Consequences of the Kakhovka hydropower plant dike explosion for the Black Sea: new data

On 6 June 2024, on the anniversary of the Kakhovka disaster, the Ministry of Environmental Protection and Natural Resources of Ukraine, together with EU4EMBLAS, the Ukrainian Research Centre for Marine Ecology and the Institute of Marine Biology of the National Academy of Sciences of Ukraine, shared the latest results of research on the impact of the disaster on river and sea waters and the Black Sea.

What did the chemical analysis of surface and groundwater and sediment samples show?

A total of 20 samples were taken on 15 June and 4 July 2023 (just after the Kakhovka disaster) in the Dnipro River, the Dnipro-Bug Estuary, and the Odesa Bay of the Black Sea.

The results of the analyses confirmed that the breach of the Kakhovka dike led to a significant deterioration in the quality of surface water, as evidenced by the comparison of chemical analysis results before and after the disaster. Compared to 2020, in 2023, ALL detected chemical pollutants were recorded at significantly higher concentrations at all sampling points.

106 organic pollutants (mainly pesticides) and their transformation products were identified in river and sea water. A new pollutant, never detected in the samples before, was found – 4-nitrotoluene (explosive residue). Concentrations of metals such as copper, arsenic and zinc in some samples exceeded toxicity thresholds.

High concentrations of the same metals, caffeine and the insecticide pyrethrin were recorded in groundwater samples taken from wells in Bilozerka and Kherson. In addition, many organic pollutants, including polyaromatic hydrocarbons typical of oil pollution, have been detected in the bottom sediments.

The possible impact of this pollution on human health and ecosystems needs to be further investigated.

Soon the EU4EMBLAS project will present the full report presenting the detailed results of the chemical analysis.

Impact on marine life in the Black Sea

As a result of the disaster, the number of blue-green algae phytoplankton increased 2000 times. In early July, the concentration of chlorophyll a in the northwestern part of the Black Sea increased to 280% compared to the regional norm. The sea turned green.

This situation led to the massive death of the main Black Sea filter, the mussel, up to 40% of the population. Instead, species that consume dead organic matter have multiplied significantly

What does our sea look like now?

In general, the Sea has recovered from the Kakhovka disaster. However, the list of chemical pollutants with concentrations close to their toxicity thresholds has changed. Now it includes pesticides, industrial chemicals, and heavy metals such as lead, copper, and zinc. There is a high chance of additional pollution of the sea during storms, when pollutants from the seabed are reintroduced into the water as a result of churning. The fact of accumulation of toxic substances in bottom fish and mussels should be also noted. One can see also the sharp increase in invasive species in the Black Sea, which are introduced, in particular, by uncontrolled discharge of ballast water from ships.