A large-scale study of the cleanliness of Varna-Beloslav Lake by a team from the Technical University of Varna found pollution, in places 10 times above standard norms. The focus of the research is an analysis of the chemical composition of the silt in the lake, which has not been done in the last 20 years, and in the past there have only been partial attempts with sampling from certain locations.
It appears that a graveyard of shipwrecks is one of the main causes of the lake’s condition. They have been sitting on the bottom for more than 30 years and in the areas where they are, the pollution is most serious.
The first large-scale study of pollution in the sediments of Lake Varna was carried out in two pre-selected areas of significant importance for economic and urban development.
The studies lasted 21 months, 15 specialists and experts, led by Prof. Todor Ganchev, took part in them. Divers take 140 samples over a distance of 200 m. Two areas were studied – the eastern parts of the lake and the two navigation channels (Channel 3 and Channel 1) connecting it to the bay and Zone 2 – the central parts of the lake, Prof. Ganchev said.
As a result, a digital map of oil and heavy metal pollution in the silt in the bottom sediments of the lake was created.
The study did not take into account contamination from the burst pipe that released faeces into the sea, as they did not measure biological contamination.
The studies show mainly copper, iron and petroleum contamination. The concentration is in small areas, but it is very saturated. In places, iron and copper contamination is up to 10 times higher than European standards. It is not uniform, and a specially prepared map shows the details. The conclusions are that this is largely due to the ships that have sunk over the years. They were not taken out, only parts of them were cut out.
Other sources of pollution are the nearby rivers, ports, chemical industries in the area, as well as the sewage treatment plants located along the shores of the lake.
The recorded high levels of iron, copper and oil pollution in the sediments of Lake Varna indicate the need for sustainable management of human activity in the area. The established findings motivate the implementation of urgent measures to clean up and improve the ecological situation in Lake Varna. The results of the study indicate that urgent action is needed to address the high risks associated with the observed sediment pollution.
The samples were processed in an accredited laboratory for the indicators of iron, lead, arsenic, copper, mercury and petroleum products.
The high content of heavy metals and oil products in sediments affects the normal functioning of the ecosystem, biodiversity and is a prerequisite for their accumulation in the body of aquatic inhabitants. This can have a serious impact on human health.
THE RESCUE SCENARIOS
Prof. Ganchev sees three possible scenarios from now on.
The first and worst – if nothing is done, it raises the question of what will happen in 5-10 years. The second – to attract minimal funds to improve the state of the water in the next few years. And the third he defines as a maximum program – to assess what can be done in the next 5 years to fundamentally change the quality of life and doing business in the area and to act.
Salvation is minerals from the Rhodopes, which are dropped to the bottom and purify it, as well as aquaculture as its natural inhabitants – the reeds, which are its traditional sanitary workers.
The most expensive option is dredging, taking the sediment out of the lake, but it is not clear where it will be stored. A possible option is for them to be buried so that they do not continue to pollute through exchange with the water.
A document with 6 specific points to improve the state of the water has already been sent to the Maritime Affairs and Fisheries Program. We count on working with the new management, a concept for attracting European funding, summarizes Prof. Ganchev.
Periodically carried out dredging activities in the water area of Lake Varna destroy bottom habitats and biological species, but on the other hand, they are beneficial and low levels of pollution are observed.
The data from the study by the TU experts have been provided to the Basin Directorate and the Maritime Administration, the regional mayors of Varna have been notified. According to Prof. Ganchev, such a picture has not been made so far, and the idea was to attract funding for cleaning the lake, but for the moment there is no such progress.
He and his team consider the results of the project as an opportunity to think about the future and if no measures are taken now, within 5-10 years there is a serious danger that things will degrade and the most unpleasant option will be reached – the lake will become unusable.
According to him, if measures are taken in time, in a few years the situation will be qualitatively different and the forgotten lake will live with various business opportunities – from aquaculture to construction of tourist attractions.
The proposal of the specialists is to create working groups to develop projects for the cleaning of the lake and to look for European funding.
The Basin Directorate stated that, according to an assessment, the two lakes are in a very bad condition, but measures are being implemented, as a result of which a slight improvement in their condition was established when developing a management plan for the river basins 2022-2027.