The aim of this study was to compare metal mobilization using DGT and partition using a sequential extraction procedure (1). The five extracted fractions were classified as: F1 (exchangeable metal), F2 (bound to carbonates), F3 (bound to Fe /Mn-oxides), F4 (bound to sulfides and organic matter), F5 (residual). For this purpose 5 sediments with a range of properties were taken in a small reservoir. It was shown that specific geochemical phases were a key factor of the mobilization of Co and Cd towards DGTs, in these sediments: Mn oxides and dissolved organic matter for Co, acid-volatile sulfides (AVS) for Cd. Moreover, it was found that particulate organic matter and possibly AVS could be the main factors of the mobilization for Pb. Linking results from DGT experiments and sequential extractions showed that the mass of Co trapped by DGT highly correlated with the metal concentration in F1 fraction. High correlation with the sum of concentrations in F1 to F2 fractions was found for Pb and with the sum of concentrations in F1 to F3 fractions for Cd. In this study, we assume that Co, Cd and Pb trapped in DGTs mostly originated from easily exchangeable, specifically sorbed metals and metals weakly bound to labile organic matter.