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The environmental risk of trace metals (TMs) in a former lead (Pb)-silver (Ag) mining district in the Vosges Mountains (France) was assessed based on two biological indices: (i) the excess of transfer TM from the soil to biota (SET index) and (ii) the toxicological risk associated with these excess transfers (ERITME index). This study constitutes the first application of the SET and ERITME indices on a past contaminated site with the inclusion of Ag and of two exposure durations. Among the eight stations studied for TM transfers in a soil-plant-snail ( Cantareus aspersus ) system, an excess of transfer (Ag, arsenic (As) and Pb mainly) was highlighted in four of the stations. High concentrations of Pb, up to 2810 ± 978 μg g −1 , were measured in snails exposed to the contaminated environment with Pb soil concentrations up to 14,978 ± 2270 μg g −1 . An excess TM transfer has been evidenced in several stations, principally in two archaeological mining sites. Very high SET indices have been calculated for these two stations, and abnormal transfer was shown for a communal garden. The associated toxicological risk (ERITME index) is high and reflects the importance of investigating past contaminated sites, as is done for recent industrial sites. The use of these two indices highlights that the time elapsed since the deposition of TMs does not lead to TM immobilization, partly due to the acidic soil pH in all stations, which ranged from 3.7 to 5.7. The accumulation of TMs in snails was mainly modulated by the sources of exposure, i.e., soil, humus and vegetation, depending on the TM. The major influence of exposure sources on TM accumulation compared to the influence of soil characteristics may be due to the speciation of the TMs deposited several centuries ago and the importance of indirect transfers from vegetation and humus. Currently, signs of past mining activities in the valley have almost completely disappeared, but we show that their waste still presents a risk for environmental and human health. [ABSTRACT FROM AUTHOR]

Mining and smelting activities have contaminated the environment with trace metals (TMs) at a worldwide scale for at least two millennia. A combination of chemical approaches and active biomonitoring was performed to analyse the environmental availability and bioavailability of TM palaeo-pollution in a former Pb Ag mining district in the Vosges Mountains, France. Along a soil TM contamination gradient that covered eight stations, including two archaeological mining sites, the toxicokinetics of six TMs (Pb, Cd, As, Ag, Co, Sb) in the snail Cantareus aspersus revealed that palaeo-pollution from the studied sites remains bioavailable. This study provides the first data on the accumulation kinetics of Ag and Co for C. aspersus . The environmental availability of the TMs was estimated with three chemical extraction methods ( aqua regia , EDTA 50 mM, CaCl 2 10 mM). Univariate regression analyses showed that EDTA extraction is the best method for estimating the bioavailability of Pb, As, Ag, Co and Sb to snails. None of the three extractants was efficient for Cd. A multivariate analysis of bioaccumulation data revealed that TM bioavailability and transfer were modulated by exposure sources (soil, humus and vegetation) rather than by soil physico-chemical characteristics. Hence, although the deposition of mining wastes dates back several centuries, these wastes still represent a source of contamination that must be considered to develop relevant site management and environmental risk assessment. [ABSTRACT FROM AUTHOR]

Over the course of history, mining and metallurgical activities have influenced the socioeconomic development of human populations. However, these past and current activities can also lead to substantial environmental contamination by various metals. Here, we used an interdisciplinary approach (incorporating archaeology, mineralogy, environmental chemistry and ecotoxicology) to investigate the origin, fate and potential ecotoxicity of anomalous manganese (Mn) concentrations detected in the ancient mining district of Berthelange (medieval period, eastern France). Mineralogical investigations of slag samples showed that smelting temperature conditions in medieval bloomeries led to the production of slags mainly composed of Fe- and Mn-rich olivine, i.e., fayalites. Further mineralogical analyses of bulk soil and clay fractions allowed us to identify the presence of serpentine. This evidence of olivine weathering can account for the release of Mn from slags into the soil. In addition, chemical analyses of total and available (exchangeable and reducible) Mn concentrations in soil samples clearly showed the contribution of slags deposited 1000 years ago to soil contamination. A complementary ecotoxicity bioassay performed on soils from a slag heap using the land snail Cantareus aspersus confirmed that a significant fraction of the Mn detected in soils remains available for partitioning with the soil solution and transfer to soil organisms. Although no growth inhibition of snails was observed after 28 days of exposure, the animals accumulated quite elevated Mn concentrations in their tissues. Our study emphasizes the environmental availability and bioavailability of Mn from ancient metallurgical wastes to soil-dwelling invertebrates, i.e., snails, even one millennium after their deposition. Hence, as for more recent industrial sites, past mining ecosystems must be a cause of concern for the scientific community and public authorities. [Display omitted] • Slags from the 11th century contain high amounts of Mn mostly found in fayalite. • Slag weathering over centuries has led to Mn release and soil contamination. • Ecotoxicity tests using snails revealed the bioavailability of Mn in soils. • Sites of past metallurgical activities remain a cause of environmental concern. [ABSTRACT FROM AUTHOR]