ОЦІНКА ЕКОЛОГІЧНОГО СТАНУ ОЗЕРА ЧЕРЕМСЬКЕ В СТРУКТУРІ ВОДНО-БОЛОТНИХ УГІДЬ У ПЕРІОД ЛІТНЬОЇ МЕЖЕНІ

Wetland indicators and trends are important for monitoring progress targets environmental sustainability development. Cheremske Lake, which is part of the hydrographic network of wetlands of the Cheremsky Nature Reserve, was explored. The territory is located in the northern part of the Manevichi district of Volyn region on the border with Rivne region. Cheremske Lake is of glacial karst origin, with a total area of 7.7 hectares. The purpose of the study is to analyze the hydrochemical parameters of Cheremske Lake to identify the ecological features of the formation of modern surface water quality of wetlands during the summer limit. Water samples from the Cheremske Lake were selected in August 2018 at 5 water points, from a depth of 0.5 m, using a bathometer. For the assessment of the ecological status of the studied lake, the samples were subjected to chemical-analytical control, which was carried out in the laboratory of water quality of the National University of Water and Environmental Engeneering (Rivne), in accordance with regulatory requirements. The general ecological assessment of water provided an assessment of the hydrochemical parameters of water according to three blocks of indicators: block of salt composition (chlorides, sulfates), block of tropho-saprobiological (sanitaryhygienic) composition (pH, ammonium, ammonium nitrogen, nitrites, nitrite nitrite, phosphates, suspended solids, PO, BOD5, content of oxygen dissolved in water, degree of saturation of water with oxygen) and block of specific substances of toxic effect (iron total, copper, zinc, manganese). The results of the measured concentrations of dissolved oxygen in the water were used to calculate the ratio of production of organic matter (P) to its destruction (D), which reflects the balance of organic matter in the reservoir. The analysis was carried out in a photic layer of water by the method of oxygen glasses. During the summer limit, at an average water temperature of 24.3 ºС, statistically significant exceedances of fishery standards of ammonium (3.98 ± 0.34 times), nitrogen of ammonium (3.10 ± 0.25), overlying substances (8 , 62 ± 1,17), indicators of permanganate oxidation and BSC5 (5.2 ± 0.42 and 11.96 ± 1.48 times, respectively), total iron content (31.66 ± 0.85), copper (500, 0 ± 16.96) and zinc (304.0 ± 21.78 times). Four of the nineteen hydrochemical parameters analyzed had the highest degree of purity by category. In particular, the water content of chlorides, sulfates, suspended solids and dissolved oxygen in Cheremske Lake is characterized as "very pure". By the content of nitrites, nitrite nitrogen and the degree of saturation of water with oxygen - "pure", and the content of nitrates and nitrogen nitrate as a transition from "pure" to "contaminated". The category "contaminated" included lake water such hydrochemical parameters as the reaction of the pH, phosphates and manganese. The content of ammonium ions, ammonium nitrogen, and iron in the general classify water as "dirty". The PO and BOD5 indicators, as well as the copper and zinc content in the water, gave it a qualitative environmental characteristic as "very dirty". Noteworthy is the fact that the worst quality water quality characteristics of certain categories were those of a block of specific toxic substances. At all checkpoints, they gave qualitative signs to the water of the lake with a state of "bad" and with a degree of purity "dirty". The tropho-saprobiological block of substances characterized mainly the state of water as “satisfactory” with a degree of purity “slightly contaminated”. The reduction of the obtained categories to the class of water quality by blocks of substances relates the general ecological status of the Cheremske Lake to III class, which testifies to the “satisfactory” state and the degree of purity of the water “contaminated”. At the same time, the production and destruction of organic matter in the photic layer of the lake were determined using the oxygen glass method. The results obtained indicate the relative stability of production and destruction processes in the photic layer of water, since the ratio of production to destruction is as close as possible to 1. Thus, at a depth of 0.5 m from the water surface, this value was 1.014, and at a depth of 1.5 m - 1,115 th most common Such values may reflect the relatively complete balance of the circulation of substances in the aquatic ecosystem with the autochthonous introduction of organic matter. In this case, the value of the gross primary production in the photic layer allows us to estimate the trophic level of the reservoir as “moderate” and the net primary production as “very low”. Given the high values of PO and BOD5, it can be argued that the decomposition of such organic matter is as complete as possible, which in turn gives an explanation for the high concentrations of ammonium, ammonium and phosphate ions present in the water. Since nitrates and nitrate nitrate had a slightly higher category than nitrite and nitrite nitrogen, it can also be predicted that oxidation processes play a decisive role and provide self-purification of the lake during the summer boundary. In our opinion, significant concentrations of total iron, copper and zinc create the specific chemical composition of surface waters of the Cheremske Lake, however, being essential elements does not pose a threat to the aquatic ecosystem. Thus, in the course of the research it was found that the nature of productiondegradation processes in the aquatic ecosystem is closer to the balance with the introduction of autochthonous organics. The assumption is made about the completeness of self-cleaning processes against the background of the unique chemical composition of surface waters, which is formed due to the local geochemical background and the wetland feeding of the studied lake. [ABSTRACT FROM AUTHOR]