Experimental Bronchography by Tantalum Insufflation

Llamas, Roberto de la Plaza; Ortiz, Juan A.; Perez, Andres; Baum, Gerald L.

doi:10.1378/chest.56.1.75

Cited by 9 publications

(2 citation statements)

References 4 publications

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“…The inhaled Ta-bearing particles deposited in the alveolar region of the lung suggested a prolonged retention in this region with a biological removal half time larger than 2 years. In disagreement with these studies, Llamas et al (1969) and Edmunds et al (1970), also using a radiographic technique to evaluate the Ta retention in the lungs, obtained a retention half-time of some days.…”

Section: Introductionmentioning

confidence: 94%

Tantalum Dissolution Rate in Simulant Lung Fluid

Lima

Coelho

Dalia

et al. 2007

Water Air Soil Pollut

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The aim of this study is to determine the solubility rate of tantalum contained in pyrochlore, columbite-tantalite and columbite in simulant lung fluid. The International Commission on Radiological Protection (ICRP), in its recommendation for limiting intakes of radionuclide by workers, has consistently recognized that the biological behavior of any specific material after incorporation can significantly diverge from model prevision. Model parameters should be adjusted to adapt the model for each specific substance material in order to estimate the dose due to this element intake. The most recent ICRP publication 66, respiratory tract dosimetry model, point out that information as data like particle size, aerosols solubility and the material chemical compounds are important parameters in the dose coefficients calculation. This paper studies the solubility in Simulant Lung Fluid (SLF) of Ta present in mineral dust particles. For this study 3 minerals were selected: pyrochlore, columbite-tantalite and columbite. Tantalum dissolution in vitro samples were obtained using the Gamble solution and PIXE (Particle Induced X-ray Emission) as analytical technique. In order to characterize the worker exposure to Ta bearing particles, one Brazilian niobium mine was selected. The mineral dust particles were collected using a sixstage cascade impactor and the elemental mass concentrations and the MMAD (Mass Median Aerodynamic Diameter) were determined. Concentrations of radionuclides from natural series of thorium and uranium were also determined. The results show that the workers are exposed to Ta bearing particles in the respirable fraction of aerosols (aerodynamic diameter (d aer ) <2.5 μm) during the mineral processing to obtain Fe-Nb alloy. The solubility in Simulant Lung Fluid (SLF) of Ta present in mineral dust particles depends on the mineral characteristics. The solubility half-time varies between 34 and 62 h depending on the associated mineral.

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Section: Introductionmentioning

confidence: 94%

Tantalum Dissolution Rate in Simulant Lung Fluid

Lima

Coelho

Dalia

et al. 2007

Water Air Soil Pollut

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“…While there are available several data about the effects of Th and U in the human body, there is very few data about Ta toxicity and these few studies are not conclusive. Some studies show that Ta retention half-time in human body is around years (Sill et al 1969;Nadel et al 1968;Friedman and Tisi 1972;Gamsu et al 1973;Andrea Blanco et al 1974) while others show that the half-time of Ta in lung is around days (Llamas et al 1969;Edmunds et al 1970). …”

Section: Introductionmentioning

confidence: 99%

Dissolution Factors of Ta, Th, and U Oxides Present in Pyrochlore

Cunha

Santos

Zouain

et al. 2009

Water Air Soil Pollut

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Air pollution can be a problem in industrial processes, but monitoring and controling the aerosols in the work place is not enough to estimate the occupational risk due to dust particle inhalation. The solubility in lung fluid is considered to estimate this risk. The aim of this study is to determine in vitro specific dissolution parameters for thorium (Th), uranium (U), and tantalum (Ta) associated to crystal lattice of a niobium mineral (pyrochlore). Th, U, and Ta dissolution factors in vitro were obtained using the Gamble solution (simulant lung fluid, SLF), particle induced X-ray emission, and alpha spectrometry as analytical techniques. Ta, Th, and U are present in the pyrochlore crystal lattice as oxide; however, they have shown different dissolution parameters. The rapid dissolution fraction (f r ), rapid dissolution rate (λ r ), slow dissolution rate (f s ), and slow dissolution fraction (λ s ) measured for tantalum oxide were equal to 0.1 and 0.45 and 0.00007 day −1 , respectively. For uranium oxide, f r was equal to 0.05, λ r was equal to 1.1 day −1 , and λ s was equal to 0.000068 day −1 . For thorium oxide, f r was 0.025, λ r was 1.5 day −1 , and λ s was 0.000065 day −1 . These results show that chemical behavior of these three compounds in the SLF could not be represented by the same parameter. The ratio of uranium concentration in urine and feces samples from workers exposed to pyrochlore dust particle was determined. These values agree with the theoretical values of estimated uranium concentration using specific parameters for uranium oxide present in pyrochlore.

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Tantalum Radiography of the Respiratory Tract in Dogs

Pickard¹,

Llamas²

1970

Archives of Otolaryngology - Head and Neck Surgery

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Experimental Bronchography by Tantalum Insufflation

Cited by 9 publications

References 4 publications

Tantalum Dissolution Rate in Simulant Lung Fluid

Tantalum Dissolution Rate in Simulant Lung Fluid

Dissolution Factors of Ta, Th, and U Oxides Present in Pyrochlore

Tantalum Radiography of the Respiratory Tract in Dogs

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