The evaluation of bioavailable forms of heavy metals in zones of anthropogenic pollution is the basis of ecological risk assessment. The characterization of the consequences of the operation of the Pechenganikel smelting plant was carried out using AAS and two methods of soil bioavailable forms of heavy metal extraction (3% nitric acid and ammonium acetate buffer with pH 4.8) along three directions from the plant, corresponding to the wind prevalence. Buffer extraction provided more significant correlations between Ni, Co, Cu, Pb, and Zn, compared to nitric acid application, indicating a negative correlation between soil Cu, Co, and the distance from the plant, while no significant correlations were recorded for nitric acid extracts. A higher significant correlation number arose between soil elements in buffer extracts along the N-E direction than the S-W one. In the former direction, the number of the mentioned correlations decreased according to the following sequence: Zn (6) > Cu (5) > Se and Co (4) > Ni and Fe (3); in nitric acid extract, only significant correlations of Cu, Zn, and Se with Co and Ni were recorded. Biocrust formation was revealed only along the N-E direction, characterized by unexpected high Se concentrations and intensive correlation between Zn and all the elements extracted by the buffer. Biocrust accumulated high levels of all the elements tested and showed antioxidant activity and polyphenol content significantly correlated with soil organic matter. The biocrust mineral content demonstrated a complex relationship with soil Fe, Cu (buffer extract), and Se, as well as Co and Zn (nitric acid extract). Application of linear mixed-effects modelling and transfer factor analysis indicate that biocrusts may serve as effective bioindicators of both absolute metal contamination and its bioavailable fractions. The results indicate the expediency of using both methods of soil extraction for assessing the ecological risk and soil–biocrust relationships.

The paper is devoted to discussing the effectiveness of measures to restore degraded lands and preserve biodiversity in the north-west of the Murmansk Region in the Pechenga Municipal District (Russian Federation). The purpose of the study was to study climate change, biodiversity, the history of nature management and environmental practices in the basin of the Paz River. Published and archived data from climatic, soil-geobotanical, archaeological, and historical studies were collected and systematized, as well as their own field geoecological studies (2021-2024). The use of reconstruction and forecasting methods made it possible to recreate an objective picture of climatic changes in the basin of the Paz River over the past 9.5 thousand years and to identify a multiple change of vegetation (from Arctic tundra to forest) after the melting of the glacier. The study of archaeological and historical materials allowed us to identify five stages of economic development of the territory, which led to a reduction in biodiversity and land degradation (with a maximum in the 70s of the XX century at the peak of the development of copper-nickel production). Three main factors hindering the restoration of degraded lands in the Paz River basin have been identified: large areas of man-made wastelands with a high content of heavy metals, long-range irradiation of microparticles of pollutants, and low rates of natural restoration of Arctic ecosystems. To accelerate the processes of natural restoration, it is proposed to replace expensive methods of reclamation of man-made wastelands with the creation of a set of conditions for the formation of biological soil crusts (communities of cryptogamous organisms).