Rehabilitation of a Riparian Site Contaminated by Tailings from the Fundão Dam, Brazil, Using Different Remediation Strategies

Abstract

The tailings spilled by the Fundão Dam rupture in the Doce River basin (Brazil) had a high pH, elevated sodium (Na) and ether amine, and low soil organic matter. With the aim of decreasing the toxic compounds, we established 2 remediation strategies: treatment 1, phytoremediation with tolerant native species of the Atlantic Forest cultivated on scraped sediment plus the incorporation of organic matter; and treatment 2, phytoremediation with native species plus superficial deposition of organic matter. The experimental site was compared with a degraded site that the dam tailings had reached and with a preserved site, a fragment of preserved Atlantic Forest. After 12 mo, plants showed an outstanding growth, especially after treatment 1 (~4 m), and the remediation procedures resulted in significant decreases in pH (from 8.0 to~6.0), Na (from 154 to 22-35 mg/kg), electrical conductivity, and ether amine (from 6.0 to 0.5 mg/kg) in both treatments. By contrast, ammonium, a product of ether amine degradation, showed a significant increase in the experimental site, along with a significant increase in nitrate and improvement of soil microbial populations assessed by phospholipid fatty acid analysis. The treatments also improved soil fertility in the experimental site, as estimated by soil nutrients, cation exchange capacity, and soil aggregation. Based on the parameters analyzed, a principal component analysis showed that samples from the degraded site and the preserved site clustered in an opposite position and those from the experimental site clustered in an intermediate position but closer to the samples from the preserved site. Overall, our results demonstrated that the remediation procedures adopted were effective and resulted in rehabilitation of a riparian forest contaminated with dam tailings that included Na and ether amine.

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].…”

Driving Factors Influencing Soil Microbial Community Succession of Coal Mining Subsidence Areas during Natural Recovery in Inner Mongolia Grasslands

“…The assessment of the microbial community structure in coal mining subsidence areas shows that when the microbial community structure is damaged, the relevant material cycle of the soil and the sustainability of the ecosystem will be affected to varying degrees [ 16 ]. Disturbances cause a decline in soil microbial diversity and affect the activity of related microorganisms, thereby affecting energy flow and material cycle and ultimately reducing soil nutrients [ 17 ].…”