Are bioplastics an ecofriendly alternative to fossil fuel plastics?

More than 390 million tons of fossil fuel plastics have been produced in 2022, and plastic pollution has become a major health issue for humans and ecosytems. Fossil fuel plastics are commonly recalcitrant, thus accumulating in the environment. Fossil fuel plastics also contains toxic chemicals that leach out to waters and are ingested by living organisms. Morevover, recent research has revealed that plastic fragmentation has led to an unprecedented global contamination by microplastics and nanoplastics, with yet poorly adverse impacts on life. In this context, bioplastics, that we will refer to as biobased plastics in this contribution, appear as a promising alternative because bioplastics are carbon neutral and most of them are biodegradable. As a consequence, the world bioplastic production has increased from 1.8 million tons in 2021 to 2.22 million tons in 2022. However, the complete degradation of most bioplastics in the environment remains difficult. Here we compare bioplastics with fossil fuel plastics with focus on life cycle assessment, biodegradability and compostability, end-of-life options, fragmentation into microplastics, and microplastic pollution of soil and aquatic systems. Overall, we observe that bioplastics are not necessarily more ecofriendly than fossil fuel plastics. Technical and cost limitations still prevent bioplastics from fully substituting fossil fuel plastics. For instance, there is still no widely accepted methodology to compare the potential environmental footprint between fossil fuel plastics and bioplastics. Some microorganisms can degrade plastics under laboratory conditions, but both fossil fuel plastics and bioplastics degradation can be limited under environmental conditions. End-of-life options for both fossil fuel and bioplastics are similar, except for composting. Both fossil fuel plastics and bioplastics contribute to environmental pollution by forming microplastics and acting as vectors for environmental pollutants. Overall, the study found that bioplastics and fossil fuel plastics have similar negative effects and both are comparable in terms of their vector role, formation of microplastics, and toxicity to biota. To conclude, the common belief that bioplastics have less or no negative impact on the environment may not be entirely accurate.