Assessment of contaminated soil recovery by Aznalcollar spill

The affected soils by Aznalcollar's mine accident, Sevilla, España, in 1998, were remediate to reduce the contamination generated mainly by As, Cu, Pb and Zn. To evaluate the recovery of soils, especially those undergoing to remediation, three soils were sampled: contaminated (SC), remediate (SR), uncontaminated soil (SNC), in the sector called "Puente de las Doblas" 10 years after the accident. We were analysed the physic-chemical properties, and perfomed bioassays with Vibrio fischeri and Lactuca sativa, to evaluate the toxicity produced by the pollutants. The SR has similar properties as the SNC, but with a higher concentration of total metals that do not exceed the critical level for natural parks and forest areas, and the concentrations of Cu and Zn in a soluble phase are higher than the maximum desirable soil solution. Moreover, these two metals generated toxic in Vibrio fischeri, to 40-50 cm depth at the acidic pH associated. We recommended continuing making periodic monitoring in order to assess the evolution and potential dispersion toxicity detected in the remediated soils, and taking the actions necessary for environmental recovery.