The study of Atazadeh et al. (2007) showed that the TDI
characterizes water quality in an arid river in Iran across a
wide range of water quality, giving results that agreed well with
the degree of pollution indicated by physical and chemical
variables and with the combined effects of these factors as indicated by the Water Quality Index developed by Sharifi
(1990). The application of biotic indices by Beltrami et al.
(2007) in the Trentino streams (Northern Italy) showed that
only the TDI reveals the presence of high eutrophic impact,
while IPS and EPI-D reach the III class only for eu-polytrophic
stations, and suggested that the application of different
indices, such as saprobic and trophic ones, can give more
detailed information on the pollution sources.