Ecological State of Lake Gusinoe—A Cooling Pond of the Gusinoozersk GRES

The study of the transformation of substances in the basin of the Selenga River—the main tributary of Lake Baikal—under anthropogenic pressure and in the context of global climate change, is especially important for the lake, a globally important source of drinking water. The ecosystem of Lake Gusinoe is one of the key objects in the Selenga River basin that is exposed to significant anthropogenic pressure. This study presents the results of an analysis of water level changes and physicochemical parameters of the water mass of Lake Gusinoe; literature data from 1951 to 2017 and own data from 2017 to 2021. The water level in the lake had depended on natural factors before the Gusinoozersk GRES was launched; however, since the plant has begun using the lake as a cooling pond, its level has actually been regulated by the economic entity. Over the years, there has been a significant increase in mineralization, sulfate, sodium, fluoride and organic matter fractions resistant to oxidation. Seasonal increases in iron and manganese concentrations in water were detected. Increased concentrations of nutrients and organic matter fractions resistant to oxidation were registered at the wastewater discharge sites. Heavy metals in the bottom sediments of Lake Gusinoe accumulate mainly in the silt of the deep zone of the lake. Plants growing in the zones of influence of the Gusinoozersk GRES and Gusinoozersk wastewater discharge accumulate the largest amount of metals.

Climate Change Impact On Flood Runoff Over Lake Baikal Catchment

Water level and distribution of dissolved and suspended matter of Lake Baikal are strongly affected by river inflow during rain-driven floods. This study analyses river flow changes at 44 streamflow gauges and related precipitation, evaporation, potential evaporation and soil moisture obtained from ERA5-Land dataset. Based on Sen-Slope trend estimator, Mann–Kendall non-parametric test, and using dominant analyses we estimated influence of meteorological parameters on river flow during 1979-2019. Using ridge-regression we found significant relationships between precipitation elasticity of river flow and catchments features. Half of the gauges in eastern part of Selenga river basin showed a significant decreasing trend of average and maximum river flow (up to -2.9%/year). No changes in central volume date of flood flow have been found. A reduction in rainfall amounts explains more than 60% of runoff decline. Decrease in evaporation is observed where precipitation decrease is 0.8%/y or more. Catchments where the precipitation trends are not as substantial are associated with increasing evaporation as a result of the increase of potential evaporation. Negative trends of precipitation are accompanied by negative trends of soil moisture. Finally, the study reveals sensitivity of the catchments with steep slopes in humid area to precipitation change.

The content of heavy metals in the water of Lake Gusinoe (Western Transbaikalia) and its tributaries

Investigation of the transformation of substances in the basin of the Selenga River, the main tributary of Lake Baikal, due to anthropogenic impact under conditions of global climate change, is especially important for Lake Baikal which is a World Natural Heritage Site and the main source of fresh drinking water not only in the region, but also in the world. One of the key research objects in the Selenga River basin, which is subject to significant anthropogenic impact, is the ecosystem of Lake Gusinoe. This study presents the results of analysis of the physical and chemical parameters of the water mass of Gusinoe Lake basin. for the period from 2017 to 2020. Thus, the results on hydrochemical indicators for a long-term period of research of the lake show changes in the chemical composition of water and the concentration of main ions. In 2020, the content of almost all metals was higher than in 2017-2020, which may be due to the rise in the level of Lake Gusinoe and groundwater that began in 2019 and continued in 2020, as a result of rain floods that caused flooding of the coastal territories and the entry of pollutants into watercourses and the lake.

Aufeis in the mountainous areas of the northwestern part of the Selenga River basin

The article presents the results of research on aufeis (icings) in the area where their concentration is maximal for the Selenga River basin. Landsat and Sentinel satellite imagery data were used to map the current location of aufeis in the valleys of permanent watercourses of the transboundary Dzhida River basin. It was found out that up to 3.5 thousand small aufeis with the area from 0.005 to 1 km2 are formed in small watersheds of the territory. The total area of aufeis within the considered territory can reach up to 92.1 km2, the aufeis coverage is 0.45%. It is revealed that in the total amount, small aufeis prevail, the area of which lies within 0.01 to 0.1 km2. In addition, ecosystem and economic aspects of the processes of ice formation on the territory of Russia and neighbouring Mongolia are considered.

First Findings of Sunbleak Leucaspius delineatus (Cyprinidae) in the Lake Baikal Basin

Since the early 1960s, the sunbleak Leucaspius delineatus (Heckel, 1843), along with carp acclimatized from European Russia, regularly entered the siberian carp ponds, first in the Ob’ basin, and then in the Yenisei and Angara basins. In the last decade, we have discovered the sunbleak in two water bodies of the Baikal basin: in May 2013 - in the water intake and discharge canals of the Gusinoozersk regional power plant situated on the large lake Gusinoe in the Selenga River basin (Republic of Buryatia), and in November 2016, the sunbleak was registered in the diet of pike inhabiting the reservoirs of the Talaya-Pokhabikha lake-bog complex in the immediate vicinity of the Baikal coastline at the southern end of the lake in Irkutsk Region. The age series in the samples of the sunbleak in the water intake canal of the power plant was represented by five age groups from 1+ (SL 34.2 mm and 0.59 g of weight) to 5+ (SL 73.9 mm and 6.73 g, respectively) with a predominance of individuals aged 1+ and 2+. In the discharge canal only group 1+ (SL 35.5 mm and 0.69 g) was noted. The sex ratio in catches at the age of 1+ was 1:1.2 with a predominance of males; by the age of 3+, the proportion of males increased significantly (1:8.6). Sexual maturity of the sunbleak from Lake Gusinoe occurs at the age of 3+. Spawning is portioned, the first portion is layed down not earlier than the second half of July. The total fecundity of the seven studied females at the age of 3–5 + varies from 632 to 1539 eggs, averaging 1312 eggs. The sunbleaks from Lake Gusinoe are predominantly benthophagous. In the first half of May 2013, near the water intake canal, the main food components were the nymphs of the Corixidae water bugs and larvae of Phryganea caddis flies, planktonic crustaceans and imago of aerial insects were also consumed. In July 2014, in the discharge channel, the main food item was the chironomid larvae. In the lake Sludyanskoye, three specimens were identified from the stomachs of the pike living there. All fish were partially digested, and therefore it was not possible to analyse it.

ASSESSMENT OF CARCINOGENIC RISK OF DRINKING SURFACE WATER CONSUMPTION OF THE TRANSBOUNDARY BASIN OF THE SELENGA RIVER IN THE TERRITORY OF MONGOLIA

The assessment of the carcinogenic risk of the impact of drinking surface waters on the population health of the transboundary basin of the Selenga river in Mongolia is described in the article. We carried out expeditionary studies of the quality of drinking surface waters on the territory of four aimags, which represent different degrees of economic development and are completely included in the Selenga river basin: Khuvsgul, Arkhangai, Bulgan and Selenge. In this work, we used the methodology used by the US Environmental Protection Agency to quantify the carcinogenic risk of exposure to chemical compounds present in surface waters using the example of these aimags in Mongolia. The application of this methodology for risk assessment gives a great advantage over traditional methods of regulation. It has been established that on the territory of the Selenge aimag, the risk of developing a carcinogenic effect from the impact of priority pollutants on public health associated with the quality of drinking water is high and in the territory of Bulgan, Khuvsgul and Arkhangai aimags are medium, which requires state regulation of the risk and the development of appropriate standards.

IMPACT OF CLIMATE CHANGE ON ECOSYSTEM SERVICES IN THE REGIONS OF INNER ASIA

The assessment of ecosystem services of the forest is presented as the most important part of natural resources in the Selenga river basin located in the territory of Inner Asia. The analysis of the dynamics of forest fires, which are one of the consequences of global climate change, is presented. The adaptation measures in the forestry sector to this change are considered.