Publicação
Phytostabilization efficiency of a combined recovery system in the improvement of physicochemical characteristics of mine tailings and their leachates
| Resumo: | Sulfide-rich mine tailings present high risk of acid drainage generation and of passing of metal(oid)s contaminated leachates to soil and waters, through runoff and percolation. The current study evaluated the physicochemical stabilisation potential of tailings with sulfides (and valorisation of the area) through the combined application of a designed Technosol and cultivation of pasture, with/without fungal inoculation. According to the physicochemical characteristics of studied tailings, collected in Aznalcóllar mining area (S of Spain), a Technosol with eutrophic-alkaline properties was designed and elaborated with different industrial wastes. Then, a mesocosm experiment was carried out in greenhouse conditions and with three treatments (Tailing+fungal inoculant; Tailing+Technosol+fungal inoculant; Tailing+Technosol) where pasture species were sown. The inoculant was a commercial mixture of Rhizoglomus irregulare+Trichoderma. The physicochemical characteristics were determined from soil/tailing samples collected at the end of assay (after eight months). The biomass production, visual signs of phytotoxicity and nutritional deficiencies, and nutrient/contaminant contents in shoots of the pasture species grown in pots were also assessed. The application of the Technosol, independently of fungal inoculation, improved the tailings characteristics, namely pH (Control: 2.42; Technosols: 8.28-8.36), Eh, cation exchange capacity, organic matter contents (Control: 1.31%; Technosols: 3.76-4.24%), available nutrients contents and C/N ratio as well as diminished the availability of several potentially hazardous elements compared to the concentrations in tailing (e.g., Al: >237-fold; Cu: >16-fold; Zn: >182; As: >11-fold; Pb: ~3.5-6.3 fold; Mn: ~2.7 fold). The fungal inoculant seemed to only significantly interact with available Fe contents in soil. Elements’ concentrations in plant shoots were considered below phytotoxic values except for Zn (first cycle) and Mn, and no visual signs of phytotoxicity were observed. Elements’ concentrations in plants were below the maximum allowable for cattle (except K). The results supported the relevance of the designed Technosol together with pasture crop in environmental rehabilitation of sulfide-rich tailings and biomass valorisation as part of carefully balanced cattle feeds. |
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| Autores principais: | Lungu, Adelaida Patrasc |
| Assunto: | plant-soil interaction sulfide-rich tailing phytostabilisation designed Technosol valorisation interação planta-solo escombreiras ricas em sulfureto fitoestabilização tecnossolo desenhado valorização |
| Ano: | 2023 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Sulfide-rich mine tailings present high risk of acid drainage generation and of passing of metal(oid)s contaminated leachates to soil and waters, through runoff and percolation. The current study evaluated the physicochemical stabilisation potential of tailings with sulfides (and valorisation of the area) through the combined application of a designed Technosol and cultivation of pasture, with/without fungal inoculation. According to the physicochemical characteristics of studied tailings, collected in Aznalcóllar mining area (S of Spain), a Technosol with eutrophic-alkaline properties was designed and elaborated with different industrial wastes. Then, a mesocosm experiment was carried out in greenhouse conditions and with three treatments (Tailing+fungal inoculant; Tailing+Technosol+fungal inoculant; Tailing+Technosol) where pasture species were sown. The inoculant was a commercial mixture of Rhizoglomus irregulare+Trichoderma. The physicochemical characteristics were determined from soil/tailing samples collected at the end of assay (after eight months). The biomass production, visual signs of phytotoxicity and nutritional deficiencies, and nutrient/contaminant contents in shoots of the pasture species grown in pots were also assessed. The application of the Technosol, independently of fungal inoculation, improved the tailings characteristics, namely pH (Control: 2.42; Technosols: 8.28-8.36), Eh, cation exchange capacity, organic matter contents (Control: 1.31%; Technosols: 3.76-4.24%), available nutrients contents and C/N ratio as well as diminished the availability of several potentially hazardous elements compared to the concentrations in tailing (e.g., Al: >237-fold; Cu: >16-fold; Zn: >182; As: >11-fold; Pb: ~3.5-6.3 fold; Mn: ~2.7 fold). The fungal inoculant seemed to only significantly interact with available Fe contents in soil. Elements’ concentrations in plant shoots were considered below phytotoxic values except for Zn (first cycle) and Mn, and no visual signs of phytotoxicity were observed. Elements’ concentrations in plants were below the maximum allowable for cattle (except K). The results supported the relevance of the designed Technosol together with pasture crop in environmental rehabilitation of sulfide-rich tailings and biomass valorisation as part of carefully balanced cattle feeds. |
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