Latex balloons do not degrade uniformly in freshwater, marine and composting environments

• Latex balloons act like plastic in the environment. We quantified balloon degradation freshwater, saltwater and compost. Degradation was equivocal: retained original size shape. Mass change, elasticity FTIR spectra varied among water compost treatments. Balloons will continue to persist as anthropogenic debris threaten wildlife. are a poorly-studied aspect of pollution that affects wildlife survival, aesthetic value waterways, may adsorb leach chemicals. Pure latex needs be vulcanised with sulphur requires many additional compounds manufacture high quality balloons. Yet, often marketed “biodegradable”, which is confusing consumers. Due persistence environment lethal, documented threat wildlife, behaviours were industrial Using metrics mass ultimate tensile strength (UTS) superficial composition via attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), for 16 weeks. Overall, their shape size. Composted lost 1–2% mass, but some freshwater gained likely due osmotic processes. Balloons’ UTS decreased from 30.7 ± 10.8–9.5 4.1 Newtons water, remained constant (34.3 13.4 N) ATR-FTIR illustrated compositional temporal differences between Taken together, did not meaningfully degrade saltwater, or indicating when released into environment, they contribute litter pose ingest them.