Ecological assessment of the Selenga River basin, the main tributary of Lake Baikal, using aquatic macroinvertebrate communities as bioindicators

The Lake Baikal history and the main problems of its regulation have been discussed. Analysis of the lake level alterations over the whole period of instrumental observations (1900–2016) has been carried out. A protracted low-water period was observed in the Baikal basin fromthe middle 90s of XX century. It was the longest for the whole period of instrumental observations. The extreme low-water situation in the lake basin in 2014–2015 has been studied. A statistically significant trend of the temperature increase and precipitations decrease has been stated. Atmospheric precipitations affect the river runoff many-year fluctuations more than other water balance elements. It was stated that the Lake Baikal level directly depends on the Selenga River water content. Minimal runoff during the low-water periods demonstrates a tendency to decrease, just like the annual runoff. It was a perpetual series of the reduced runoff that caused the minimal runoff negative trend, as a result of which the water resources inflow to the Lake Baikal was recordbreaking minimal over the previous years. The Selenga River basin runoff parameters spatial-temporal reconstruction was performed according the hydrometric posts and dendro/climatic stations data. The water runoff reconstruction statistic models show a good agreement between the Archangel fir ring amount of growth and annual water flow. The historic chronicles and moisture regimes have been chronologically compared on the basis of the obtained water regime reconstructions. The historic chronicles analysis is an indirect verification of the obtained time series related to the water flows in the Selenga River basin.

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River Water Quality of the Selenga-Baikal Basin: Part I—Spatio-Temporal Patterns of Dissolved and Suspended Metals

Water ◽

10.3390/w12082137 ◽

2020 ◽

Vol 12 (8) ◽

pp. 2137 ◽

Cited By ~ 2

Author(s):

Nikolay Kasimov ◽

Galina Shinkareva ◽

Mikhail Lychagin ◽

Natalia Kosheleva ◽

Sergey Chalov ◽

...

Keyword(s):

River Basin ◽

Lake Baikal ◽

Large Scale ◽

Anthropogenic Impacts ◽

World Average ◽

Selenga River Basin ◽

Baikal Basin ◽

Selenga River ◽

The World ◽

Spatio Temporal

Lake Baikal is the largest freshwater body on Earth, once famous for its pristine conditions. However, the lake and its drainage basin with their unique ecosystems have in recent decades been subject to both climate warming above the world average and severe anthropogenic pressures from mining and agriculture. Although previous studies have targeted various hydroclimatic, geochemical, and biological conditions of the Lake Baikal basin, the heterogeneous nature and large size of the basin leave considerable knowledge gaps regarding ongoing metal contamination of the basin’s suspended sediments and waters. To address these knowledge gaps, the main objectives of this study are to (i) determine regional background values for water and suspended sediment quality with respect to multiple metals (representing undisturbed conditions) and (ii) further evaluate spatio-temporal concentration patterns of these metals, including regions with heavy anthropogenic impacts. We synthesize data from extensive field measurements within the Selenga River basin performed between 2011 and 2016, covering over 100 sampling locations. Results show that although the background metal concentrations (of both dissolved and suspended metal forms) in the alkaline Selenga River waters were close to the world averages, metal concentrations of up to two orders of magnitude above the background values were seen for Zn, As, Cd, Cu, Mo, and Pb in regions subject to anthropogenic impacts (cities and the mining industry). Specifically, dissolved As levels within the Selenga River basin were 2–5 times higher than the world average and well above the global guideline value in several regions. Notable hotspots for anthropogenic impacts of Cd were particularly found in Zakamensk and Ulaanbaatar. Our results highlight clear anthropogenic impacts and large-scale spreading of several pollutants of concern, with risks even to downstream parts including the Selenga delta and Lake Baikal. We expect that these results will aid in increasing the understanding of large-scale metal transport processes, as well as for designing relevant measures to mitigate further spreading of metals to Lake Baikal.

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