School of Urban Planning and Design, Peking University Shenzhen Graduate School, Shenzhen 518055, China.
School of Urban Planning and Design, Peking University Shenzhen Graduate School, Shenzhen 518055, China.
Sci Total Environ. 2022 May 1;819:152041. doi: 10.1016/j.scitotenv.2021.152041. Epub 2021 Nov 29.
Agricultural plastic film (APF) is widely used in modern agriculture. Under natural environmental conditions, the structure, surface properties and mechanical properties of APFs change because of sunlight, wind and other factors and gradually break into debris, resulting in the generation of microplastics (MPs). Studies have reported that the MPs concentration in soil is positively correlated with the use intensity and duration of APFs. Unfortunately, to the best of our knowledge, no method to measure the emissions of in situ APFs has been developed. In this study, the effects of mechanical abrasion driven by wind on MPs fragmentation by polyethylene (PE) and polyvinyl chloride (PVC) APFs with the increase of exposure time were investigated. Meanwhile, based on the release rate model of PS fragmented MPs under natural sunlight, a modified model to quantify the effect of ultraviolet (UV) radiation exposure duration on the production of APF fragmented MPs was developed. Based on these models, the amount of MPs produced from APFs in farmland in China was estimated. The national annual MPs mass emissions from APFs in agricultural soil were approximately 5 × 10 to 6.8 × 10 tons in 2018 due to wind and 6.5 × 10 tons due to sunlight, and the total emission level due to both wind and sunlight was 5.1 × 10 to 7.0 × 10 tons. Compared with that of wind, the contribution of UV radiation to MPs emission is smaller. Our estimates are comparable to data reported in previous studies, indicating that our models have good practical applications and are of great significance for predicting MPs production from APFs in farmland.
农用塑料薄膜（APF）在现代农业中被广泛使用。在自然环境条件下，APF 的结构、表面性能和机械性能会因阳光、风和其他因素而发生变化，并逐渐分解成碎片，从而产生微塑料（MPs）。研究报告称，土壤中 MPs 的浓度与 APF 的使用强度和持续时间呈正相关。不幸的是，据我们所知，目前还没有开发出测量原位 APF 排放的方法。在这项研究中，研究了风驱动的机械磨损对聚乙烯（PE）和聚氯乙烯（PVC）APF 中 MPs 破碎的影响，同时考察了暴露时间的增加对 MPs 破碎的影响。此外，基于 PS 碎片 MPs 在自然阳光下降解的释放率模型，开发了一个修正模型来量化紫外线（UV）辐射暴露时间对 APF 碎片 MPs 生成的影响。基于这些模型，对中国农田中 APF 产生的 MPs 量进行了估算。由于风和阳光的作用，2018 年农业土壤中 APF 每年向大气排放的 MPs 质量约为 5×10 到 6.8×10 吨，由于阳光的作用每年向大气排放的 MPs 质量约为 6.5×10 吨，风和阳光共同作用导致的总排放量约为 5.1×10 到 7.0×10 吨。与风相比，UV 辐射对 MPs 排放的贡献较小。我们的估计与之前研究报告的数据相当，表明我们的模型具有良好的实际应用价值，对预测农田中 APF 产生的 MPs 具有重要意义。
