title: Trace metal partitioning over a tidal cycle in an estuary affected by acid mine drainage (Tinto estuary, SW Spain).
abstract: The Tinto River estuary is highly polluted with the acid lixiviates from old sulphide mines. In this work the behaviour of dissolved and particulate trace metals under strong chemical gradients during a tidal cycle is studied. The pH values range from 4.4 with low tide to 6.9 with high tide. Precipitation of Fe and Al is intense during rising tides and As and Pb are almost exclusively found in the particulate matter (PM). Sorption processes are very important in controlling the mobility (and hence bioavailability) of some metals and particularly affect Cu below pH 6. Above pH~6 Cu is desorbed, probably by the formation of Cu(I)-chloride complexes. Although less pronounced than Cu, also Zn desorption above pH 6.5 seems to occur. Mn and Co are affected by sorption processes at pH higher than ca. 6. Cd behaves conservatively and Ni is slightly affected by sorption processes.
authors.affiliation: Department of Physics, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain; Department of Applied Physics, Facultad de Ciencias Experimentales, University of Huelva, Campus de El Carmen, Campus de Excelencia Internacional del Mar CEIMAR, 21071 Huelva, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Hierro
authors.affiliation: Department of Geodynamics and Paleontology, Facultad de Ciencias Experimentales, University of Huelva, Campus de El Carmen, Campus de Excelencia Internacional del Mar CEIMAR, 21071 Huelva, Spain. Electronic address: manuel.olias@dgyp.uhu.es.
authors.forename: M
authors.initials: M
authors.lastname: Olías
authors.affiliation: Department of Geodynamics and Paleontology, Facultad de Ciencias Experimentales, University of Huelva, Campus de El Carmen, Campus de Excelencia Internacional del Mar CEIMAR, 21071 Huelva, Spain.
authors.forename: C R
authors.initials: CR
authors.lastname: Cánovas
authors.affiliation: Department of Applied Physics, Facultad de Ciencias Experimentales, University of Huelva, Campus de El Carmen, Campus de Excelencia Internacional del Mar CEIMAR, 21071 Huelva, Spain.
authors.forename: J E
authors.initials: JE
authors.lastname: Martín
authors.affiliation: Department of Applied Physics, Facultad de Ciencias Experimentales, University of Huelva, Campus de El Carmen, Campus de Excelencia Internacional del Mar CEIMAR, 21071 Huelva, Spain.
authors.forename: J P
authors.initials: JP
authors.lastname: Bolivar
mesh_terms: D004784:Environmental Monitoring; D063366:Estuaries; D008670:Metals / Q000032:analysis*; D045483:Rivers / Q000737:chemistry*; D013030:Spain; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D008670:Metals; D014874:Water Pollutants, Chemical
keywords: Acid mine drainage; Ría of Huelva; Sorption/desorption; Trace elements