Annual observations of surface concentrations of ozone and other atmospheric trace gases in the Karadag nature reserve, Crimea, are presented. Concentrations of primary air pollutants (oxides of carbon, nitrogen, and sulfur) were several orders of magnitude less than Russian maximum permissible levels throughout the year. Variations in the ozone concentration are close to those on rural terrains of the southern countries of western Europe. The diurnal maximum of ozone concentration is observed 2–5 hours after noon. In seasonal behavior of the ozone concentration, there are two maxima: a major peak in late July – early August, and a lower peak in April. During hot seasons, there were episodes when, for a few days, the ozone level exceeded maximum permissible one-time concentration according to the national sanitary standards, but by no more than 10%. Based on World Health Organization criteria, the air quality on the territory of the reserve and, seemingly, along the entire Black Sea coast of Crimea is totally determined by the ozone concentration.

The importance of using the barks of trees and shrubs as powerful natural antioxidants suggests the necessity to evaluate the effect of different environmental factors on bark extracts’ quality. The determination of total antioxidant activity (AOA) and polyphenol content (TP) in the bark of 58 tree and shrub species from 7 regions differing in mean annual temperature, insolation, humidity, salinity level, and altitude was performed. The above stress factors positively affected bark AOA but did not have a statistically significant effect on TP. The bark of trees grown in the seashore proximity was characterized by significantly higher AOA than samples gathered in other areas, similarly to the trees grown at high altitude. The bark antioxidant status of 18 species was described for the first time. New sources of powerful antioxidants were represented by the ornamental shrubs Cornus sanguinea and Cornus alba, which showed the highest AOA (169–171 mg GAE g⁻¹ d.w.). Among the typical halophytes, Calligonum and Tamarix had high AOA (172 and 85 mg GAE g⁻¹ d.w.), while in the bark of tamarisk, an Se accumulator, an Se concentration of about 900 µg kg⁻¹ d.w. was recorded. A significant positive correlation was found between leaves and bark AOA in the Karadag Nature Reserve’s deciduous trees (r = 0.898, p < 0.01). The relationship between bark AOA and TP was highly significant (r = 0.809; p < 0.001) for all samples except the mountainous ones. The results of the present research revealed new opportunities in successive bark utilization.

Natural reserves play a fundamental role in maintaining flora and fauna biodiversity, but the biochemical characteristics of such ecosystems have been studied in an extremely fragmentary way. For the first time, mineral composition and antioxidant status of three systematic groups of organisms, lichens (Diplischistes ocellatus), mushrooms (Calvatia candida and Battarrea phalloides) and wormwood (Artemisia lerchiana) have been described at the territory of Bogdinsko-Baskunchak Nature Reserve (Astrakhan region, Russia), characterized by high salinity and solar radiation, and water deficiency. Through ICP-MS, it was determined that scale lichen D. ocellatus accumulated up to 10–15% Ca, 0.5% Fe, 15 mg kg⁻¹ d.w. iodine (I), 54.5 mg kg⁻¹ Cr. Battarrea phalloides demonstrated anomalously high concentrations of B, Cu, Fe, Mn Se, Zn, Sr and low Na levels, contrary to Calvatia candida mushrooms accumulating up to 10,850 mg kg⁻¹ Na and only 3 mg kg⁻¹ Sr. The peculiarity of A. lerchiana plants was the high accumulation of B (22.23 mg kg⁻¹ d.w.), Mn (57.48 mg kg⁻¹ d.w.), and antioxidants (total antioxidant activity: 68.6 mg GAE g⁻¹ d.w.; polyphenols: 21.0 mg GAE g⁻¹ d.w.; and proline: 5.45 mg g⁻¹ d.w.). Diploschistes ocellatus and Calvatia candida demonstrated the lowest antioxidant status: 3.6–3.8 mg GAE g⁻¹ d.w. total antioxidant activity, 1.73–2.10 mg GAE g⁻¹ d.w. polyphenols and 2.0–5.3 mg g⁻¹ d.w. proline. Overall, according to the elemental analysis of lichen from Baskunchak Nature Reserve compared to the Southern Crimean seashore, the vicinity of Baskunchak Salty Lake elicited increased environmental levels of Cr, Si, Li, Fe, Co, Ni and Ca.

In this work, a study of the biogenic composition of atmospheric precipitation and its change during the passage through the crowns of trees of a downy oak forest was carried out. First of all, the content of rainwater-soluble compounds of all the considered elements in rainwater under the forest canopy was higher than in rainwater in an open area. It was revealed that the main forms of nitrogen in the atmospheric fallout were nitrates and ammonium. The average concentrations of nitrogen anions in rainwater collected under the canopy were higher than in rainwater collected in the open area. The proportion of nitrite nitrogen in rainwater under the canopy was 6% higher than in rainwater collected in the open area. Simultaneously with the increase in the proportion of nitrite nitrogen, nitrate nitrogen decreased. For all considered biogenic substances, an increase in their content was observed in the warm period of the year. We found an inverse relationship between the concentration of inorganic nitrogen and phosphorus in precipitation and the relative air humidity and wind speed. It was established that the pH of precipitation falling under the crowns of trees was lower than the pH of precipitation in the open area. It was revealed that the increase in the concentration of biogenic elements was in accordance with the phase of plant development during the growing season.

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.

In this study, we analyzed the content of chemical elements in rainwater and investigated the influence of forest cover on the composition of precipitation. The results obtained showed that the concentration of some elements in the rainwater collected under the forest canopy was higher than that in the open area. As part of the work, we calculated the enrichment factor and examined the sources of chemical elements in rainwater. We found that all macro-elements had increased values of the enrichment factors compared to the supporting elements of the Earth’s crust. Ca had the highest value. The values of the remaining elements (Sr, Pb, Mn, Cr, Ba, V, Fe) indicated their lithogenic and anthropogenic origins. We noted that the enrichment factor under the forest canopy was significantly lower than in the open area, indicating the dilution of these elements during water passage through the canopy. Elements such as Zn, Co, Cu, and Ni also had high enrichment factors, which indicate their anthropogenic origin. In the open area, most elements had an inverse relationship with pH, except for the alkali metals Na, Mg, and Ca, which had a positive relationship with the pH value. The concentration of K was not dependent on pH. In rainwater that had passed through the forest canopy, the concentrations of Na, Mg, and Ca were also not dependent on pH, while the concentration of K had an inverse relationship with pH. As the concentration of heavy metals in rainwater increases, the role of Na, Mg, and Ca in the process of water neutralization decreases.