The combined pollution of microplastics (MPs) and arsenic (As) in paddy soils has attracted more attention worldwide. However, there are few comparative studies on the effects of biodegradable and conventional MPs on As migration and transformation. Therefore, conventional (polystyrene, polyethylene, polyvinyl chloride) and biodegradable (polybutadiene styrene, polylactic acid, polybutylene adipate terephthalate) MPs were selected to explore and demonstrate their influences and mechanism on As migration from paddy soils to overlying water and As speciation transformation through microcosmic experiment with measuring the changes of As chemical distribution, physicochemical indexes and microbial community in paddy soils. The results showed that biodegradable MPs enhanced As migration and transformation more effective than conventional MPs during 60 d. Biodegradable MPs indirectly increased the content of As(Ⅲ) and bioavailable As by changing the microbial community structure and affecting the biogeochemical cycles of carbon, nitrogen, sulfur and iron in soils, and promoted the As migration and transformation. PBS showed the strongest promoting effect, transforming to more As(Ⅲ) (11.43%) and bioavailable As (4.28%) than control. This helps to a better understanding of the effects of MPs on As biogeochemical cycle and to clarify the ecological and food safety risks of their combined pollution in soils.

中文翻译：

---

可生物降解微塑料对水稻土中砷迁移转化的影响：与常规微塑料的对比分析

稻田土壤中微塑料（MPs）和砷（As）的联合污染引起了全世界的广泛关注。然而，关于可生物降解和常规MP对As迁移和转化影响的比较研究却很少。因此，选择常规（聚苯乙烯、聚乙烯、聚氯乙烯）和可生物降解（聚丁二烯苯乙烯、聚乳酸、聚己二酸对苯二甲酸丁二酯）MPs，通过微观探索和论证它们对稻田土壤中砷迁移到上覆水体以及砷形态转化的影响和机制。测定水稻土中砷化学分布、理化指标和微生物群落变化的试验。结果表明，在 60 d 内，可生物降解 MPs 比传统 MPs 更有效地促进 As 迁移和转化。可生物降解MPs通过改变微生物群落结构、影响土壤中碳、氮、硫、铁的生物地球化学循环，间接增加As(Ⅲ)和生物有效As的含量，促进As的迁移和转化。 PBS表现出最强的促进作用，比对照转化更多的As(Ⅲ)(11.43%)和生物可利用的As(4.28%)。这有助于更好地了解MPs对As生物地球化学循环的影响，并阐明其在土壤中的综合污染的生态和食品安全风险。