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A 1D coupled hydrodynamic and contaminant fate model was applied to simulate the distribution of polychlorinated biphenyls (PCBs) in the Ispra Bay located in the southern part of Lake Maggiore (Italy). The model succeeded in representing the hydrodynamic processes occurring in the lake such as thermal stratification during summer 2005 followed by the complete mixing of the water column in February 2006. The results of the PCB fate model highlighted that these processes play a key role for the settling of particles and consequently for the distribution of PCBs in the water column as well as for the contaminant flux at the sediment–water interface. On the air–water front, the simulations emphasised that the net atmospheric PCB input fluxes are generally more important during the cold season and show peaks during periods of high wet deposition. Finally, the seasonal variability of the distribution of PCB in the water column was assessed. [Copyright &y& Elsevier]

A bioaccumulation model to predict concentrations of s-triazine herbicides in the macroalgae Ulva rigida and in clams Tapes philippinarum has been implemented, calibrated and validated. The model uses input data from a 3D biogeochemical model that provides biomasses in the different compartments, i.e. phytoplankton, zooplankton and bacteria; and from a 3D fate model that provides the herbicides concentrations in the water column as well as in the sediments. Simulated data were compared with experimental data collected during a set of sampling campaigns carried out in 2004 and 2005 in the Sacca di Goro lagoon (Northern Adriatic). The model predicts correctly the concentrations of herbicides measured in Ulva rigida and reproduces with good agreement the values of concentration of herbicides found in clams. Furthermore, the simulated spatial and temporal dynamics in the biota compartment, following those of the water and sediments, are also in agreement with the experimental data. This integrated approach combining biogeochemical, fate and bioaccumulation models provide an overall assessment of the importance of the different environmental compartments and it can also support the testing of different management strategies to improve ecosystem state and functioning. Further research is necessary to elucidate the role and importance of the metabolism of these compounds by clams. [Copyright &y& Elsevier]