The environmental impact of ancient iron mining and smelting on Elba Island, Italy – A geochemical soil survey of the Magazzini site

Elba Island was a hotspot of iron mining and smelting in Italy since Etruscan times (6th century BCE). Whereas the environmental burden of modern (base) metal mining in Tuscany is well studied, the impact of both ancient iron mining and smelting on soils in the region is poorly understood. Therefore, we took soil samples from an ancient smelting site and adjacent areas to evaluate the release of trace metal(loid)s from smelting. Additionally, we evaluated ‘metallurgical activity markers’ on the site, i.e. the chemical signature of the production process. The evaluation is based on the soils' element composition, total and pyrogenic carbon contents, pH, and magnetic susceptibility. Statistical analysis include clustering, principal component analysis, and inference tests. Our results indicate that (i) Fe, As, Cu, Ca, total organic, and pyrogenic carbon contents and pH are increased on the smelting site. (ii) This increase corresponds to relatively high contents in these parameters in slag, ore, charcoal, and ash compared to values from background soils. (iii) Metal(loid) contents partly exceed guideline values, but appear negligible compared to (modern) mining – mostly hematite was mined in antiquity, whereas limonite (associated with galena) was only extracted in modern times.