The global plastic production has steadily increased from 1.7 million tons in 1950 to over 400 million tons in 2022, with about 60% of plastic ultimately ending up in landfills and oceans. There is also growing evidence that microplastics exert negative effects on biota and ecosystems. Biodegradable plastics may represent a safe alternative, yet their potential adverse effects have not been comprehensively analyzed. Here, we reviewed biodegradable plastics, with focus on their conversion into microplastics, their interactions with pollutants, and their combined toxicity for aquatic biota. Biodegradable plastics include polylactic acid, polyhydroxyalkanoates, polybutylene succinate, poly(butylene adipate-co-terephthalate), and poly(ε-caprolactone). We found that some biobased plastics are hardly biodegradable. Some biobased plastics are compostable but require specific environmental conditions for their biodegradation. Biobased plastics can generate microplastics when released into the environment, which can impact biota. Contrary to the common public belief, biodegradable plastics may not only originate from biosources but can be synthesized from fossil fuels. Microplastics originating from biodegradable plastics can interact with pollutants, adsorbing and transporting these pollutants, resulting in synergistic or antagonistic effects on exposed organisms. Biofilm formation on microplastics impacts their degradation and pollutant interactions.

全球塑料产量从 1950 年的 170 万吨稳步增长到 2022 年的 4 亿吨以上，其中约 60% 的塑料最终进入垃圾填埋场和海洋。越来越多的证据表明微塑料对生物群和生态系统产生负面影响。可生物降解塑料可能是一种安全的替代品，但其潜在的不利影响尚未得到全面分析。在这里，我们回顾了可生物降解塑料，重点关注它们转化为微塑料、它们与污染物的相互作用以及它们对水生生物的综合毒性。可生物降解塑料包括聚乳酸、聚羟基链烷酸酯、聚丁二酸丁二醇酯、聚(己二酸-对苯二甲酸丁二醇酯)和聚(ε-己内酯)。我们发现一些生物基塑料很难生物降解。一些生物基塑料是可堆肥的，但需要特定的环境条件才能进行生物降解。生物基塑料释放到环境中时会产生微塑料，从而影响生物群。与公众的普遍看法相反，可生物降解塑料可能不仅源自生物来源，而且可以从化石燃料合成。源自可生物降解塑料的微塑料可以与污染物相互作用，吸附和运输这些污染物，对暴露的生物体产生协同或拮抗作用。微塑料上生物膜的形成影响其降解和污染物相互作用。