An in continuum sampling: a new approach to identify the eutrophication sources.

In the Northeast of Italy the Brenta and Tagliamento large drainage basins have been investigated in order to quantify pollutants responsible of the well known coastal eutrophication which arise periodically despite to the very oligotrophic conditions of the central part of the sea. The aim of the research was to evaluate the total amount of nutrients and eutrophication-related microstimulants discharged in the Adriatic Sea, in order to evaluate the Adriatic Sea nutrient-sustainable capacity and therefore to provide the necessary enforcement to improve the watershed quality. A new approch is chosen to quantify really the pollutants amount: the sampling were done four times per day continuously for a week a repeated seasonally, with a special radio-operating device. The analysed parameters were chosen on a wide spectrum of chemical substances, as the river watersheds had urban, agriculture and industrial background. Chemical-physical parameters and nutrients were analysed on the sample obtained daily. Contemporaries measurements on the flow and velocity of the rivers were carried out allowing to calculate the mass balance for the substances arriving to the Adriatic Sea. Preliminary results show that the main nutrient seems to be the Nitrogen (mostly as Ammonia), being the P concentration above the eutrophication levels. Micropollutants which can act as stimulant like heavy metals and chlorinated compounds, are, also, present in sufficient amount to start the trophic process.