Ecotoxicity of chemicals
The aim of the BMBF-funded collaborative project Glymik (duration Nov. 2020- Oct. 2023) is to demonstrate possible effects of the herbicide glyphosate, one of its formulations (Roundup) and its main metabolite AMPA on brown trout as representatives of aquatic ecosystems. For this purpose, the health status of exposed fish, the integrity of their gut and gill microbiome, and their immunocompetence will be investigated.
Ecotoxicological biotests are conducted to evaluate effects on non-target organisms under standardised conditions. Usually, those protocols direct testing at a single neutral pH. However, natural conditions vary greatly and, in aquatic environments, pH values between 6 and 8 usually prevail. Depending on hydrogeological characteristics and anthropogenic impact, surface waters can even shift towards clearly both acidic and alkaline conditions with pH values between 4.5 and 10. Results obtained from toxicity tests conducted at a neutral pH may thus not apply to such divergent conditions. This is the case particularly for ionisable substances that are known to change their electric charge depending on the pH of the surrounding matrix. To exert their toxicity, uptake of the compound into the organism is prerequisite, thus, neutral or ionic species have to pass through a biomembrane. Whereas neutral species enter cells by passive diffusion along a concentration gradient, ions have to overcome the electrostatic barrier of the membrane. To pursue the investigation of a potential over- or underestimation of toxicity of ionisable substances due to shifts in pH, PHION, a joint project of the Animal Physiological Ecology group with the University of Athens, which is funded by the German Federal Environment Agency (UBA) will systematically generate data on fish embryo toxicity and chemical accumulation and aims at developing models that allow extrapolation of the toxicity of ionisable substances for different pH.
In the Baden-Baden and Rastatt regions, both Baden-Württemberg, Germany, about 470 hectares of agricultural land and, partially, ground water have been contaminated with per- and polyfluorinated chemicals (PFC). However, per- and polyfluorinated compounds other than PFOA ans PFOS are poorly characterized regarding their toxicity. The project EOFplus aims at compiling existing knowledge, at outlining knowledge gaps, and at suggesting threshold data for human consumption for a number of these compounds whenever possible.
The project Effect-Net (Effect Network in Water Research) investigated the effects of highly consumed chemicals for lifestyle diseases in aquatic ecosystems. Effect-Net was one of the three projects funded by the Wassernetzwerk Baden-Württemberg.
The project Eff-Pharm aims to establish new, effect-based monitoring tools for pharmaceuticals in the aquatic environment. In this project, funded by the "Umweltbundesamt" (German Environment Agency), in vitro-systems that react to specific pharmaceutical classes are to be developed. The effects visible in these in vitro-systems are compared to effects in fish, gammarids and annelids in vivo.