Concentrations and History of Heavy Metals in Sediment Cores: Geochemistry and Geochronology Using 210Pb

This paper aims at assessing the concentrations of heavy metals and the isotopic composition of lead 210Pb in different fractions of sediment produced in the watershed that makes up the Mãe d'água dam and thus characterizing the distribution of metals along the sedimentary column and inferencing in the urbanization of the same process. Sample collection was carried out in June 2014; eight sediment cores were sampled in the lake of the dam. For extraction of the sediments core, a core sampler “Piston Core” was used. The trace metal concentrations were determined by conventional atomic absorption spectrophotometric methods. The samples were subjected to radiochemical analysis of 210Po. 210Pb activity was obtained by measuring 210Po activity. The chronology was calculated using the constant rate of supply (CRS). Pb is used to estimate the sedimentation rate. Keywords—210Pb dating method, heavy metal, lakes urban, pollution history.