Research project MN/DD2/012 (Research action MN)
Framework of the project
The recent Quality Status Report on the Greater North Sea (referred as "QSR 2000") includes almost no data for those compounds of major concern. These compounds are however subject to new EC policies aiming the reduction of the population exposure. Furthermore, the report points out a lack in Quality Assurance procedures leading to useless data production concerning organic contaminants.
The aim of this project is to provide the authorities with efficient, validated monitoring tools for dioxin-like compounds based on the application of a three-levels analysis strategy to a real sampling campaign situation. The analytical strategy is a three levels modular strategy, in which, according to the level of information required, the cost/efficiency is optimized.
The three levels are the following: Total toxicity in TCDD equivalents (TEQ) screening by bioassays, congener specific TEQ screening and semi-quantification by HRGC/MSMS with large volume injection, confirmation and reference measurements by HRGC/HRMS. In addition, the scope of the strategy will be extended to newly added compounds in the Priority Substances List of OSPAR. The proposed strategy will allow a sound assessment of an integrated monitoring tool in a real sampling situation.
The optimisation and the validation of the analytical strategy will include the following steps :
1. Optimisation of the sample preparation;
2. Optimisation of the detection step (MS methodology or bioassays);
3. Comparison of TEQ values obtained at the different levels;
4. Statistical analysis of the results and implications for quality managment.
This tool finds its place within the framework of international efforts aiming at the reduction of inputs and the monitoring of these compounds in the marine environment. It will allow the optimal use of resources, bringing together the best currently available analytical methods within an officially recognised quality system.
Goals
Our goal is to make reliable, fast and low cost analytical tools available to authorities for the identification and quantification of organic micro-pollutants. Those tools will fit the priority needs for the OSPAR convention. The laboratory has focused on dioxins, furans and dioxin-like PCBs, within the perspective of developpping a general strategy ready for BELTEST accreditation. Analyses of other compounds such as poly-brominated molecules are under development. The results obtained by the different techniques will be compared on the same marine matrices. This should allow defining figures of merit for each method and to optimize their complementary use in real situations. This optimization will allow a better use of the resources allocated to the monitoring and contribute to a better knowledge and understanding of toxic persistent compounds in marine environment.
Expected results
The laboratory is developing an analytical strategy that fit the requested degree of precision. Three degrees can be drawn out :
1. The rapid screening will give a global image of the contamination in target compounds, without discrimination between molecules of similar effects. The response will be expressed as total toxic equivalents. Techniques for such application will consist in biological methods (EIA, CALUX, BIACORE). Such results are useful in a phase of exploratory measurements, in order to follow a temporal or spatial trend of a pollution, as well as for the determination of the contamination levels with reference to an established norm.
2. The semi-quantitative evaluation of the pattern of congeners within a compounds family allows to obtain an image of the sources of contamination and to follow the preferential bio-accumulation of certain congeners. The method used in this case is a coupling between gas chromatography and MS/MS mass spectrometry.
3. The confirmation of data is performed with a reference method. This method allows to quantify variations in the contamination patterns, to compare results obtained in different sampling conditions (seasonal variations, compartments of a sampling site, ...), and to reach very low quantification limits. Such a reference method requires a coupling between gas chromatography and high resolution mass spectrometry. The quantification is obtained by the isotopic dilution method, with compounds labelled with 12 atoms of carbon 13 (13C12).
This strategy is currently applied for the analysis of dioxins, furans and coplanar PCBs. Its application to other compounds is also under development in our laboratory, which possess not only the necessary measuring techniques but also efficient sample preparation apparatuses (SFE, ASE, GPC, Power-PrepTM, ...).
In parallel, a proteomic approach is in preparation. Its goal is the identification and estimation of the intoxication level by proteic bio-markers, and requires techniques as matrix assisted laser desorption (MALDI-MS) and electrospray (ESI-MS).
The Partners
In order to apply the developed methods, the laboratory is in contact with partners providing marine samples.
"Birds and mammals of the North Sea : pathology and eco-toxicology". Samples of mammals and birds are provided by the laboratory for oceanology, U.Lg. (Professeur J.-M. Bouquegneau).
"ICAS : impact of heavy metals and poly-chloro biphenyls associated with the sediments of the North Sea". Samples of sea-stars and sediments are provided by the laboratory of marine biology, U.L.B. (Docteur P. Dubois).
"IDOD : Integrated and dynamic management of oceanographic data" (S. Scory, MUMM). These contacts are taken for future analyses campaigns.
Information :
Professor E. De Pauw
Mass Spectrometry Laboratory, B6c
University of Liège
B-4000 Liège
Sart-Tilman, Bât. B6c
e.depauw@ulg.ac.be
Fast and low cost analysis of dioxin and dioxin-like compounds in marine matrices : final report
Debacker, V. - Windal, I. - Danis, B. ... et al Brussels : Federal Science Policy, 2004 (SP1350)
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