Sanitary-Microbiological Assessment of Water Quality in Lake Baikal
March – December 2018
One of Lake Baikal Foundation’s priorities is to decrease the level of anthropogenic influence on the lake. To this end it is necessary to define its actual level and to do microbiological assessment of water. Research of such kind is important either for the state monitoring of the Baikal’s ecosystem and for local population or for the producers of water waste treatment facilities who lack information about waste in water. Lake Baikal Foundation supported the project of the Limnological Institute of the SB RAS on the sanitary and microbiological assessment of water quality in the mouths of rivers flowing into lake Baikal in coastal areas, including tourist and recreational zones and near settlements and tourist centers, as well as in pelagic lakes standardized indicators SanPIN 2.1.5.980-00 within the framework of an accredited laboratory (certificate No. RA.RU.21KB02).
Goal:
- to do an objective assessment of water quality in the Baikal according to standardized sanitary-microbiological indicators.
Targets:
- to provide grant assistance to the Limnological Institute of the SB RAS for implementing the project;
- as a part of grant assistance to conduct the following works in May-December 2018:
1) to collect samples of water and coastline ground in areas with high anthropogenic impact (Sluydyanka, Kultuk, Baikalsk, Listvyanka, Goloustnoe, Bolshiye Koty, Peschanaya bay, Babushka bay, bays of the Small Sea) and also water samples at bathymetrical station. The samples will be collected at least twice a year (May-June and August-September);
2) to analyze samples of water and ground according to sanitary-microbiological indicators (detecting general coliform bacteria, TCB, Enterococcus bacteria, coliphages, coli, salmonella, coefficient of water body natural purification;
3) to create a collection of pure growth creation of opportunistic pathogenic bacteria, a description of their morphological and physiological-biochemical properties, determination of the level of pathogenicity and enzymatic activity, identification of resistance and / or sensitivity to antibiotics;
4) to develop new methods for identification of opportunistic microflora (methods of sequencing of a new generation and a system for accelerated identification of microorganisms with the help of MALDI Biotyper; metagenomic analysis).
What was done:
- The Foundation’s grant in 2018 amounted to 500 000 rubles. These funds were spent for implementation of the targets listed above, project’s employees’ salaries and for technical assistance.
First stage results:
- The first part of the study took place on 2-6 July. Coliform bacteria were detected in all the bays of the Maloe More in numbers not exceeding admissible values regulated by SanPiN 2.1.5.980-00. The highest numbers of CB and TCB were found in the bays Mukhor, Hugir-Nugaisky, Irkutskaya Guba and Bazarnaya (OCB equalized 1-129 CFU/100 ml, which means 500 CFU/100 ml; ТCB – 1-78 CFU/100 ml, less than 100 CFU/100 ml). Enterococci were also detected in all water samples. In the Mukhor bay the numbers were 86 CFU/100 ml, in the Irkutskaya Guba bay – 164 CFU/100 ml. Such indicators imply recent fecal contamination ingress into the water. It is worth saying that there are a lot of camping site on these bays’ coastlines. On the contrary, in the bays Hugir and Zagli characterized by low anthropogenic impact coliforms and Enterococci were found in single quantities. In all the samples the scientists found high index of self-purification which indicates the completeness of self-purification processes.
Second stage results:
- The second part of the study was held on 8-17 August. The research revealed unfavorable microbiological condition in 4 out of 8 examined bays. In samples from the Bazarnaya bay the CB number is double the norm, TCB are seven times the norm, the Enterococci number is six times the norm and index of self-purification is low (2,1-3,8). In the Mukhor bay, near the mouth of the Kuchulga river, they revealed the exceedance of Enterococci signal numbers 1,5 times higher the norm, in the bay Zuun-Khagun the number of TCB and Enterococci was double the norm. In the Kurkut bay, where there are harbours, the scientists also registered slightly higher numbers of TCB (1,2 the norm). In the Khugir-Nugaisky bay they saw quite big numbers of Enterococci, 5-7 times the norm, in the bays Khugirsky, Khul and Tutai Coliform bacteria and Enterococci did not exceed allowed and signal values.
- Thus, the quality of water in the bays Mukhor, Kurkut, Zagli and Bazarnaya does not correspond SanPin 2.1.5.980-00 norm. The worst water quality was registered in the Bazarnaya bay. In the Khugir-Nugaisky bay Enterococci were found in numbers exceeding the signal values which implies recent fecal contamination ingress.
Third stage results:
- The final part of the study took place in September-November. In autumn waters of the pelagic zone of the lake corresponded to the standards (SanPin 2.1.5.980-00) and recommendations (MUK 4.2.1884-04). Exceeded values of normalized and signalized sanitary microbiological indicators were identified in the waters near the Listvyanka settlement (total coliform bacteria of 501.7 CFU/100 ml, thermotolerant coliform bacteria of 134-501.7 CFU/100 ml and enterococci of 292 CFU/100 ml) of the southern basin, in the water area of Maloye More Strait, Bazarnaya Bay (thermotolerant coliform bacteria of 392 CFU/100 ml and enterococci of 102 CFU/100 ml) and Khuzhir Bay (total coliform bacteria of 400 CFU/100 ml), of the central basin, and in the coastal waters of the Maksimikha settlement (thermotolerant coliform bacteria of 140 CFU/100 ml and enterococci of 96 CFU/100 ml) of the northern basin. Like in the spring-summer period, the water areas near the capes Izhimey and Bolshoy Solontsovy showed the most favourable sanitary microbiological state.
Researchers’ conclusions:
- Based on the assessment of the water quality in lake Baikal, in May-November, 2018, the researchers found out that in terms of sanitary microbiology the coastal waters of the Listvyanka settlement and the bays of Maloye More strait are the most unfavourable water areas among the sites characterized by the intensive recreational load. Values of the sanitary microbiological indicators exceeded the permissible ones (SanPin 2.1.5.980-00) during the entire study period. The highest number of coliform bacteria and enterococci was recorded in August at the peak of recreation. In addition, unfavourable sanitary microbiological situation was observed in the water areas of the Zarechny settlement in June and August, the Maksimikha settlement in August and September, the Senogda bay and the mouth of the Turka river in June, and the Tankhoy settlement in August. Notably, the state of the waters in the Snezhnaya river near the Vydrino settlement, where in August significantly exceeded values of the normalized indicators were identified, indicates the inflow of fresh fecal contamination and potential epidemiological hazard to the population using the river water for recreational purposes.
- Based on the metagenomic analysis of communities and identification of culturable bacteria from the surface and bottom water, water column, biofilms of various substrates and bottom sediments, the researchers conclude that bacteria which are opportunistic pathogens for humans and warm-blooded animals represent the allochthonous microbiota of the littoral zone of lake Baikal. Bacteria identified in the biotopes of lake Baikal are members of the family Enterobacteriaceae. They are the most common cause of community-acquired and nosocomial infections, thus, becoming dangerous for the local population and tourists.
- Most isolated strains showed poly-resistance to broad-spectrum antibiotics (β-lactam antibiotics (penicillins and cephalosporins) and sulphonamides), which can indirectly indicate their anthropogenic origin and ability to cause infectious diseases. Presence of such bacteria in the environmental objects supports the pool of antibiotic-resistant strains due to the transfer of resistance genes among the autochthonous bacterial communities of the ecosystem.
Thus, the study brought modern data about the species diversity of opportunistic microorganisms and their survival in cold-water and deep lake Baikal. The data are the source of fundamental knowledge and can be included to basic publications in scientific magazines.
You can read the detailed scientific report on the project here.