A review on the occurrence, detection methods, and ecotoxicity of biodegradable microplastics in the aquatic environment: New cause for concern

Biodegradable plastics (BPs) have been widely advocated as a sustainable alternative to petroleum-derived polymers, aiming to mitigate the burgeoning crisis of microplastic pollution. However, incomplete biodegradation of BPs can generate more and smaller particles, such as microplastics, which may persist in environments. Knowledge of the fate and effects of BPs, especially biodegradable microplastics, in the aquatic environment remains limited. We investigate the concentrations, detection methods, and adverse effects of biodegradable microplastics on aquatic organisms in various aquatic environments. Biodegradable microplastics, such as poly(lactic acid), polyhydroxyalkanoates, poly(butylene adipate-co-terephthalate), and poly(butylene succinate), are found in wastewater, reservoirs, and marine environments at concentrations between 0.054 and 180 μg/L. Their environmental levels are negatively correlated with their degradation capacity in water. Biodegradable microplastics adversely affect aquatic microbial communities, plant adaptability, and animal physiology, with their toxicity increasing upon degradation. This review advocates for a critical reassessment of the use, disposal, and management strategies surrounding BPs.