File:FRACCIONAMIENTO DE LOS METALES PESADOS Fe, Cd, Cr Y Pb EN LOS SEDIMENTOS SUPERFICIALES DE LA LAGUNA DE PÍRITU. ESTADO ANZOÁTEGUI, VENEZUELA.pdf

Surface sediments were collected from 23 stations in Laguna de Píritu, state of Anzoategui, Venezuela, to ascertain the geochemical fractioning of Fe, Cd, Cr, and Pb. Seven of the stations selected are close to the lagoon’s confluence with the sea, nine lie to the center, and the rest towards its innermost end. Four operationally defined fractions -identified as F1 through F4- were assayed by the selective chemical extraction technique: exchangeable ions, carbonate-bound metals, metals bound to Fe and Mn oxides and to organic matter, and metals associated to residual minerals. Quantification by atomic absorption spectroscopy yielded the following results: Fe, Cr, and Pb were bound to the residual fraction, averaging 63, 82, and 58%, respectively. Cd was mainly associated to the exchangeable ions in 28% of the cases and to carbonates in 24% of the cases. Metals bound to exchangeable ions and to carbonates, the fractions with the highest available potential, tended to accumulate towards the innermost section of the lagoon. It is suggested that the Fe, Cr, and Pb found in these sediments are mostly lithogenic in origin, while the Cd is mainly anthropogenic.