Remediation of metal-contaminated mine tailings by the application of organic and mineral amendments

Abstract

Purpose Tailings are generally characterized by severe physicochemical conditions that limit the establishment of vegetation. The present study aimed to select suitable combinations of organo-mineral amendments to improve the physicochemical, biochemical, and biological properties of spolic technosols, highly contaminated with metals. Materials and methods Several substrates were prepared by mixing mine tailings (MT) of an abandoned mining area with non-contaminated agricultural soil (anthrosol), green waste compost, lime, and rock phosphate at different rates: S1 -50% of MT + 50% of agricultural soil; S2 -S1 + 3% of lime (CaCO 3 ); S3 -S1 + 6% of rock phosphate; S4 -S1 + 10% of compost; S5 -S1 + 10% of compost + 3% of lime; S6 -S1 + 10% of compost + 6% of rock phosphate. Untreated MT and agricultural soil were analyzed immediately, and 8 months after incorporating the amendments. Results and discussion Heterotrophic microorganisms were not recovered from untreated MT due to the highly acidic pH and available metal concentrations. However, the addition of organo-mineral amendments ameliorated the tailings' characteristics by increasing pH, conductivity, total organic carbon, and available P levels. Moreover, after 8 months, heterotrophic microorganisms were recovered from those substrates and dehydrogenase activity was enhanced. The incorporation of agricultural soil and green waste compost mixed either with lime (S5) or rock phosphate (S6) was the most effective treatment. Conclusions Both S5 and S6 mixtures successfully reduced the environmental risk posed by tailings, suggesting the potential use of these amendments for the remediation of pyrite mines.

A Review on Remediation of Iron Ore Mine Tailings via Organic Amendments Coupled with Phytoremediation

“…Bacterial enumeration and enzymatic activities showed an apparent deterioration of microbial communities in the mine tailings, since no viable bacterial cells were detected, and dehydrogenase enzyme activity was extremely low [37]. Further, [38] pointed out that microbial activity in metal-polluted bare soils is disrupted by the toxic effects on microorganisms due to the absence of vegetation cover. It is worth noting that [39] showed that microbial diversity and structure in the rhizosphere and in bulk soils from mine tailings were mainly influenced by the presence of pioneer plants and the environmental conditions, especially nutrient elements and Fe contents, alongside plant community colonisation.…”

Physical, Chemical, and Microbiological Characterization of Kettara Mine Tailings, Morocco

“…The Kettara mine tailings presented very low contents of TOC, TN, and available P, constituting major limiting factors for the establishment and development of plants in these areas [8,22,38,39]. Indeed, low levels of organic matter and nutrients are commonly found in mine tailings [40][41][42][43], which may be explained by the fact that these wastes have resulted from a succession of ore processing stages [44].…”

Enhancing Native Plant Establishment in Mine Tailings under Drought Stress Conditions through the Application of Organo-Mineral Amendments and Microbial Inoculants

“…Exploring these beneficial interactions is a valuable tool to improve the overall effectiveness of phytoremediation strategies in metal-contaminated areas. Several authors have reported the beneficial effects of inoculating plant growth-promoting rhizobacteria (PGPR) on plant establishment and development in metal-contaminated areas [ 6 , 8 , 23 , 25 , 26 , 27 ]. Microbial inoculants are known to decrease the availability of contaminants and enhance plant growth under stressed conditions through various mechanisms, including the production of indole-3-acetic acid (IAA) and siderophores, the solubilization of mineral phosphorus, and the activity of the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase [ 8 , 23 , 26 ].…”