Sea

“The high concentrations of chemicals are alarming, such that you would not expect in the Sea 400km from the shore. The samples these scientists take from the seafloor also contain microplastics, which means that this type of pollution has already penetrated deep into the ecosystem.”

Jaroslav Slobodnik from the EMBLAS-Plus project

Once pollution has reached the open sea, addressing it becomes significantly more challenging, primarily because it becomes highly diffuse, although it can still be traced back to some extent to a point-source. The pollution effectively spreads, being fed by rivers, coasts, and neighboring seas through processes such as advection, adsorption, and dispersion.

Some of the pollution will undergo decay or be absorbed by organisms, entering the food chain. Alternatively, it may be deposited into the depths of the Black Sea or remain suspended in the water column, depending on the chemicals' persistence. Chemicals that exhibit persistence in the environment, bioaccumulate in people and/or wildlife, and possess toxicity are referred to as PBTs (persistent, bioaccumulative, and toxic). These properties make them a threat to the health of humans and wildlife.

The polluted waters enter the Black Sea through coastal areas and rivers, and to a certain extent, from direct dumping by ships and vessels crossing the sea. According to satellite imagery analyses from the environmental watchdog organization SkyTruth, there have been over 68 multi-kilometre oil slicks detected between 2021 and 2023, which are likely the result of bilge oil dumping (done to reduce operational costs of vessels) (Sky Truth Alerts, 2023).