Analysis of terrestrial and riverine sources of plastic litter contributing to plastic pollution in the Western Black Sea using а lagrangian particle tracking model

The present case study aims to understand the complex dynamics and implications of plastic pollution along the Bulgarian Black Sea coast through a detailed assessment of plastic marine litter. This includes examining the density of floating litter and indicators like the Pollution Load Index. The study identifies primary sources of plastic pollution, focusing on rivers and land-based settings through the Probability of Plastic Emissions. The OpenDrift Lagrangian model was used to track litter sources and patterns of transportation. Findings show that major sources include Varna, Bourgas, the Kamchia River, and transboundary transport via the Danube. These sources significantly impact the southwestern region due to anti-clockwise surface currents and eddies. Validation against field data confirmed that the Lagrangian simulations accurately reflect in-situ distribution. •Study examines plastic pollution in Bulgarian Black Sea waters from 2016 to 2021.•Coastal areas produce about 4700 tons of plastic waste annually.•Major pollution sources include Varna, Bourgas, Kamchiya River, and Danube.•Stokes drift and currents are key drivers of plastic movement over wind drift.•Improved monitoring and regional cooperation are crucial for tackling pollution.