Lille, 18/09/03 INTERREG III: STARDUST January September 2003 VLIZ

Lille, 18/09/03 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

Lille, 18/09/03 High resolution profiles in the solid phase Sediment impregnation techniques: 2 techniques were tested: –Polyester resin –Polyethylene glycol Tests performed on sediments of the North Sea and the Rupel Cutting/polishing Analysis by LA-ICPMS

Lille, 18/09/03 Vacuum impregnation in polyester resin -sectioning of core -lyophilisation -vacuum impregnation: polester, aceton, hardener

Lille, 18/09/03 Vacuum impregnation in polyester resin Problems encountered: -amount of hardener, aceton; impregnation time has to be optimised for different sediment types: low porosity samples require more aceton, less hardener and longer impregantion time relatively easily solved

Lille, 18/09/03 Polyethyleneglycol (PEG) impregnation Equilibation of porewater with PEG for 3 to 5 weeks at 50°C Lyophilisation

Lille, 18/09/03 Polyethyleneglycol (PEG) impregnation Problems encountered -very slow method (3-5 weeks) -evaporation of PEG -optimal concentration of PEG depends on nature of the sample -good results for sandy marine sediment -poor results for muddy sediments, especially Rupel

Lille, 18/09/03 Rupel sediment after polyester impreganation cut in 4cm sections with a diamond cutter

Lille, 18/09/03 LA- ICPMS analysis compared to classical digestion-ICPMS

Lille, 18/09/03 LA- ICPMS analysis Problems encountered -choice of internal standard: spiked with In, Re or major element with constant concentration (Ca,P, …) -choice of standard: better results with polyester impregnated reference sediment than with LA glass standard -validation of high resolution profiles: comparison with other methods (Synchroton XRF) are being performed