Aging of biodegradable blended plastic generates microplastics and attached bacterial communities in air and aqueous environments

The use of biodegradable plastics (BPs) has been widely promoted in recent years, but before their complete degradation, the phase of microplastics (MPs) is inevitable. However, little information concerning the production of MPs from blended polymers is available. This study aimed to explore the characteristics of MPs produced from blended plastics and the development of biofilms on plastic surfaces under long-term aging. Here, three blended materials (i.e., PBAT (53%)+PLA (10%)+Starch (20%), PBAT (80%)+Starch (20%), HDPE (60%)+CaCO3 (40%)) were aged for 90 days in air, deionized (DI) water and seawater. The results showed massive production of MPs (9653 +/- 3920-20,348 +/- 5857 items/g) from blended plastics accompanied by a large quantity of flocculent substances during 90 days aging period. Furthermore, the richness of bacteria communities on hydrophobic plastics (i.e., PBAT (53%)+PLA (10%)+Starch (20%), PBAT (80%)+Starch (20%)) was higher than hydrophilic plastics (i.e., HDPE (60%)+CaCO3 (40%)), and bacterial communities attached to blended plastics exhibited significantly variation with aging times. Overall, promoting the marketable application of blended plastics is risky if their environmental behavior is not effectively addressed.

Automated summary

The use of biodegradable plastics has been promoted in recent years, but the production of microplastics from blended polymers is not well studied. This study investigated the characteristics of microplastics produced from blended plastics and the development of biofilms on plastic surfaces under long-term aging. The results showed significant production of microplastics from blended plastics and variation in bacterial communities attached to the plastics.