Fate of contaminants of emerging concern in the Oslofjord: A model based analysis

Six contaminants of emerging concern (CECs): clarithromycin, citalopram, tributylphosphate, benzotriazole, octocrylene and teflubenzuron, with differing sources, applications, and contrasting properties were selected for modeling their fate in the water column and the sediments of the Oslofjord. The FABM family models was used, which couples the benthic-pelagic model 2DBP with the biogeochemical model BROM and the elaborated contaminants transformation module. This approach parameterized processes of CECs partitioning with organic matter, and CECs decay due to biodegradation, photolysis, and hydrolysis. This combination of modules allows for the simulation of spatial and temporal variability of CECs during a period of intensive pollution and restoration. It was shown that: (i) the biological pump significantly affects transformations of CECs leading to seasonal variation of concentration in the water column; (ii) during the pollution period fluxes of particulate and dissolved matter are directed to the sediments; while there is a flux of dissolved CECs from the sediments; (iii) after cessation of the pollution a flux of dissolved CECs from the sediments was predicted for a certain period; (iv) properties of the CECs determine the effectiveness of the biological pump and duration of CECs existence in the water column and the sediments following the cessation of pollution.