Researchers of the St. Petersburg Federal Research Center of the Russian Academy of Sciences (SPC RAS) have detected a high content of harmful substances in the Gulf of Finland waters in the Resort District of the Northern Capital, that is caused by the operation’s insufficient efficiency of the sewage treatment plants, including those at boarding houses, cottages and public catering enterprises located on the coast line. Pollution poses a threat to the safety of people swimming in these waters, and also leads to the marine inhabitants’ health deterioration.
"Our latest studies on the mollusca example have shown that marine animals feel bad in these waters. Moreover, it was shown that the above is caused by the operation’s insufficient efficiency of the local water disposal and sewerage systems, first and foremost, at boarding houses, public catering enterprises and private cottages located on the coast line” - said Sergey Kholodkevich, Chief Researcher, Head of Bio-electronic Methods in Geo-ecological Monitoring Laboratory of SRCES RAS - SPC RAS.
Waste is generated during the cooking process, after dish washing and toilets visiting. The presence of caffeine, diclofenac (used in many pain relievers), along with certain hormonal medications serves as an indicator of water pollution in reservoirs by municipal wastewater, for instance, in the Leningrad Region. The large cities, as a rule, implement powerful systems of wastewater treatment and sewerage that can cope with a large amount of waste processing, and the local treatment facilities at the restaurants and cottages cannot cope with such a load.
The liquid part of the waste ends up in the Gulf of Finland or nearby rivers and lakes, whose ecosystem is being gradually destroyed, since the aquatic animals due to the excess of pollutants for many years are getting sick. As shown by the latest research done at SPC RAS, the animals digestive system is disturbed, as a result, they cease to contribute to the coastal waters self-purification.
"Moreover, we can localize the area of pollution quite accurately: in Sestroretsk, everything is fine with the reservoirs, and Rospotrebnadzor allows for use these beaches for swimming. To the North in Repino and Zelenogorsk everything is bad, that is, there exists a strong pollution of the water area. Then, starting from Ushkovo, everything comes back to normal, and the fenomenon explanation is quite simple - there are no public catering points, and private houses are located far enough on a sandy elevation, unlike Repino and Zelenogorsk, " - explained Professor S. Kholodkevich.
The only direct and most effective way to assess the wastewater purity is a study of the water animals living there. Other, in particular, chemical methods of water quality research do not possess such an accuracy. St. Petersburg scientists use about 30 species of marine and freshwater animals as bio-indicators, namely, crustaceans, crabs, mollusca and some others.
“We have developed and got patented an original biological monitoring technology. It is based on the measurement of the animals’ functional load. By analogy with people: when you visit a doctor, you are subjected to a reasonable physical exercise, for example, squats, and then the doctor monitors how quickly initial heartbeat restores. This approach was initially developed to select healthy people to function as pilots and astronauts. We also use a functional load test. To do so, a method was developed for measuring the heartbeat in animals as well as a less than 3 mm in size probe. Thanks to this unique development the biorhythm in animals of a minimal size of 3-5 mm can be studied "- the scientist said.
According to the scientist’s comments, such probes have been used for many years to monitor water at the treatment facilities in St. Petersburg; they have also been tested under some international environmental projects on the waters and animals of the Mediterranean, Baltic, Northern, Black, and White Seas. In the last few years, the technology developed by the St. Petersburg scientists has drawn attention in China. The planned implementation of the bio-monitoring system at several Chinese communal enterprises was somewhat delayed because of the pandemic.
"At SPC RAS the environmental research is one of the most important scientific directions. Particularly important is the study of various aspects of the Gulf of Finland environmental safety in whose vicinity such a large megalopolis as St. Petersburg is located. Here, the interdisciplinary focus of our center acquires a particular importance, since the scientists from different scientific fields can be engaged to form the most complete picture of what is currently happening in the Gulf of Finland" - pointed out Professor Andrey Ronzhin, SPC RAS Director.
Reducing the load on the water area primarily depends on the consciousness of each person. For instance, owners of cottages or restaurants near a reservoir should take much more responsible approach when building the local wastewater treatment systems. In addition, it is necessary to reduce water consumption in places where centralized waste treatment systems do not exist.
"Since it is hard to keep track of the above, some countries, like Norway, legally prohibit the wells and wells at dachas. So, if you want to drink - bring water along. Actually, just a few liters of water will be enough for a picnic. At our dachas swimming pools and showers are developed on comparatively small plots; fresh water consumption by such facilities, is comparable to the big cities’ ones - about 200 liters a day per person, and consequently a family of five people consumes one thousand liters per day. At that, the treatment facilities at the dachas are not the same as in the city - local, they mostly do not match to such a load, what eventually leads to the degradation of the ponds, small and large lakes and rivers water areas "- the scientist said.