This study focuses on the distribution of selected trace metals, 137 Cs and 210 Pb, in floodplain deposits of the lowland Warta River (southern Poland) downstream of Częstochowa, a large city with an iron smelter. The depth profiles of trace metal (Zn, Pb, Cu, Ni, Cd and Mn), 210 Pb and 137 Cs contents in floodplain sediments were used to derive deposition rates on the floodplain for the twentieth century. The applicability of particular chronometric tools is considered within the context of their mutual relationships and confirmed by the consistency of the results. Deposition rate estimates for the past 50 years based on the vertical patterns of trace metal concentrations, which were correlated with particular events in the development of the smelter, range from 0.4 cm·year −1 in profiles situated in backswamps far from the channel to over 1.1 cm·year −1 in profiles of the natural levee adjacent to the river. Deposition rates based on 210 Pb inventories in the profiles range from 0.08 to 0.66 g·cm −2 ·year −1 , which corresponds to linear sedimentation rates of 0.10 to 0.91 cm·year −1 , respectively. Dating of characteristic levels associated with peak fallout of 137 Cs gives sediment accretion rates resembling those obtained from trace metals and 210 Pb. The period of the highest sediment accumulation rate could be related to the highest loads of effluent from the iron smelter and city of Często-chowa, which were substantially reduced after the construction of effluent treatment plant.