French CNRS scientists said Baikal is facing an unprecedented environmental crisis. Endemic sponges are dying on a mass scale, and a dangerous alga is spreading on the bottom and shores. They say the main causes are industrial plants without modern treatment systems and growing tourism, which brings pollutants into the water, including phosphorus from detergents. The article also explains what measures experts propose to save the lake and why the problem needs urgent action.

Employees of the National Center for Scientific Research of France (CNRS) diagnosed the waters of Lake Baikal at the request of colleagues from the Limnological Institute of the Siberian Branch of the Russian Academy of Sciences.
As a result, French scientists stated that "Lake Baikal is currently facing an unprecedented environmental crisis, most vividly expressed in the mass death of endemic sponges, which make up a key element of the underwater landscapes".
"Underwater dives that we carried out from March 28 to 31 allowed us to assess this catastrophic situation with our own eyes. The only serious factor clouding the future of Baikal's ecology is undoubtedly the existence and operation on its shores of industrial enterprises both in the south and in the north, which do not have modern treatment facilities and which have polluted and continue to pollute the lake's waters for many years," the report by CNRS scientists Thierry Perez and Alexander Ereskovsky says.
Also, the spread of the toxic algae may be caused by the growth of tourism on the shores of Baikal — phosphorus contained in cleaning products has entered the lake. This has destroyed the active (biological) silt, the specialists explain, writes the magazine "Expert".
The scientists first noticed changes in the waters of Baikal in 2011 — the entire bottom began to be covered with a layer of dark algae. It filled the shores of the lake almost along the entire perimeter, but especially where there are many tourists.
"Over four years, the situation worsened, and all this time we conducted research. We now know the likely cause — tourists who discharge wastewater into the lake after washing clothes and dishes, and in 2014 alone 800,000 tourists visited Olkhon Island," admits the director of the Limnological Institute of the Siberian Branch of the Russian Academy of Sciences, Academician Mikhail Grachev.
The academician sees two ways to solve the current emergency situation: banning phosphorus-containing cleaning products and building treatment facilities.
"If you take everything a person is capable of pouring there, the concentration will still be very low. However, we did not think about the fact that the coastal zone is small, but it is precisely in this volume that Spirogyra lives," says Mikhail Grachev.
After the expedition, employees of the National Center for Scientific Research of France advised their colleagues from the Limnological Institute to support research that would help bring understanding of the mechanisms of sponge disease closer and reveal its connection with changes in the quality of Baikal water.
According to the scientists, "it is necessary to promote and support the application of the concept of sustainable development in relation to the increasing industrial and tourist activity around Baikal, but at the same time try as soon as possible to reduce the main sources of pollution and eutrophication of the water".
"Constant interaction with local and regional organizations engaged in the preservation of Baikal's biodiversity should become a priority area of interaction between science and government. Another important area should be raising the environmental education of the local population," Thierry Perez and Alexander Ereskovsky said.
According to the director of the Limnological Institute, the authorities are in no hurry to begin work and implement measures to build treatment facilities for Baikal.
The Public Chamber of the Russian Federation discussed the main problems of the lake and the worsening environmental situation in the region, including due to the poor operation of treatment facilities.
Preserving Baikal is a matter of international prestige for Russia. The public hearings were opened by the secretary of the Public Chamber of the Russian Federation, Alexander Brechalov. In February, an informal meeting was held with active citizens of the region.
However, in the Angara region several criminal cases have already been opened over the dumping of household waste into Baikal. It is known that in the Olkhon district (the village of Khuzhir) in the water protection zone of Baikal, liquid household waste is being discharged in several places.