CITE seminar series
CITE - Chemicals In the Environment - is a research topic within the Helmholtz programm oriented funding. CITE addresses multiple aspects of the impact of chemicals in the environment. The seminar series (irregular) with invited external speakers aims to reflect these different aspects.
10.03.2014 (Mo), 3 p.m., KUBUS Saal 1 C+D
National Research Centre for Environmental Toxicology (Entox), The University of Queensland, Brisbane, Australia
Processes governing surfactant facilitated transport of superhydrophobic organic compounds
Superhydrophobic organic contaminants (SHOCs) are practically insoluble in water and have a high affinity for organic matter, and therefore are generally considered immobile in soil. Examples include polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated biphenyls and a range of brominated flame retardants and pesticides. Surfactants, however, have the ability to solubilise SHOCs in soil-water and consequently significantly change their mobility in the subsurface. As a result, contaminants may be transported through the soil column, leading to unexpected groundwater contamination. However, surfactant facilitated transport (SFT) processes for SHOCs are still poorly understood and the significance of these transport processes at sites where surfactants and SHOCs are occurring together, such as agricultural sites, is not known. Both these factors need to be understood in order to quantify and if necessary manage, the risks from SFT. If the underlying mechanisms and the parameters that drive these processes are known, then modelling tools can be developed/applied to predict where and to what extent contaminant transport may be occurring in the environment.
The mobility of SHOCs under SFT is largely driven by the partitioning behaviour of these contaminants between water, soil and surfactants. SHOCs can partition to mobile surfactant phases (micelles and monomers) and be transported with soil-water. Conversely, sorption to soil and surfactants sorbed to soil can reduce their mobility. My PhD aims to investigate/quantify the underlying partitioning processes for SFT of SHOCs and apply this knowledge to simulate these processes under conditions relevant to agricultural sites.
Veronika Schacht is PhD student at the University of Queensland, working under the supervision of Dr. Sharon Grant on a Discovery Project funded by the Australian Research Council entitled “Unintentional surfactant facilitated solubilisation and transport of apparently immobile chemicals”, a collaboration between A/Prof. Caroline Gaus and Prof. Beate Escher at the University of Queensland and Dr. Michael Finkel of Tübingen University.
Host: Beate Escher (ZELLTOX)
14.03.2014 (Fr), 1 p.m., Building 6, Room 111
Department of Biological Sciences
Graduate Program in Environmental and Molecular Toxicology
North Carolina State University
Physiological approaches to understanding thermal controls on aquatic insect performance
Virtually every aspect of aquatic insect life history is controlled by temperature. Yet, surprisingly little is known about the physiological drivers of thermally mediated life history outcomes. In this talk, I will present the results of several recent laboratory studies that explore the influence of warming on the physiology and life history outcomes of mayflies. A combination of respirometry, qPCR and metabolic profiling work all point towards the importance of temperature controls on bioenergetics. We specifically explored whether oxygen limitation (the mismatch between oxygen supply and demand) could explain ecologically life history outcomes, and found that oxygen limitation only appears relevant during the molt, and during acute thermal challenge (Ct maximum type of experiments), but not ecologically relevant thermal regimes. I will further discuss the respiratory challenge, environmental sensitivity, and costliness of molting.
Host: Matthias Liess (OEKOTOX)