Czech scientists spark concerns over water quality in Ukraine after finding dangerous pollutants in former Kakhovka Reservoir. What are the solutions?

What's the problem? 

The destruction of Ukraine's Kakhovka Hydroelectric Power Plant dam in June 2023 stands out as one of the most striking instances of environmental damage from Russia's full-scale war against Ukraine. The Russian forces blowing up the plant and dam in the occupied city of Nova Kakhovka caused a massive flood that affected towns and farmland across the southern region. In less than a month, the reservoir, with an area of 1,870 square kilometers, almost completely disappeared. A natural network of river channels reemerged, surrounded by willow forests that grow twice as fast as anywhere else in the world.

Czech environmentalists from the non-profit Arnika, who have worked in Ukraine since 2017 as part of the Clean Air for Ukraine program, took several samples of bottom sediments from the Dnipro River in the southeastern city of Zaporizhzhia, downstream to the former Kakhovka Reservoir, and in the southern city of Kherson, to record the environmental damage to Ukraine's ecosystems after the catastrophe. The samples revealed heavy metals, insecticides, organochlorine pesticides, and other harmful substances.

In an interview with Rubryka, Marcela Černochová, coordinator of the Clean Air for Ukraine project, explained how the research was conducted, the dangers of the substances found in the sediments, and what needs to be done to avoid harmful effects on the health of locals.

The bottom of the former Kakhovka Reservoir. Photo: Majda Slámová/ Arnika

"Clean Air for Ukraine" is an international long-term program run by the Czech non-profit organization Arnika in cooperation with Ukrainian partners Free Arduino (Ivano-Frankivsk) and Green World (Dnipro). 

"We have two main work areas: industrial air pollution, and since February 2022, we also focus on the environmental damage caused by the war and on preparing for post-war recovery," says Marcela Černochová, the project coordinator. "As for environmental damage, we are currently focusing on pollution partly caused by hostilities but also related to industrial activities. A specific example is the study of sediments in the Dnipro River and Kakhovka Reservoir."

Environmentalists started studying the bottom of the Kakhovka Reservoir in 2023 and will continue until 2025 with research in the Dnipropetrovsk, Zaporizhzhia, and Kharkiv regions. They took the first samples from the bottom of the Dnipro River and the mouth of the Kakhovka Reservoir near Zaporizhzhia last July and late October.

"When we first visited Zaporizhzhia after the Kakhovka catastrophe, we were hit with strong and sharp emotions. We took samples from the mouth of the former reservoir and saw a vast empty space. Words like lunar landscape and apocalypse describe what we experienced well. A few months later, when we returned to the same place, young willows were growing there. Nature is winning," says Marcela.

In Zaporizhzhia and downstream to the Kakhovka Reservoir, scientists took five samples of bottom sediments from the Dnipro River and two soil samples from rocket explosion craters. Another sediment sample from the Dnipro, which flooded the city during the disaster, was taken in Kherson.

"The main goal of this study, given limited resources and access difficulties in some areas, was to assess the risk level and provide initial information for further discussions on the future of the Kakhovka dam and plans for dealing with the disaster's aftermath. Of course, to create a more complex picture, more samples will need to be taken, including from currently inaccessible areas," says the Czech environmentalist.

The list of dangerous substances found is striking: heavy metals, polycyclic aromatic hydrocarbons, non-polar extractable compounds, C10-C40 hydrocarbons, cyanides, polychlorinated biphenyls, hexachlorobenzene, pentachlorobenzene, hexachlorobutadiene, organochlorine pesticides, acid residues, brominated flame retardants, Dechlorane Plus, polychlorinated naphthalenes, and poly- and perfluorinated substances. 

"The results indicate significant pollution related to industrial activities, with contaminant levels exceeding risk limits," Marcela says. "Ten samples were taken from the bottom of the dam, with four samples exceeding limits for polycyclic aromatic hydrocarbons. Two samples had especially high concentrations of petroleum hydrocarbons; one had a high concentration of PCBs, and another had a high DDT concentration. Some samples showed elevated levels of heavy metals, including mercury and arsenic, which can enter the food chain or lungs. These results suggest that these areas need to be reclaimed."

Marcela also added that she and her team will continue investigating the situation. In June of this year, she revisited Zaporizhzhia and collected samples after the Russian shelling of the DniproHES dam.

"We expect the sediments to be contaminated with oil substances," says the Arnika specialist.

What's the solution?

The open bottom is a vast land resource for the communities, so the people living there hope to use it for grazing livestock, growing vegetables, installing solar panels, recreation, and other needs. Considering the study results, such plans seem unrealistic. However, a conclusion about whether these areas can be used has not yet been made:

"First of all, more samples from more locations need to be taken and analyzed before any proper conclusion can be made," says Marcela, adding that once they know the final results, locals can begin discussing reclaiming these areas, which means cleaning and restoring them.

According to the researcher, the reservoir can be used for mitigating the effects of climate change, conducting educational activities, conserving rare species, and many other valuable and sustainable purposes:

"Some areas can become wetlands, while others can be homes for organisms that need support and protection," says Marcela. "The empty reservoir can be used for environmental education, including hikes, bird watching, and other outdoor activities. We recommend promoting sustainable farming near the waterbody, considering the same water source is no longer available. This will help restore groundwater supplies."

Currently, the pollution of the bottom of the former reservoir could threaten nearby towns that use the surrounding areas. The concern is the migration of substances found in the samples into groundwater and wells used for drinking water.

"It's important to inform the local community about the potential dangers, including contamination of drinking water and the introduction of water organisms. To address these issues, we recommend establishing water quality monitoring. This may involve installing temporary purification systems for drinking water," Marcela says.

 The report published as part of the project also contains recommendations for reclaiming the contaminated area. Given the scale of the impact and resource shortages, the Czech ecologist believes that the most realistic scenario for such recovery is phytoremediation—the use of plants to clean up contaminated environments—of the most polluted areas that could threaten drinking water sources.

"One problem with phytoremediation is that while it can help remove heavy metals and persistent organic pollutants from the soil, they can remain in the plants," says Marcela. "However, priority should be given to the contaminated areas that threaten drinking water sources. Considering the limited resources available, developing and implementing cost-effective, locally viable reclamation methods tailored to specific pollutants and environmental conditions at the Kakhovka dam site may be needed. International aid might also be needed for recovery."

However, carrying out any measures on the former Kakhovka Reservoir territory is currently impossible due to Russian troops on the other side of the former reservoir. So, the only available option is monitoring water quality.

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