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Fluvial systems can be strongly influenced by human activity, acting as and/or the carrier of pollutants, becoming a source of pollution if environ- mental conditions change. The transport of potentially toxic elements (PTEs) and persistent organic pollutants (POPs) depends on topography, the oxic- anoxic conditions and kinetics of the sorption/desorption processes. Moreo- ver, pH, salinity, and the presence of organic matter, clay minerals, sulphates, and carbonates also affect metal mobility in the sediments (bottom and stream sediments, suspended matter sediment, floodplain sediment). Sedi- ments provide detailed information on the historical record of pollution in a watershed, and if the PTEs and POPs are attached to stored alluvium, it can turn them from being a sink to a source of pollutants for the sediment inter- face, bioturbation and resuspension during dredging or flooding (Audry et al., 2004).