Lability and bioavailability of Co, Fe, Pb, U and Zn in a uranium mining restoration site using DGT and phytoscreening.

Mine restoration is a long and ongoing process, requiring careful management, which must be informed by site-specific, geochemical risk assessment. Paired topsoil and tree core samples from 4 sites within the uranium mining complex of INB Caldas in Minas Gerais (Brazil) were collected. Soil samples were analysed for their total content of Co, Fe, Pb, U and Zn by XRF, and subsequently, the potential environmental bioavailability of these metals were investigated by DGT and pore water analysis. In addition, results were compared with metal concentrations obtained by Tree Coring from the forest vegetation. In all sampling areas, mean total concentrations of U (Ctot. = 100.5 ± 66.5 to 129.6 ± 57.1 mg kg-1), Pb (Ctot. = 30.8 ± 12.7 to 90.8 ± 90.8 mg kg-1), Zn (Ctot. = 91.5 ± 24.7 to 99.6 ± 10.3 mg kg-1) and Co (Ctot. = 73.8 ± 25.5 to 119.7 ± 26.4 mg kg-1) in soils exceeded respective quality reference values. Study results suggest that AMD caused the increase of labile concentrations of Zn in affected soils. The high lability of the elements Pb (R = 62 ± 34 to 81 ± 29%), U (R = 57 ± 20 to 77 ± 28%) and Zn (R = 21 ± 25 to 34 ± 31%) in soils together with high bioconcentration factors found in wood samples for Pb (BCF = 0.0004 ± 0.0003 to 0.0026 ± 0.0033) and Zn (BCF = 0.012 ± 0.013 to 0.025 ± 0.021) indicated a high toxic potential of these elements to the biota in the soils of the study site. The combination of pore water and DGT analysis with Tree Coring showed to be a useful approach to specify the risk of metal polluted soils. However, the comparison of the results from DGT and Tree Coring could not predict the uptake of metals into the xylems of the sampled tree individuals.

Evaluation of the radiological quality of water released by a uranium mining in Brazil.

A mine in an area of naturally occurring radioactive materials (NORM), characterized by acid mine drainage, generates effluents with natural radionuclide concentrations, usually above the limits authorized by the regulator. The plant exploiting NORM controls the water quality and discharges it into the aquatic environment after meeting technical requirements. Downstream, water usage is unrestricted. In order to reach activity concentrations in the released effluents below the authorized values, the facility applies a chemical treatment to the effluent. Then, to ensure the effectiveness of the treatment, the facility performs sampling of treated effluent and determines the activity concentration of natural radionuclides (Unat, 226Ra, and 210Pb from the uranium series and 232Th and 228Ra from the thorium series). In the current study, the proportion and distribution of these radionuclides between the soluble and particulate fractions were determined. The measured activity concentrations were compared with the values proposed by the World Health Organization and Brazilian legislation, as well as other authorities, as regards the potable use from the radioprotection point of view. It was observed that the radionuclides are not in secular equilibrium. The fractions contribute differently to the total release of radionuclide, and there is no linear relationship between the fractions. The average activity concentrations did not result in radiological restrictions to water use, and the committed effective dose due to ingestion was estimated at 0.06 mSv y-1. Therefore, there is no radiological restriction to water use, since the dose which was found was below the constraint value for the public.

A mineração de urânio em questão: análise da comunicação pública das Indústrias Nucleares do Brasil (INB) em Caetité, Bahia / Questioning uranium mining: an analysis of the public communication stated by Indústrias Nucleares do Brasil (INB) in Caetité, Bahia / La minería de uranio en cuestión: un análisis de la comunicación pública transmitida por la INB (Indústrias Nucleares do Brasil) en Caetité, Bahia

O objetivo deste artigo é discutir, através de análise de conteúdo, as estratégias de comunicação pública adotadas pelas Indústrias Nucleares do Brasil no 'Espaço INB', um centro de informações localizado na cidade baiana de Caetité, onde a empresa realiza a mineração e o beneficiamento de urânio. Desde que foram iniciadas, essas atividades levantaram inúmeras suspeitas de danos ambientais e problemas de saúde pública. Diante disso, buscamos compreender como a INB se posiciona diante dessas suspeitas e se relaciona com as populações atingidas por suas atividades. De acordo com nosso argumento, ao adotar uma postura que denominamos tecnoentusiasta e tecnocrática, a empresa dificulta um debate público aberto e descentralizado sobre as controvérsias em torno da mineração de urânio

This article aims to use the content analysis to discuss the public communication stated by the 'Espaço INB', an information center managed by Indústrias Nucleares do Brasil located in the city of Caetité ­ BA, where the company mines and processes uranium. Since INB started its activities in Caetité, several suspicions of environmental damage and public health problems emerged. Thus, we analyze how INB responds to these suspicions and relates to the populations affected by its activities. We argue that INB adopts an attitude that we call techno-enthusiastic and technocratic, hindering an open public and decentralized debate about the controversies surrounding uranium mining.

El objetivo de este artículo es discutir, a través del análisis de contenido, la comunicación pública transmitida por el 'Espaço INB', un centro de información administrado por Indústrias Nucleares do Brasil ubicado en la ciudad de Caetité/Bahia, donde la empresa hace la mínería y el procesamiento del uranio. Desde que comenzaron, estas actividades han generado numerosas sospechas de daños ambientales y problemas de salud pública. Por eso, analizamos como el INB contesta estas sospechas y se relaciona con las poblaciones afectadas por sus actividades. Argumentamos que el INB adopta una actitud que llamamos tecno-entusiasta y tecnocrática, lo que dificulta un debate público abierto y descentralizado sobre las controversias respecto a la minería de uranio.

Assessment of uranium release to the environment from a disabled uranium mine in Brazil.

The Ore Treatment Unit (in Portuguese Unidade de Tratamento de Minérios - UTM) located in Caldas, MG, Brazil is a disabled uranium mine. Environmental conditions generate acid drainage leaching metals and radionuclides from the waste rock pile. This drainage is treated to remove the heavy metals and radionuclides, before allowing the release of the effluent to the environment. To validate the treatment, samples of the released effluents were collected at the interface of the installation with the environment. Sampling was carried out from 2010 to 2015, and the activity concentration (AC, in Bq·l-1) of uranium in the liquid effluent was analyzed by arzenazo UV-Vis spectrophotometry of the soluble and particulate fractions, and of the sum of both fractions. Descriptive statistics, Z test and Pearson R2 correlation among the fractions were performed. Then, the data were organized by year and both ANOVA and Tukey test were carried out to group the means by magnitude of AC. The annual mean ranged from 0.02 Bq·l-1 in 2015 to 0.11 Bq·l-1 in 2010. The soluble fraction showed a higher AC mean when compared to the mean of the particulate fraction and no correlation of the data could be observed. Concerning the magnitude of the release, the ANOVA associated with the Tukey test, identified three groups of annual means (AC2010> AC2011 = AC2012 = AC2013 = AC2014 > AC2015). The mean values of uranium release at the interface installation-environment checking point (point 014) were within the Authorized Annual Limit (AAL) set by the regulator (0.2 Bq·l-1) indicating compliance of treatment with the licensing established for the unit. Finally, the data showed a decreasing tendency of U release.