Exploring Environmental Behaviors and Health Impacts of Biodegradable Microplastics

Biodegradable plastics (BPs) are promoted as eco-friendly alternatives to conventional plastics. However, compared to conventional microplastics (MPs), they degrade rapidly into biodegradable microplastics (BMPs), which may lead to a more significant accumulation of BMPs in the environment. This review systematically compares BMPs and MPs, summarizes current knowledge on their environmental behaviors and impacts on ecosystems and human health, and offers recommendations for future research. BMPs are detected in water, sediments, indoor dust, food, marine organisms, and human samples. Compared to MPs, BMPs are more prone to environmental transformations, such as photodegradation and biodegradation, which results in a shorter migration distance across different matrices. Like MPs, BMPs can adsorb pollutants and transport them into organisms, enhancing toxicity and health risks through the Trojan horse effect. Studies indicate that BMPs may negatively impact terrestrial and aquatic ecosystems more than MPs by disrupting nutrient cycling and inhibiting plant and animal growth. <i>In vivo</i> and <i>in vitro</i> research also shows that BMP degradation products increase bioavailability, exacerbating neurotoxicity and overall toxicity. However, findings on BMPs' environmental and health effects remain inconsistent. Further evaluation of the trade-offs between BMP risks and their biodegradability is needed to address these uncertainties.