title: Radon as a natural tracer for gas transport within uranium waste rock piles.
abstract: Acid mine drainage (AMD) has been identified as the main cause for outflow of acid water and radioactive/non-radioactive contaminants. AMD encompasses pyrites oxidation when water and oxygen are available. AMD was identified in uranium waste rock piles (WRPs) of Indústrias Nucleares do Brasil-Caldas facility (Brazilian uranium mine), resulting in high costs for water treatment. AMD reduction is the main challenge, and scientific investigation has been conducted to understand oxygen and water transportation within WRPs, where 222Rn is used as natural tracer for oxygen transportation. The study consists of soil radon gas mapping in the top layer of WRP4 using active soil gas pumping, radon adsorption in active charcoal and 222Rn determination using high-resolution gamma-ray spectrometry. A sampling network of 71 points was built where samples were collected at a depth of 40 cm. Soil radon gas concentration ranged from 33.7 to 1484.2 kBq m(-3) with mean concentration of 320.7±263.3 kBq m(-3).
authors.affiliation: Laboratory of Poços de Caldas - LAPOC/CNEN, Rod. P. Caldas - Andradas km13, P. Caldas, MG 37701-970, Brazil ncsilva@cnen.gov.br.
authors.forename: N C
authors.initials: NC
authors.lastname: Silva
authors.affiliation: Laboratory of Poços de Caldas - LAPOC/CNEN, Rod. P. Caldas - Andradas km13, P. Caldas, MG 37701-970, Brazil.
authors.forename: E G L
authors.initials: EG
authors.lastname: Chagas
authors.affiliation: Universidade Federal de Minas Gerais - UFMG, Belo Horizonte, MG 31270-901, Brazil.
authors.forename: C B
authors.initials: CB
authors.lastname: Abreu
authors.affiliation: Laboratory of Poços de Caldas - LAPOC/CNEN, Rod. P. Caldas - Andradas km13, P. Caldas, MG 37701-970, Brazil.
authors.forename: D C S
authors.initials: DC
authors.lastname: Dias
authors.affiliation: Ohio University, Athens, OH OH45701, USA.
authors.forename: D
authors.initials: D
authors.lastname: Lopez
authors.affiliation: Laboratory of Poços de Caldas - LAPOC/CNEN, Rod. P. Caldas - Andradas km13, P. Caldas, MG 37701-970, Brazil.
authors.forename: E T Z
authors.initials: ET
authors.lastname: Guerreiro
authors.affiliation: Laboratory of Poços de Caldas - LAPOC/CNEN, Rod. P. Caldas - Andradas km13, P. Caldas, MG 37701-970, Brazil.
authors.forename: H L C
authors.initials: HL
authors.lastname: Alberti
authors.affiliation: Laboratory of Poços de Caldas - LAPOC/CNEN, Rod. P. Caldas - Andradas km13, P. Caldas, MG 37701-970, Brazil.
authors.forename: M L
authors.initials: ML
authors.lastname: Braz
authors.affiliation: Universidade Federal de Juiz de Fora - UFJF, Juiz de Fora, MG 30036-900, Brazil.
authors.forename: O
authors.initials: O
authors.lastname: Branco
authors.affiliation: Centre for Development of Nuclear Technology - CDTN/CNEN, Belo Horizonte, MG 31270-901, Brazil.
authors.forename: P
authors.initials: P
authors.lastname: Fleming
mesh_terms: D005740:Gases / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry; D008906:Mining; D011834:Radiation Monitoring; D011849:Radioactive Tracers; D011886:Radon / Q000032:analysis*; D012990:Soil Pollutants, Radioactive / Q000032:analysis*; D013051:Spectrometry, Gamma; D014501:Uranium / Q000032:analysis*
chemical_list: D005740:Gases; D011849:Radioactive Tracers; D012990:Soil Pollutants, Radioactive; D014501:Uranium; D007501:Iron; D011886:Radon