ABSTRACT
The calculation of the costs of different nutrient-reductions strategies for the Baltic Sea requires information on the human activities generating the nitrogen and phosphorous emissions and their locations. The approach used to link nutrient loads with emission sources can be divided into two steps: a geographical information system (GIS) description of land use and population patterns that enables the analyst to identify sources; and augmentation of the GIS is by data from various official statistical sources on input use, such as fertilizers and petroleum, that generate nitrogen and phosphorus emissions. Baltic Sea is determined, not only by the source emissions, but also by the characteristics determining the transformation of nutrients during transportation from the source to the coastal waters of the Sea. Polish nutrient emissions are undoubtedly the most important source of both nutrient loads, and correspond to 33 per cent of the total nitrogen load and 50 per cent of the total phosphorus load.
