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Our research

My group uses the expertise that I have acquired in environmental analytical chemistry and toxicity bioassays in the last 10 years to perform innovative studies that aim to answer the following questions: What other TOCs of concern are present in the environment and at what concentrations? How are EOCs biotransformed in the environment? Are mixtures of trace amounts of TOCs toxic to biota?

Research topic : Occurrence

How can we improve sample preparation and separation methodologies to detect new trace organic contaminants (TOCs) of concern?

Many contaminants have gone unnoticed in the environment for years because of poor methodology, PPCPs are perhaps the most recent example. As many TOCs produced in large quantities may find their way into the environment, new methodologies are required to cope with this diversity. My research on this topic aims at improving the efficiency of screening methods to detect larger numbers of TOCs (PPCPs, plastic additives) of diverse properties (e.g. molecular shape, pKa, octanol-water distribution coefficient). In order to do this, improvements in the sample preparation and chromatography are necessary since the chemical diversity of these contaminants makes their extraction and separation very difficult with a single method. The advantages of improving the extraction efficiency and chromatographic separation of screening methods are increased sensibility and easier identification of EOCs during the data analysis workflow.

Examples of Trace Organic Contaminants (TOCs)
Bis(2-ethylhexyl) phthalate (plasticizer)
Carbamazepine
(anticonvulsant,mood regulator)
Lyngbya wollei toxin-1 (cyanotoxin)
Trimethoprim(antibiotic)
Tris-(2-chloro-, 1-methyl-ethyl)-phosphate (flame retardant)
Venlafaxine (antidepressant)

 

Research topic: fate

What tranformation products of organic contaminants are present in the aquatic environment ?

Biological activity of TOCs can be enhanced or maintained upon transformation in the environment or in wastewater treatment palnts. For that reason, it is important to develop sensitive methods of analysis of transformation products of organic contaminants in the aquatic enviroment. Given the multitude of organic contaminants present in surface waters, nontarget methods based on analysis by liquid chromatography-high resolution mass spectrometry are more adequate to perform initial studies that allow to perform wide screening studies. We are presently optimizing nontarget methods in order to improve sensitivity and widen the number of compounds that can be detected in a single injection. We are also developping complementary diagnostic techniques to increase the confidence in the identification of transformation products. Examples are mass spectral accuracy, post-column hydrogen-deuterium exchange and retention time preditction.

Research topic: toxicity

Can we use changes in the metabolic profile of D. magna caused by the exposure to mixtures of TOCs as a sensitive toxicity bioassay?

The presence of traces of TOCs in the environment is worrisome since effects of these substances on non-target species such as invertebrates and fish are not yet well understood. Traditional bioassays using test organism such as D. magna to measure survival, growth or fecundity as toxicity endpoints are only able to detect significant differences between controls and exposed groups at concentrations of individual TOCs > 10 ppb. These concentrations are about 100 to 10000 times higher than reported TOCs concentrations in surface waters. For that reason, we will develop a sensitive metabolic profiling bioassay based on a model species in ecotoxicology, the water flea D. magna. This novel metabolic toxicity bioassay will allow us to measure subtle effects caused by mixtures of TOCs that cannot be detected by standard bioassays.