Suchergebnisse

2 pages.-- International Estuarine Biogeochemistry Symposium, Vigo (Spain), 4-5th June 2019 ; The globalization of the industrialization is being pointed out as the synchronous and global event that potentially marks the starting point of a current-proposed stratigraphic epoch: the 'Anthropocene'. Its study makes necessary high-resolution (yearly) works on recent stratigraphic records such as estuarine sediments. Concerning industrialization, the Ria of Ferrol represents a paradigmatic example in the NW of the Iberian Peninsula. This area is under the impact of military shipyards since 1730. Their maximum activity happened after 1947, consequence of the industry restructuring and the implementation of civil shipbuilding (including oil super-tankers). The present study focused on a sediment core of 50 cm long that holds record since the beginning of the 20th century, according to Pb-210 dating. Trace metal contents were evaluated to identify the human imprint. Background levels established in nearby areas with similar mineralogical characteristics were considered. Three main periods can be distinguished based on the trace-element to Al ratios: (i) from the beginning of the 20th century until about 1970, when ratios increase usually about 1.5 to 2.4 times, (ii) between around 1970 to 1990, when these ratios decrease usually about 1.4 to 2.3 times, and (iii) from 1990 to 2010, when ratios maintained. The studied sediments reflect the human-environment relationship in the area during the 20th century: the metal to Al ratios, sediment accumulation rates, total metal fluxes and enrichment factors show a first period of increasing industrialization without environmental concern, followed by an industrial collapse and a subsequent reactivation while implementing environmental friendly processes and policies ; This study from the project "Coastal contributions of trace elements during different oceanographic periods" (CTM2011-28792-C02-02), funded by MINECO ; Peer reviewed

14 pages, 3 tables, 5 figures ; Trace element contributions from small rivers to estuaries is an issue barely addressed in the literature. In this work, freshwater flowing into the Ria of Cedeira (NW Iberian Peninsula) was studied during a hydrological year through the input from three rivers, one considered uncontaminated (the Das-Mestas River), a second affected by urban treated wastewater discharges (the Condomiñas River), and the third containing a water reservoir for urban supply (the Forcadas River). With the objective of assessing the possible influence of human pressure, the annual yields for selected trace elements (Al, Fe, As, Cd, Co, Cr, Cu, Mn, Mo, Ni and Pb) were estimated and compared by normalizing by basin surface. Both dissolved and particulate transported elements were considered. After the data treatment and analysis it can be highlighted that: (i) the Das Mestas River is suitable to be included between the short European pristine baseline of small rivers, at least regarding the transported trace elements; (ii) natural enrichments were identified associated to the lithology of the basin in the Das-Mestas River (i.e. As) and in the Condomiñas River (i.e. Co, Cr and Ni); this fact highlights the importance of considering the local background for a proper assessment; (iii) the impoundment in the Forcadas River is related with a general decrease, even depletion, of the particulate and dissolved transported trace elements, except Mn; (iv) the discharge of sewage to the Condomiñas River is increasing the inputs to the ria of some trace elements in the particulate phase (i.e. Al, Cu and Pb). Both observed human-induced changes can be regarded as typical disturbances of trace element contributions from small rivers to estuaries ; M.A. Álvarez-Vázquez expresses gratitude for the support of 'Plan I2C (2011–2015)' of the 'Xunta de Galicia' in collaboration with the International 'Campus do Mar (ED481A-2015/410)' by means of a preDoc contract. This study was supported by the research subproject "Coastal contributions of trace elements during different oceanographic periods" (acronym: MEFIO, ref. CTM 2011-28792-C02-02) financed by 'Ministerio de Economía y Competitividad' of Spanish government ; Peer reviewed