Search Results (7)

The Sierra Peña Blanca (SPB) region in Chihuahua, Mexico contains a significant uranium deposit representing about 40% of the country’s reserves. Common uranium minerals in this area include uranophane, schoepite, and weeksite/boltwoodite, with several superficial occurrences. Mining activities in the 1980s left unprocessed uranium ore exposed to weathering, with potential transport towards Laguna del Cuervo. This study presents an experimental simulation of uranium transport in SPB sediments using three approaches: (i) a batch experiment to evaluate the ideal adsorption of (UO₂)²⁺ by fine sediment; (ii) a column system fed with 569 mgU L⁻¹ UO₂(NO₃)₂ to simulate adsorption by different sediment particle sizes; (iii) a column system with an upper horizon of uranophane from the area, fed with deionized water, to simulate uranium weathering and transport in particulate material, determined by liquid scintillation counting, revealed that the clay fraction had the highest adsorption capacity for U. X-ray Absorption Fine Structure (XAFS) analysis at the U L₃ edge confirmed the U(IV) oxidation state and the fittings of the extended XAFS spectra confirmed the presence of the uranophane group of minerals. X-ray tomography further corroborated the distribution of particulate minerals along the column. The results suggest that the primary transport mechanism in SPB involves the fragmentation of uranium minerals, accompanied by eventual dissolution and subsequent adsorption of U onto sediments. Full article

Considered are: (i) separation of gaseous molecules of different weight by the Ultra Centrifuge with application to large scale uranium enrichment to fuel nuclear power plants; (ii) separation of micron-sized particulate matter from fluids in mechanical devices in which use is made of inertial and centrifugal forces; (iii) separation of gaseous mixtures by fast expansion and cooling such that one of the gaseous components forms a mist of micron-sized droplets which are separated by centrifugation; and (iv) separation of components from gases by absorbing liquid films in small sized rotating channels. For each of these technologies we consider: physics of the separation process, assessment of the influence of fluid flow in the separation device, identification of leading parameters and their effect on design, experimental evidence, status of development, areas of application, position compared to other technologies, and economic value. Full article

This study aimed at assessing the activity concentration and the annual effective dose of polonium-210 (²¹⁰Po) in fruit wines derived from four locations in Poland (Warmian–Masurian, Podlaskie, Lubelskie and Małopolskie voivodeships). The fruit wines differed significantly (p < 0.05) in ²¹⁰Po activity depending on the production site, with the Małopolskie site having the highest activity (61.4–221.4 mBq/L) and the Podlaskie having the lowest (3.5–97.1 mBq/L). The site differentiation was due to environmental conditions—soil parameters (uranium concentration), precipitations and terrain characteristics, e.g., the proximity of the lakes. The increased activity concentration of ²¹⁰Po in samples from Małopolska compared with the other sites probably derived from the environment polluted with aqueous wastes and particulate air pollution. The annual effective dose due to the ingestion of fruit wines ranged from 0.112 to 1.214 µSv/year. These levels of exposure are safe according to the WHO criterion (0.1 mSv per year for ingestion) and to the IAEA reference level for public exposure including food (1 mSv per year). Summing up, the data obtained provide information on the activity concentration of ²¹⁰Po in fruit wines and increase databases on the natural radioactivity of foodstuffs. Future work is needed to examine ²¹⁰Po activity in samples from all vineyard regions in Poland. Full article

Uranium contamination has become a nonnegligible global health problem. Inhalation of particulate uranium is one of the predominant routes of occupational and environmental exposure. Uranium particle is a complex two-phase flow of matter that is both particulate and flowable. This particular physicochemical property may alter its biological activity. Epidemiological studies from occupationally exposed populations in the uranium industry have concluded that there is a possible association between lung cancer risk and uranium exposure, while the evidence for the risk of other tumors is not sufficient. The toxicological effects of particulate uranium exposure to animals have been shown in laboratory tests to focus on respiratory and central nervous system damage. Fibrosis and tumors can occur in the lung tissue of the respiratory tract. Uranium particles can also induce a concentration-dependent increase in cytotoxicity, targeting mitochondria. The understanding of the health risks and potential toxicological mechanisms of particulate uranium contamination is still at a preliminary stage. The diversity of particle parameters has limited the in-depth exploration. This review summarizes the current evidence on the toxicology of particulate uranium and highlights the knowledge gaps and research prospects. Full article

Uranium and thorium are two common natural radioactive elements with high concentrations in Earth’s crust. The main aim of this study is to estimate the inhaled effective dose of uranium and thorium caused by a typical radioactive rare earth ore to the occupational population and the surrounding public. The particulate matter (PM) concentrations in the atmosphere of four typical workplaces and one surrounding living area were obtained by a high-flow sampling equipment with a natural cellulose filter membrane. The critical parameter for the inhaled effective dose estimation—the activity median aerodynamic diameter (AMAD)—was determined. The AMAD values of uranium and thorium in the atmosphere PM were 3.36 and 3.64 μm, respectively. The estimated median effective dose caused by inhalation thorium among the occupational population ranged from 15.3 to 269.0 μSv/a, and the corresponding value for the surrounding public was 2.3 μSv/a. All values for the effective dose caused by the inhalation of uranium were in the nSv magnitude. Full article

We aimed to estimate the association of urinary metal content with the exposure to hazardous household factors and ambient air pollution in pregnant women. We analyzed urine samples of 143 women enrolled at delivery and assessed household exposure by questionnaire. Air pollution estimates were based on monitoring stations and satellite-based models. Complaints about noise, rubbish, and sewage in the neighborhood were associated with higher uranium concentrations (prevalence ratio (PR) = 1.42, 1.46, and 1.18, respectively). Complaints about noise were more frequent in women with higher cobalt, nickel, molybdenum, cadmium, and vanadium urine concentrations (PRs = 2.42–9.43), and complaints about smell in women with higher cobalt and strontium (PRs = 2.55–6.27). Exposure to nitrogen oxides was associated with higher concentrations of nickel, aluminum, lead, and chromium in urine (PRs = 1.80–5.85). Women exposed to elevated levels of particulate matter were more likely to have higher concentrations of cobalt, nickel, thallium, lead, iron, strontium, barium, silver, and chromium (PRs = 1.97–13.64). Exposure to high levels of sulfur dioxide was positively associated with cobalt and nickel (PR = 1.98 and 1.88, respectively). The current analysis suggests the possibility of a related simultaneous exposure to multiple pollutants. Further studies are warranted to corroborate the findings and reveal the multiple exposure effect on human health. Full article

We investigated the associations of urinary concentrations of antimony, cadmium, tungsten and uranium with geographic locations and with ambient air pollution in 304 adults in the Multi-Ethnic Study of Atherosclerosis from six US cities. After adjustment for sociodemographics, body mass index, and smoking status, urinary cadmium was the highest in Winston-Salem among all study sites (the geometric mean [GM] in Winston-Salem was 0.84 µg/L [95% confidence interval (CI) 0.57–1.22]). The adjusted GMs of urinary tungsten and uranium were highest in Los Angeles (0.11 µg/L [95% CI 0.08–0.16] and 0.019 µg/L [95% CI 0.016–0.023], respectively). The adjusted GM ratio comparing fine particulate matter (PM_2.5) tertiles 2 and 3 with the lowest tertile were 1.64 (95% CI 1.05–2.56) and 3.55 (95% CI 2.24–5.63) for tungsten, and 1.18 (95% CI 0.94–1.48) and 1.70 (95% CI 1.34–2.14) for uranium. The results for tungsten remained similar after adjustment for study site. Urinary cadmium, tungsten and uranium concentrations differed by geographic locations in MESA (Multi-Ethnic Study of Atherosclerosis) communities. PM_2.5 levels could contribute to geographic differences in tungsten exposure. These findings highlight the need to implement preventive strategies to decrease toxic metal exposure and to evaluate the health effects of chronic exposure to those metals. Full article