Biological monitoring of some Apennine rivers (central Italy) using the diatom-based Eutrophication/Pollution Index (EPI-D) compared to other European diatom indices.

The EPI-D diatom index was used in monitoring seven rivers situated in the central-eastern Apennine sector (Italy) in agreement with the European Directive, WFD/60/2000/EC, which encourages all member states to use available instruments in order to assess the ecological status of rivers, including algae. This index is based, above all, on the high sensitivity of diatoms to organic matter, nutrients and mineral salts dissolved in water, particularly chlorides. A total of 148 samples were examined and 209 diatom taxa were identified to the species and varieties level. The 100 species most representative ofthe studied watercourses typology were chosen and subjected to cluster analysis, in order to determine more information about their ecological requirements. Moreover, a comparison between the results obtained by the EPI-D and other European diatom indices was made and it indicated a very high correlation between them. The EPI-D index when compared with the chemical data and the general sifuation of the examined watercourses showed an excellent capacity for synthesis; therefore it can represent a useful instrument for ecological assessment of ltalian rivers.