Aging and effects of microplastics from rubber tyres in the aquatic environmentHenjak, Mia (Avtor) Kalčikova, Gabriela (Mentor) Tire wear microplasticsagingtoxicityfreshwaterMicroplastic from rubber tires known as tire wear microplastics (TWMs) are one of the major contributors to microplastic pollution. TWMs are generated by friction between tire tread and road surface. From roads they can be transported through runoff or air reaching all segments of environment. In aquatic environment they can affect various organisms, but they can also be subjected to aging process, altering initial properties of the particles and thus their fate and effects. Aging involves formation of biofilms around the particles, which is the initial step in the biodegradation process. The aim of this study was to investigate toxicity of TWMs on aquatic macrophyte Lemna minor, together with aging process and biodegradation of TWMs in natural freshwater under laboratory conditions. Aging process was evaluated by monitoring of biofilm development and its effect on TWMs surface and density. Moreover, leaching of zinc and organics was also investigated. The results showed minimal effect of TWMs on Lemna minor and thus their ecotoxic potential was assessed as low. The aging experiment revealed colonization of TWMs by microorganisms, however amount of biofilm was low and with time it started to detach from the TWMs surface. It is plausible that chemicals and heavy metals from TWMs negatively affected microorganisms. Microscopic analysis together with FTIR analysis confirmed the presence of microorganisms on the surface of TWMs. However, there was no sign of initial biodegradation of TWMs which was also confirmed with the biodegradability test. This suggests that TWMs may persist and accumulate in freshwater environments, posing a long-term environmental challenge.20232023-09-26 13:15:00Magistrsko delo/naloga150991VisID: 22655COBISS_ID: 173372675sl