A better understanding of long-term trace metals dispersal and their bioavailability in the critical zone is required to anticipate future impacts of present-day mining activity. The Pb-Ag district of Peisey-Nancroix (northern French Alps) is an excellent target to study the long-term environmental impacts (> 150 years) of former mines and trace metal dispersal in the critical zone, considering that every steps of the mining cycle, from ore extraction to ore processing, were located on a few hectares site that has been unmodified since mine closure in 1866 (no reclamation). A cross-disciplinary study is conducted using several proxies (ore, waste dumps, soil, water, stream sediments and related microbial communities, vegetation) in order to characterize present-day contamination on the mining site, to determine trace metals transfer in the various compartment of the critical zone, and to evaluate the effect of trace metals on microbial communities functioning. Top soils are significantly enriched in Pb, and locally in As, Sb and Cu compared to the local geological background. Soils developed on top of waste deposits contains up to 3.4% Pb, 1695 ppm Zn, 381 ppm Sb and 168 ppm Cu. Trace metal transfer from contaminated soils to the vegetation is evidenced by XRF profile across larch tree trunk sections. Contamination of streambed sediments is restricted to the vicinity of the mine and to the mine drainage outlets. The concentration of Pb2+ in pore waters, which ranges from 18 to 56 µg/L (EU potability limit = 10 µg/L), is well correlated to the sediment total Pb content and represents the main source of bioavailable metal. Microbial investigations will be performed to evaluate the ecotoxicological effects of Pb and Cu exposure on the genetic structure and the ecological functions (respiration, denitrification, organic matter decomposition...) of the bacterial communities naturally present in the contaminated sediments and soils