title: Arsenic-bearing calcite in natural travertines: evidence from sequential extraction, μXAS, and μXRF.
abstract: Recent studies demonstrated that synthetic calcite may host considerable amounts of arsenic (As). In this paper, the concentration of As in natural calcite was determined using two novel, specifically designed, sequential extraction procedures. In addition, the oxidation state of As and its distribution between calcite and coexisting Fe-oxyhydroxides was unravelled by μXRF elemental mapping and As K-edge μXAS spectroscopy. Our results conclusively demonstrate that arsenic can be found in natural calcite up to 2 orders of magnitude over the normal crustal As abundances. Because of the large diffusion of calcite in the environment, this phase may exert an important control on As geochemistry, mobility, and bioavailability.
authors.affiliation: Dipartimento di Scienze della Terra, Università di Firenze, Via G La Pira 4, 50121 Firenze, Italy.
authors.forename: Pilario
authors.initials: P
authors.lastname: Costagliola
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Bardelli
authors.forename: Marco
authors.initials: M
authors.lastname: Benvenuti
authors.forename: Francesco
authors.initials: F
authors.lastname: Di Benedetto
authors.forename: Pierfranco
authors.initials: P
authors.lastname: Lattanzi
authors.forename: Maurizio
authors.initials: M
authors.lastname: Romanelli
authors.forename: Mario
authors.initials: M
authors.lastname: Paolieri
authors.forename: Valentina
authors.initials: V
authors.lastname: Rimondi
authors.forename: Gloria
authors.initials: G
authors.lastname: Vaggelli
mesh_terms: D001151:Arsenic / Q000737:chemistry*; D002119:Calcium Carbonate / Q000737:chemistry*
chemical_list: D002119:Calcium Carbonate; D001151:Arsenic