Browsing by Author "Acuna, E."

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    Evaluation of sulfate rhizofiltration by Carpobrotus chilensis for treating mining waters
    (2024) Tapia, Y.; Salazar, O.; Joven, A.; Castillo, B.; Urdiales, C.; Garcia, A.; Ihle, C.; Acuna, E.
    Chile, the world's leading copper producer, generates significant volumes of mining waters, some of which cannot be recirculated into the production process. These mining waters are characterized by elevated sulfate (SO42-) concentrations, requiring sustainable management strategies for potential reuse. This study aims to evaluate the rhizofiltration technique using Carpobrotus chilensis for treating mining waters with a high SO(4)(2- )concentration. Initially, the mining waters exhibited a pH of 7.97 +/- 0.16 and a SO42- concentration of 2,743 +/- 137 mg L-1, while the control water had a pH of 7.88 +/- 0.08 and a SO42- concentration of 775 +/- 19.0 mg L-1. The plants were hydroponically cultivated in 40 L containers with mining waters and drinking water as a control. Over an 8-week period, the pH of the mining water decreased to 3.12 +/- 0.01, and the SO42- concentration declined to 2,200 +/- 110 mg L-1. Notably, the fresh weight of roots was significantly higher in plants grown in mining water (22.2 +/- 6.66 g) compared to those in the control treatment (14.3 +/- 4.28 g). However, an undesirable increase in the acidity was observed in the mining waters after rhizofiltration, which was attributed to hydrogen sulfate (HSO4-) and/or root exudates. Despite the unexpected increase in acidity, C. chilensis effectively reduced the concentration of SO42- in mining waters by 20%. Additionally, the C. chilensis roots accumulated 4.84 +/- 1.40% of sulfur (S), a level comparable to thiophore plants. This study provides evidence that this non-aquatic plant can be used in sulfate rhizofiltration. NOVELTY STATEMENT Caprobrotus chilensis is a good candidate for sulfate rhizolfiltration in mining waters. The accumulation of sulfur by the roots of Carpobrotus chilensis reached 4.84% Mining waters with a high concentration of sulfates require control of the redox potential
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    Monitoring of Chemical Species in Soils, Waters and Plants Near the Active Copper Mine Tailing Dam Ovejeria (Central Chile)
    (2024) Tapia, Y.; Garcia, A.; Acuna, E.; Salazar, O.; Casanova, M.; Najera, F.; Kremer, C.; Castillo, B.; Joven, A.; Diaz, O.; Pastene, R.; Antilen, M.; Cornejo, P.; Neaman, A.
    Chile, the world's largest copper producer, generates massive amounts of mine tailings that are a source of ongoing environmental concern for local communities. The main objective of this work is to evaluate the concentration of As, Cd, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Zn and SO42- in soils, water and vegetation in the communities surrounding the Cu Ovejeria mine tailings dam, in central Chile. Soils, water and plants samples were collected from the towns of Chacabuco, Huechun, Huertos Familiares, Punta Peuco and Santa Matilde, which are located at 3 to 8 km from the mine tailings site, operated by CODELCO since 1999. The results showed that the levels of metals/metalloids and SO42- in water (pH 6.7-7.9) met both WHO limits and Chilean water quality standards for multiples uses. In soil (pH 7.7-8.4), total and available concentrations of metals/metalloids did not exceed international reference values. Plants with acceptable levels of metals and S were Citrus limon, Eucalyptus, Schinus molle, Prunus persica, Medicago sativa, Citrus sinensis and Ficus carica. The only species with Fe content well above the reference value and with high concentrations of other metals (Cu, Mn, Mo and Pb) was Acacia caven. The concentrations of chemical species determined between 2015 and 2018, in different media and locations near the active Cu tailings dam Ovejeria, in central Chile, allow to conclude that in general the levels are comparable to national and international references and do not indicate contamination.