title: Studying radon exhalation rates variability from phosphogypsum piles in the SW of Spain.
abstract: Nearly 1.0 × 10(8) tonnes of phosphogypsum were accumulated during last 50 years on a 1,200 ha disposal site near Huelva town (SW of Spain). Previous measurements of exhalation rates offered very variable values, in such a way that a worst case scenario could not be established. Here, new experimental data coupled to numerical simulations show that increasing the moisture contents or the temperature reduces the exhalation rate whilst increasing the radon potential or porosity has the contrary effect. Once the relative effects are compared, it can be drawn that the most relevant parameters controlling the exhalation rate are radon potential (product of emanation factor by (226)Ra concentration) and moisture saturation of PG. From wastes management point of view, it can be concluded that piling up the waste increasing the height instead of the surface allows the reduction of the exhalation rate. Furthermore, a proposed cover here is expected to allow exhalation rates reductions up to 95%. We established that the worst case scenario corresponds to a situation of extremely dry winter. Under these conditions, the radon exhalation rate (0.508 Bqm(-2)s(-1)) would be below though close to the upper limit established by U.S.E.P.A. for inactive phopsphogypsum piles (0.722 Bqm(-2)s(-1)).
authors.affiliation: Dpto. Física Aplicada, Facultad CC. Experimentales, University of Huelva, Campus de El Carmen s/n, 21007 Huelva, Spain. Electronic address: israel.lopez@dfa.uhu.es.
authors.forename: I
authors.initials: I
authors.lastname: López-Coto
authors.affiliation: Dpto. Física Aplicada I. Escuela Politécnica Superior, University of Sevilla, C/Virgen de Africa 7, 41012 Sevilla, Spain.
authors.forename: J L
authors.initials: JL
authors.lastname: Mas
authors.affiliation: Universitat Politècnica de Catalunya, Instituto de Técnicas Energéticas, Campus Sud Edificio ETSEIB, Planta 0, Pabellón C, Av. Diagonal 647, 08028 Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Vargas
authors.affiliation: Dpto. Física Aplicada, Facultad CC. Experimentales, University of Huelva, Campus de El Carmen s/n, 21007 Huelva, Spain.
authors.forename: J P
authors.initials: JP
authors.lastname: Bolívar
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D002133:Calcium Sulfate / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry*; D011874:Radiometry; D011886:Radon / Q000032:analysis*; D013030:Spain
chemical_list: D000396:Air Pollutants, Radioactive; C077769:phosphogypsum; D010758:Phosphorus; D011886:Radon; D002133:Calcium Sulfate
keywords: Exhalation rate; Mitigation; Phopsphogypsum piles; Radon; Variability