Protecting glacial geoheritage: Pollution indices reveal trace element contamination in cryoconites and soils of protected and touristic valleys, Central Caucasus

Abstract

Glacial and periglacial environments in alpine regions are increasingly threatened by anthropogenic activities and climate change, yet the supraglacial-periglacial redistribution of trace elements and role of nature reserves in these fragile ecosystems remains understudied. This research evaluates contamination levels in cryoconites and soils of two adjacent gorges in the Central Caucasus: the strictly protected Tsey Gorge and the tourism-intensive Skazka Gorge. Trace elements (Cu, Zn, Ni, Pb, Cd), basic physicochemical properties and pollution indices were analyzed. Zn was the most abundant element in both gorges (maximum of 79.00 mg·kg⁻¹), attributed to natural geological background and legacy Pb-Zn mining. Conversely, Cu (max. 23.30 mg·kg⁻¹) and Ni (maximum of 34.15 mg·kg⁻¹) contamination in Skazka Gorge correlated with tourism infrastructure and related processes. Cryoconites acted as transient reservoirs, with meltwater facilitating the downstream transfer of trace elements to soils, evidenced by higher contamination in periglacial zone. Pollution indices classified Tsey as “unpolluted” and Skazka as “slightly polluted,” with moderate ecological risks in soils. The study demonstrates that protected areas and promotion of “eco-tourism” effectively reduced tourism-driven contamination, while geogenic and mining influences continue to affect the environmental quality of the studied alpine zone.

Keywords

Environmental quality / Heavy metals / Caucasus mountains / North Ossetian nature reserve / Ecotourism / Alpine tourism / Mining

Funding

This research was supported by the Russian Science Foundation grant N° 24-44-00006 “Comparative metagenomics study on carbon-cycling microbiome in permafrost regions in Yamal and the Qinghai-Tibet Plateau.”

Ethical statement

There is no animal or human subjects, human participants, human data or human tissue involved in this research. No trees were damaged nor displaced in any way during this research. The soil plant cover at the soil section was taken back without damaging after investigation of soil section.

CRediT authorship contribution statement

Ivan Kushnov: Writing - original draft, Visualization, Software, Resources, Methodology, Investigation, Formal analysis, Data curation. Rustam Tembotov: Writing - review & editing, Validation, Supervision, Resources, Conceptualization. Evgeny Abakumov: Writing - review & editing, Supervision, Resources, Project administration, Funding acquisition, Conceptualization.

Declaration of generative AI and AI-assisted technologies in the writing process

During the preparation of this work the authors have used AI service only in order to correct grammar and expression errors. After using this service, the authors reviewed and edited the content as needed and takes full responsibility for content of the publication.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

The authors gratefully acknowledge the NOAA Air Resources Laboratory (ARL) for the provision of the HYSPLIT transport and dispersion model and/or READY website https://www.ready.noaa.gov used in this publication. We also acknowledge the critical comments from the editor and two anonymous reviewers, whose suggestions helped us to improve our manuscript.

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