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Artyukhov et al. Carbon Footprints 2026, 5, 8 Page 17 of 21

Limitations of the research
At this stage, soil contamination was assessed for nine heavy metals and their compounds; in the future, a
broader list of pollutants could be included for a more comprehensive ecotoxicological assessment of the
area. In addition, the ecotoxicological analysis focused on total heavy metal content in soils, which does not
fully reflect their bioavailability. Finally, the laboratory incubation conditions used to study SOC
mineralization differed from those in the field.

CONCLUSIONS
This study provides comprehensive data on SOM mineralization dynamics and the ecotoxicological state
across major soil types in the Yamal region of West Siberia. Significant spatial variability in PMC was
observed, ranging from 279.50 mg/kg to 37,254.15 mg/kg (2.74%-11.59% of SOC), with the highest
mineralization rates in the topsoil horizons. Temperature dependence was evident, with higher
mineralization rates at 25 °C in most samples. However, some mineral horizons showed the opposite pattern,
suggesting complex microbial responses to warming in cryogenic environments that require further
investigation. The demonstrated temperature sensitivity of SOM mineralization, particularly in organogenic
horizons, indicates that warming affects carbon emissions from these soils. The highest Q values (> 1.5 for
10
90-day incubation) occurred in soils with thick organogenic horizons and high SOC content (e.g., Cryic
Histosol and Histic Cryosol), indicating that SOM mineralization in these layers is highly sensitive to
increased temperatures. Kinetic parameters derived from the 90-day incubation experiments can be
incorporated into biogeochemical models to refine projections of carbon-climate feedbacks in permafrost
regions, though further validation is needed.

Regarding ecotoxicological state, 68% of analyzed soil samples (32 of 47) exhibited low (acceptable)
contamination levels (Zc < 16), 28% (13 samples) showed moderate contamination, and 4% (2 samples)
demonstrated high contamination levels. The primary ecotoxicological threat arises from oil and gas industry
activities. Soils near production facilities and transport infrastructure exhibited substantially higher
contamination levels, with Zc values reaching up to 40 in some cases. Radial differentiation analysis revealed
distinct patterns of element redistribution across soil profiles, with Pb, Zn, and V showing strong
accumulation in upper horizons of anthropogenically impacted sites. Temperature sensitivity (Q ) was
10
highest in SOC rich soil horizons, indicating they are potential hotspots for carbon release under warming.
Although a direct inhibitory effect of heavy metals on mineralization was not consistently observed, the
spatial coincidence of elevated pollution levels and large labile carbon pools in soils near industrial
infrastructure warrants further study. These areas should be prioritized for long-term monitoring, as
potential changes in contaminant bioavailability or microbial community responses to warming could
modulate the permafrost-carbon feedback.

These findings underscore the urgent need for integrated monitoring programs that track both carbon
cycling and contaminant loads in Arctic soils. As development pressures increase in the Russian Arctic,
maintaining the balance between economic activity and environmental protection will require science-based
regulatory frameworks informed by comprehensive soil assessments. Future research should focus on
long-term monitoring of SOM mineralization under natural field conditions and expanded ecotoxicological
assessments across broader spatial scales to establish baseline conditions in this rapidly changing region.

DECLARATIONS
Acknowledgments
The authors are grateful to the staff of the “Chemical Analysis and Materials Research Centre”, St. Petersburg
University Research Park, for performing the elemental analysis of soil samples.

Authors’ contributions
Conceptualization, methodology, data acquisition, fieldwork: Abakumov, E.; Nizamutdinov, T.