POLLUTION OF THE SEA COAST WITH POLYURETHANE FOAM: SOURCES OF SUPPLY AND CONDITIONS OF DEGRADATION

The article considers the transfer and accumulation of plastic as a component of marine debris, which belongs to the current challenges of modern oceanology. Previously fieldwork was carried out to monitor the accumulation of marine debris at a sequence of spots along the Eastern coast of the Sea of Azov (within the confines of the Russian Federation). A significant presence of polyurethane foam (PUF) in plastic waste was revealed. The purpose of this work was to identify the main ways of PUF supply to the coastal zones of the Sea of Azov, as well as the likely influence of such natural factors as the level of insolation and temperature regime on the process of PUF degradation. Natural factors were considered in the context of local climatic belts. The study examines the PUF presence in the river’s coastal zone and the surface layer of the river Don. Large fragments of the MP were identified in accumulations of drifting debris. PUF micro-sized particles were detected in all water samples taken in the water area of the river Don delta and Taganrog Bay. Based on the observations from the river Don, it was shown that the main channel for the entry of PUF into the marine area and subsequent transfer to the coast are large plain rivers. The light density from the UV component of the sunlight for the moderately warm climatic belts II7 and II9 of the Sea of Azov coast has been calculated. Based on the experimental data, it was shown that PUF degrades rather rapidly under the influence of natural factors typical of the coast of the Sea of Azov. In this case, the degradation of large porous PUF fragments leads to their fragmentation into multiple microplastics and their compaction. The occurrence of such processes requires special attention from environmentalists and regulatory authorities.