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(38-53) Effect of site management on ageing of PAH is a restored salt marsh ecosystem system. Vorenhout, Michel*,1, Raquel, Gutierrez Lanza1, Howsam, Mike1, Van Straalen, Nico1, Eijsackers, Herman1, 1 Institute of Ecological Science, AMSTERDAM, The Netherlands ABSTRACT- Ageing of PAH in soil is a well-studied subject in laboratory settings. It is mainly influenced by wetting-drying cycles, degradation of organic matter and contact time. Few studies have focused on ageing in field settings. We have measured ageing of PAH in soil columns, taken from a restored salt marsh in the north of the Netherlands. Columns were separated in a deep layer and a top layer. The deep layers are representative for a situation with frequent inundation or for a situation with sheep grazing and drainage of the soil. The top layers are representative for a restored salt marsh, e.g. very wet during the year with high sedimentation, or a natural salt marsh. Soil columns were sequentially extracted with H2O, MeOH, DCM and a saponification with KOH/MeOH. Samples were analysed on a HPLC with variable wavelength. Ageing is expressed as the fraction of total PAH found in the saponification. Results show that the deeper layer with the drainage and grazing situation has a higher ageing than the layer of same age with inundation and no drainage. Top layers, with a similar age and management show a similar ageing. With our results we can show that published results found in the laboratory can be extrapolated to a field situation, and that site-management effects ageing of PAH and subsequent availability (Vorenhout et al., 2000). Key words: PAH profile, salt-marsh, feedback effect, ecological restoration |
