In several countries, mining generates a high volume of tailing deposits, significantly impacting on soils. One of the non-metallic elements found in high concentrations in mine tailings is sulphur (S), in the form of sulphide minerals, whose oxidation causes acid drainage and metal mobility. The absorption of S in plants cultivated in mine tailings has been scarcely investigated. The objective of this study was to evaluate the extent to which a commercial humic substances and a vegetable waste compost can enhance the phytoremediation capacity of Atriplex nummularia for S and metals (Cu, Mo) in mine tailings. The plants were cultivated for 120 days under greenhouse conditions in pots with mine tailings (MT), with the addition of vegetable waste compost (VC) and a commercial humic substance (HS) in a 5% dose (W/W). At the end of the assay, the concentration of S in the aerial parts of plants cultivated in mine tailings, without amendments, reached 19,538 ± 4554 mg kg⁻¹, indicating a potential thiophore plant. In MT in which HS were applied, S and Cu concentration decreased significantly in aerial parts, while VC significantly increased Mo. The addition of HS generated significantly greater dry weight, reaching 11.55 ± 1.92 g in the aerial parts versus 2.08 ± 0.52 g in MT, which increased significantly S and Cu content in plant root and therefore favourable to phytostabilization. Regarding organic amendments, their chemical characteristics, availability, cost and quality in relation to organic matter are very important aspects for phytoremediation of mine tailings.

Understanding plant behaviour in polluted soils is critical for the sustainable remediation of metal-polluted sites including abandoned mines. Post-operational and abandoned metal mines particularly in semi-arid and arid zones are one of the major sources of pollution by soil erosion or plant hyperaccumulation bringing ecological impacts. We have selected from the literature 157 species belonging to 50 families to present a global overview of ‘plants under action’ against heavy metal pollution. Generally, all species of plants that are drought, salt and metal tolerant are candidates of interest to deal with harsh environmental conditions, particularly at semi-arid and arid mine sites. Pioneer metallophytes namely Atriplex nummularia, Atriplex semibaccata, Salsola kali, Phragmites australis and Medicago sativa, representing the taxonomic orders Caryophyllales, Poales and Fabales are evaluated in terms of phytoremediation in this review. Phytoremediation processes, microbial and algal bioremediation, the use and implication of tissue culture and biotechnology are critically examined. Overall, an integration of available remediation plant-based technologies, referred to here as ‘integrated remediation technology,’ is proposed to be one of the possible ways ahead to effectively address problems of toxic heavy metal pollution. Graphical abstract Integrated remediation technology (IRT) in metal-contaminated semi-arid and arid conditions. The hexagonal red line represents an IRT concept based on remediation decisions by combination of plants and microbial processes.