Initiation of soil formation in weathered sulfidic Cu-Pb-Zn tailings under subtropical and semi-arid climatic conditions

• Published in: Chemosphere (Oxford) Vol. 204; pp. 318 - 326
• Main Authors: You, Fang, Dalal, Ram, Huang, Longbin
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.08.2018
• Subjects: buffering capacity; cation exchange capacity; climatic factors; Cu-Pb-Zn tailings; enzyme activity; Enzymes; field experimentation; grasses; indigenous species; microbial biomass; microbial communities; Microbial community; mine tailings; organic carbon; Organic carbon fractions; organomineral complexes; phytoremediation; Soil formation; Technosols; water solubility; wood chips; Organic carbon fractions; Enzymes; Soil formation; Cu-Pb-Zn tailings; Microbial community
• ISSN: 0045-6535; 1879-1298; 1879-1298
• DOI: 10.1016/j.chemosphere.2018.04.037

Field evidence has been scarce about soil (or technosol) formation and direct phytostabilization of base metal mine tailings under field conditions. The present study evaluated key attributes of soil formation in weathered and neutral Cu-Pb-Zn tailings subject to organic amendment (WC: woodchips) and colonization of pioneer native plant species (mixed native woody and grass plant species) in a 2.5-year field trial under subtropical and semi-arid climatic conditions. Key soil indicators of engineered soil formation process were characterized, including organic carbon fractions, aggregation, microbial community and key enzymatic activities. The majority (64–87%) of the OC was stabilized in microaggregate or organo-mineral complexes in the amended tailings. The levels of OC and water soluble OC were elevated by 2–3 folds across the treatments, with the highest level in the treatment of WC and plant colonization (WC+P). Specifically, the WC+P treatment increased the proportion of water stable macroaggregates. Plants further contributed to the N rich organic matter in the tailings, favouring organo-mineral interactions and organic stabilization. Besides, the plants played a major role in boosting microbial biomass and activities in the treated tailings. WC and plants enhanced the contents of organic carbon (OC) associated with aggregates (e.g., physically protected OC), formation of water-stable aggregates (e.g., micro and macroaggregates), chemical buffering capacity (e.g., cation exchange capacity). Microbial community and enzymatic activities were also stimulated in the amended tailings. The present results showed that the formation of functional technosol was initiated in the eco-engineered and weathered Cu-Pb-Zn tailings under field conditions for direct phytostabilization. •Plant growth and WC input initiated soil formation in weathered Cu-Pb-Zn tailings.•The treatments increased water-stable aggregates and organic carbon stabilization.•The treatments elevated microbial biomass and key enzymatic activities in the tailings.•Combined woodchips and native plants were preferred to stimulate tailing-soil formation.