Pollution of the ocean by oil and plastic has long been recognized as one of the most pressing environmental issues of our time. Recent studies have shown that these two types of pollutants can combine, forming hybrid substances capable of traveling vast distances across the seas.

Interaction of Oil and Plastic in the Ocean

Plastic debris and petroleum products remain among the main threats to the world’s oceans. Until recently, their impact was studied mostly separately. It was believed that spilled oil rarely spread more than a few hundred kilometers from its source due to rapid natural decomposition under the influence of sunlight, waves, and microorganisms.

However, a new study published in the journal Environmental Science & Technology was the first to examine plastic and oil as interconnected pollutants. As an example, scientists analyzed the 2019 oil spill off the coast of Brazil, the source of which was never identified. In the summer of 2020, volunteers on Florida’s beaches (USA) began finding unusual plastic and glass bottles coated with a layer of black, tar-like substance.

Transoceanic Movement of Pollutants

Using mathematical modeling, researchers calculated the trajectories of these objects. It turned out that ocean currents could carry particles from the Brazilian coast to Florida in about 240 days. At the same time, a comparative chemical analysis was conducted using two-dimensional gas chromatography and ultra-high-resolution mass spectrometry, allowing for a detailed study of the pollutant’s composition.

The analysis revealed that the detected compounds were processed petroleum products, not crude oil. The absence of light fractions indicated that the pollutant had spent a long time in the open sea, losing these components through evaporation and dissolution. Meanwhile, complex hydrocarbons resistant to decomposition found in samples from both Florida and Brazil were identical, confirming their common origin.

The Emergence of a New Type of Pollutant

For the first time, it was proven that oil pollution can cross such vast transoceanic distances. Moreover, the resulting pollutant turned out to be a unique hybrid, which scientists called “oil-plastic.” The interaction of the ocean’s two main pollutants led to the emergence of a new, more persistent and mobile threat: plastic protected the oil from rapid degradation, while the oil, in turn, altered the properties of the plastic, such as its buoyancy and ability to absorb other substances.

Unknown Consequences for Ecosystems

It remains unclear how strongly such a hybrid pollutant affects marine ecosystems and the ocean as a whole during its long journeys. This is partly because monitoring of “oil-plastic” as a separate class of pollutants is practically nonexistent.