Search

The need to evaluate the impact of the Tiber River on the receiving marine ecosystem, and the extent of pollution abatement required to safeguard the various coastal water uses, promoted an interdiscipl i nary experimental investigation. First stage results of investigation carried out off the river mouth are presented. The extension of the area influenced by the river has been estimated at 400 km2. Due to the river's high nutrient input rates, eutrophic processes occur with an intensity depending on sample distances from the mouth. Some data concerning the limiting factor have also been derived. Toxicity studies have revealed an incipient threat from Cd and Hg concentration. HCB was only occasionally found in the zone; PCB's were found in surprisingly high levels further away from the river mouth. Bacteriological data led to conclude that the river's impact on beach bathing conditions is only limited to an area immediately adjacent the two outfalls. With the exception of minor changes due to the eurhyaline nature of the zone, no major variation in receiving area ecology was detected (for benthos and nekton).