Effect thresholds for the earthworm Eisenia fetida: Toxicity comparison between conventional and biodegradable microplastics

Biodegradable plastics have been developed to eliminate the progressive accumulation and ever-growing threat posed by conventional fossil fuel-derived plastics. The impact of these bioplastics, particularly in an agricultural context (e.g. biopolymer mulch films), however, remains poorly understood. In this study, we compared biotoxicity biodegradable (polylactic acid, PLA; polypropylene carbonate, PPC) non-degradable (polyethylene, PE) microplastics using a series standardized bioassays earthworm Eisenia fetida. responses studied included: avoidance behavior, mortality, biomass, reproduction responses. We incubated earthworms artificial soils amended with different concentrations microplastic (0, 0.125, 1.25, 12.5, 125, 250, 500 g kg?1) under laboratory conditions. This wide range allowed linear regression modeling estimation effect thresholds. Our results showed that concentration rather than plastic type was more important regulating soil contamination. critical threshold for contamination 40 kg?1, after which exhibit behavior. A significant reduction (EC10) number cocoons juvenile occurred at 53 kg?1 97 respectively; while no found survival until levels kg?1. Overall, two materials (PLA PPC), appeared be biofriendly PE. Based on reported up 67 conclude are now starting pose population. To better evaluate risk nondegradable plastics, further mechanistic studies how affect behavior potential long-term impacts functioning required.