Verbindung von Aufnahme, subzellulärer Partitionierung/Toxikokinetik und Toxikodynamik für die Modellierung von Cu2+ Toxizität bei der Zebramuschel unter Berücksichtigung der Wasserchemie
Ökologie und Biodiversität der Tiere und Ökosysteme, Organismische Interaktionen
Zusammenfassung der Projektergebnisse
A two-compartment kinetic model is capable of simulating Cu accumulation in gills and in the remaining tissues of aquatic organisms like the zebra mussel. The copper uptake rate constant slightly decreased with decreasing pH down to 6.5, indicating potential interactions between Cu and H+ at uptake sites, in addition to interactions at abiotic ligands in the external medium. At the investigated range of Na+ concentrations, Na+ had no significant effects on Cu uptake by the zebra mussel. Moreover, a model calibrated at environmentally relevant conditions can be extrapolated to various conditions. A higher concentration of Cu in the BDM (including metal-rich granules and the metallothionein fraction) than in the MSF (including enzymes and organelles) clearly demonstrates the ability of the zebra mussel to detoxify accumulated Cu. Another consistent trend is a more important contribution of the metallothionein fraction than the metal-rich granules among detoxified fractions of Cu-exposed mussels. No consistent trend was revealed from the measurements of biomarkers in the zebra mussel exposed to Cu at various Cu exposure concentration. Significant stimulation of the GST activity was followed by a decline to the level of unexposed mussels, indicating recovery of the antioxidant system. Moreover, the LPO level was not significantly affected by Cu exposure. These results reflect regulations by the zebra mussel, as exemplified by accumulation of accumulated Cu in detoxified fractions. Considering metal partitioning to subcellular fractions allows for including both toxicokinetics and toxicodynamics model for predicting responses of organisms from the exposure level in the environment. The influence of environmental chemistry was considered in modelling metal uptake. The capacity of organisms to detoxify accumulated metals is considered in predicting biological responses. Potential recovery of the antioxidant system was also covered by the model. Results from the project are being used for subsequent research. The first one is to develop a TK-TD model that takes enzyme kinetics into account. A consideration of the inhibition of the Na+/K+-ATPase activity might improve characterization of metal toxicodynamics. Considering ionoregulatory disturbance as an important mechanism of Cu (maybe also other metals) toxicity, it is of importance to include potential inhibition of the Na+/K+-ATPase activity in TK-TD models. The model is going to be validated using empirical data generated in this project. Moreover, the empirical data on subcellular fractionation is going to be used for another proposal that aims to model the trophic transfer of metals.
Projektbezogene Publikationen (Auswahl)
- (2020): Modelling copper toxicokinetics in the zebra mussel, Dreissena polymorpha, from chronic exposures at various pH and sodium concentrations. Chemosphere, 267, 2021, 129278
T.T. Yen Le; Daniel Grabner; Milen Nachev; Willie J.G.M. Peijnenburg; Hendriks, A.J.; Sures, B.
(Siehe online unter https://doi.org/10.1016/j.chemosphere.2020.129278)
