Insights into a 20-ha multi-contaminated brownfield megasite: An environmental forensics approach.

Here we addressed the contamination of soils in an abandoned brownfield located in an industrial area. Detailed soil and waste characterisation guided by historical information about the site revealed pyrite ashes (a residue derived from the roasting of pyrite ores) as the main environmental risk. In fact, the disposal of pyrite ashes and the mixing of these ashes with soils have affected a large area of the site, thereby causing heavy metal(loid) pollution (As and Pb levels reaching several thousands of ppm).