Pb dispersion pathways in mountain soils contaminated by ancient mining and smelting activities

• Published in: Applied geochemistry Vol. 150; p. 105556
• Main Authors: Guillevic, Floriane, Rossi, Magali, Develle, Anne-Lise, Spadini, Lorenzo, Martins, Jean M.F., Arnaud, Fabien, Poulenard, Jérôme
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-03-2023; Elsevier
• Subjects: Biodiversity and Ecology; Chemical Sciences; Earth Sciences; Environmental Sciences; Geochemistry; Mining and smelting soils; Other; Pb mobilisation; Pb-bearing Mn (Hydr-)oxides; Pb-bearing phases; Sciences of the Universe; Pb-bearing Mn (Hydr-)oxides; Pb mobilisation; Mining and smelting soils; Pb-bearing phases; Pb-bearing Mn (hydr-)oxides
• ISSN: 0883-2927; 1872-9134
• DOI: 10.1016/j.apgeochem.2022.105556

Over the last millennia, mining and smelting activities have produced large amounts of mine and metallurgical wastes that remain enriched in potentially toxic trace elements (PTE). A spatial distribution of Pb content was coupled to mineralogical observations and single extraction tests to characterise the Pb contamination legacy and Pb dispersion trajectories in an ancient mining and smelting site that has been abandoned for approximatively 200 years. In the Peisey-Nancroix Pb–Ag mine (Savoy, France), extreme anthropogenic Pb contamination is located close to the slag heaps and along ore and slag transport paths. The contamination gradient is restricted to a few hundred metres downhill, down to background Pb values. The Pb-bearing phases change along the contamination gradient. The most contaminated soils contain significant amounts of galena and slags that are more or less weathered into pyromorphite and cerussite. Pb-bearing Mn (hydr-)oxides are the most stable and ubiquitous forms of Pb, which proportions increase downgradient. Despite the presence of some stable Pb-bearing phases (pyromorphite, Pb-bearing Mn (hydr-)oxides), extraction tests indicate that a small proportion of Pb may still be mobile over time.
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•Extreme anthropogenic Pb contamination of 200 years old, related to mining and smelting activities.•Downgradient changes in Pb-bearing phases.•Mn–Pb (hydr-)oxides are the most stable Pb-bearing phases.•Significant amounts of Pb remain mobilisable in the long term.