New chemical signatures from Weißseespitze ice cores (Eastern Alps): pre-industrial pollution traces from Roman Empire to Early Modern Period

Azzurra Spagnesi^1,2*David Wachs^3,4Pascal Bohleber^1,5*Elena Barbaro^1,6Matteo Feltracco¹Daniela Festi⁷Klaus Oeggl⁸Jacopo Gabrieli^1,6Werner Aeschbach³Markus Oberthaler⁹Martin Stocker-Waldhuber²Andrea Gambaro¹Carlo Barbante^1,6Andrea Fischer^2*

• ¹Universita Ca' Foscari Dipartimento di Scienze Ambientali Informatica e Statistica, Venice, Italy
• ²Osterreichische Akademie der Wissenschaften Institut fur Interdisziplinare Gebirgsforschung, Innsbruck, Austria
• ³Universitat Heidelberg Institut fur Umweltphysik, Heidelberg, Germany
• ⁴Universitat Heidelberg Kirchhoff-Institut fur Physik, Heidelberg, Germany
• ⁵Alfred-Wegener-Institut Helmholtz-Zentrum fur Polar- und Meeresforschung, Bremerhaven, Germany
• ⁶Istituto di Scienze Polari Consiglio Nazionale delle Ricerche, Venice, Italy
• ⁷GeoSphere Austria, Department of Geoanalytics and Reference Collections, Vienna, Austria, Vienna, Austria
• ⁸University of Innsbruck, Department of Botany, Innsbruck, Austria, Innsbruck, Austria
• ⁹Kirchhoff-Institute for Physics, Heidelberg University, Heidelberg, Germany, Heidelberg, Germany

High-altitude glaciers in the Western European Alps have yielded crucial records of anthropogenic air pollution, revealing a sharp rise in pollutant levels over the past two centuries due to industrialisation. In contrast, studies in the Eastern Alps have been scarce, as their lower-elevation glaciers were often considered less suitable for preserving undisturbed records. Nevertheless, recent findings indicate that, under specific conditions, cold ice frozen to bedrock can persist below 4000 m. This is exemplified by the Weißseespitze (WSS) summit ice cap (3499 m a.s.l.), which, despite ongoing surface mass loss, preserved a 6000-year-old record within just ~10 meters of ice depth. Building on earlier research, this study provides an expanded chemical dataset of the upper 8.5 m of the 9.95 m ice core drilled in 2019 (core 2), now including 18 trace elements (Li, V, Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, Ag, Cd, Ba, Tl, Pb, Bi, U), carboxylic and dicarboxylic acids, and a deepened discussion on ionic compounds, which refines the already published record. To differentiate between natural contributions and anthropogenic sources, a Positive Matrix Factorisation analysis was applied to the full dataset. This analysis was further supported by Enrichment Factors calculations, which helped to discriminate between crustal and non-crustal sources. Thanks to the novel age-depth scale obtained with 39Ar dating, in addition to previous 14C ages, the glacier’s age-depth model was further refined, revealing that the glacier surface formed approximately 371_(-60)^(+96) years before 2019, while tying the prominent peak in chemistry found at 640 cm depth to about 891 years before 2019. Further insights on this horizon came from the comparison between the levoglucosan record, measured within the WSS ice core, and the micro-charcoal data available for the nearby Schwarzboden mire. This study underscores the exceptional value of the WSS glacier as a long-term archive of pre-industrial pollution. Alarmingly, approximately 4.5 meters of ice have been lost as of 2025, accelerating the disappearance of this archive. With industrial-era layers already lost due to ice mass reduction and projections showing 30% of Ötztal glaciers could vanish by 2030, preserving and studying these records appears increasingly urgent.