Introduction
In recent years, awareness of the risks of plastics entering the environment has increased significantly, given their widespread use, durability and flexibility, as well as their potential to contain or absorb pollutants (MacLeod et al. Reference MacLeod, Arp, Tekman and Jahnke2021). Consequently, plastic waste in the oceans and microplastics have been identified as some of the most important global environmental problems. The Antarctic and the surrounding Southern Ocean are no longer exempt from global plastic pollution (De la Torre et al. Reference De la Torre, Santillán, Dioses-Salinas, Yenney, Toapanta and Okoffo2024), which is why the issue has been formally raised as a concern within the Antarctic Treaty System (ATS 2019).
The plastic waste floating in the Southern Ocean and washing up on the coasts of Antarctica mainly consists of packaging materials, plastic bottles and fishing-related items such as nets, ropes and buoys (Waluda et al. Reference Waluda, Staniland, Dunn, Thorpe, Grilly, Whitelaw and Hughes2020). Potential sources of this pollution include local activities, such as fisheries in the Southern Ocean, ship traffic (cruise, research, supply or patrol vessels) and the operation of Antarctic stations (Waller et al. Reference Waller, Griffiths, Waluda, Thorpe, Alamo and Moreno2017). However, the latter now plays only a minor role due to their generally good waste management, although exceptions have been reported (Braun et al. Reference Braun, Mustafa, Nordt, Pfeiffer and Peter2012). A major source of plastic in the Antarctic is transport by ocean currents from lower latitudes, particularly in the Scotia Arc region (Waller et al. Reference Waller, Griffiths, Waluda, Thorpe, Alamo and Moreno2017). The Antarctic Circumpolar Current surrounding the Antarctic represents a biogeographical barrier against influences from lower latitudes to a certain extent but does not completely prevent the north-south spread of natural and anthropogenic materials drifting in the sea (Fraser et al. Reference Fraser, Morrison, Hogg, Macaya, van Sebille and Ryan2018). Striking examples of global input include the discovery of primary pellets (nurdles) on the Antarctic coast (Lozoya et al. Reference Lozoya, Rodríguez, Azcune, Lacerot, Pérez-Parada and Lenzi2022), highlighting the vulnerability of the region to pollution sources originating outside the Southern Ocean.
The study area is Fildes Peninsula, located in the south-west of King George Island, South Shetland Islands, in the Maritime Antarctic (Fig. 1). This area hosts the highest concentration of research stations in the Antarctic and experiences comparatively intense human activity (Braun et al. Reference Braun, Mustafa, Nordt, Pfeiffer and Peter2012), making it a key area for research and monitoring of the presence and impacts of anthropogenic litter. Given its combination of local pressures and potential exposure to long-range transport, Fildes Peninsula provides an ideal setting for detecting emerging or previously undocumented types of pollutants.
Location of the study area on Fildes Peninsula (Fildes Pen.).
Through initiatives developed by various research groups in this area (Peter et al. Reference Peter, Buesser, Mustafa and Pfeiffer2008, Braun et al. Reference Braun, Mustafa, Nordt, Pfeiffer and Peter2012, Reference Braun, Grämer and Hertel2024, Lozoya et al. Reference Lozoya, Lacerot, De Feo, Krojmal, González-Pleiter, Ramos and de Teixeira2024, Vesman et al. Reference Vesman, Ershova, Litina and Chukmasov2024) and based on the spatial coordination of sampled areas and data exchange over recent years, the occurrence of plastic biomedia in Antarctica is documented here for the first time. This research expands current knowledge on the diversity of plastic items reaching Antarctic environments and underscores the need for the targeted monitoring of novel pollutants.
Results
During the 2022/2023 season, in an opportunistic inspection of a 2 m-wide drift line for anthropogenic material, three conspicuous cylindrical, cogwheel-like plastic objects, each with a diameter of 1.0 cm, were found for the first time (Fig. 2). Additional items were documented in the following seasons of 2023/2024 (three items) and 2024/2025 (one item) during systematic annual surveys at selected beach sections (Braun et al. Reference Braun, Grämer and Hertel2024). A total of seven of these objects have been recovered to date, all from sandy beach sections along the west coast of Fildes Peninsula, directly adjacent to Drake Passage (Fig. 1). Five of them were confirmed as polyethylene (PE)/polyethylene-vinyl acetate (PEVA) plastics through attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) using a Shimadzu IRSpirit spectrometer, operated with LabSolution IR software (Shimadzu Corporation). Spectra were collected at a resolution of 4 cm-1, with a minimum match threshold of 70% for polymer identification (Fig. 2). The cogwheel-like plastic objects were identified as plastic biomedia or biocarriers used in the biological treatment stage of sewage treatment plants.
a. & b. Plastic biomedia/biocarriers found on sandy beaches of Fildes Peninsula, King George Island. Polymer identification by attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) confirmed these as being polyethylene-vinyl acetate (PEVA; c.) and polyethylene (PE; d.).
Discussion
The input and accumulation of marine debris is strongly dependent on oceanography, wind patterns and shoreline geomorphology (Gallagher et al. Reference Gallagher, Cimino, Dinniman and Lynch2024). Previous studies showed that, as a result of long-standing deficiencies in the waste management of the research stations on Fildes Peninsula, there is a considerable amount of litter in the environment (Peter et al. Reference Peter, Buesser, Mustafa and Pfeiffer2008). However, the prevailing strong westerly winds, combined with the local topography, minimize the likelihood of litter input from these local stations, all of which are located on the east coast of Fildes Peninsula. Hence, the anthropogenic material on the western coast, where the plastic biomedia were found, consists almost exclusively of marine debris. It is not known to what extent the distribution of these objects found in the study area is underestimated, as most of the beaches are covered with coarse gravel, making it difficult to detect smaller objects. This physical constraint highlights the need for harmonized monitoring approaches that explicitly account for the detectability of small and lightweight debris types.
Biomedia or biocarriers are floating high-density PE (HDPE)/PE plastic objects used in large numbers to treat wastewater in the moving bed bioreactor process by increasing the surface area available for colonization by microorganisms and thus increasing the efficiency of wastewater treatment (Tunstad Reference Tunstad2012). In the event of biocarrier leaks triggered by heavy rainfall events, these objects can enter the oceans via rivers and thus contribute to additional plastic pollution of the environment (Tunstad Reference Tunstad2012, Bencivengo et al. Reference Bencivengo, Barreau and Verdet2023). Given their neutral to slightly positive buoyancy and small size, biomedia are particularly prone to long-distance transport once released into the environment.
The pollution of the coasts with plastic biomedia first attracted attention in 2007 when large numbers were found along the French Atlantic coast (Bailly et al. Reference Bailly, Barreau, Bencivengo and Verdet2018). Subsequent occurrences have been reported from the Atlantic coasts of Spain and Portugal, as well as Denmark, the UK, the Netherlands and Switzerland and from the Mediterranean coasts of France, Spain, Italy, Corsica, Morocco, Algeria and Tunisia (Bailly et al. Reference Bailly, Barreau, Bencivengo and Verdet2018). They are also considered widespread in the coastal areas of the north-east Atlantic (Tunstad Reference Tunstad2012). In response to their increasing prevalence and growing recognition as a source of plastic pollution, plastic biomedia were included in the beach litter monitoring of the Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR Convention) in 2021 (OSPAR 2024). Further research is needed to determine the extent to which plastic biomedia are used in the Southern Hemisphere or even in locations near the Southern Ocean. However, a recent publication reports the presence of plastic biomedia on Brazilian beaches in 2023 (Nagai et al. Reference Nagai, Mesquita, Alvarenga and Nascimento2024). Currently, no information is available regarding the use of such materials in wastewater treatment plants at Antarctic stations. This gap underscores the need for improved reporting and transparency regarding the wastewater treatment technologies used in polar research facilities.
The report presented here is the first ever documented evidence of plastic biomedia in the Antarctic despite many recent studies on marine debris on Antarctic coasts (e.g. Anfuso et al. Reference Anfuso, Bolívar-Anillo, Asensio-Montesinos, Portantiolo Manzolli, Portz and Villate Daza2020, Waluda et al. Reference Waluda, Staniland, Dunn, Thorpe, Grilly, Whitelaw and Hughes2020, Albarrán et al. Reference Albarrán, Alfonso, Fógel, Rozas Sía, Abbeduto, Casaux and Juáres2024). This means that these objects have a much wider global distribution than was understood before, and they represent a novel pollutant to the Antarctic. Consequently, this research provides further evidence of the long-distance transport of marine debris through the Antarctic Circumpolar Current. The detection of biomedia in this region reinforces the notion that the Antarctic is becoming increasingly exposed to pollution sources originating outside the Southern Ocean, despite the partial barrier effect of the Antarctic Circumpolar Current (Lozoya et al. Reference Lozoya, Rodríguez, Azcune, Lacerot, Pérez-Parada and Lenzi2022). Further studies on marine debris could provide more information on the occurrence and distribution of plastic biomedia in the Antarctic, which could be submitted to the Scientific Committee on Antarctic Research (SCAR) Plastics group’s layer on SOOSmap and the Surfrider Foundation database. The Scotia Arc, with the archipelagos of the South Georgia, South Sandwich, South Orkney and South Shetland islands, is particularly suitable for monitoring marine debris from lower latitudes into the Antarctic due to its relative proximity to South America (do Sul et al. Reference Sul, Barnes, Costa, Convey and Campos2011). Information on specific types of marine debris, such as lost fishing gear, plastic bottles or biomedia, can help to shed light on temporal trends, source attributions and ecological implications. Expanding coordinated monitoring networks across these regions would therefore contribute substantially to understanding the pathways, persistence and emerging categories of plastic pollution in Antarctic environments.
Acknowledgements
We would like to thank the Instituto Antártico Uruguayo and especially the BCAA staff of the XXXV and XXXVI Uruguayan Antarctic expeditions (2023–2025). We would also like to express our gratitude to P. Chukmasov. CB and HG want to thank Fuerza Aérea Uruguaya, Aerovías DAP, ANTARCTICA XXI and Polartours for logistical support. We especially thank F. Hertel from the German Environment Agency for the valuable support over many years. Finally, we thank the anonymous reviewer who contributed to improving the quality of this work.
Financial support
The fieldwork of the CB and HG was commissioned by the German Environment Agency (FKZ 3721 12 201 0 and FKZ 3724 1870 10). JPL, GL and FTdM would also like to acknowledge the International Atomic Energy Agency (IAEA) for the support received within REMARCO, the RLA7028 and the NUTEC Plastics initiatives, as well as the SNI and PEDECIBA (Program for the Development of Basic Sciences).
Competing interests
The authors declare none.
Author contributions
Authors are listed in order of contribution: CB developed the original ideas presented in the manuscript. BDF, CB, EK, FTdM, GL and JPL participated in the investigation and field operations. Polymer analysis was performed by EK and BDF. CB wrote the first draft of the paper, and further drafts were written by all the authors.
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