SEARCHCROSS-SECTIONALenvironmental health, geochemistry

cross-sectional·environmental health, geochemistry, toxicology, ecology, public health·PMC10001012

Geochemical Characteristics of the Vertical Distribution of Heavy Metals in the Hummocky Peatlands of the Cryolithozone

International Journal of Environmental Research and Public Health · 4 authors, 2 centres

AI SUMMARY

FIDELITY 100%

POPULATIONHummocky peatlands (Histosols) in the extreme northern taiga of the European Northeast of Russia (Kosyu River basin, Pechora River basin), including background sites (Plots 1 and 2, 20 km SE of Inta) and a technogenic site (Plot 3, 5 km NW of Inta near the Inta coal heat power plant).

INTERVENTIONNot applicable (observational study of HM and As distribution across peat profiles).

COMPARISONComparison of HM and As content between background (Plots 1 and 2) and technogenic (Plot 3) landscapes; comparison between STL and PL; comparison with average Earth's crust content (clarkes).

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AGENT 01 · STRUCTURED SUMMARY

TRACE TO SOURCE

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TL;DR

This study examines heavy metal (HM) and arsenic (As) distribution in hummocky peatlands of the Russian Subarctic cryolithozone, comparing background and technogenically polluted sites near the Inta coal power plant. The upper seasonally thawed layer (STL) accumulates HMs from aerogenic pollution, while the permafrost layer (PL) acts as a cryogenic geochemical barrier, with sorption on aluminum-iron complexes and sulfide barriers driving accumulation. Climate-warming-driven permafrost thaw poses a risk of mobilizing these toxicants into the Arctic hydrological network and food chains.

Full summary

4,229 CHARS

**Background:** Wetland ecosystems in high-latitude regions are major reservoirs for pollutants. Climate warming is causing permafrost degradation in cryolitic peatlands, risking the release of heavy metals (HMs) into the Arctic Ocean basin. The subarctic European Northeast is particularly climate-sensitive, with the seasonally thawed layer (STL) being the most temperature-vulnerable permafrost soil segment. This study aimed to (1) quantify HMs and As across Histosol profiles in background and technogenic Subarctic landscapes, (2) evaluate anthropogenic contributions from energy plants to trace element accumulation in the STL, and (3) identify the effects of biogeochemical barriers on vertical HM and As distribution.

**Methods:** Peat samples were collected every 5–10 cm from three plots: two background sites (Plot 1 and Plot 2, 20 km SE of Inta) and one technogenic site (Plot 3, 5 km NW of Inta, near the Inta coal heat power plant). Sampling depths reached 2.6 m (Plot 1), 1.8 m (Plot 2), and 2.5 m (Plot 3). Acid-soluble forms of macroelements (Na, K, Mg, Ca, Al, Fe) and HMs (Hg, Pb, Cd, Cu, Zn, Cr, V, Ni, Mn, Co, Sr, Ba), S, P, and As were analyzed by inductively coupled plasma atomic emission spectroscopy (Spectro Arcos, Spectro Cyros CCD). Total Hg was determined by atomic absorption spectroscopy (RA-915+). Water-soluble forms and exchangeable Ca/Mg were also measured. Mineral particle morphology was examined by scanning electron microscopy (Tescan Vega 3 LMH) with energy-dispersive X-ray spectroscopy (X-MAX 50). Humic (HAs) and fulvic acids (FAs) were extracted per IHSS method. Radiocarbon dating (^14^C) was performed at the Institute of Geography RAS (lab code IGAN). Statistical analyses included Pearson correlation and principal component analysis (PCA) using Statistica v. 12.1.

**Key Results:** Radiocarbon dating showed peat accumulation began in the late boreal period (8953 cal year BP), with the most intense accumulation during the Atlantic period (8953–5661 cal years BP). The STL peat was acidic (pH 3.4–4.0). Ash content in background STL peat was 2–6% (carbon 54–59%), while Plot 3 reached 11% ash. The upper level of microelement accumulation was associated with the STL. The total concentration factor (ΣKi) relative to Earth's crust decreased down-profile to the permafrost boundary (40 cm) from 8.7 to 4.4 for Plot 3 and from 6.8 to 2.5 for Plot 1. Below permafrost, ΣKi increased to 2.3–18.0, with As exceeding clarkes up to 4.0 times and Cd up to 2.3 times. Plot 3 showed excess over background of Hg (1.2×), Cd (1.6×), Pb (2.0×), Cu (3.1×), As (1.2×), Ni (1.8×), Co (2.1×), Cr (3.7×), V (3.3×), and Fe (4.6×). Spheroidal microparticles (<1 μm to 30–50 μm) composed of aluminosilicates with iron oxides and trace metals were found only in the upper 5 cm of Plot 3, serving as indicators of coal combustion pollution. At the permafrost boundary, the proportion of water-soluble forms increased for Pb (up to 1.4%), V (up to 2.1%), Cr (up to 2.7%), Cd (up to 3.4%), Zn (up to 4.0%), Mn (up to 7.1%), and As (up to 15%). Significant correlations were found between Hg and HAs (r = 0.65, n = 29), and between Cd, Zn, Mn, K, Na, Mg and FAs (r = 0.52–0.71). In the PL, significant correlations were found between total sulfur and chalcophile elements (Hg r = 0.57, Cd r = 0.61, Cu r = 0.66, As r = 0.53), and between Fe/Al and siderophile elements (Ni, Cr, Mn, Co, V; r = 0.76–0.96, n = 43, p = 0.95). PCA for STL samples explained 75.36% of variability (PC1 50.67%, PC2 24.70%); for PL samples, 71.04% (PC1 56.75%, PC2 14.29%).

**Clinical Implications:** This study provides critical baseline data on HM and As concentrations in Subarctic peatlands, demonstrating that permafrost acts as a geochemical barrier trapping toxicants. With climate warming, permafrost thaw could mobilize these pollutants into hydrological networks and food chains, posing environmental and public health risks to Arctic communities. The identification of spheroidal microparticles as markers of coal combustion pollution offers a monitoring tool for industrial impacts. The findings underscore the need for environmental monitoring of HMs in permafrost regions undergoing climate-driven degradation.

PICO

PPOPULATION

Hummocky peatlands (Histosols) in the extreme northern taiga of the European Northeast of Russia (Kosyu River basin, Pechora River basin), including background sites (Plots 1 and 2, 20 km SE of Inta) and a technogenic site (Plot 3, 5 km NW of Inta near the Inta coal heat power plant).

IINTERVENTION

Not applicable (observational study of HM and As distribution across peat profiles).

OOUTCOME

Concentrations of acid-soluble and water-soluble forms of HMs (Hg, Pb, Cd, Cu, Zn, Cr, V, Ni, Mn, Co, Sr, Ba) and As; total concentration factor (ΣKi); correlation with peat properties (pH, Eh, humic/fulvic acids, botanical composition, sulfur, chloride, TOC, etc.).

STUDY TYPE

cross-sectional

SPECIALTY

environmental health

SUMMARISED BY

AI pipeline

FIDELITY CHECK

100% · A

ORIGINAL PAPER

PMC10001012

Geochemical Characteristics of the Vertical Distribution of Heavy Metals in the Hummocky Peatlands of the Cryolithozone

International Journal of Environmental Research and Public Health

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ABSTRACT

One of the main reservoirs depositing various classes of pollutants in high latitude regions are wetland ecosystems. Climate warming trends result in the degradation of permafrost in cryolitic peatlands, which exposes the hydrological network to risks of heavy metal (HM) ingress and its subsequent migration to the Arctic Ocean basin. The objectives included: (1) carrying out a quantitative analysis of the content of HMs and As across the profile of Histosols in background and technogenic landscapes of the Subarctic region, (2) evaluating the contribution of the anthropogenic impact to the accumulation of trace elements in the seasonally thawed layer (STL) of peat deposits, (3) discovering the effect of biogeochemical barriers on the vertical distribution of HMs and As. The analyses of elements were conducted by atom emission spectroscopy with inductively coupled plasma, atomic absorption spectroscopy and scanning electron microscopy with an energy-dispersive X-ray detecting. The study focused on the characteristics of the layer-by-layer accumulation of HMs and As in hummocky peatlands of the extreme northern taiga. It revealed the upper level of microelement accumulation to be associated with the STL as a result of aerogenic pollution. Specifically composed spheroidal microparticles found in the upper layer of peat may serve as indicators of the area polluted by power plants. The accumulation of water-soluble forms of most of the pollutants studied on the upper boundary of the permafrost layer (PL) is explained by the high mobility of elements in an acidic environment. In the STL, humic acids act as a significant sorption geochemical barrier for elements with a high stability constant value. In the PL, the accumulation of pollutants is associated with their sorption on aluminum-iron complexes and interaction with the sulfide barrier. A significant contribution of biogenic element accumulation was shown by statistical analysis.

CITATION EXPORT

Roman Vasilevich, Mariya Vasilevich, Evgeny Lodygin et al.. Geochemical Characteristics of the Vertical Distribution of Heavy Metals in the Hummocky Peatlands of the Cryolithozone. International Journal of Environmental Research and Public Health. (2023). https://doi.org/10.3390/ijerph20053847

AUTHORS

4 · 2 CENTRES

Roman Vasilevich, Mariya Vasilevich, Evgeny Lodygin, Evgeny Abakumov

1Institute of Biology, Komi Science Center, Ural Branch, Russian Academy of Sciences, 167982 Syktyvkar, Russia
2Department of Applied Ecology, Faculty of Biology, Saint Petersburg State University, 199178 St. Petersburg, Russia

EDITOR / REVIEWER

Lanqin Yang