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In copper smelting processes, acidic effluents are generated that contain inorganic contaminants such as arsenic and copper. Nowadays, the treatment of wastewater is done by physicochemical methods without copper recovery. Electrodialysis is an alternative process that can recover copper. Moreover, when electrocoagulation is applied to remove arsenic from wastewater, a more stable final sludge of less volume is obtained. The present research studies the application of a combined electrodialysis and electrocoagulation process to (1) recover Cu and (2) precipitate and remove arsenic simultaneously in the same batch reactor, using synthetic wastewater that simulates wastewater from a copper smelter. Copper and arsenic could be removed and separated by the electrodialysis part, and the electrocoagulation of arsenic was verified. With electrodialysis, the arsenic and copper removals were 67% and 100%, respectively, while 82% of the arsenic arriving at the electrocoagulation part of the cell could be precipitated and removed by this process. Initial concentrations were around 815 mg L-1 Cu and 7700 mg L-1 As. The optimal current was found to be 1.36 A due to the shorter treatment times necessary to get removal percentages, recovery percentages and energy/removed copper mass ratios in the same ranges as the values achieved with a current of 1.02 A. In summary, the combined process is a promising tool for simultaneous copper recovery and arsenic removal.

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Mining activities have been a part of the history of Chile since time immemorial, generating pollution and environmental liabilities. Due to the lack of regulation, many tailings are deposited close to rivers or/and on unstable ground, near which towns have been built, generally in locations with no budget for their treatment. This study tested three plant species from Northern and Central Chile to remove total chromium, nickel, and zinc from tailings: Solidago chilensis, Haplopappus foliosus, and Lycium chilense, which complements the few existing studies on heavy metals removal with native or endemic Chilean shrubs. The experiments were conducted ex situ, and the initial and final concentrations of metals were determined in tailings and plants to obtain the removal efficiency, translocation and bioconcentration factors. Among these species, the best performance was obtained using Solidago chilensis, achieving removal efficiencies of 24% for Cr, 19% for Ni, and 17% for Zn, showing the ability to phytostabilize chromium and the higher resistance concerning the toxicity threshold. Haplopappus foliosus and Lycium chilense presented a slight tendency to stabilize chromium. Only Solidago chilensis showed little ability to extract Zn.

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In Chile, there are several abandoned mine tailing impoundments near population centers that need to be remediated. In this study, the ability of Oxalis gigantea, Cistanthe grandiflora, and Puya berteroniana to remove Zn, Ni, and Cr from mine tailings was evaluated. The plants' removal efficiency, bioconcentration, and translocation factors regarding these metals were determined to assess the ability of certain endemic species from Northern and Central Chile to extract or stabilize metals. After a period of seven months, the chemical analysis of plants and tailings, together with the statistical treatment of data, indicated the inability of all the species to translocate Ni, Cr, or Zn with a translocation factor lower than one. The results showed the stabilizing character of Oxalis gigantea, Puya berteroniana, and Cistanthe grandiflora for Zn, with a bioconcentration factor close to 1.2 in all cases, and the same ability of the latter two species for Cr, with a bioconcentration factor of 1.5 in the case of Cistanthe grandiflora and 1.7 for Puya berteroniana. Finally, a removal efficiency of 9.3% was obtained with Cistanthe grandiflora for Cr and 15% for Ni; values lower than 6.4% were obtained for Zn in all cases. Improvements in the process should be sought to enhance the performance of these species for the accumulation of the target metals.

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The analysis of Cu distribution in pre-treated mine tailings after electrodialytic remediation was carried out by using two methods of sequential extraction. The initial content of copper in the tailings was 1109 mg Cu/kg of dry tailing, where close to 40% of the sample in weight corresponded to a soluble fraction. The tailing was treated with a leaching solution for 24 h. Three different solutions were tested: H2SO4 + HNO3 with pH = 1.9; H2SO4 + HNO3 with pH = 4.2; and NH4Cl 0.8 mol/L with pH = 5.5. After that, electrodialytic remediation experiments were carried out using an electric field of 2.7 V/cm for 15 days. The best performance for the complete cell was obtained with H2SO4 + HNO3 solutions, with a copper removal efficiency in the range of 62% to 67% and a current efficiency between 6% and 9%. The results of the remaining copper concentration between anode and cathode, from both procedures of sequential extraction, showed similar trends. The differences were mainly attributed to the use of different extractant solutions and extraction times. Soluble and exchangeable fractions were easily removed, with efficiencies higher than 80%. The lowest copper removal efficiency was obtained with NH4Cl 0.8 mol/L.

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Mine tailings have been analyzed by a sequential extraction procedure after their pre-treatment with a leaching solution for 24 h and electrodialytic remediation during 15 days with a constant electric field of 2.7 V cm-1. Four leaching solutions were tested: H2SO4 + HNO3 (2:1 vol.) pH = 1.9; H2SO4 + HNO3 (2:1 vol) pH = 4.2; NH4Cl 0.8M, pH = 5.5 and 30% H2O2 adjusted to pH 2 with HNO3 1M + HCl 1M. After the treatment, the tailings were divided in six slices from anode to cathode. The highest removal efficiency of copper was obtained with H2SO4 + HNO3 pH = 1.9, which allows one to remove 67% of the copper in the total cell and 85% of the copper in the slice closest to anode. The same solution with pH = 4.2 allows one to remove 62% of the total copper. The analysis realized by the sequential extraction method indicates the easy removal of water-soluble and exchangeable fractions in all experiments, moreover, residual and sulfide are the less mobile fractions. The general trend was the movement of copper associated to different fractions from anode to cathode and its accumulation closest to the cathode in the case of exchangeable, Fe-Mn oxides and acid soluble fractions, possibly due to some precipitation of copper compounds associated with less acidic conditions.

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Resumen. Objetivo: Comparar el nivel de conocimiento sobre asma bronquialentre padres de niños asmaticos. Diseño: Este estudio es observacional, analítico, seccional, transversal. Lugar donde se realizó el estudio: Hospital IV Victor Lazarte Echegaray-Essalud 2009. Participantes: Se encuestaron 246 padres de niños de 5 a 14 años asmáticos y no asmáticos. Intervención: Se realizó una encuesta que consistió en 15 preguntas sobre asma bronquial; para categorizarlos posteriormente en padres con niveles de conocimiento bueno, regular y deficiente. Pricipales medidas de resultados: Nivel de conocimiento sobre asma bronquial, diferencia entre niveles asmáticos o no asmáticos, edad de los encuestados y de sus hijos. Resultados: Se obtuvieron diferencias significativas (p manor que 0.05) entre los niveles de conocimiento sobre asma bronquial entre padres de niños asmáticos y no asmáticos y no asmáticos encuestados, ya que el 20 por ciento de los padres de niños asmáticos obtuvieron un buen nivel de conocimiento sobre asma bronquial, en comparación con el 6,7 por ciento de padres de niños no asmáticos con buen nivel de conocimiento sobre asma bronquial, con respecto al nivel de conocimiento deficiente, el 9,8 por ciento de padres de niños asmáticos obtuvieron un nivel de conocimiento deficiente, comparado con el 12,2 por ciento de padres de niños nos asmáticos que obtuvieron una calificación deficiente; mientras que el 69,5 por ciento de padres de niños asmáticos obtuvieron una calificación regular, y el 81,1 por ciento de padres de niños no asmáticos obtuvieron una clasificación regular. Conclusiones: Los padres de niños asmáticos tienen un mejor nivel de conocimiento sobre asma bronquial que los padres de niños no asmáticos, no se encontraron diferencias significativas entre las edades de los niños con respecto al nivel de conocimiento de los padres de niños asmáticos y no asmáticos.

Abstract. Objective: To compare the level of knowledge about asthma among parents of asthmatic and non-asthmatics children. Desing: This study was observational, analytical, sectional, transverse. Setting: Victor Lazarte Echegaray-IV EsSalud Hospital, 2009. Participants: We surveyed 246 parents of asthmatic and non-asthmatics children of 5 to 14 years ald. Intervention: We conducted a survey that consisted of 15 question about asthma, to categorize them in levels of knowledge (good, fair and poor level of knowledge about asthma). Main outcome measures: Level of knowledge about asthma, the difference between levels of knowledge in parents of asthmatic and non-asthmatics children, age of respondents and their chidren. Results: There were significant differences (p minor that 0.05) between levels of knowledge about asthma among parents of asthmatic and non-asthmatic children, as 20 per cent af parents of asthmatic children had a good level of knowledge about asthma, compared with 6,7 per cent of parents of non-asthmatic children with good level of knowledge about asthma; with respect to the poor level of knowledge, 9,8 per cent of parents of asthmatic children had a poor level of knowledge, compared with 12.2 per cent of parents of non-asthmatic children that we were rated as poor; while 69,5 per cent of parents of asthmatic children had a regular level of konowledge about asthma and 81.1 per cent of parents of non-asthmatic children had a regular level of knowledge about asthma. Conclusions: The parents of asthmatic children had better level of knowledge about asthma than parent of non asthmatic children. There were no significant differences betwen the ages of children and the level of knowledge about asthma.

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