Short Historical Review of Contribution of a Major River Basin to Adriatic Sea Eutrophication and Heavy Metal Micropollution: the Brenta-Bacchiglione Watershed

Despite the very oligotrophic conditions of Adriatic Sea, coastal eutrophication periodically takes place. In order to quantify some of the pollutants responsible for this phenomenon, our research (granted by "Autorità di Bacino" within the EURIOS UNO project in the year 2000) aimed to evaluate the total amount of some selected nutrients and of the eutrophication-related microstimulants discharged by the Brenta, the Bacchiglione, and the Gorzone Rivers into the Adriatic Sea. The corresponding watershed collects the pollution produced by one of the most populated region of Italy consisting of urban, industrial, and agricultural areas surrounding the northern border of the Adriatic Sea. Accordingly, a new approach was chosen. The three aforementioned rivers were sampled seasonally, along a transect perpendicular to their water flow and located close to their mouth. A continuous sampling took place during a specific week and it was performed by an on-line radio-operating device. The analysed parameters were chosen among a wide array of chemicals. Chemical-physical parameters and nutrients were analysed daily. Simultaneous river flow and velocity measurements allowed to calculate pollutant loads. Results showed that the Brenta and the Gorzone Rivers were the major responsible for the organic and inorganic pollutant loading. However, although the Bacchiglione displays lower contaminant loading, this last one was not negligible.