Association between urinary concentrations of toxic metals/metalloids and oxidative stress in Brazilians living in areas affected by the Fundão dam failure.

The Fundão Dam failure has been the most significant environmental disaster in Brazil. The catastrophe released large amounts of mining waste into the environment, including toxic metals/metalloids, which are recognized to induce carcinogenic effects. The urinary levels of 8-hydroxy-2'-deoxyguanosine (8OHdG), a widely accepted oxidative stress and carcinogenesis biomarker, provide a potential tool for assessing the disaster's health implications. This study investigated the association between urinary levels of some toxic metals/metalloids and 8OHdG in Brazilian individuals living in areas affected by the Fundão dam failure. Urinary concentrations of arsenic (As), cadmium (Cd), mercury (Hg), nickel (Ni), and lead (Pb) were determined using inductively coupled plasma mass spectrometry, while 8OHdG was analyzed by liquid chromatography-tandem mass spectrometry. Non-parametric bootstrap regression was used to estimate the associations between the urinary levels of toxic elements and 8OHdG. The results showed that except for Hg, urinary concentrations of all metals/metalloids analyzed here exceeded the reference ranges for the Brazilian population. The regression analysis revealed that As (0.337; CI 95%: 0.203; 0.474), Cd (0.268; CI 95%: 0.036; 0.520), and Ni (0.296; CI 950.108; 0.469) were positively associated with creatinine-adjusted urinary 8OHdG levels. Associations were not found for Hg (0.0122; CI 95%: -0.155; 0.183) and Pb (0.201; CI 95%: -0.040; 0.498). The current findings suggest that high exposure to toxic metals/metalloids might increase 8OHdG levels with potential adverse health effects. This study is the first one in which the relationship between toxic metals/metalloids and oxidative stress biomarkers is investigated in populations affected by environmental disasters. Further prospective studies are necessary to monitor exposure levels and explore additional health impacts.

Fundão tailings dam failure in Brazil: Evidence of a population exposed to high levels of Al, As, Hg, and Ni after a human biomonitoring study.

BACKGROUND: On November 5th, 2015, the Fundão mine tailings dam in Minas Gerais State, Brazil, failed, releasing more than 50 million m3 of mud, rich in toxic metals. After that, a massive environmental disaster began with the mud wave flowing more than 600 km, until the mouth of Doce River, in Espírito Santo State, and finally reaching the Atlantic Ocean. A vast area was contaminated, affecting the ecosystem and several communities. Despite the tremendous environmental disaster, little is known concerning the population's exposure to toxic elements yet. METHODS: Thus, a cross-sectional study was for the first time conducted in three communities directly affected by the disaster (Regência, Povoação, and Campo Grande) in Espírito Santo State, to evaluate the levels of 11 chemical elements (Al, As, Cd, Co, Cu, Hg, Mn, Ni, Pb, Se, and Zn) in blood. Sample analysis (n = 300) was performed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). RESULTS: Our data show high levels of exposure to Al, As, Hg, and Ni. Mean values in blood were 60 µg/L (ranging from 9 to 434 µg/L), 10.9 µg/L (ranging from 5.81 to 269 µg/L), 6.4 µg/L (ranging from 0.05 to 103 µg/L) and 2.7 µg/L (ranging from 0.08 to 21 µg/L) for Al, As, Hg and Ni, respectively. Moreover, after applying a multiple regression model, we found community, drinking water, fish, seafood consumption, and smoking habits associated with metal/metalloid levels in their body. Well and tap water intake were identified as important sources of exposure to aluminum and nickel. CONCLUSIONS: Our findings represent health risks to the groups living in the areas affected by the tailings dam failure, calling for further studies to evaluate the potential health effects of high exposure to metals and remediation actions from public health Brazilian authorities.

High Eu3+ concentration quenching in Y3TaO7 solid solution for orange-reddish emission in photonics.

We report the synthesis of a Y3TaO7 solid solution containing a high Eu3+ concentration (from 7 up to 50 mol%) and investigate how Eu3+ influences the Y3TaO7 crystallization process. To this end, we evaluate the Y3TaO7 structural features and photoluminescence properties after Eu3+ introduction into the Y3TaO7 lattice. The higher the Eu3+ ion concentration, the more stable the crystallization process of the Y3TaO7 phase seems to be. The Eu3+-containing Y3TaO7 displays intense orange-reddish, broad band emission because Eu3+ occupies different symmetry sites in the host and causes inhomogeneous broadening. Eu3+ emission quenching due to Eu3+ concentration is negligible up to 30 mol% and absolute quantum yield values of up to nearly 30% were obtained, making Eu3+-containing Y3TaO7 interesting materials for application as high-intensity emitters in photonics.