Remediation of As-Contaminated Soils in the Guadiamar River Basin (SW, Spain)

Abstract

Soil remediation has been studied after a spill from a settling pond of a pyrite mine in Aznalcollar (SW Spain). The affected area was approximately 55 km 2 and extended about 40 km from the spill. The Pb concentration in soils ranged from 35.8 to 3231.0 mg kg −1 , with a mean value of 385.8 mg kg −1 . The remediation techniques investigated included: manual and mechanical removal of the contaminated soil, mixing the upper part of the soils by ploughing, and addition of different amendment materials to reduce the Pb solubility, such as carbonates, zeolites, iron-rich soils, bentonites and yeasts. A combination of liming with iron-rich soils proved the most effective treatment.