title: Heavy metal contamination in sediments of an artificial reservoir impacted by long-term mining activity in the Almadén mercury district (Spain).
abstract: Sediments from the Castilseras reservoir, located downstream on the Valdeazogues River in the Almadén mercury district, were collected to assess the potential contamination status related to metals(oids) associated with river sediment inputs from several decommissioned mines. Metals(oids) concentrations in the reservoir sediments were investigated using different physical and chemical techniques. The results were analyzed by principal component analysis (PCA) to explain the correlations between the sets of variables. The degree of contamination was evaluated using the enrichment factor (EF) and the geoaccumulation index (Igeo). PCA revealed that the silty fraction is the main metals(oids) carrier in the sediments. Among the potentially harmful elements, there is a group (Al, Cr, Cu, Fe, Mn, Ni, and Zn) that cannot be strictly correlated to the mining activity since their concentrations depend on the lithological and edaphological characteristics of the materials. In contrast, As, Co, Hg, Pb, and S showed significant enrichment and contamination, thus suggesting relevant contributions from the decommissioned mines through fluvial sediment inputs. As far as Hg and S are concerned, the high enrichment levels pose a question concerning the potential environmental risk of transfer of the organic forms of Hg (mainly methylmercury) from the bottom sediments to the aquatic food chain.
authors.affiliation: Mining, Energy and Materials Engineering School, University of Oviedo, Oviedo, Spain. garciaefren@uniovi.es.
authors.forename: Efrén
authors.initials: E
authors.lastname: García-Ordiales
authors.affiliation: IGEA, Biogeochemistry Laboratory of Heavy Metals, UCLM, Almadén, Ciudad Real, Spain.
authors.forename: José María
authors.initials: JM
authors.lastname: Esbrí
authors.affiliation: Department of Mathematics and Geosciences, University of Trieste, Trieste, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Covelli
authors.affiliation: IGEA, Biogeochemistry Laboratory of Heavy Metals, UCLM, Almadén, Ciudad Real, Spain.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: López-Berdonces
authors.affiliation: IGEA, Biogeochemistry Laboratory of Heavy Metals, UCLM, Almadén, Ciudad Real, Spain.
authors.forename: Pablo L
authors.initials: PL
authors.lastname: Higueras
authors.affiliation: Mining, Energy and Materials Engineering School, University of Oviedo, Oviedo, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Loredo
mesh_terms: D004784:Environmental Monitoring; D020387:Food Chain; D019015:Geologic Sediments / Q000032:analysis / Q000737:chemistry*; D008628:Mercury / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis*; D008906:Mining; D045483:Rivers; D013030:Spain; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D008628:Mercury
keywords: Almadén mining district; Heavy metals; Reservoir; Sediments