Environmental degradation and loss of polyester marker flags are major sources of localized plastic pollution in the Antarctic

Reducing plastic pollution of the Antarctic environment is a priority for the Antarctic Treaty Consultative Meeting (ATCM) and Council of Managers of National Antarctic Programs (COMNAP). Polyester flags mounted on bamboo poles are commonly used by governmental and tourism operators as markers of safe travel routes, scientific equipment and depots in snow-covered areas. Polar environmental conditions can rapidly degrade polyester flags, resulting in plastic release into the environment. This study aimed to quantify the degree of polyester flag degradation and investigate alternative, less polluting flag types. Pre-weighed flags of four types - standard polyester, hemmed polyester, organic cotton canvas and Ventile (a tight-weave cotton fabric) - were deployed close to Rothera Research Station, Antarctic Peninsula, from February 2023 to January 2024, after which any changes in weight were recorded. On average, each standard polyester flag lost 25.5% (± standard error (SE) 0.8) of its weight, equating to the release of 8.3 g of plastic into the environment; however, hemming the flag reduced this loss to 13.3% (± SE 3.7). Ventile was almost as durable as unhemmed polyester (loss of 26.9% (± SE 3.8)), whereas cotton canvas was the least durable (loss of 44.1% (± SE 4.3)). Switching from standard polyester to Ventile flags would prevent the annual release of > 8.3 kg of plastic into the environment around Rothera Research Station, and potentially ~300 kg across all Antarctic operator activities. This is a conservative estimate compared to a potential additional 800 kg of plastic that could be lost to the environment due a high proportion of deployed flags not being recovered. Further investigations to identify cost-effective sustainable flag materials are recommended to comply with ATCM and COMNAP recommendations concerning plastic management in Antarctica.