Effect of microplastics in sludge impacts on the vermicomposting

To investigate the effect of microplastics (MPs) particles in vermicomposting, polyethylene (PE) particles added into sludge. Results showed that the vermicomposting with high MPs addition obtained lower removal efficiencies for organics than the vermicomposting with low MPs addition. The content of DOC and NH₄⁺-N in M₄ reactor (with the highest MPs addition) at 80 days was 8.4 mg/kg and 74.2 mg/kg, respectively. The pH, C/N, electrical conductivity (EC), and germination index (GI) results showed that the addition amount of MPs was directly proportional to the negative effect of composting. The negative effect mainly occurred after 20 days of composting. High MPs addition resulted in apparent oxidative stress and neurotoxicity on earthworm, the values of catalase (CAT) and acetylcholine esterase (AChE) in M₄ reactor increased by 2.03 times and 1.60 times. The bacteria in M₄ were more barren and lower in terms of diversity.