|
3F - Coastal Zone Mgnt (WEP/184) Fate models for alkylphenol ethoxylates and carboxylated metabolites in Dutch estuaries. Jonkers, Niels1, Laane, Remi1, 2, De Voogt, Pim1, 1 University of Amsterdam, Amsterdam, The Netherlands, The Netherlands2 National Institute for Coastal and Marine Management - RIKZ, The Hague, The Netherlands, The Netherlands ABSTRACT- Alkylphenol ethoxylates (APEO), a group of nonionic surfactants, are of major environmental concern, because the estrogenic effects of some of their possible metabolites. Fate models for APEO and metabolites in the Dutch Scheldt and Rhine estuaries were developed, based on extensive sampling campaigns. Specific attention was paid to the possible metabolites alkylphenoxy ethoxy acetic acids (APEC) and nonylphenol. The results from the sampling campaign in the Scheldt estuary showed that in the water phase, the APEC metabolites were present at higher concentrations than the APEO surfactants. Their concentrations decreased much slower than APEO when going downstream in the estuary, suggesting estuarine formation of APEC out of APEO. The ECoS 3.0 fate modeling software was implemented to construct a hydrodynamic, one-dimensional advection-dispersion model for the Scheldt estuary, which was validated using actual water inputs and salinity values. With this model, an estimation could be made of the contribution of different processes (biodegradation, local sources, sorption, dilution) to the concentration profiles of both APEO and its metabolites. In the stratified Rhine estuary, the behaviour of APEO is more complex. In a new sampling campaign, water samples from different depths were taken. Based on these data, an attempt was made to construct a two-dimensional fate model for this area, to describe the stratification of the estuary more accurately. Key words: estuaries, alkylphenol ethoxylates , fate modeling, monitoring |
