Application of remediation techniques for immobilization of metals in soils contaminated by pyrite tailing spill in Spain

Abstract

Remediation techniques for soil pollution have been studied in the aftermath of a tailing spill from a pyrite-mine holding pond in Aznalcóllar (southwest Spain). Given the extent of the accident and the characteristics of the affected area, we conclude that, after the removal of the tailings, the only feasible remediation measure involves chemical immobilization of the pollutants. The best treatment tested proved to be liming in combination with amendment materials such as soils rich in iron oxides and clay. Monitoring for 3 years has demonstrated that the system is effective for reducing the solubility of the most mobile forms of the main pollutant elements, although further monitoring is recommended.