Hallo, my name is Hanne Hetjens and I am a PhD student at the University of Antwerp, working on Work Package 3. In my work I am focus on the evaluation of the toxicity of contaminated natural sediments on related organisms such as benthic macroinvertebrates and rooted plants.
More specifically we are working with the worm Lumbriculus variegatus, the amphipod Gammarus spp. and the plant Myriophyllum spicatum. These organisms live in or on the sediment and are therefore in close contact with the sediment and highly dependent on its quality. As plants, herbivores and detritivores form the basis of each food web, toxicological effects such as altered feeding rates, grow rates, reproduction or survival found here, can propagate through the whole food web (cascade effect) and have widespread effects on the biological status and health of related species communities, the surrounding ecosystem and eventually also for us. Contaminants that are less strongly bound to the sediment can accumulate in the tissue of organisms and accumulate in predators feeding on those organisms. Through this, contaminants that are stored in the sediment can end up in high concentrations in top predators such as fish, birds and mammals, even though they are not in direct contact with the sediments. Studying the effects and the bioaccumulation of sediment-bound contaminants on the chosen organisms can therefore give important information about the ecotoxicological risk and remediation necessity of natural sediments.
Together with other project partners, different bioassays will be performed and a test battery developed, with the aim of facilitating and improving sediment evaluation processes. I am interested in the results that we will get within the next two years and I am glad that my work can help to improve sediment evaluation and management in the near future. As sediments are located at the receiving end of all processes going on within an aquatic ecosystem, they surely deserve more attention in aquatic ecosystem management than they got so far.