Micro-litter waste in Deception Island (South Shetland Islands, Antarctica): A multi-matrix assessment

The Southern Ocean, one of Earth's most remote regions, is impacted by anthropogenic activities, with micro-litter waste posing a significant environmental concern. This study, conducted within the Deception Island caldera, presents one of the most comprehensive assessments of marine micro-litter in Antarctica to date. We provide novel data on stranded beach micro-litter and report the first Antarctic multi-matrix assessment encompassing beach sediments, ascidians, and surface waters. Micro-litter was widespread across the inner bay intertidal, with concentrations ranging from 0 - 11.85 items kg⁻¹ (mean 1.41 ± 2.46 items kg⁻¹). The highest levels were recorded near the BAA Decepción station (5.69 ± 5.39 items kg⁻¹), driven by the abundance of red alkyd paint fragments linked to station infrastructure, indicating that local, land-based human activities represent a major waste source. Fibres dominated all matrices, although their size and polymer composition varied, reflecting matrix-specific distribution. Beach sediments were mainly characterised by cellulose and nylon fibres (1 - 1.49 mm), ascidians predominantly contained smaller cellulose fibres (0.25 - 0.99 mm), and surface waters were dominated by larger polyester fibres (3.5 - >5 mm). Our results indicate dynamic exchanges among environmental compartments, with surface waters likely serving as the primary entry pathway for micro-litter, intertidal sediments functioning as transient fragmentation zones, and benthic organisms representing biological sinks for smaller and denser waste. This study provides essential baseline data for understanding micro-litter dynamics in Antarctic coastal environments. The results also underscore the urgent need for improved waste management of local activities, especially at research facilities. • Multi-matrix study reveals widespread micro-litter in Deception Island's caldera • Higher micro-litter concentrations were observed near research stations • Fibre size and polymer type are key in differentiating micro-litter across matrices • Need for improved waste management and long-term micro-litter monitoring