Brussels, 14/03/03 INTERREG III: STARDUST July 2002-December 2002 VLIZ
Jan 04, 2016
Brussels, 14/03/03
INTERREG III: STARDUST
July 2002-December 2002
VLIZ
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
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
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 20022002/29: December 2002
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
Brussels, 14/03/03
Detection limits 25_02_03 calibration blanks (2% HNO3, 1ppb In)
Cd Hg Pb Mn Fe Co Ni Cu Zn AsDL ppt 0.17 8.1 4.2 0.74 29 0.65 5.5 6.2 37 4.8
Detection limits DET 11_03_03 ( stdev blanks DET, dilution 100)
Cd Hg Pb Mn Fe Co Ni Cu Zn AsDL (ppb) 0.04 0.36 0.97 2.60 52 0.13 7 1.97 142 0.05
Calibration detection limits
DET detection limits
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)
Brussels, 14/03/03
Reynek boxcorerSediment core
Brussels, 14/03/03
Presectioned cores held together with plastic mantle
Sectioning of cores and transfer to squeezing pot
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Porewater squeezingsystem
Glovebag: N2 atmosphereprevent oxidation of sediment
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Mn Zeebrugge 2
-16-14-12-10-8-6-4-2024
0 2 4 6 8 10 12
squeez
cent
DGT
DET
Fe Zeebrugge
-14
-12
-10
-8
-6
-4
-2
0
2
4
0 50 100 150 200
squeez
cent
DGT
DET
Mn and Fe profiles (concentrations in ppm), october 2002
Muddy sedimentnear Zeebrugge
Brussels, 14/03/03
Co Zeebrugge
-14-12
-10-8-6
-4-20
24
0 5 10 15 20
squeez
cent
dgt
Ni Zeebrugge
-14-12
-10-8-6
-4-20
24
0 50 100 150
squeez
cent
dgt
Cd Zeebrugge
-14-12
-10-8-6
-4-20
24
0 0.5 1 1.5 2 2.5
cent
dgt
Pb Zeebrugge
-14-12
-10-8-6
-4-20
24
0 20 40 60 80
squeez
cent
dgt
Trace metal profiles (concentrations in ppb), october 2002
Brussels, 14/03/03
B2002/23 stat ZB
-14
-12
-10
-8
-6
-4
-2
0
2
4
0 50 100 150 200 250
As µg/L
Fe mg/L
As and Fe DET profiles: Analysis with HR-ICPMS
Brussels, 14/03/03
Fe Sierra Ventana µg/L
-10-8
-6-4
-20
24
68
0 2000 4000 6000 8000 10000 12000 14000
As Sierra Vantana µg/L
-10-8
-6-4
-20
24
68
0 2 4 6 8 10 12
As,Fe and Mn DET profiles, december 2002
Fe st 700 µg/L
-8-6
-4-2
02
46
810
0 1000 2000 3000 4000 5000 6000
As st 700 µg/L
-8
-6
-4
-2
0
2
4
6
8
10
0 5 10 15
Mn Sierra Ventana µg/L
-10-8
-6-4
-20
24
68
0 500 1000 1500 2000 2500
Mn st 700 µg/L
-8-6
-4-2
02
46
810
0 500 1000 1500 2000
Fe st 701 µg/L
-8-6
-4-2
02
46
810
0 500 1000 1500 2000 2500 3000 3500
As st 701 µg/L
-8
-6
-4
-2
0
2
4
6
8
10
Mn st 701 µg/L
-8-6
-4-2
02
46
810
0 20 40 60 80 100 120
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
Brussels, 14/03/03
Vacuum impregnation in polyester resin
-sectioning of core-lyophilisation-vacuum impregnation:polester, aceton, hardener
Brussels, 14/03/03
Polyethyleneglycol (PEG) impregnation
•Equilibation of porewater with PEG for 3 to 5 weeks at 50°C•Lyophilisation
Brussels, 14/03/03
Brussels, 14/03/03
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