The Rhone River (France) is equipped with many navigation and electricity production facilities. Annually, ~ 0.5 Mm3 of sediment from the Arve river, a torrential tributary of the Rhone river, is trapped upstream of Verbois and Chancy-Pougny dams. This accumulation over time requires conducting regular dam flushing operations to limit sedimentation and prevent flood risks for Geneva due to bed elevation. In 2012, suspended particulate matter (SPM) were sampled during the dam flushing operations (8 days) showing that particulate Hg concentrations were not altered but As concentrations slightly increased during this period. However, the dissolved fraction was not monitored during this transient event, whereas sediment stocks remobilization could lead to a potential contaminants release in the dissolved phase. In this context and during last dam flushing operations (20-31 May 2016), we aimed to assess how DGT (Diffusive Gradient in Thin films) could integrate a quick potential release of metals from the particulate to the dissolved phase. Thus, we deployed 3 types of DGT for measuring time-averaged concentrations for cationic metals and As, before, during and after the event (7, 13 and 13 days respectively) at 3 sampling stations along the river (Pougny, Seyssel, Jons) located respectively at 10, 45 and 160 km downstream the dam. This allowed identifying mitigation phenomenon. We sampled dissolved and particulate phases on the sites every other day to explain integration of trace metals potential release by DGT. The sharp increase of SPM concentrations (0.5 [Jons] to 15 g/L [Pougny and Seyssel]) generated an increase in NH4+ concentrations, indicating a change in redox conditions. These changes in water composition induced the release of contaminants (As, Mn, Co, Ni), which was well integrated by DGT measurements. Comparing DGT measurements with time-weighted average of dissolved concentrations in grabbed samples, we can assess the representativeness of DGT measurements for some metals (As, Mn, Pb) and identify metals not so labile and much complexed with organic matter such as Cu.