The slow reaction rates to chemical and photochemical degradation are well-known properties of plastics. However, large plastic surfaces exposed to environmental conditions release particles and compounds that affect ecosystems and human health. The aim of this work was to identify compounds associated with the degradation of polyethylene (PE), polystyrene (PS), and polyvinyl chloride (PVC) microplastics (markers) on silica and sand and evaluate their use to screen microplastics on natural sand. Products were identified by using targeted and untargeted LC-HRMS analysis. All polymers underwent chemical oxidation on silica. PE released dicarboxylic acids (HO₂C-(CH₂)_n-CO₂H (n = 4–30), while PS released cis/trans-chalcone, trans-dypnone, 3-phenylpropiophenone, and dibenzoylmethane. PVC released dicarboxylic acids and aromatic compounds. Upon irradiation, PE was stable while PS released the same compounds as under chemical oxidation but at lower yields. Under the above condition, PVC generated HO₂C-[CH₂–CHCl]_n-CH₂–CO₂H and HO₂C-[CH₂–CHCl]_n-CO₂H (n = 2–19) dicarboxylic acids. The same products were detected on sand but at a lower concentration than on silica due to better retention within the pores. Detection of markers of PE and PS on natural sand allowed us to screen microplastics by following a targeted analysis. Markers of PVC were not detected before or after thermal/photo-oxidation due to the low release of compounds and limitations associated with surface exposure/penetration of radiation.

中文翻译：

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塑料和微塑料的环境标志物

化学和光化学降解的反应速率缓慢是众所周知的塑料特性。然而，暴露在环境条件下的大型塑料表面会释放影响生态系统和人类健康的颗粒和化合物。这项工作的目的是识别与二氧化硅和沙子上聚乙烯 (PE)、聚苯乙烯 (PS) 和聚氯乙烯 (PVC) 微塑料（标记物）降解相关的化合物，并评估它们在筛选天然沙子上微塑料的用途。通过使用靶向和非靶向 LC-HRMS 分析来鉴定产物。所有聚合物都在二氧化硅上进行了化学氧化。 PE 释放二元羧酸 (HO ₂ C-(CH ₂ ) _n -CO ₂ H ( n = 4–30)，而 PS 释放顺/反式查耳酮、反式二苯酮、3-苯基苯丙酮和二苯甲酰甲烷。PVC 释放二元羧酸辐照后，PE 稳定，而 PS 释放出与化学氧化相同的化合物，但在上述条件下，PVC 生成 HO ₂ C-[CH ₂ –CHCl] _n -CH ₂ –CO ₂ H。和 HO ₂ C-[CH ₂ –CHCl] _n -CO ₂ H ( n = 2–19) 二羧酸在沙子上检测到相同的产物，但由于在孔隙内保留更好，其浓度低于二氧化硅。天然沙上的 PE 和 PS 标记物使我们能够通过有针对性的分析来筛选微塑料。由于化合物释放量低以及与表面暴露/渗透相关的限制，在热/光氧化之前或之后未检测到 PVC 标记物。辐射。