Copper extraction and phytotoxicity of organic acid leached mine tailings in Brassica napus

). This resulted in poor plant growth, likely due to Cu and Al toxicity. At 1/128 dilution, all acids had minimal impact on growth, with plant biomass similar to controls (41 g), though citric acid mobilised more elements at nutritional levels. Increased macronutrient (Ca, K, Mg) availability from diluted acids led to lower root/shoot ratios, suggesting partial alleviation of nutrient deficiencies. Multivariate analyses showed distinct elemental leaching profiles among LMWOAs, that converge with dilution, except for citric acid, which retained discrete patterns even at 1/128 dilution. These findings indicate that citric acid has strong potential for Cu-tailings remediation and rehabilitation, initially extracting high Cu and Al concentrations and supplying essential nutrients as concentrations are diluted.