The Dating Academic Service (SAF in Spanish) is specialized on 210Pb analysis of sediments from aquatic ecosystems (such as lakes, lagoons, seas, dams, rivers, marshes) to establish the temporal framework of recent sedimentary records, used to study global change (e.g. pollution, climate change, and eutrophication). We also characterize sediments by analyzing grain size distribution, organic matter and carbonates contents, magnetic susceptibility, elemental composition and pollutants (heavy metals).

The analysis of 210Pb in undisturbed sedimentary cores allows the determination within the past ~100 years of mass accumulation rates (MAR, g cm-2 year-1) and sediment accumulation rates (SAR, cm year-1) and pollutant fluxes (µg cm-2 year-1) to water bodies, useful to identify accumulation rate changes related to land use changes and siltation (both natural and anthropogenic) and to verify the benefits of environmental management programs, such as the regulation of sediment loads and toxic substances fluxes in the study sites. This information can be very useful to researchers, environmental consultants and decision makers responsible for environmental management programs.

210Pb is a natural radionuclide of the 238U decay series. 210Pb is found in sediments due to i) the presence of minerals containing its parent radionuclide (226Ra), and ii) the accumulation of atmospheric fallout and water column sedimentation. In our laboratory, 210Pb activities are determined through its descendant radionuclide 210Po by alpha spectrometry, under the assumption that both radionuclides are in secular equilibrium. 226Ra activities are established either through the 210Pb activities in the deepest core sections, or through gamma spectrometry, which also allows to determine 137Cs in sites where the signal is detectable.