PARENT SESSION
TP5b Bioavailability of Organic Chemicals: Concepts, tools and consequences
4:30 PM to 6:30 PM, Tuesday, 08 May 2001
Session Chair: J.J. Ortega
Room 5

(256) Tenax extraction predicts uptake of PAHs by oligochaetes in lake Ketelmeer sediment.

ten Hulscher, Dorien¹, Cornelissen, Gerard¹, van Noort, Paul¹, Wilkens, Menno¹, de Haan, Wietske¹, Postma, Jaap², van de Guchte, Kees¹, de Boer, Sylvia¹, Steketee, Philip¹, ^{1 2}

ABSTRACT- In lake Ketelmeer, a range of sediments taken from both the top layer and from deeper layers were evaluated. The aim of this study was not only to detemine the total amount of selected contaminants present in the sediment but also to determine their bioavailability. The results indicate that determination of the concentration in the fast desorbing pool gives a better indication of availability and potential risk than the total amount present does. The approach taken was: 1. to determine total amount of a range of organic micropollutants (among which PAHs) 2. to determine the concentration present in the fast desorbing pool in all sediment samples by use of a single step Tenax extraction 3. to determine amounts accumulated in oligochaetes after 28 days of exposure to these sediments 4. to measure freely dissolved concentrations in pore water of some selected samples by complexation and flocculation of DOC. The results demonstrate that uptake of PAHs is better correlated with the concentration present in the fast desorbing pool than with the total concentration of a contaminant as determined by solvent extraction. The relation with freely dissolved concentration in pore water will also be addressed.

Key words: tenax extraction, desorption kinetics, freely dissolved concentrations, bioaccumulation