Chemical and mineralogical characterization of the sediments from the Mira, Ilhavo and Ovar channels of Aveiro Lagoon (Portugal)

Abstract

The paleoenvironmental reconstruction of Aveiro Lagoon is being carried out based on the sedimentological, paleoecological, geochemical and mineralogical characterization of sediment samples collected systematically in the lagoon. This paper presents results concerning the changes in the chemical and mineralogical composition of the fine fraction (<63 µm) and the clay fraction (<2 µm) in sediment samples from Aveiro Lagoon, mainly collected from the lower intertidal plain and subtidal deposits located along the Mira, ÿlhavo and Ovar channels. A zonography of the lagoon was established based on the parameters analyzed. The results show that the surface and near-surface sediments of Aveiro Lagoon trap relatively large quantities of trace metals, such as Cu, Pb, Co, Ni, Cd, Zn, Fe, Mn and Cr, considered to be partially adsorbed, particularly on silty and clayey particles, and coprecipitated on Fe and Mn oxyhydroxide forms precipitated in the topmost layers of sediments. Series of statistically significant relationships were established between trace metal concentrations and clay content and semi-quantitatively determined clay mineral species in the sediments.

Influence of Aveiro Lagoon heavy metal contents in the adjacent continental shelf (Portugal)

“…The results obtained by Rocha et al (2005) show that the surface and near-surface sediments of Aveiro Lagoon trap relatively large quantities of trace metals, such as Cu, Pb, Co, Ni, de la plataforma media y la plataforma externa de la parte sur muestran valores mucho mayores que las otras.…”

“…Como ya se mencionó, el Pb mostró una concentración excepcionalmente alta en los sedimentos de la plataforma the surface sediments of Aveiro Lagoon, Rocha et al (2005) found a clear association between Ni and Cr variables, the peculiar cartographic distribution of the factor scores suggesting either a lithological/mineralogical control (related to vermiculite and smectite rich muds) or some influence of different chemical parks surrounding the lagoon (Ovar, Estarreja and Ílhavo), and pointing out the influence of the naval activities (port and shipyards) linked with Aveiro harbour (located close to the lagoon mouth). Factor 2 is associated with Fe distribution.…”

“…Los resultados obtenidos por Rocha et al (2005) muestran que los sedimentos superficiales y los que se encuentran cerca de la superficie, en la Laguna de Aveiro, atrapan cantidades relativamente grandes de metales traza como Cu, Pb, Co, Ni, Cd, Zn, Fe, Mn y Cr, los cuales se consideran parcialmente adsorbidos en partículas de limo y arcilla, y también coprecipitados en oxihidróxidos de Fe y Mn precipitados en los niveles más superficiales de los sedimentos.…”

“…Studying Rocha et al (2005) encontraron una clara asociación entre las variables de Ni y Cr. La particular distribución cartográfica de las puntuaciones factoriales sugiere un control litológico/mineralógico (relacionado con lodos ricos en vermiculita y esmectita) o cierto grado de influencia de los diferentes complejos químicos alrededor de la laguna (Ovar, Estarreja e Ílhavo).…”

Multivariate Analyses to Determine the Origin of Potentially Harmful Heavy Metals in Beach and Dune Sediments from Kizkalesi Coast (Mersin), Turkey

“…Therefore, it is important to determine heavy metal concentrations and to investigate their geochemical distribution. There have been several recent studies on distribution of heavy metals along coastal areas (Evans 1971;Scoullos and Dassenakis 1982;Duan 2000;Wolf et al 2001;Araujo et al 2002;Rocha et al 2005;Abrantes et al 2005;Vidinha et al 2006;Ramirez et al 2005). To explain the differences between geogenic and anthropogenic sources of heavy metals, some methods have been developed.…”