1993
Comportamiento_de_los_metales_trazas_Cu__Pb__Mn_y_Zn_en_fracciones_geoqu_micas_de_n_cleos_de_sedimentos_de_la_laguna_Unare__Venezuela-v1.pdf
Comportamiento de los metales trazas Cu, Pb, Mn y Zn en fracciones geoquĂmicas de nĂșcleos de sedimentos de la laguna Unare, Venezuela
<p><br />The concentrations of the metals<br />Cu, Pb, Mn and Zn in fra ctions geochemistry in<br />six sediment core of the lagoon Unare, Venezuela.<br />A procedure of sequential extraction of metals<br />was determined, for each fraction was used<br />reagents different and conditions of digestion<br />and the concentrations of metals determined<br />with spectrophotometer of Atomic Absorption.<br />The fractionating of metals indicated an order of<br />decreasing concentration as it follows: residual<br />fraction > organic/sulfur matter > carbonates><br />interchangeable. The metals displayed values<br />in the reactive phase between : n.d-7,90; 0,00-<br />4,90; 133,95-961 ,79 and 0,05-9,61 IJg /g for Cu,<br />Pb, Mn and Zn, respectively; being observed<br />in most of the core an increase in the superior<br />layers caused by diagenetics processes,<br />changes in the textural composition (contained<br />of clay or organic matter) due to the anthropics<br />contributions that the lagoon receives. The Mn<br />presented in core 1, 2 and 3 the smaller concentrations<br />to the surface, which suggests an<br />alteration of the natural geochemical cycles that<br />tends to a diminution of the manganese contributions<br />through tlíe time. In the Zn, its vertical<br />distribution reflects a strong relation between the<br />metal, the organic matter and texture in relation<br />to the depth, which is of sandy and poor texture<br />in organic matter, with a contained minor of th is<br />metal. The concentrations average of metals<br />total are were: 36,31; 7,57; 445,60 and 64.07<br />IJg/g for Cu, Pb, Mn and Zn respectively. These<br />results are analogous to the reported ones for<br />sediments no contaminated; nevertheless, some<br />metals in the reactive phase, showed to slight<br />increases towards the surface, indicating recent<br />contamination, product of the intervention that<br />has undergone this lagoon in the last decades<br />and to the contributions of the Unare river.<br /> </p>
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William Senior
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http://www.myexperiment.org/files/1993/download/Comportamiento_de_los_metales_trazas_Cu__Pb__Mn_y_Zn_en_fracciones_geoqu_micas_de_n_cleos_de_sedimentos_de_la_laguna_Unare__Venezuela-v1.pdf
2018-07-29 15:33:20 UTC
by-sa
metal fractionating
reactive phase
sediment core
sequential extraction
unare lagoon
venezuela.