Legacy Pb pollution in the contemporary environment and its potential bioavailability in three mountain catchments

Sophia V. Hansson (1, 2) , Youen Grusson , Marianna Chimienti (2) , Adrien Claustres (1) , Séverine Jean (1) , Gael Le Roux (1)

1 LEFE - Laboratoire Ecologie Fonctionnelle et Environnement
2 Aarhus University [Aarhus]

Historical mining has a millennial scale history on the globe often leaving a long-lasting imprint on the environment. Previous results on trace metal concentrations in the Pyrenees, where extensive mining (Ag, Fe) occurred from the Antiquity to the 19th century, suggest that ≥600 tons of anthropogenic lead (Pb) is stored in soils in the Haut-Vicdessos area (France). Yet the potential bioavailability of this legacy contamination to contemporary biota remains unclear. We therefore asked if previously reported high-levels of legacy Pb can be seen in other environmental compartments including aquatic biota, and how these are distributed within the biota. Based on Pb-isotopic data, we also assessed if any Pb contamination found in contemporary biota can be linked to local/regional mining. Samples of sphagnum, soil, sediment, biofilm, and fish (Salmo trutta and Phoxinus phoxinus) were collected from three adjacent valleys in the Haut-Vicdessos area. Pb concentrations varied both between sites (i.e. decreasing concentrations with increasing distance from the former mine) and between within-site environmental compartments (i.e. soil > biofilm ≥ sediment > sphagnum > fish) as well as within organisms (i.e. entire organism > liver > muscle). Further, Pb-isotopic ratios (206Pb/207Pb, 208Pb/207Pb and 208Pb/206Pb) measured in soil, biofilm, and fish indicated both natural (weathering bedrock) and anthropogenic (industrial, transportation and/or former mining activities) sources of Pb-deposition to the area. Generally, body Pb-concentrations were within regulatory guidelines, yet contemporary biota in the upper Haut-Vicdessos area, and their prey, still showed a large range of Pb isotopic signatures, of which former mining activities appeared to have a strong influence. Our study showed that mining derived legacy Pb continues to affect onsite biota even if mining activities ceased >100 years ago, thus reflecting the long-lasting impact of human-environment interaction, suggesting that ecosystem conditions may remain impaired centuries after activities have ceased.

Mots clés: Mining; Pb; Pb-isotopes; Soil; Biofilm; Fish

Domaines: Sciences de l'environnement

Sophia V. Hansson, Youen Grusson, Marianna Chimienti, Adrien Claustres, Séverine Jean, et al.. Legacy Pb pollution in the contemporary environment and its potential bioavailability in three mountain catchments. Science of the Total Environment, 2019, 671, pp.1227-1236. ⟨10.1016/J.SCITOTENV.2019.03.403⟩. ⟨hal-02353213⟩