ORALS

SESSION: MineralWedPM2-R7	Torem International Symposium (8th Intl. Symp. on Sustainable Mineral Processing)
Wed. 29 Nov. 2023 / Room: Sunflower
Session Chairs: Marcos De Campos; Session Monitor: TBA

16:50: [MineralWedPM211] OS
CYANIDE PERSISTENCE IN A GOLD PHYTOEXTRACTION TRIAL
Hector Gamboa-Baez¹ ; Mayra C. Rodriguez-Lopez² ; Joel Lopez-Perez³ ; Victor Wilson-Corral⁴ ; ¹Tecnológico Nacional de México/Instituto Tecnológico Superior de Eldorado, Eldorado, Mexico; ²Centro de Estudios Justo Sierra (CEJUS), Surutato, Mexico; ³Centro de Innovacion y Desarrollo Educativo (CIDE) A. C, Culiacan, Mexico; ⁴Centro de Innovacion y Desarrollo Educativo (CIDE)-Seccion Sinaloa, Culiacan, Mexico;
Paper Id: 227 [Abstract]

Sodium cyanide (NaCN) is a solubilizer that improves gold uptake in phytomining [1]. However, concerns have been expressed about the persistence of this adjuvant and their associated detrimental repercussions for environment. Therefore, evaluating the persistence of residual CN in the remained substrates is relevant [2]. In order to assess the loss of CN in a gold phytoextraction process with Helianthus annuus L. (sunflower) on a gold mining waste. Pots containing 3.5 kg of substrate were prepared for this study. Sunflower plants were cultivated in a homemade greenhouse. Temperature range was 24-38° C and environment humidity range was of 40-60%. Twelve weeks after seeding, all containers were treated with a dose of 250 mg.kg-1 of NaCN in solution. Seven days later, plants were harvested. Samples with 30 g of substrate were obtained in all containers at time of plant harvest 7, 14, 21, 28, 35, and 42 days after harvest. Samples were prepared and analyzed in laboratory to determine the total content of CN. We found that 7 days after the application, the CN total concentration was reduced in a 91.7% for containers without plants and 90.8%, for containers with plants, respectively. Plants cultivated in mine waste produces a small increase in loss of adjuvant[3]. These results suggest that concerns about CN could be reduced, because it is enough one week of natural intemperization processes, to reduce significantly the CN in soil. This study could be applied to the mining waste management and the environmental impact of CN application in the gold mining industry.

References:
[1] Wilson-Corral, V., et al., Gold concentrations in mine tailings. Potential application of phytomining, in Ecology in an Era of Globalization: Challenges and Opportunities for Environmental Scientist in the Americas. 2006, ESA. p. 156-157. [2] Ebbs, S.D., et al., Initial loss of cyanide, thiocyanate, and thiosulfate adjuvants following amendment to an oxidic gold ore. Minerals Engineering, 2011. 24(14): p. 1641-1643. [3] Cañón-Cortázar, R.G., L.M. Avellaneda-Torres, and E. Torres-Rojas, Associated microorganisms to the nitrogen cycle in soils under three systems of use: potato crop, livestock and páramo, in Los Nevados National Natural Park, Colombia. Acta Agronómica, 2012. 61(4): p. 371-379.

SESSION: MineralWedPM2-R7	Torem International Symposium (8th Intl. Symp. on Sustainable Mineral Processing)
Wed. 29 Nov. 2023 / Room: Sunflower
Session Chairs: Marcos De Campos; Session Monitor: TBA

17:15: [MineralWedPM212] OS
EFFICIENCY OF EDDS IN PHYTOREMEDIATION PROCESS OF COPPER-CONTAMINATED MINE WASTE
Mayra C. Rodriguez-Lopez¹ ; Hector Gamboa-Baez² ; Joel Lopez-Perez³ ; Victor Wilson-Corral⁴ ; ¹Centro de Estudios Justo Sierra (CEJUS), Surutato, Mexico; ²Tecnológico Nacional de México/Instituto Tecnológico Superior de Eldorado, Eldorado, Mexico; ³Centro de Innovacion y Desarrollo Educativo (CIDE) A. C, Culiacan, Mexico; ⁴Centro de Innovacion y Desarrollo Educativo (CIDE)-Seccion Sinaloa, Culiacan, Mexico;
Paper Id: 185 [Abstract]

Mining industry annually generates millions of tons of waste that needs to be adequately managed in order to prevent environmental risks. Assisted phytoremediation with chelating agents has been proposed as a viable alternative for cleaning of Cu-contaminated soils [2]. Particularly, ethylenediaminedisuccinic acid (EDDS) has been suggested as an option because it has shown the ability to increase the bioavailability of metals such as Cu [3]. In assisted phytoremediation EDDS has been characterized by a short half-life in the environment [4], and as not leaching chemical. In this study, the efficiency of 4 doses of EDDS in the phytoremediation of Cu lodged in a mine waste substrate was evaluated. Helianthus annuus L. (sunflower) plant species was cultivated in homemade greenhouse for 10 weeks in a previously prepared mining waste substrate. After this period, 4 treatments (0, 0.2, 0.4 and 0.8 mMol/kg) of EDDS were applied to the substrate to improve the bioavailability of Cu. One week later, plants were harvested, prepared, and analyzed by atomic absorption spectrometry to determine Cu concentrations in plant tissue. According to results, the dose of 0.8 mMol/kg showed the highest efficiency. In this case, the translocation factor was equivalent to 0.65, which was 116% higher than recorded in the plants used as control (0.30). In addition, the Cu bioconcentration factor, in the aerial part of plant, for the dose of 0.8 mMol/kg was 8.32, which is 407% higher than recorded in the aerial part of the controls (1.64). Regarding the underground part of the plants, the bioconcentration factor occurred in the dose of 0.8 mMol/kg was 12.85, which was 137% higher than registered in the underground part of the plants used as a control (5.42). Our results suggest that a phytoremediation process of mine waste substrate, assisted with EDDS, could be viable using H. annuus. This study provides useful data for the design of efficient strategies in Cu phytoremediation processes, for waste substrates generated by the mining industry.

References:
[1] Helser, J., E. Vassilieva, and V. Cappuyns, Environmental and human health risk assessment of sulfidic mine waste: Bioaccessibility, leaching and mineralogy. Journal of Hazardous Materials, 2022. 424: p. 127313.
[2] Ju, W., et al., Co-inoculation effect of plant-growth-promoting rhizobacteria and rhizobium on EDDS assisted phytoremediation of Cu contaminated soils. Chemosphere, 2020. 254: p. 126724.
[3] Wang, X., et al., Biodegradation and effects of EDDS and NTA on Zn in soil solutions during phytoextraction by alfalfa in soils with three Zn levels. Chemosphere, 2022. 292: p. 133519.
[4] Tandy, S., et al., Extraction of Heavy Metals from Soils Using Biodegradable Chelating Agents. Environmental Science & Technology, 2004. 38(3): p. 937-944.