1. Brussels, 14/03/03 INTERREG III: STARDUST July 2002-December 2002 VLIZ

2. Brussels, 14/03/03 Aim Understanding of fate and mobility of pollutants in sediments requires high resolution profiles of pollutants Dissolved phase DGT, DET Solid phase Laser ablation ICPMS

3. Brussels, 14/03/03 Dissolved phase DET DGT Equibrium of porewater with agarose gel TOTAL concentration of pollutants Binding of trace metals on Chelex resin gel Preconcentration capability In sediments: interpretation depends on remobilisation rate from the sediment phase Only metals which bind on Chelex: SPECIATION Free metal ions and weakly bound metals As: AsIII Hg: HgII

4. Brussels, 14/03/03 DGT, DET Laboratory experiments Field work Method development and Quality Control Gel preparations Blanks and detection limits Reproducibility Recovery Linearity Capability of HR-SF-ICPMS Application of the method on sediments of the North Sea: Belgian coast Belgica expeditions: 2002/23: October 2002 2002/29: December 2002

5. Brussels, 14/03/03 Advantages of high resolution sector field ICPMS High sensitivity; low detection limits Low sample volume required (1ml) Posibility to work with variable resolutions: –low resolution for elements with little isobaric interfences –Medium and high resolution for elements with important isobaric interferences Possible to measure Fe in water and As in seawater: Both elements not possible with normal quadrupole ICPMS Fe: ArO intereference As: ArCl intereference

6. Brussels, 14/03/03 Calibration detection limits DET detection limits

7. Brussels, 14/03/03 Field work Comparison of DGT_DET and classical porewater sampling methods: squeezing and centrifugation Performed on different sediment types: sandy, muddy, carbonate rich sediment cores collected with Reynek boxcorer DGT, DET performed on cores placed in an incubator on deck of the ship (24 hours)

8. Brussels, 14/03/03 Reynek boxcorer Sediment core

9. Brussels, 14/03/03 Presectioned cores held together with plastic mantle Sectioning of cores and transfer to squeezing pot

10. Brussels, 14/03/03 Porewater squeezing system Glovebag: N2 atmosphere prevent oxidation of sediment

11. Brussels, 14/03/03 Mn and Fe profiles (concentrations in ppm), october 2002 Muddy sediment near Zeebrugge

12. Brussels, 14/03/03 Trace metal profiles (concentrations in ppb), october 2002

13. Brussels, 14/03/03 As and Fe DET profiles: Analysis with HR-ICPMS

14. Brussels, 14/03/03 As,Fe and Mn DET profiles, december 2002

15. Brussels, 14/03/03 High resolution profiles in the solid phase Sediment impregnation techniques: 2 techniques are being tested: –Polyester resin –Polyethylene glycol Tests performed on sediments of the North Sea Cutting/polishing Analysis by LA-ICPMS

16. Brussels, 14/03/03 Vacuum impregnation in polyester resin -sectioning of core -lyophilisation -vacuum impregnation: polester, aceton, hardener

17. Brussels, 14/03/03 Polyethyleneglycol (PEG) impregnation Equilibation of porewater with PEG for 3 to 5 weeks at 50°C Lyophilisation

18. Brussels, 14/03/03

19. Perspectives Application of DGT, DET methods: Scheldt river and tributaries DET-HR-ICPMS: improve detection limits for a number of elements and expand range of elements measured As speciation: –DET: Total As –DGT: AsIII –coupling of DET with HPLC-AFS? Hg speciation –DGT: Chelex: HgII –DGT: Sumichelate resin: HgII, methylmercury