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Neurochemical pollutants in the aquatic medium: the results of studies with model organisms (microalgae)
The constantly extending list of humankind-produced environmentally toxic compounds currently includes pharmacological preparations. Among them, of potential relevance are neurotransmitters including such biogenic amines as norepinephrine, dopamine, serotonin, and histamine, as well as acetylcholine. These neurotransmitters were tested in the present work using such model organisms as the green microalgae Chlorella vulgaris Beijer, Scenedesmus quadricauda (Turp.) Breb. К-1149, and Haematococcus lacustris (= pluvialis) strains IPPAS H-239 and BM-1, as well as the cyanobacterium Limnospira platensis IPPAS B-256. It was established that all tested neurotransmitters significantly stimulate the growth of the cultures of microalgae at sufficiently low (micromolar) concentrations. In light of the results of this work, uncontrollable microalgal growth seems to be possible under the influence of trace amounts of neurotransmitters in natural and artificial water bodies, which might cause their eutrophication. All tested substances influenced the photosynthetic pigment content at micromolar (or submicromolar) concentrations, acetylcholine being a quasi-universal promoter of their biosynthesis that presumably stimulates the photosynthetic activity of the microalgae. The effects of the other tested substances varied depending on the microalgal species involved but predominantly resulted in promoting photosynthetic pigment biosynthesis. A biotechnological project aimed at stimulating the microalgal biomass yield by supplementing microalgal cultures with neurotransmitters seems to hold promise for producing drugs, food additives, or biofuel.
Long-term dynamics of metal concentrations in river suspended matter (Oka River, 1983–2018)
Distribution features of cadmium, lead, partly Ag, Bi, In, Hg and Tl in suspended solids are considered. Studies were made on the Oka River in the area of the Prioksko-Terrasny Natural Biosphere Reserve on a river section remote from the zone of formation of the technogenic scattering stream, in the period 1983–2018. To assess the general trend of changes in the concentration of the elements over the period of the experiment, it was proposed to consider the results on their prevalence in the composition of suspended matter obtained in the intermediate hydrological phase of the river between the spring flood and the summer midden. This is the main feature and essence of our proposed approach in order to eliminate the influence of significant seasonal changes in the macro- and micro-component composition of suspensions. It is shown that the 35-year time interval can be divided into two periods, namely: the first one is characterized by a decrease in the concentration of heavy metals (Cd, Pb), while the second one is characterized by the absence of any trend, relatively weak fluctuations in values. The direction of changes in the concentration of elements in the first period correlates with the literature data on the dynamics of a decrease in the intake of anthropogenic wastewater into surface waters in recent decades and with the results of our assessment of the decrease in river water pollution upstream from the experimental area.
On the influence of Holocene tectonics on the formation of the river network of the Alpine-Himalayan and Pacific mobile belts of Eurasia
This article continues the series of publications on the indicators of Holocene activation. Using the examples of the Volga and Amur rivers with their tributaries and the Razdolnaya River, the interaction of the river network with the Holocene orogenic system of the Alpine–Himalayan and Pacific mobile belts of Eurasia was studied. The river network is conformal to their orogenic system. Examples of the control of river valleys by shear systems of active faults are given. The influence of the rivers on the formation of erosional relief was studied. It is shown that loose sediments of the Mesozoic-Cenozoic rifts thrown up in the Holocene are actively destroyed by the river network, with a shear of up to many hundreds of meters. The rises on the riftogen framing and their internal rises, composed of strong pre-Mesozoic rocks, are weakly eroded. Many of them have a contrasting, nonequilibrium relief. The study was conducted within the framework of the pulsatingly expanding Earth model developed by the author.
Chemical composition and geoecological assessment of bottom sediments of watercourses in the town of Volsk (Saratov region)
For many decades, two main watercourses in the town of Volsk (Saratov region) have been serving the transit function of sewage effluents to the Volgograd reservoir. Sampling of bottom sediments was carried out along the length of the Verkhnyaya and Nizhnyaya Malykovka watercourses in order to analyze the specificity of the chemical composition of alluvial formations under technogenic impact conditions. The fraction of technogenic particles (plastics, coal, paint, synthetic fibers, etc.) was 4–20%. In terms of chemical composition, alluvium is represented by silicites with varying degrees of clay content., Bottom sediments are characterized as clay silicites, with the maximum content of heavy metals and organic matter (based on the value of loss on ignition) in the areas where wastewater enters the watercourses. The most typical contamination is with zinc, lead, and barium. The overall level of technogenic pollution of bottom sediments is high and can be named considerable in the upper reaches of the Nizhnyaya Malykovka watercourse only. In order to improve the ecological status of the watercourses, a set of measures is needed, including reconstruction and the creation of new infrastructure facilities of the urban environment.
On the prevalence of background and technogenically dependent concentrations of heavy metals in river waters
Features of the prevalence of Cd and Pb dissolved forms in the water of sections of the Oka river and other rivers of the Russian Plain are considered. The influence of anthropogenic wastewater (industrial, municipal and agricultural) containing heavy metals is clearly manifested only in certain sections of the rivers of central Russia (Oka River, Volga River, and Moscow River) against the background of natural landscape and geochemical processes. An attempt is made to develop approaches to assessing the degree of anthropogenic influence on the water composition of various river sections, including those remote from pollution zones. An ecological and geochemical lead–cadmium indicator is proposed, which makes it possible to assess the anthropogenic impact and divide river sections into 3 categories (strong, medium and weak pollution, respectively). The river sections with low anthropogenic pollution have high values of this indicator corresponding to waters with the background (or close to background) concentration. A decrease in the indicator values means an increase in the role of anthropogenic effluents in the water composition, and estimates of the average concentrations of elements are technogenically dependent.
Usage and preservation of land and soil fertility is a matter of state (to the 75th anniversary of the State plan for nature transformation)
The fulfillment of the tasks set by the 1949-1965 State Plan for Nature Transformation became the work of the whole country. Its goal was the development of sustainable agriculture in the steppe and forest–steppe regions of the European part of the USSR. It is an example of a responsible state attitude to the use and preservation of our lands and soil fertility. The State Plan for nature transformation was bases on the integrated reclamation of agricultural landscapes using a scientific systematic approach to the objects of research and management. State authorities, Academy of Sciences of the USSR, scientists from dozens of universities and research institutes, ministries, 80 thousand collective farms, 2 thousand state farms, and 3 thousand machine tractor stations took an active part in the organization and large-scale implementation of protective afforestation and the development of a grass-field farming system. The plan provided for the creation of 8 large state forest strips with a total length of 5,320 km, located along floodplains and watersheds of the Volga, Dnieper, Don, Ural, Seversky Donets rivers etc.; protective forest plantations in the fields of collective farms and state farms; consolidation and afforestation of sands on an area of 322 thousand ha; the introduction and development of a system of field and fodder grass-field crop rotations; and the creation of over 44 thousand ponds and reservoirs. Over the 5 years of the plan's implementation, more than 2.3 million ha of forest plantations have been planted in the country; an ecological framework of agricultural landscapes has been created on agricultural lands; over 13 thousand ponds and reservoirs have been created. The prototype of the scientific basis of the State Plan for Nature Transformation was the works by V. V. Dokuchaev, V. R. Williams and V. I. Vernadsky on the conservation of land and soil fertility. The implementation of the plan stopped in 1953 and the development of virgin and fallow lands began. Currently, the state, scientists, society, regions and agricultural producers need combining their efforts in the rational usage of natural resources, the preservation of agricultural land and soil fertility for the present and future generations.