Wykorzystanie 210Pb i metali cężkich do oceny tempa współczesnej sedymentacji zanieczyszczonych osadów fluwialnych w dolinie górnej Warty

Abstract

Using 210Pb end heavy metals to estimate Recent sedimentation rates of polluted fluvial deposits in Upper Warta River Valley.S u m m a r y . River floodplains have been recognized as an important sink for suspended sediments and associated contaminants mobilized from upstream catchments. However, information on rates of overbank sedimentation within time span of several tens of years is impossible to obtain using conventional sediment traps. Measurements of the 210Pb content in floodplain sediments provide an alternative approach for obtaining estimates of medium-term (100–150 years) rates of overbank sediment deposition. The use of 210Pb method and heavy metals concentration profiles allowed to obtain retrospective estimates of recent sedimentation rates on floodplain of the Warta River (the Cracow Upland, southern Poland). The results are compared with dating of sediment layers by characteristic peaks of heavy metal concentrations. The highest sediment accretion rate, of the order of 1 cm/year, was found in a levee along river bank. Sediment deposition in flood basin is much slower and usually does not exceed 1 mm/year.