Objective: To estimate the incidence, mortality and lethality rates of COVID-19 among Indigenous Peoples in the Brazilian Amazon. Additionally, to analyze how external threats can contribute to spread the disease in Indigenous Lands (IL).Methods: The Brazilian Amazon is home to nearly half a million Indigenous persons, representing more than 170 ethnic groups. As a pioneer in heading Indigenous community-based surveillance (I-CBS) in Brazil, the Coordination of the Indigenous Organizations of the Brazilian Amazon (COIAB) started to monitor Indigenous COVID-19 cases in March of 2020. Brazil's Ministry of Health (MOH) was the main source of data regarding non-Indigenous cases and deaths; to contrast the government's tally, we used the information collected by I-CBS covering 25 Special Indigenous Sanitary Districts (DSEI) in the Brazilian Amazon. The incidence and mortality rates of COVID-19 were calculated using the total number of new cases and deaths accumulated between the 9th and 40th epidemiological weeks. We studied (a) the availability of health care facilities to attend to Indigenous Peoples; (b) illegal mines, land grabbing, and deforestation to perform a geospatial analysis to assess how external threats affect Indigenous incidence and mortality rates. We used the Generalized Linear Model (GLM) with Poisson regression to show the results.Results: MOH registered 22,127 cases and 330 deaths, while COIAB's survey recorded 25,356 confirmed cases and 670 deaths, indicating an under-reporting of 14 and 103%, respectively. Likewise, the incidence and mortality rates were 136 and 110% higher among Indigenous when compared with the national average. In terms of mortality, the most critical DSEIs were Alto Rio Solimões, Cuiabá, Xavante, Vilhena and Kaiapó do Pará. The GLM model reveals a direct correlation between deforestation, land grabbing and mining, and the incidence of cases among the Indigenous.Conclusion: Through this investigation it was possible to verify that not only the incidence and mortality rates due to COVID-19 among Indigenous Peoples are higher than those observed in the general population, but also that the data presented by the federal government are underreported. Additionally, it was evident that the presence of illegal economic activities increased the risk of spreading COVID-19 in ILs.
The proposition that hydrolysis may account for the selective adsorption of heavy metals by clay surfaces is compared with an alternate explanation of specific exchange of the metal with weakly dissociable H+. It is shown that past evidence offered in support of the two hypotheses is somewhat ambiguous. Theoretical treatment is presented for the competition of ions in adsorption reactions which provides a means of distinguishing between the two alternatives through the effect of H+ on the metal‐clay reaction in the presence of a competing ion. Experimentally, the effect of H+ on the reaction of Co2+ with montmorillonite is studied in the presence and absence of Mg2+, a weakly competing ion. Ionic strength is held constant, and nonspecific reactions are minimized with an excess of CaCl2. The results are interpreted as favoring the hydrolysis hypothesis. Inherent assumptions are considered.
Pretreatment of montmorillonite with F interferes with the adsorption of Co by montmorillonite. Since the effect is reversible with base, the F is thought to replace surface hydroxyl groups that serve as the adsorption sites for Co. The Co reaction with these sites increases with temperature, indicating that the reaction is endothermic. Therefore, either heat is required to form the Co‐to‐surface bond or the cation is replacing more strongly bound surface hydrogens such as those associated with the hydroxyls mentioned above. While certain other heavy metal cations were previously shown to exchange with adsorbed Co, Ca is found to have no effect on the reaction, except to alter the activity coefficient of Co in solution. This is interpreted as indicating the absence of any charge associated with the bonding site. Alcohol is found to enhance the reaction of Co with montmorillonite in contrast to what would be expected if hydrolysis played a role in the reaction.
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