Brighenti Stefano, Colombo Nicola, Wagner Thomas, Pettauer Michael, Guyennon Nicolas, Krainer Karl, Tolotti Monica, Rogora Michela, Paro Luca, Steingruber Sandra M, Del Siro Chantal, Scapozza Cristian, Sileo Noelia R, Villarroel Cristian D, Hayashi Masaki, Munroe Jeffrey, Liaudat Dario Trombotto, Cerasino Leonardo, Tirler Werner, Comiti Francesco, Freppaz Michele, Salerno Franco, Litaor M Iggy, Cremonese Edoardo, di Cella Umberto Morra, Winkler Gerfried
Competence Centre for Mountain Innovation Ecosystems, Free University of Bozen/Bolzano, Bolzano 39100, Italy.
Department of Agricultural, Forest and Food Sciences, University of Turin, Grugliasco 10095, Italy; Research Center on Natural Risk in Mountain and Hilly Environments - NatRisk, University of Turin, Grugliasco 10095, Italy.
Sci Total Environ. 2024 Nov 25;953:175706. doi: 10.1016/j.scitotenv.2024.175706. Epub 2024 Aug 27.
Rock glaciers (RGs) provide significant water resources in mountain areas under climate change. Recent research has highlighted high concentrations of solutes including trace elements in RG-fed waters, with negative implications on water quality. Yet, sparse studies from a few locations hinder conclusions about the main drivers of solute export from RGs. Here, in an unprecedented effort, we collected published and unpublished data on rock glacier hydrochemistry around the globe. We considered 201 RG springs from mountain ranges across Europe, North and South America, using a combination of machine learning, multivariate and univariate analyses, and geochemical modeling. We found that 35 % of springs issuing from intact RGs (containing internal ice) have water quality below drinking water standards, compared to 5 % of springs connected to relict RGs (without internal ice). The interaction of ice and bedrock lithology is responsible for solute concentrations in RG springs. Indeed, we found higher concentrations of sulfate and trace elements in springs sourcing from intact RGs compared to water originating from relict RGs, mostly in specific lithological settings. Enhanced sulfide oxidation in intact RGs is responsible for the elevated trace element concentrations. Challenges for water management may arise in mountain catchments rich in intact RGs, and where the predisposing geology would make these areas geochemical RG hotspots. Our work represents a first comprehensive attempt to identify the main drivers of solute concentrations in RG waters.
在气候变化背景下，石冰川（RGs）为山区提供了重要的水资源。近期研究凸显了由石冰川补给的水体中存在包括微量元素在内的高浓度溶质，这对水质产生了负面影响。然而，来自少数地点的稀疏研究阻碍了我们得出关于石冰川溶质输出主要驱动因素的结论。在此，我们付出了前所未有的努力，收集了全球范围内已发表和未发表的石冰川水化学数据。我们综合运用机器学习、多变量和单变量分析以及地球化学建模，研究了来自欧洲、南北美洲山脉的201个石冰川泉。我们发现，源自完整石冰川（含有内部冰体）的泉水中，有35%的水质低于饮用水标准，而与残余石冰川（无内部冰体）相连的泉水中这一比例为5%。冰体与基岩岩性的相互作用决定了石冰川泉中的溶质浓度。实际上，我们发现，与源自残余石冰川的水相比，源自完整石冰川的泉水中硫酸盐和微量元素浓度更高，这种情况主要出现在特定的岩性环境中。完整石冰川中硫化物氧化作用增强导致了微量元素浓度升高。在富含完整石冰川且易引发地质条件使这些区域成为石冰川地球化学热点的山区集水区，可能会出现水资源管理方面的挑战。我们的研究首次全面尝试确定石冰川水体中溶质浓度的主要驱动因素。
