The use of feeding of aquatic invertebrates as an assay to evaluate toxic effects of micro pollutants under laboratory and field conditions
Supervisor: Prof. Lieven Bervoets
Toxic effects of micro pollutants can take place at different levels of biological organisation, ranging from the molecular to the ecosystem level. An organismal response which has proved to be sensitive at in situ exposures to toxicants is the feeding rate of invertebrates (e.g. the amphipod Gammarus pulex or the Isopode Asellus aquaticus). In addition, a recently developed artificial cellulose substrate (DECOTAB) has been found to mimic feeding rates of aquatic invertebrates under natural conditions. However, little is known on the reaction of feeding rate on different types of toxicants and on the combined effect of environmental factors such as pH and temperature.
The aim of this subject is to assess the applicability of feeding rate for different priority pollutants for different aquatic invertebrate species and to compare the results with the use of DECOTAB substrates. Organisms will be exposed in the laboratory at different pollutants and under different environmental conditions such as pH, oxygen and temperature.Subsequently organisms will be exposed in the field at sites contaminated with the same pollutants.
This project is in close cooperation with the University of Amsterdam.
The use of terrestrial invertebrates as biomonitors for contaminated sites in Flanders
Supervisor: Prof. Lieven Bervoets
Within biomonitorring a distinction can be made between passive (PBM) and Active Biopmontoring (ABM). PBM implies the sampling of resident organisms and the measurement of accumulated micropollutants and effects. In the ABM approach organisms originating from a controlled culture or from a reference site are exposed in cages at different sites for a dedicated time. After this exposure period organisms are collected and again pollutants and/or effects are measured.
In both approaches accumulation can be related to environmental levels and effects (such as survival, growth, fertility,..) can be related to accumulated levels.
Within this topic two different subjects are possible.
- A first subject tries to investigate the applicability of woodlice and/or slugs for the biomonitoring of soil contamination in and around the city of Antwerp. At several sites both soil and invertebrates will be collected. Metals will be measured in all samples and soil characteristics will be assessed. It will be investigated if a relationship can be found between levels in soil with levels in inveretbrates.
- In a second subject caged snails will be exposed at several contaminated sites in Flanders and again accumulation and effects will be assessed.
Risk of pesticide exposure for reptile species on Croatian islands
Supervisors: Prof. L. Bervoets, Prof. R. Van Damme
Pollution of the terrestrial environment with pesticides may have a high impact on wildlife. However, despite the fact that many reptiles in the European Union are considered as threatened, data on exposure to or effects of pesticides on reptiles are very scarce. Nevertheless reptile species may occur within agricultural areas with regular pesticide applications and thus be potentially at risk.
In this study it will be assessed if differences exist in species diversity in areas with intensive agriculture (e.g. viniculture) and diversity will be compared with ‘natural’ islands. Secondly from a selection of species buccal swabs will be taken to analyse enzymatic biomarkers that are indicative for pesticide exposure. This non-invasive method will allow us to determine the seriousness of exposure of reptiles to pesticides in different areas.