title: Colloidal mobilization of arsenic from mining-affected soils by surface runoff.
abstract: Scorodite-rich wastes left as a legacy of mining and smelting operations pose a threat to environmental health. Colloids formed by the weathering of processing wastes may control the release of arsenic (As) into surface waters. At a former mine site in Madrid (Spain), we investigated the mobilization of colloidal As by surface runoff from weathered processing wastes and from sediments in the bed of a draining creek and a downstream sedimentation-pond. Colloids mobilized by surface runoff during simulated rain events were characterized for their composition, structure and mode of As uptake using asymmetric flow field-flow fractionation coupled to inductively plasma mass spectrometry (AF4-ICP-MS) and X-ray absorption spectroscopy (XAS) at the As and Fe K-edges. Colloidal scorodite mobilized in surface runoff from the waste pile is acting as a mobile As carrier. In surface runoff from the river bed and the sedimentation pond, ferrihydrite was identified as the dominant As-bearing colloidal phase. The results from this study suggest that mobilization of As-bearing colloids by surface runoff may play an important role in the dispersion of As from metallurgical wastes deposited above ground and needs to be considered in risk assessment.
authors.affiliation: Museo Nacional de Ciencias Naturales (MNCN, CSIC), C/ Jose Gutierrez Abascal 2, 28006 Madrid, Spain.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Gomez-Gonzalez
authors.affiliation: EAWAG, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600 Duebendorf, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Voegelin
authors.affiliation: Museo Nacional de Ciencias Naturales (MNCN, CSIC), C/ Jose Gutierrez Abascal 2, 28006 Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Garcia-Guinea
authors.affiliation: Grupo de Espectroscopía Analítica y Sensores (GEAS), Instituto Universitario de Ciencias Ambientales de Aragón (IUCA), Universidad de Zaragoza, C/ Pedro Cerbuna 12, 50009 Zaragoza, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Bolea
authors.affiliation: Grupo de Espectroscopía Analítica y Sensores (GEAS), Instituto Universitario de Ciencias Ambientales de Aragón (IUCA), Universidad de Zaragoza, C/ Pedro Cerbuna 12, 50009 Zaragoza, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Laborda
authors.affiliation: Museo Nacional de Ciencias Naturales (MNCN, CSIC), C/ Jose Gutierrez Abascal 2, 28006 Madrid, Spain. Electronic address: fernando.garrido@mncn.csic.es.
authors.forename: Fernando
authors.initials: F
authors.lastname: Garrido
mesh_terms: D001152:Arsenicals / Q000032:analysis*; D003102:Colloids / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry; D008906:Mining; D053758:Nanoparticles / Q000737:chemistry; D011891:Rain / Q000737:chemistry; D045483:Rivers / Q000737:chemistry; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*; D013030:Spain; D013499:Surface Properties; D014874:Water Pollutants, Chemical / Q000032:analysis*; D056928:X-Ray Absorption Spectroscopy
chemical_list: D001152:Arsenicals; D003102:Colloids; D005290:Ferric Compounds; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; C548094:scorodite; C092844:ferric oxyhydroxide
keywords: AF4-ICP-MS; Arsenic; Colloids; Rainfall simulation; Runoff; XAS