Monitoring of nuisance impacts in running waters becomes
a necessary task. Instrumental monitoring of running waters is
not the best, leaving expensive equipment in the field puts it at
a risk. In addition, it is difficult to predict the interactive or
synergistic combined influences of chemicals on aquatic biota
through instrumental monitoring (Lowe and Pan, 1996).
Aquatic organisms integrate all of the influential of biotic
and abiotic parameters in their habitats; they provide continuous
records of environmental quality (Simon, 2000). Cazaubon
(1991) considered the epipelon as a memory of stress that represents
a warning of severe water quality. This consideration is
applicable to the epipelic diatomic flora of rivers that serve as a
good descriptor of those perturbations.