The wastewater micropollutant carbamazepine in insectivorous birds-an exposure estimate.

Insects with aquatic life stages can transfer sediment and water pollutants to terrestrial ecosystems, which has been described for metals, polyaromatic hydrocarbons, and polychlorinated chemicals. However, knowledge of the transfer of aquatic micropollutants released by wastewater treatment plants is scarce despite some preliminary studies on their occurrence in riparian spiders. In our study, we address a major analytical gap focusing on the transfer of the micropollutant carbamazepine from the larvae to the adult midges of Chironomus riparius using an optimized QuEChERS extraction method and HPLC-MS/MS applicable to both life stages down to the level of about three individuals. We show that the uptake of carbamazepine by larvae is concentration-dependent and reduces the emergence rate. Importantly, the body burden remained constant in adult midges. Using this information, we estimated the daily exposure of insectivorous tree swallows as terrestrial predators to carbamazepine using the energy demand of the predator and the energy content of the prey. Assuming environmentally relevant water concentrations of about 1 µg/L, the daily dose per kilogram of body weight for tree swallows was estimated to be 0.5 µg/kg/day. At places of high water contamination of 10 µg/L, the exposure may reach 5 µg/kg/day for this micropollutant of medium polarity. Considering body burden changes upon metamorphosis, this study fills the missing link between aquatic contamination and exposure in terrestrial habitats showing that wastewater pollutants can impact birds' life. Clearly, further analytical methods for biota analysis in both habitats are urgently required to improve risk assessment.

Laboratory-to-field extrapolation: Increase in carbamazepine toxicity in a higher tier, multiple-stress experiment.

The toxicity and environmental risk of chemicals, such as the antiepileptic drug carbamazepine (CBZ), is commonly assessed using standardized laboratory tests and laboratory-to-field extrapolation. To investigate the toxicity of CBZ to aquatic key organisms in a more complex and environmentally relevant scenario, we conducted a 32-day multiple-stress experiment in artificial indoor streams. We exposed the non-biting midge Chironomus riparius, the blackworm Lumbriculus variegatus, and the New Zealand mud snail Potamopyrgus antipodarum to 80 and 400 µg CBZ/L in six artificial indoor streams. In addition to hydraulic stress, species' interaction, and low organic content in the sediment, organisms were co-exposed to the herbicide terbutryn (TBY) as a second chemical stressor at a concentration of 6 µg/L. The exposure to CBZ under multiple stress conditions resulted in a 10- to more than 25-fold higher toxicity in C. riparius and P. antipodarum when compared to a previous, standardized laboratory experiment. The co-exposure to TBY enhanced the adverse effects of CBZ on snails (reduced production of embryos). This effect was additive as the single exposure to TBY also reduced the reproduction of snails, most likely through the reduction of biofilm biomass. The emergence of C. riparius declined at a CBZ concentration of 400 µg/L (without the co-exposure to TBY) and at 80 µg/L in combination with TBY. The difference in sensitivity between laboratory and indoor stream experiments is indicative of a potential underestimation of risk when toxicity data are extrapolated to field conditions. The present results suggest the inclusion of non-chemical and chemical stressors in environmental hazard and risk assessments.

Interactive effects of biotic and abiotic environmental stressors on carbamazepine toxicity in the non-biting midge Chironomus riparius.

The toxicity of contaminants in freshwater ecosystems can increase in combination with environmental stress, leading to a potential underestimation of risk in conventional assessments. The number of multiple-stress experiments in ecotoxicology is growing constantly, but pharmaceuticals have mostly been disregarded. As an omnipresent pharmaceutical in the water cycle, the antiepileptic drug carbamazepine (CBZ) was chosen as test substance for our 28-day binary stress experiments with the non-biting midge Chironomus riparius. Elevated population densities, food limitation, temperature, and a reduction of organic matter (OM) were chosen as relevant environmental stressors. In five stress intensities, they were combined with the 10% lethal concentration (LC10) of CBZ to investigate the joint effect of stress and CBZ exposure. We were able to demonstrate that the toxicity of CBZ increased with higher larval densities and reduced OM. Mortality of the midges exposed to CBZ increased by a factor of 1.69 with 100 larvae per vessel and by a factor of 2.87 at 0.25% OM compared to the conventional test protocol, while the stressors alone did not reduce survival. Conventional low-stress laboratory tests as conducted for the risk assessment of chemicals would have underestimated the toxicity of CBZ. Even though it is necessary that more than binary stressor combinations are included in future experiments, the present results extend our knowledge about the toxicity of pharmaceuticals, such as CBZ, in stressful environments and emphasize the importance of including pharmaceuticals in multiple stress experiments.

Ecotoxicological characterization of the antiepileptic drug carbamazepine using eight aquatic species: baseline study for future higher tier tests.

Ecotoxicological effects of the antiepileptic drug carbamazepine (CBZ) were investigated in one primary producer (Desmodesmus subspicatus) and seven invertebrate species (Daphnia magna, Daphnia pulex, Ceriodaphnia dubia, Gammarus fossarum, Potamopyrgus antipodarum, Lumbriculus variegatus and Chironomus riparius) using OECD and US EPA guidelines for chronic toxicity testing. The present data set was used to conduct a hazard assessment for CBZ including confirmatory data. While most of our results were in accordance with previous studies, published effect data for C. dubia and D. pulex could not be confirmed, even though they have previously been considered to be the most sensitive invertebrate species to CBZ exposure. The non-biting midge, C. riparius, was the most sensitive test organism in the present study. From an EC10 of 406 µg/L and a no observed effect concentration (NOEC) of 400 µg/L, a predicted no effect concentration (PNEC) of 8 µg/L was calculated. With regard to realistic predicted and measured environmental concentrations, the environmental risk can be considered as low for CBZ when the assessment is based on laboratory-based effect data. To conduct a refined and more realistic assessment, this study provides foundational data for two future, higher tier studies: one multiple-stressor experiment and one mesocosm study.

SETAC GLB and SETAC Europe SAC: a liaison promoting the next generation of ecotoxicologists and environmental chemists.

This commentary is an introduction for students to the Society of Environmental Toxicology and Chemistry (SETAC) and its Student Advisory Council (SAC). As young academics face challenges while trying to develop their careers, SETAC and the SAC help facilitate student involvement in the various communities within the society that can help to develop the students' careers within the environmental sciences [e.g. the German Language Branch (GLB)]. This piece would also like to emphasize and pay homage to the continual cooperation between the SAC and the ESEU, which provides a scientific platform to communicate internationally and beyond the borders of SETAC, as well as offer heartfelt congratulations from the SAC to the GLB for their "20 Years SETAC GLB" and deep gratitude for their strong advocacy and support of the SAC.

The 2015 Annual Meeting of SETAC German Language Branch in Zurich (7-10 September, 2015): Ecotoxicology and environmental chemistry-from research to application.

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.

Genetic variation in photosynthetic performance and tolerance to osmotic stress (desiccation, freezing, hyposalinity) in the rocky littoral foundation species Fucus vesiculosus (Fucales, Phaeophyceae).

Genetic diversity may play an analogous role to species diversity, as it can contribute to ecosystem function and stability, and provision of ecosystem services. In the Baltic Sea, perennial algal beds are often comprised of only Fucus vesiculosus and the amount of genetic variation in fitness-related traits (i.e., the ability of the alga to photosynthesize or withstand stress) will thus determine the alga's local persistence in a changing environment. To study genetic variation in the crucial traits behind persistence we grew replicate vegetative branches that came from the same genotype in common gardens. We quantified osmotic stress tolerance and recovery responses by exposing branches to desiccation, freezing, and hyposalinity regimens. Our results show that genetic variation among genotypes was apparent for some photosynthetic parameters (maximal electron transport rate, saturation irradiance for electron transport, nonphotochemical quenching) and growth. Algae tolerated freezing (1,440 min at -2.5°C) and hyposalinity (1,560 min at 2.5) well, but did not recover from desiccation (70 min at 12°C, causing ~94% water loss). Furthermore, we found very little if any evidence on genetic variation in tolerance to these stressors. Our results suggest that low salinity and cold winters in the northern marginal populations selected for hyposalinity and freezing tolerant genotypes, possibly eroding genetic variation in tolerance, but that tolerance to harsh desiccation has been lost, likely due to relaxed selection. The overall availability of genetic variation in fitness related traits might be supportive for F. vesiculosus during adaptation to gradual changes of its environment.

Effects of carbamazepine and two of its metabolites on the non-biting midge Chironomus riparius in a sediment full life cycle toxicity test.

The antiepileptic drug carbamazepine (CBZ) and its main metabolites carbamazepine-10,11-epoxide (EP-CBZ) and 10,11-dihydro-10,11-dihydroxy-carbamazepine (DiOH-CBZ) were chosen as test substances to assess chronic toxicity on the non-biting midge Chironomus riparius. All the three substances were tested in a 40-day sediment full life cycle test (according to OECD 233) in which mortality, emergence, fertility, and clutch size were evaluated. In addition, these parameters were considered to calculate the population growth rate which represents an integrated measure to assess population relevant effects. With an LC50 of 0.20 mg/kg (time-weighted mean), the metabolite EP-CBZ was significantly more toxic than the parent substance CBZ (LC50: 1.1 mg/kg). Especially mortality, emergence, and fertility showed to be sensitive parameters under the exposure to CBZ and EP-CBZ. By using classical molecular dynamics (MD) simulations, the binding of CBZ to the ecdysone receptor was investigated as one possible mode of action (MoA) but appeared to be unlikely. The second metabolite DiOH-CBZ did not cause any effects within the tested concentration rage (0.17-1.2 mg/kg). Even though CBZ was less toxic compared to EP-CBZ, CBZ is found in the environment at much higher concentrations and therefore causes a higher potential risk for sediment dwelling organisms compared to its metabolites. Nevertheless, the current study illustrates the importance of including commonly found metabolites into the risk assessment of parent substances.