Proposed PhD project: Bioavailability of sorbed compounds for aquatic organisms - 14.07.2011

Background: Contaminants in the environment occur in several compartments of the ecosystems, with the main driver of their distribution being their lipophilicity, charge and ligand properties.

Lipophilic compounds sorbs to particles and even large organic molecules dissolved in the water. The kinetics of these processes and of their transformation will determine their bioavailability. Surface reactions can facilitate (de-)conjugation and degradation, as well as mobility across biological membranes, but sorption can also make compounds non-available to biota. Traditionally, exposures of aquatic organisms to contaminants are done in pure water, where rates of uptake and elimination (toxicokinetics) and the effects of the contaminants on the organisms (toxicodynamics) can be determined.

 

In the environment, however, organisms will be exposed to contaminants sorbed to
organic macromolecules, suspended particles, sediments & food stuff. How the organism is exposed will depend on its living- and eating habits. The question is how bioavailable contaminants sorbed to different matrices are compared to the toxicity of the free compound?

 

 

Goal of the Ph.D. project: The goal of this project is to understand distribution patterns of strongly sorbing organic micro-pollutants in natural aqueous ecosystems and to investigate the toxicokinetics and -dynamics of the sorbed contaminants in aquatic organisms with varying living habits.

 

This includes studies on sorption and desorption kinetics in systems with sediments and dissolved organic matter. Advanced analytical chemistry techniques for separation and determination of microcontaminants in experimental model systems and fractionation in organism matrices will need to be
developed, as will biomarkers of physiological effects of the target organisms.

 

The candidate will be based in the Environmental Chemistry and Physics group, at University of Copenhagen, Faculty of Life Sciences.

 

 

Project supervisors: Main-supervisor: Bjarne W. Strobel (KU-LIFE).

Co-supervisors: Nina Cedergreen (KU-LIFE).
Project collaborators: Juliane Hollender, EAWAG, Zürich. 

 

Further information: http://www.life.ku.dk/~/media/Pers/docs/Elitephd_projektbeskrivelse/EnvirhemEcotox_2.ashx