Heavy metal and nutrient uptake in plants colonizing post-flotation copper tailings

Area of Science:

• Environmental Science
• Biogeochemistry
• Phytoremediation

Background:

• Copper ore mining generates hazardous post-flotation wastes (tailings) that are difficult to remediate.
• These tailings exhibit extreme copper enrichment (1800 mg kg⁻¹) and contamination with cobalt (Co) and manganese (Mn).
• Limited availability of phosphorus (P), iron (Fe), and zinc (Zn) further complicates remediation efforts.

Purpose of the Study:

• To assess the phytoremediation potential of plants growing in copper-rich mine tailings.
• To investigate the relationship between substrate element availability and plant shoot chemical composition.
• To identify plant species suitable for phytostabilization of contaminated mine tailings.

Main Methods:

• Analysis of elemental composition in tailings and plant shoots.
• Redundancy analysis to correlate substrate elements with plant composition.
• Principal component analysis to differentiate plant element accumulation patterns.

Main Results:

• Plants in tailings showed enrichment in Cu, cadmium (Cd), Co, nickel (Ni), and lead (Pb), with critical copper toxicity levels in some species.
• Agrostis stolonifera and Calamagrostis epigejos (grasses) accumulated less Cu but also had lower P, Fe, and Zn compared to dicotyledonous species.
• Agrostis stolonifera demonstrated lower shoot Cu and better acquisition of limiting nutrients, indicating suitability for phytostabilization.

Conclusions:

• Agrostis stolonifera is a promising candidate for phytostabilization of copper mine tailings.
• Amendments such as improving soil texture, phosphorus fertilization, and introducing leguminous species are recommended.
• Understanding plant-element interactions is crucial for effective phytoremediation strategies.