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 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

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

Biological impact of organotin compounds on mollusks in marine and freshwater ecosystems

Organotin compounds, like tributyltin (TBT) and triphenyltin (TPT), degrade only slowly in the environment. Today, TBT is known to evoke a variety of effects in animals, even at very low environmental concentrations. In terms of sensitivity, none rivals that of two virilisation phenomena-intersex and imposex-in prosobranch gastropods. The effects of TBT and TPT on various marine and freshwater snails were investigated in newly developed sediment biotests in the laboratory. Most tested species showed very low effect concentrations for both organotin compounds (e. g. the freshwater mudsnail Potamopyrgus antipodarum with an EC10 of 0.03 μg TPT as Sn/kg and 0.98μg TBT as Sn/kg for the reduction of fertility). In order to assess the actual TBT contamination of coastal sediments, extensive surveys were carried out in France and Ireland, indicating that there is still a continuing threat for sensitive marine organisms. To obtain information on the contamination of fluvial and estuarine sediments in Germany, an effect monitoring was conducted using the biotests with the netted whelk Nassarius reticulatus and P. antipodarum. From our investigations we may conclude that a variety of benthic mollusks is strongly affected by low concentrations of organotin compounds in aquatic ecosystems. Due to their persistence in the environment, a continuing impact on aquatic wildlife has to be expected

Spoilt for choice: A critical review on the chemical and biological assessment of current wastewater treatment technologies

The knowledge we have gained in recent years on the presence and effects of compounds discharged by wastewater treatment plants (WWTPs) brings us to a point where we must question the appropriateness of current water quality evaluation methodologies. An increasing number of anthropogenic chemicals is detected in treated wastewater and there is increasing evidence of adverse environmental effects related to WWTP discharges. It has thus become clear that new strategies are needed to assess overall quality of conventional and advanced treated wastewaters. There is an urgent need for multidisciplinary approaches combining expertise from engineering, analytical and environmental chemistry, (eco)toxicology, and microbiology. This review summarizes the current approaches used to assess treated wastewater quality from the chemical and ecotoxicological perspective. Discussed chemical approaches include target, non-target and suspect analysis, sum parameters, identification and monitoring of transformation products, computational modeling as well as effect directed analysis and toxicity identification evaluation. The discussed ecotoxicological methodologies encompass in vitro testing (cytotoxicity, genotoxicity, mutagenicity, endocrine disruption, adaptive stress response activation, toxicogenomics) and in vivo tests (single and multi species, biomonitoring). We critically discuss the benefits and limitations of the different methodologies reviewed. Additionally, we provide an overview of the current state of research regarding the chemical and ecotoxicological evaluation of conventional as well as the most widely used advanced wastewater treatment technologies, i.e., ozonation, advanced oxidation processes, chlorination, activated carbon, and membrane filtration. In particular, possible directions for future research activities in this area are provided

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

COMPRENDO: Focus and approach

Tens of thousands of man-made chemicals are in regular use and discharged into the environment. Many of them are known to interfere with the hormonal systems in humans and wildlife. Given the complexity of endocrine systems, there are many ways in which endocrine-disrupting chemicals (EDCs) can affect the body’s signaling system, and this makes unraveling the mechanisms of action of these chemicals difficult. A major concern is that some of these EDCs appear to be biologically active at extremely low concentrations. There is growing evidence to indicate that the guiding principle of traditional toxicology that “the dose makes the poison” may not always be the case because some EDCs do not induce the classical dose–response relationships. The European Union project COMPRENDO (Comparative Research on Endocrine Disrupters—Phylogenetic Approach and Common Principles focussing on Androgenic/Antiandrogenic Compounds) therefore aims to develop an understanding of potential health problems posed by androgenic and antiandrogenic compounds (AACs) to wildlife and humans by focusing on the commonalities and differences in responses to AACs across the animal kingdom (from invertebrates to vertebrates)

Lösungsstrategien zur Verminderung von Einträgen von urbanem Plastik in limnische Systeme - PLASTRAT - Synthesebericht

Der Einsatz von Plastik gehört zu den großen Errungenschaften unserer Zeit. Die Nutzung von Plastik in unseren verschiedenen Lebensbereichen ermöglicht uns heute Vieles. Dabei setzen wir Plastik oft ein, ohne dass uns dies bewusst ist. Wieviel „virtuelles Plastik“ war allein notwendig, um diesen Synthesebericht zu erstellen? Wieviel Plastik benötigen Sie gerade, um diesen Synthesebericht zu lesen? Wie so oft, so hat auch der Einsatz von Plastik zwei Seiten: den positiven Errungenschaften stehen negative Auswirkungen gegenüber, vor allem nach der Nutzung von Plastik. Im Fokus stehen hierbei Fragestellungen der Toxikologie sowie der Abfallverwertung. Im Gegensatz zu vielen anderen Stoffen, mit denen wir täglich in Berührung sind, hat Plastik die Eigenschaft, dass sich kleinste Partikel bilden. So ist es nicht verwunderlich, dass sich mittlerweile in allen Umweltmedien Mikroplastikpartikel finden lassen. Die Idee von PLASTRAT war es, in einem interdisziplinären Team Ansätze für die Verminderung von Einträgen von Plastik in Gewässer zu untersuchen. Dabei standen über den Ansatz der systemischen Risikoanalyse die unterschiedlichen Sektoren im Fokus, angefangen von der Erzeugung, über die Nutzung bis hin zu den Eintragspfaden und die toxikologische Bewertung. Der Synthesebericht fasst die Ergebnisse von PLASTRAT zusammen. Vor allem zeigt der Synthesebericht die großen Herausforderungen sowie Lösungsansätze zum Thema Mikroplastik auf. Dabei wird auch deutlich, dass wir bei vielen Fragestellungen zum Umgang mit Plastik erst am Anfang stehen. Die ersten Ideen zu PLASTRAT entstanden 2016. In den vergangenen fünf Jahren stand das Thema Plastik im Fokus von Öffentlichkeit und Presse. In dieser Zeit gab es bereits wichtige Veränderungen beim Einsatz von Plastik bei diversen Produkten, beispielsweise durch die Substitution durch alternative Materialien. Dies zeigt deutlich, dass eine Bewusstseinsveränderung stattgefunden hat, die sich sicherlich in der Zukunft fortsetzten wird. Die Arbeiten und Diskussionen im Projektteam von PLASTRAT waren spannend. In vielen Projektbesprechungen wurde an den Forschungsfragestellungen gearbeitet und nach Lösungen gesucht. Es gab einen intensiven persönlichen Austausch mit allen am Projekt beteiligten Personen, so dass uns die seit 2020 geltenden Einschränkungen durch die Corona-Pandemie nicht immer leichtgefallen sind. Wir möchten uns bei allen bedanken, die bei PLASTRAT mitgewirkt haben. Allen Lesern des Syntheseberichts wünschen wir viele Freude beim Lesen und hoffen, dass wir Ihnen einen Impuls für den zukünftigen Umgang mit (Mikro-)Plastik geben können