Eugenia Krasavtseva’s research while affiliated with Russian Academy of Sciences and other places

The article presents the results of the study of the effect of fluoride on the morphometric and physiological parameters of higher plants. The test culture was the seeds of oat Avena sativa L. Phytotesting was carried out according to standard methods in eluate and contact versions. Four different levels (0.09, 0.9, 9 and 90 mgF/L) of NaF solution for eluate phytotesting and five levels (10, 100, 500, 1000 and 2000 mgF⸱kg−1 dry soil) for contact phytotesting were applied. The decrease in root length, plant height and biomass at the maximum pollution level (90 mgF/L and 2000 mgF⸱kg−1 dry soil, respectively) relative to the control was 35.5, 23.86 and 62.47%, respectively. Statistical data processing was conducted. In addition, using a portable mini-spectrometer for leaves CI-710S, indices characterizing changes in chlorophyll content in plants were determined: Chlorophyll Content Index, Green Chlorophyll Index, Red-Edge Chlorophyll Index, Leaf Chlorophyll Index, Soil–Plant Analysis Development. The decrease in CCI, CI Green, CI Red, LCI, and SPAD indices at the maximum pollution level (2000 mgF⸱kg−1 dry soil) relative to the control was 86.2, 42.0, 57.9, 32.8 and 70.4%, respectively. Correlation analysis using the Pearson coefficient made it possible to establish a significant relationship between individual morphometric and physiological indicators. It was found that high levels of soil fluoride contamination cause significant changes in the morphometric and physiological parameters of Avena sativa L. The results of the study may have implications for agriculture or environmental protection in areas exposed to fluoride.

A comprehensive study (monitoring, thermodynamic modeling) of natural and anthropogenically polluted waters of the Lovozero Massif has been carried out. A thermodynamic study of the weathering of the Lovozero Massif within the “water-rock-atmosphere” system at a temperature of 5 °C showed that the elements contained in the rocks of the studied massif influence the formation of the chemical composition of natural waters. It has been established that an increase in the degree of “water-rock” interaction leads to an increase in the concentrations of F−, Cl−, SO42−, and HCO3− in the solution. This affects the mobility of lanthanum, cerium, and other elements due to the formation of complex compounds with them. The relatively high content of fluorine, phosphorus, and HCO3− (weak and medium acids) in the solution promotes the dissolution of silicates while Si, Al, and P are released into the solution. Monitoring of water from a flooded mine in which there is an increase in the degree of interaction of water with rock showed higher pH values for the concentrations of Na, HCO3−, F−, P, Al, Si, V, U, La, and Ce. The conclusions are relevant in the context of the use of groundwater for drinking water supply purposes. The obtained information is useful to evaluate the health of the population of the region under study.

A geoecological assessment of fluorine contamination of environmental components in the zone of influence of an abandoned rare-metal mine in the Murmansk region was carried out. Samples were taken of loparite ore enrichment tailings, soils around the tailings pond and the Loparitovy, Alluaiv, Azimut creeks and the watercourse flowing through the mine after the mining impact. The content of water-soluble fluorine in the collected samples was determined. No exceedance of maximum permissible concentration (MPC) of fluorides in soil was found. Increased content of fluoride ions (up to 15 MPC) in water samples from the watercourse was recorded. It is concluded that the production facility closed more than 15 years ago has a negative impact on ecosystems.

A comprehensive study (monitoring, thermodynamic modeling) of natural and anthropogenically polluted waters of the Lovozero Massif has been carried out. A thermodynamic study of the weathering of the Lovozero Massif within the “water-rock-atmosphere” system at a temperature of 5°C showed that the elements contained in the rocks of the studied massif influence the formation of the chemical composition of natural waters. It has been established that an increase in the degree of “water-rock” interaction leads to an increase in the concentrations of F, Cl, SО42-, HCO3- in the solution. This affects the mobility of lanthanum, cerium and other elements due to the formation of complex compounds with them. The relatively high content of fluorine, phosphorus, HCO3- (weak and medium acids) in the solution promotes the dissolution of silicates while Si, Al, P are released into the solution. Monitoring of water from a flooded mine in which there is an increase in the degree of interaction of water with rock showed higher pH values for the concentrations of Na, HCO3-, F-, P, Al, Si, V, U, La, Ce. The conclusions are relevant in the context of groundwater extraction for drinking water supply purposes. The obtained information is useful to evaluated the health of the population of the region under study.

The development of the mining industry inevitably has a negative impact on the environment. Sources of pollution of soils, air and water bodies can come from both operating enterprises and abandoned mines and tailings ponds. Samples of the surface layer (0-8 cm) of the loparite ore enrichment tailings, stored in the tailings of an abandoned processing plant in the Murmansk region, were collected and studied. The effective specific activity of natural radionuclides of less than 1500 Bq/kg allows the tailings to be classified as waste category I. Most of the samples belong to class II building materials. At the same time, almost all samples - 0.071 mm are characterized by an Aeff value above 740 Bq/kg, which means they belong to mineral raw materials and materials with a high content of natural radionuclides (II class of mineral raw materials and materials, III class of building materials). The established features should be taken into account when developing environmental protection measures in the zone of influence of the tailings dump and technologies for processing technogenic raw materials.

The paper presents the results of environment safety assessment of Russian and foreign binding reagents (Syntex-65, Lukoil DD 3000, Voltes PP-300 and Dustbind) used for remediation of objects of accumulated environmental damage in the Murmansk region. The paper shows that in the presence of anti-erosion and water-retentive phytocenosis on technosoil of loparite ore tailings, these reagents have a partial inhibitory effect on the first first seedlings of timothy grass (Phleum pratense L.) and red fescue (Festuca rubra L.) and statistically (p <0.005) affect its main quality indicators (plant height and biomass). Effective methods of applying reagents to the dusty surface of technosoil were identified. When using the Lukoil DD 3000 reagent as an analogue of Dustbin – continuous, for Voltes PP-300 – fragmentary, when using Syntex-65 – continuous in the mode of simulated hydroseeding.

Mining activities create disturbed and polluted areas in which revegetation is complicated, especially in northern areas. For the first time, the state of the ecosystems in the impact zone of tailings formed during the processing of rare earth element deposits in the Subarctic have been studied. This work aimed to reveal aspects of accumulation and translocation of trace and biogenic elements in plants (Avenella flexuosa (L.) Drejer, Salix sp., and Betula pubescens Ehrh.) that are predominantly found in primary ecosystems on the tailings of loparite ores processing. The chemical composition of soil, initial and washed plant samples was analyzed using inductively coupled plasma mass spectrometry. Factor analysis revealed that anthropogenic and biogenic factors affected the plants’ chemical composition. A deficiency of nutrients (Ca, Mg, Mn) in plants growing on tailings was found. The absorption of REE (Ce, La, Sm, Nd) by A. flexuosa roots correlated with the soil content of these elements and was maximal in the hydromorphic, which had a high content of organic matter. The content of these elements in leaves in the same site was minimal; the coefficient of REE bioaccumulation was two orders of magnitude less than in the other two sites. The high efficiency of dust capturing and the low translocation coefficient of trace elements allow us to advise A. flexuosa for remediation of REE-contained tailings and soils.

Pilot experiments to remove lanthanum and cerium ions from model one-component solutions using reagents: opoka, brucite, amorphous silica, thermovermiculite (500 °С, 2 hours), sawdust, thermally activated brucite (600 °С, 2 hours), activated carbon, zeolite, were carried out. Promising sorbents of rare-earth elements of the light group have been identified, which can be used to purify water with a high content of the elements under consideration or in combined sorption technologies for restoring disturbed lands in the areas of extraction and enrichment of rare metal ores.