LAUSR

The freely dissolved concentration (Cfree) was measured for PAHs and PCBs in sediments of the German Bight and Wadden Sea. Ex-situ Solid Phase Microextraction (SPME) was applied using Polydimethlysiloxane (PDMS) coated glass fibers followed by automated thermal desorption and GC-MS analysis. This study provides the first dataset on the spatial distribution of Cfree for PAHs and PCBs in the German Bight and the Wadden Sea. We found elevated PCB concentrations in the Wadden Sea and especially in the Weser estuary. Sandy North Sea sediments were rather less contaminated, except for some former dumping sites. The sorption strength of PAHs was generally stronger, while PCBs in the Wadden Sea sediments were only weakly bound. This SPME method is a rapid and sensitive tool to study Cfree of hydrophobic organic chemicals to improve todays sediment risk assessment.