A review on the release and environmental effects of biodegradable plastic degradation products

The increasing use of biodegradable plastics (BPs) has raised concerns about their environmental fate and potential adverse impacts on ecosystems. At present, many studies have demonstrated that BPs do not fully mineralize in the short term, and their unstable molecular structures cause them to fragment and depolymerize more rapidly in the natural environment compared with conventional plastics (CPs). This results in the generation of more micro(nano)plastics, oligomers, and monomers, posing a significant threat to ecological health. This paper provides a comprehensive review of recent advances in the ecotoxicity of these BP degradation products. Current toxicity studies have predominantly focused on short-term, high-concentration micro(nano)plastic exposures, with an emphasis on polylactic acid, while often overlooking a wider variety of oligomers and monomers. In this review, we highlight the unique characteristics and resulting potential consequences of BPs, underscoring that the behaviors and ecotoxicity of the released particles or chemicals from BPs are far more complex than those derived from CPs. Finally, recognizing the significant gaps in current research, we propose several future directions for advancing ecological risk studies of BP degradation products, emphasizing the need for a deeper understanding of their long-term impacts on environmental health.