INTERREG III: STARDUST

1
INTERREG III STARDUST

• July 2002-December 2002

VLIZ
2
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
Dissolved phase
DGT
DET

• 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

• Equibrium of porewater with agarose gel
• TOTAL concentration of pollutants

4
DGT, DET
Laboratory experiments
Field work
Application of the method on sediments of the
North Sea Belgian coast Belgica
expeditions 2002/23 October 2002 2002/29
December 2002

• Method development and Quality Control
• Gel preparations
• Blanks and detection limits
• Reproducibility
• Recovery
• Linearity
• Capability of HR-SF-ICPMS

5
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
Calibration detection limits
DET detection limits
7
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
Reynek boxcorer
Sediment core
9
Sectioning of cores and transfer to squeezing pot
Presectioned cores held together with plastic
mantle
10
Porewater squeezing system
Glovebag N2 atmosphere prevent oxidation of
sediment
11
Muddy sediment near Zeebrugge
Mn and Fe profiles (concentrations in ppm),
october 2002
12
Trace metal profiles (concentrations in ppb),
october 2002
13
As and Fe DET profiles Analysis with HR-ICPMS
14
As,Fe and Mn DET profiles, december 2002
15
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
Vacuum impregnation in polyester resin
-sectioning of core -lyophilisation -vacuum
impregnation polester, aceton, hardener
17
Polyethyleneglycol (PEG) impregnation

• Equilibation of porewater with PEG for 3 to 5
  weeks at 50C
• Lyophilisation

18
(No Transcript)
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