Capture de micromammifères dans le Morvan, photo: E. Camizuli
L’étude “Bioaccumulation of trace metals deriving from historical mining in wood mice (Apodemus sylvaticus)” par E. Camizuli, F. Monna, R. Scheifler, C. Gourault, G. Hamm, R. Losno, C. Lachiche, G. Delivret, & P. Alibert présentée à la SETAC Asia/Pacific, 24-27 Septembre, Kamamuto, Japon. [pdf].
Projet “Identification et impact des sites miniers abandonnés sur les écosystèmes aquatiques et terrestres actuels”.
Résumé: In the past, when ores were exhausted, wastes were abandoned around mining and metallurgical areas. Today, this industrial history may have been forgotten by local inhabitants, so that mines are no longer considered dangerous. Yet ancient wastes still represent a threat, as long-term weathering leads to chronic emissions of pollutants, potentially reaching toxic levels of trace metals to wildlife.
This study investigates the spatial distribution of trace metals in soils affected by past mining and also evaluates the impact of such metals, using wood mice (Apodemus sylvaticus) as biomonitors. Two French regions were selected: the Morvan and the Cévennes. Both areas experienced active metal mining and smelting from prehistory onwards. Nowadays, mines are no longer exploited. These areas are now protected by constraining environmental policies and are largely considered as pristine. In each region, three zones covering 1 km² were selected in relation to the presence of local mining (no mining, discrete mining, and intense mining). A total of 288 topsoils were analysed by ICP-AES, together with kidneys from 157 wood mice (Apodemus sylvaticus identified from DNA analysis) in order to examine possible relationships between abiotic and biotic parameters. Developmental instability, assessed by fluctuating asymmetry (FA), was also used as an indicator of environmental stress. The lowest concentrations in Cd (<0.50 µg g-1) and Pb (50 µg g-1) were found in soils from areas without any mines. Other areas presented much higher concentrations in Cd (>50 µg g-1) and Pb (>5000 µg g-1). Spatial distribution of metal concentrations mirrors the presence of former mines. No effect of sex, weight, or size was found statistically significant with metal concentrations in wood mouse kidneys. Concentrations of Cu and Zn in kidneys were approximately the same whatever the region or the site, suggesting efficient homeostatic regulation in these organisms. In contrast, Cd and Pb appeared to be highly site-dependent, since concentrations in kidneys exhibit variations reaching three orders of magnitude. The pattern observed in mouse kidneys matched patterns observed in soils, demonstrating the current impact of past mining on trace metals bioaccumulation in fauna. Results from FA are still being evaluated.
SETAC Asia Pacific 2012 Meeting “Learning from History and Applying Advancing Science to Build a Safer and Sustainable Environment” 24th – 27th September, 2012. Session 19a: Wildlife ecotoxicology