In an initial series of experiments, study results from the reproductive phase of the snails were evaluated in the sub-micrograms per liter range. Before and after the spawning season, superfemale responses were observed [NOEC (no observed effect concentration) 7.9 ng/L, EC10 (effective concentration at 10%) 13.9 ng/L], which were absent during the spawning season. A further experiment investigated the temperature dependence of BPA responses by exposing snails at two temperatures in parallel. The adverse effect of BPA was at least partially masked at 27°C (EC10 998 ng/L) when compared with 20°C (EC10 14.8 ng/L). In M. cornuarietis, BPA acts as an estrogen receptor (ER) agonist, because effects were completely antagonized by a co-exposure to tamoxifen and Faslodex. Antiandrogenic effects of BPA, such as a significant decrease in penis length at 20°C, were also observed. Competitive receptor displacement experiments indicate the presence of androgen- and estrogen-specific binding sites. The affinity for BPA of the estrogen binding sites in M. cornuarietis is higher than that of the ER in aquatic vertebrates. The results emphasize that prosobranchs are affected by BPA at lower concentrations than are other wildlife groups, and the findings also highlight the importance of exposure conditions

Effects of BPA in snails : Oehlmann et al. respond

We welcome critical appraisals that help to provide balance; however, Dietrich et al. gave an unjustified reproach. We feel that Dietrich’s position is severely compromised because he serves as an expert for the bisphenol A (BPA) Industry Group (Brussels, Belgium). We would like to respond to the issues raised by Dietrich et al., as well as to their oversights and inappropriate interpretations of our findings..

Bisphenol A Induces Superfeminization in the Ramshorn Snail (Gastropoda: Prosobranchia) at Environmentally Relevant Concentrations

Previous investigations have shown that bisphenol A (BPA) induces a superfeminization syndrome in the freshwater snail Marisa cornuarietis at concentrations as low as 1 μg/L. Superfemales are characterized by the formation of additional female organs, enlarged accessory sex glands, gross malformations of the pallial oviduct, and a stimulation of egg and clutch production, resulting in increased female mortality. However, these studies were challenged on the basis of incomplete experimentation. Therefore, the objective of the current approach was to bridge several gaps in knowledge by conducting additional experiments. In an initial series of experiments, study results from the reproductive phase of the snails were evaluated in the sub-micrograms per liter range. Before and after the spawning season, superfemale responses were observed [NOEC (no observed effect concentration) 7.9 ng/L, EC10 (effective concentration at 10%) 13.9 ng/L], which were absent during the spawning season. A further experiment investigated the temperature dependence of BPA responses by exposing snails at two temperatures in parallel. The adverse effect of BPA was at least partially masked at 27°C (EC10 998 ng/L) when compared with 20°C (EC10 14.8 ng/L). In M. cornuarietis, BPA acts as an estrogen receptor (ER) agonist, because effects were completely antagonized by a co-exposure to tamoxifen and Faslodex. Antiandrogenic effects of BPA, such as a significant decrease in penis length at 20°C, were also observed. Competitive receptor displacement experiments indicate the presence of androgen- and estrogen-specific binding sites. The affinity for BPA of the estrogen binding sites in M. cornuarietis is higher than that of the ER in aquatic vertebrates. The results emphasize that prosobranchs are affected by BPA at lower concentrations than are other wildlife groups, and the findings also highlight the importance of exposure conditions

Superfeminization as an effect of bisphenol A in \u3ci\u3eMarisa cornuarietis\u3c/i\u3e & Response from Forbes et al. to Oehlmann et al.

[Oehlmann et al.]: Recently, we had the opportunity to read two articles in volume 66 of Ecotoxicology and Environmental Safety. Forbes et al. (2007a, , 2007b) declare “to explore the reproducibility of prior work” showing that bisphenol A (BPA) induces superfeminization in the freshwater snail Marisa cornuarietis (Oehlmann et al., 2000, 2006; Schulte- Oehlmann et al., 2001). Based on the outcome of a toxicity test with the same species, the authors conclude that their results “do not support previous claims of enhanced reproduction in M. cornuarietis in response to exposure to BPA.” We take issue with the declaration of exploring the reproducibility of our challenged work and the validity of the conclusions made by Forbes et al. (2007a, 2007b). Furthermore, we feel the toxicity test is flawed because its experimental design and the selected exposure conditions result in an irresponsiveness of test animals to the tested compound. ... [Forbes et al.]:We thank the editor for giving us the opportunity to respond to Oehlmann et al.’s comments (Oehlmann et al., 2008) on our papers (Forbes et al., 2007a,b). In response to the criticisms of our studies we would first like to emphasize that it was not our aim to exactly repeat the experiments of Oehlmann and colleagues, but rather to produce robust and reproducible results that were statistically valid and that therefore could be used in the risk assessment of bisphenol A (BPA). We are disturbed by the highly speculative suggestion by Oehlmann et al. that we may have studied a different ‘cryptic’ species of Marisa cornuarietis, as there is no evidence to support such suggestion. Furthermore, the snails used in our studies were collected from a documented pristine field site and identified to species by Dr. Sharon File-Emperador from University of Puerto Rico, a recognized snail expert. They were reared for a known number of generations under tightly controlled and documented conditions. In contrast, the snails used in Oehlmann et al.’s studies (e.g., Oehlmann et al., 2006) came from the Dusseldorf Zoo (original site of field collection not indicated) and were periodically supplemented with snails from Florida (location not indicated). There is likewise very little information in the published studies about the culture and husbandry conditions of Oehlmann et al.’s snails, whereas a major portion of our research aimed to identify appropriate husbandry and culture conditions for M. cornuarietis. It is on the basis of such detailed study that our toxicity tests with BPA were conducted

Efekty oscylacyjne na elektrodzie glinowej - przykład tworzenia nietrwałych struktur w układzie elektrochemicznym

Untersucht wurde das Oszillationsverhalten von Aluminium in alkalischer Lösung bei anodischer Belastung unter potentio-galvano-dynamischen Bedingungen. Unter diesen Bedingungen konnten Oszillationen des Potentials und des Stromflusses beobachtet werden. Weiter wurden Strom-Potential-Kurven von Aluminium in bewegter und unbewegter Lösung aufgenommen. Mit Hilfe dieser Kurven wurde ein Modell entwikelt, das einen periodischen Aufbau und Abbau einer passivierenden Deckschicht auf der Aluminiumelektrode vorsieht. Dieser Prozeß Ist mit einem diffusionkontrollierten OH - Transport zwichen der Elektrodenoberfläche und dem Elektrolyten gekoppelt. Mit der Anwendung von Untersuchungsmethoden der nichtlinearen Dynamik wird eine neue Möglichkeit zur Charakterisierung dynamischen Verhaltens vorgestellt.Anodic oscillatory behavior of aluminum in alkaline solution has been studied under potentiogalvano-dynamical conditions. In such low restricted systems it is possible to observe potential and current oscillations. We examined the anodic polarisation behavior of aluminium over a wide potential range and studied further the influence stirring. We developed a model for these oscillations based on the growth and dissolution of a passiv film on the electrode surface. This process is coupled with a diffusion-controlled OH - transport between the electrode surface and the bulk liquid. By using the tools of nonlinear dynamics another method is presented to characterise this electrochemical system.W pracy zbadano oscylacje potencjału elektrody glinowej w wodnych roztworach alkalicznych, w warunkach potencjalodynamicznych i galwanodynamicznych. Otrzymane krzywe polaryzacyjne analizowano za pomocą odpowiednio zaprogramowanego komputera. Zaobserwowano pojawiające się oscylacje potencjału elektrody glinowej i towarzyszące im harmoniczne oscylacje prądu płynącego w układzie. Oscylacje te związane są z wytworzeniem pasywnej warstwy tlenku glinu z lukami struktury i tworzeniem jonów kompleksowych. Oscylacje poddano analizie harmonicznej w funkcji czasu, dla systemów liniowych, dwuwymiarowych i trójwymiarowych. wyniki badań świadczą o nieliniowej dynamicznie charakterystyce układu.Zadanie pt. Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki nr 885/P-DUN/2014 zostało dofinansowane ze środków MNiSW w ramach działalności upowszechniającej naukę

Detection of chemically induced ecotoxicological effects in rivers of the Nidda catchment (Hessen, Germany) and development of an ecotoxicological, Water Framework Directive–compliant assessment system

Abstract Background Approximately 90% of German surface waters do not meet the objectives of the European Water Framework Directive (EU-WFD). This is primarily due to deficits in water body structure and biological quality components, which in turn are negatively affected by chemical pollution. In this context, hydromorphological restoration measures have often been conducted to improve habitat and species diversity and, therefore, the ecological status of water bodies. However, habitat improvement is not necessarily accompanied by biota enhancement and thus by the improvement of the ecological status of rivers. To prioritize water management measures, decision criteria for the water management practice are necessary, which enable the prognosis, whether chemical pollution and its resulting effects or other factors, such as structural deficits of the water bodies, are the main cause for the failure to meet the objective of a good ecological status. Results To address this need, we applied the freshwater mudsnail Potamopyrgus antipodarum and the amphipod Gammarus fossarum in active monitoring campaigns and in laboratory experiments with combined water/sediment samples and analyzed water and sediment samples with in vitro assays quarterly over the course of 1 year to provide evidence and guideline to assess if chemical contamination is a relevant stress factor for the aquatic biodiversity in rivers of the Nidda catchment (Hessen, Germany). On the basis of these results, an ecotoxicological, WFD–compliant assessment system was developed which, in comparison with the ecological status classes of the EU-WFD, permits the identification of the probable causes for the failure to meet the objectives of the EU-WFD. From these findings, recommendations for action were derived for the implementation of priority measures in water management practice. For the rivers Nidda, Usa, and Horloff, we identified a need for action to improve water and sediment quality at all investigated sampling sites except for the reference sites in the headwaters. The ecotoxicological assessment system also highlighted that hydromorphological restoration measures on their own will not lead to a good ecological status of rivers, as long as water and sediment quality are deficient. Conclusion Hydromorphological restoration measures should be performed in conjunction with measures to reduce chemical contamination to achieve a good ecological status of the rivers Nidda, Usa, and Horloff