Fig. 5. Nutrient loads at the Oder/Odra river mouth for phosphorus (a) and nitrogen (b). Shown are historic loads, present loads, the loads resulting from the optimal nutrient emission reduction scenario, and background loads (assuming no human activity and no land use in the river basin). Further indicated are threshold loads resulting from water-quality threshold concentrations, according to LAWA-AO (2007, unpublished working paper) and BMU 2001 (see Table 1). For the lagoon (c), the critical load concept for phosphorus after Vollenweider (1976) has been adapted. It shows the trophic status in the lagoon that would result from different riverine loads.