环境科学  2025, Vol. 46 Issue (3): 1850-1860   PDF    
引用本文
杨妮娜, 左剑恶, 张艳艳, 门聪. 塑料老化过程及其环境危害研究进展[J]. 环境科学, 2025, 46(3): 1850-1860.
YANG Ni-na, ZUO Jian-e, ZHANG Yan-yan, MEN Cong. Research Progress on Plastic Aging Processes and Their Environmental Hazards[J]. Environmental Science, 2025, 46(3): 1850-1860.
塑料老化过程及其环境危害研究进展
杨妮娜1, 左剑恶1,2, 张艳艳1, 门聪3     
1. 清华大学环境学院, 环境模拟与污染控制国家重点联合实验室, 北京 100084;
2. 清华大学深圳国际研究生院, 深圳 518055;
3. 北京交通大学土木建筑工程学院, 水中典型污染物控制与水质保障北京市重点实验室, 北京 100044
收稿日期: 2024-04-06; 修订日期: 2024-04-27
基金项目: 深圳市科技创新委员会稳定支持项目（WDZC20200819163549002）
作者简介: 杨妮娜（2001~）, 女, 硕士研究生, 主要研究方向为微塑料, E-mail：ynn22@mails.tsinghua.edu.cn
通信作者: 左剑恶, E-mail：jiane.zuo@mail.tsinghua.edu.cn
摘要: 塑料污染已成为全球性的环境问题, 对生态系统和人类健康构成了显著威胁. 塑料老化是一个持续的动态过程, 此过程中会有各种尺寸级别的塑料产生与存在, 如：大型塑料、微塑料及纳米塑料. 无论哪个尺寸级别的塑料, 其都会持续破碎并释放塑料添加剂及其他溶解性产物. 此外, 由于分子组成与结构相同, 微纳米塑料与宏观塑料的老化机制及呈现的老化特性相似, 但颗粒的尺寸越小危害越大. 为加深对塑料环境效应的了解, 聚焦于塑料从初始形态到老化降解的整个动态过程, 综述了塑料在此过程中所涉及的老化机制、特性变化及释放产物. 以上产物包括大型塑料、微纳米塑料、塑料添加剂及其他溶解性产物. 同时, 归纳了塑料老化实验的相关研究及主要结论, 并进一步探讨了影响塑料添加剂浸出和微纳米颗粒释放的因素. 最后, 总结了塑料老化产物可能造成的环境危害.
关键词: 塑料      老化      环境危害      微纳米塑料      添加剂     
Research Progress on Plastic Aging Processes and Their Environmental Hazards
YANG Ni-na1 , ZUO Jian-e1,2 , ZHANG Yan-yan1 , MEN Cong3     
1. Joint State Key Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China;
2. Tsinghua Shenzhen International Graduate School, Shenzhen 518055, China;
3. Key Laboratory of Typical Pollutants Control and Water Quality Guarantee for Water Transport in Beijing, School of Civil and Environmental Engineering, Beijing Jiaotong University, Beijing 100044, China
Abstract: Plastic pollution has become a global environmental issue, posing notable threats to ecosystems and human health. Plastic aging is a continuous dynamic process, during which plastics of various sizes are produced and exist, such as large plastics, microplastics, and nanoplastics. Regardless of the size, plastics continuously fragment and release plastic additives and other soluble products. Moreover, due to the same molecular composition, the aging mechanisms and characteristics of micro and nanoplastics are similar to those of macroplastics. However, the smaller the particle size, the greater the potential harm. To enhance understanding of the environmental effects of plastics, this review focused on the entire dynamic process from the initial form of plastics to their degradation and summarized the aging mechanisms involved, changes in properties, and the products released during this process. These products include macroplastics, micro and nanoplastics, plastic additives, and other soluble substances. The paper also summarized relevant studies and main conclusions on plastic aging experiments, further exploring factors that influence the leaching of plastic additives and the release of micro and nanoplastic particles. Finally, it provided a summary of the environmental hazards that were caused by plastic aging products.
Key words: plastics      aging      environmental hazards      micro and nanoplastics      additives     

自1950年以来, 塑料制品因其成本效益和易用性而在全球范围内得到广泛应用[1]. 目前, 全球每年生产的塑料总量已迅速增至近4亿t, 预计到2050年可能会翻一番[2]. 然而, 由于缺乏有效的管理政策和措施, 约60%的塑料被丢弃至自然环境中, 其环境影响日益显著, 已成为全球关注的焦点[3]. 常见塑料及其英文缩写见表 1. 塑料一旦进入环境, 会在多种环境因素的作用下老化. 塑料老化是指在非生物（机械磨损、光氧化、热氧化）和生物降解作用下, 塑料失去完整性并释放不同尺寸级别的颗粒[4]. 根据尺寸, 塑料可分为宏观塑料（>25 mm）、中观塑料（5~25 mm）、微塑料（1 µm~5 mm）和纳米塑料（1<µm）[5]. 微纳米塑料由于尺寸小而易吸附环境中的有毒物质, 形成的复合污染物易被生物所摄取, 并广泛分布于各种环境介质中, 对整个生态系统构成威胁[6]. 塑料制品普遍含有用于增强性能和满足特定需求的添加剂, 以上大多数不与塑料化学结合. 在老化过程中, 添加剂和其他溶解性产物会逐渐从塑料中浸出, 使塑料制品成为以上污染物的潜在来源.

表 1 常见塑料的英文缩写及玻璃化转变温度值（Tg） Table 1 Abbreviations and glass transition temperature values (Tg) of common plastics

现有的综述文献主要集中于微塑料的老化, 但往往忽略了一个事实：环境中的微塑料主要源自较大塑料物品的破碎, 微塑料只是塑料的存在形态之一. 本文以塑料从初始形态到老化降解的整个动态过程为重点, 详细论述了塑料在此期间可能经历的老化机制、物理化学性质变化、各类降解产物及其危害, 以期加深对塑料环境效应的了解.

1 塑料老化机制

塑料老化可以通过多种机制进行, 包括非生物降解和生物降解. 虽然生物降解对于降低环境中的污染物至关重要, 但由于聚乙烯（PE）、聚丙烯（PP）、聚苯乙烯（PS）和聚氯乙烯（PVC）等大多数塑料具有高相对分子质量和缺乏官能团的结构特征, 其生物降解受到限制[7, 8]. 因此, 以上聚合物必须先经过非生物降解过程, 形成更小的片段后, 才能被细胞吸收并进一步降解[9].

1.1 非生物降解

环境中塑料的非生物降解作用主要包括光降解、热氧化和机械力作用, 其中光降解是最常见的非生物降解途径. 塑料的光降解过程可分为3个阶段：引发（聚合物链的断裂和自由基的形成）、扩散（自氧化）和终止（形成惰性产物）[10]. 塑料的热降解过程与光降解过程相似, 不同之处在于热是热降解反应的引发剂, 聚合物吸收足够的热量后发生链断裂并产生自由基[11]. 在环境中, 塑料的热降解通常与其他降解作用同时发生. 如在光氧化和生物堆肥过程中, 热量的释放与积聚可引发热降解, 而温度的上升则会加速紫外线的作用和生物降解过程[12, 13]. 机械力的降解作用是指在外力作用下塑料的分解过程. 在自然环境中, 这种外力可能来自波浪、潮汐、岩石和沙子的碰撞及磨损.

1.2 生物降解

塑料的生物降解包括两个方面：一是生物通过咬、咀嚼或消化对塑料进行物理降解；二是生物分泌的细胞外酶将大分子聚合物分解成小分子产物, 以上小分子物质进入细胞并通过胞内酶作用最终转化为CO2和H2O[14]. 根据塑料中是否存在酯或酰胺基团, 它们可分为可水解或不可水解聚合物. 对于可水解聚合物, 如聚对苯二甲酸乙二醇酯（PET）、聚酰胺（PA）和聚氨酯（PU）, 由于存在自然界中纤维素和蛋白质降解的生物酶路径, 较易被生物降解[14]. 然而, 对于PE、PP、PS和PVC等不可水解聚合物, 其生物降解较为困难. 为应对这一挑战, 研究人员已经开始筛选能够降解以上聚合物的微生物. 例如, Auta等[15]从红树林沉积物中分离出的红球菌株36和芽孢杆菌株27, 分别使PP的重量减轻了6.4%和4.0%. 另一项研究从石油污染的土壤中分离出了一种独特的Raoultella sp. DY2415菌株, 这种菌株具有分解PE和PS的能力[16]. 尽管目前已陆续发现能够降解各种塑料类型的微生物, 但以上微生物对塑料的生物降解效率仍然非常有限.

迄今为止, 许多学者已经针对不同机制下塑料的老化情况进行了研究（表 2）. 结果表明, 通过生物和非生物的降解作用, 塑料的表面特征会发生变化[17], 并释放出一系列颗粒态和溶解态产物（图 1）.

表 2 塑料老化过程相关研究 Table 2 Study on aging process of plastics

图 1 塑料污染物的老化过程 Fig. 1 Aging processes of plastic contaminants

2 老化后塑料的特性变化

老化会导致聚合物表面氧化和链断裂, 从而改变塑料的外观和质地、物理特性、化学结构与成分以及化学特性等. 以上变化有利于生物膜在塑料表面的形成.

2.1 物理特性

塑料表面的颜色通常随着老化的进行逐渐加深, 呈现出黄色、褐色或黑色[34, 35], 这是由于氧化过程中醌类或其他含氧基团的增加影响了塑料对光的吸收[34, 36]. Song等[18]对聚苯乙烯泡沫（EPS）进行了为期3个月的户外老化实验, 结果发现EPS样本出现收缩、变黄并变得易碎等现象.

老化后的塑料表面呈现出几种典型的退化模式, 如颗粒氧化、裂纹及片状结构的形成[37]. 这反映了塑料从表面到内部的结构退化, 这种退化会增加塑料的粗糙度以及比表面积, 影响其吸附性能[4, 38]. 老化时间对塑料所呈现的退化特征具有重要影响. 有研究表明, 经过3个月的紫外照射, PE颗粒表面并未出现裂纹[4]；然而, 当照射时间延长至6个月后, 可以观察到较明显的裂纹和裂缝[39]. 通常, 塑料的退化模式表现为初期的颗粒氧化和后期的裂纹扩展或片状生成. 具有裂纹或片状的塑料更易受外界环境的影响, 释放出更小尺寸的碎片颗粒[4, 37].

老化过程会影响塑料的结晶度, 结晶度是用来表示聚合物中结晶区域所占比例的物理量, 结晶度的增加往往意味着塑料会变得更加脆弱[40]. Rouillon等[41]对PP进行辐照处理后观察到其结晶度有所增加. 这是因为非结晶区域会优先降解, 产生的小分子聚合物重新排列并形成更紧密的结构[40, 42]. 然而, 在某些情况下, 共聚物的结晶度在降解后会降低[43], 这可能是新物质的产生破坏了部分结晶区域.

塑料的力学和热学性能可能会因老化后聚合物的解聚而恶化[44, 45]. Iñiguez等[46]研究了4种塑料（尼龙、PE、PET和PP）在海洋环境中暴露6.5个月后的变化, 发现以上塑料的热性能和机械性能均受到影响, 表现为弹性降低和刚性增强. 另一项研究也证实了室外老化1.5 a的PP的抗拉强度较原始状态有所降低, 并提出其抗拉强度的变化与平均相对分子质量有关[47].

2.2 化学特性

光氧化会破坏聚合物中的碳氢键（C—H）和碳碳键（C—C）, 导致含氧官能团如羰基、羟基和羧基的增加[48, 49]. 以上含氧官能团的增加使得聚合物中的氧碳比（O/C）升高. 目前, 大多数研究使用由傅里叶变换红外光谱仪（FTIR）测定的羰基指数（CI）和由X射线光电子能谱（XPS）测定的O/C来评估塑料的风化程度[50]. 含氧官能团的种类、数量及出现顺序与聚合物类型和老化条件有关[51]. 如在水环境中, 由于氢原子较多, 酚羟基优先在PS微塑料表面形成；而在干燥环境中, 羰基更容易形成[52]. 聚合物在老化过程中发生的链断裂会导致相对分子质量降低[53, 54]. Halle等[55]对北大西洋亚热带环流中的PE塑料进行收集, 检测发现其平均摩尔质量（Mn）远小于原始PE塑料颗粒.

含氧官能团的增加不仅会提高塑料的亲水性[56, 57], 还可能改变其表面电荷特性[58, 59]. 以上性质的改变会影响塑料的环境行为[60, 61]. 例如, 随着塑料亲水性和极性的增加, 其对疏水性有机污染物的吸附能力会减弱, 而对亲水性污染物的吸附能力则会增强. Fu等[62]的研究发现, 老化后塑料的零电荷点降低, 其表面呈现负电荷, 这有利于吸附水中带正电的金属阳离子. 然而, 也有研究指出老化后塑料的零电荷点可能会增高[63], 这主要取决于环境因素和塑料类型.

2.3 生物膜的覆盖

老化后的微塑料表面更有利于生物膜的生长[64], 而生物膜的存在则会改变塑料的吸附能力、老化过程以及沉降性能[65]. 作为一种复杂的表层有机相, 生物膜的成分会影响塑料对各种污染物的吸附能力[66]. 一方面, 生物膜上的微生物能够促进塑料的生物降解, 加速其老化过程；另一方面, 生物膜也可以作为屏障保护塑料免受紫外线照射, 减弱光降解作用[67]. 对于密度较低的塑料, 生物膜的存在可以增加其密度, 从而增强其沉降性能；而对于密度较高的塑料, 生物膜的存在可能会导致其向上迁移.

综上所述, 塑料在老化过程中所经历的变化, 如破碎、表面粗糙度的增加、含氧基团的增多以及生物膜附着, 均会对微塑料（MPs）与污染物或微生物的吸附行为产生影响. 以上变化不仅改变了塑料与环境中其他物质的相互作用方式, 还可能影响其在水体中的迁移和分散性, 从而干扰生态系统的正常功能. 因此, 深入掌握塑料在老化过程中发生的物理和化学性质变化, 对于评估环境中的塑料污染风险、制定有效的环境保护措施至关重要.

3 塑料老化产物 3.1 塑料颗粒 3.1.1 颗粒释放规律

塑料在老化过程中会释放大量的微纳米颗粒. Song等[18]进行了为期24个月的室外老化实验, 并观察到EPS在较短时间内能持续释放大量颗粒, 达到约6.7 × 107个·cm-2. Lambert[68]研究了PS一次性咖啡杯盖中纳米颗粒的释放情况, 发现在56d后, 纳米塑料的丰度为1.26×108个·mL-1, 且颗粒丰度随时间的延长而增加. Mattsson等[69]在观察热氧化与水动力老化条件下EPS的破碎情况也发现, 第4 d后小颗粒的释放丰度高于第2 d.

水生环境中微纳米颗粒的尺寸分布对光的散射和吸收、物质的交换和输送以及生物间的相互作用等具有重要影响[22]. 有研究显示, 在塑料释放的微纳米颗粒中, 颗粒尺寸越小, 其占比越高. 如Lambert等[70]分析了7种塑料释放的颗粒粒径分布（30 nm~60 µm）后发现, 对于所有塑料, 释放的颗粒丰度都随着颗粒粒径的减小而增加. 另外, Song等[39]也发现在所有实验的塑料（PE、PP和EPS）中, 紫外线照射和机械磨损产生的碎片数量随着尺寸的减小而增加.

3.1.2 颗粒释放的影响因素

塑料降解主要经历两个关键阶段：一是初期的光氧化, 二是随后的微裂纹形成和破碎[22]. 虽然光氧化是导致多数塑料破碎的先决条件[71], 但Song等[39]的研究发现, 仅经过紫外照射的PE和PP颗粒表面未观察到碎片, 这说明老化后裂纹的出现并不会直接导致聚合物破碎；碎片的形成还依赖于外界机械力的作用. Julienne等[19]在实验室对PE薄膜进行光降解研究时发现, 虽然空气中薄膜的氧化程度较高, 但塑料的碎裂仅在水中发生. 综上所述, 紫外线和机械力的协同作用是塑料破碎的关键因素.

塑料的化学结构和物理性质在其老化降解过程中起着关键作用[19, 72]. 相较于PS、PE和PP, EPS在机械应力下更易破碎[18, 39]；PS因含有苯环结构而更易发生光降解[73]；与PE相比, PP的稳定性较差, 这主要是因为PP主链上的叔碳原子更易受到化学侵蚀[7]. 此外, 低密度和多孔结构的塑料更容易受到外界环境的影响, 从而具有较快的老化速度.

塑料添加剂的种类和含量也会对塑料的老化过程产生影响. 以上添加剂不仅可以通过改变塑料的密度和结晶度来间接影响其环境行为, 还可以直接影响塑料的老化反应[74]. 稳定剂和抗氧化剂可延缓降解过程[75], 而某些添加剂如增塑剂（DBP）和溴化阻燃剂（BFRs）则可以扩展塑料的吸收光谱, 增强塑料对光的吸收[76]. 另外, 环境条件如水和阳光也会直接影响塑料的老化反应. 水中较低的温度和较弱的光辐射导致塑料在水中的老化速率低于在空气中的速率[52], 但潮湿环境有利于塑料的生物降解[19]. 综上所述, 塑料老化过程中微纳米塑料的释放受到其化学和物理特性、环境条件及外部作用力的综合影响（图 2）.

图 2 影响微纳米颗粒的释放因素 Fig. 2 Factors affecting the release of micro and nanoparticles

3.2 塑料添加剂 3.2.1 塑料添加剂的成分

塑料制品通常含有以满足其特定使用需求的添加剂. 以上添加剂包括功能添加剂（增塑剂、抗氧化剂、阻燃剂、抗静电剂、润滑剂）、着色剂（颜料、偶氮染料等）、填料（云母、滑石、粘土、碳酸盐）和稳定剂（铅盐、有机锡、锌/钙络合物）这四大类[77], 其中增塑剂、阻燃剂、抗氧化剂和光热稳定剂的使用最为广泛.

塑料产品中添加剂的类型与含量取决于其性能要求[78, 79]. 如为提高PVC和PET的柔韧性, 常添加邻苯二甲酸酯类增塑剂（PAEs）；在电子和绝缘材料中, 普遍添加阻燃剂以提高塑料产品的安全性；光稳定剂、抗氧化剂以及颜料被广泛用于各种聚合物中, 如PE和PP等；防滑剂主要被用于聚烯烃, 抗菌物质则通常被添加到PVC、PU、PE或PET中. 绝大多数添加剂并未与聚合物化学结合, 因此它们容易从塑料中浸出并增加环境中的污染物种类, 如溴代阻燃剂、邻苯二甲酸酯类、多环芳烃、多氯联苯、金属基添加剂、壬基酚和双酚A等[80]. 以上污染物的浓度水平从pg·L-1到mg·L-1不等, 且大多数为内分泌干扰物.

3.2.2 塑料添加剂的浸出及影响因素

近年来, 塑料中添加剂的浸出行为成为研究重点, 特别是对于那些含量高且潜在危害大的添加剂. Guney等[80]以12种塑料制品为样本研究了PAEs的释放行为, 结果显示铅笔盒（PVC）中总∑15 PAEs的迁移量最大, 达到（6 660±513）ng·g-1. 有研究还发现添加剂的释放量与聚合物类型密切相关. 另一项光解实验发现双酚类化合物可从PET、PA和聚丙烯腈（PAN））微塑料纤维中浸出, 最高浸出含量可达165 ng·g-1[25]. Pan等[81]将EPS浮标置于海水中15个月后发现, 塑料中六溴环十二烷（HBCD）阻燃剂的含量显著减少.

塑料添加剂的浸出过程主要涉及3个步骤：内部扩散、跨越塑料介质边界层以及水环境扩散（图 3）[82, 83]. 添加剂的整体浸出速率取决于塑料内部扩散或水边界层扩散, 这与添加剂在塑料相与水相间的分配系数（KPW）有关. 如果添加剂在此两相间的分配系数较大, 则水边界层扩散可能成为限制步骤. 随着塑料碎片在老化过程中逐渐分解, 其添加剂释放量随时间增加, 但这一浸出行为受其他多种因素影响（图 4）.

图 3 微塑料中塑料添加剂的浸出过程 Fig. 3 Leaching process of plastic additives in microplastics

图 4 影响塑料添加剂的释放因素 Fig. 4 Factors affecting the release of plastic additives

（1）添加剂含量与性质

添加剂的含量及种类对其浸出过程有直接影响. 浸出量与其在塑料中的含量成正比, 且相对分子质量越小, 扩散速度越快[84, 85]. 有研究表明相对分子质量较小的邻苯二甲酸二丁酯（DBP）的浸出率高于相对分子质量较大的邻苯二甲酸二（2-乙基己基）酯（DEHP）的浸出率[86]. 此外, 添加剂的化学结构会通过影响其溶解度和与塑料基体之间的作用而影响浸出. 如PAEs因极性较大而易浸出至水中[31]；添加剂与基体间的相互作用较强时, 其浸出速率较低[84].

（2）塑料的性质

塑料聚合物的种类、尺寸和制造工艺（如交联密度）也会影响添加剂的浸出. 低玻璃化转变温度值（Tg）、交联度和结晶度的塑料更易于促进物质的扩散和浸出[87, 88], 这可以从分子运动和空间可用性角度理解. Tg表示塑料从硬且脆的玻璃态向柔软且有弹性的高弹态转变的温度点, 在Tg以下, 塑料展现出高黏度和低分子运动性, 因此添加剂的浸出速率相对较低, 一些常见塑料聚合物的Tg值见表 1. 有研究发现在25℃时, PE（Tg为-120℃）中六氯苯的扩散系数远高于PP（Tg为-10℃）中的扩散系数[82]. 高交联密度的塑料因分子间隙小, 分子运动受到更大的限制, 从而减缓添加剂的浸出. 结晶度高的塑料含有更多的有序排列分子链（结晶区）, 对添加剂分子的穿透性较低, 导致添加剂浸出速率降低. 另外, 塑料颗粒尺寸越小, 释放通量越大, 其释放添加剂的能力越强.

（3）老化程度

老化过程中塑料碎片的逐步降解会极大刺激添加剂的浸出[89], 并且老化后的塑料会减弱对添加剂的束缚, 还可能通过增加表面裂纹等微观结构变化, 加速添加剂的释放[90, 91].

（4）环境条件

温度、湿度和pH值等对添加剂的浸出有显著影响[92]. 温度升高通常会加速添加剂扩散[93], 而湿度和pH值的变化会影响添加剂与塑料的相容性以及老化过程的化学反应.

（5）其他共存物质

共存的其他添加剂（例如增塑剂）及其表面生物膜对添加剂浸出同样产生影响. 有研究发现增塑剂可以通过增加聚合物段的迁移率而促进阻燃剂的迁移[94]. 生物膜一方面作为一个额外扩散阻力抑制添加剂的浸出, 另一方面由于微生物增加添加剂的极性而加速其浸出[78]. 此外, 塑料老化过程中释放的添加剂也可能会发生化学转化[95], 形成新的潜在有毒物质.

3.3 其他溶解性产物

塑料制品的母体是由不同单体聚合形成的高分子物质, 如PE、PP、PVC以及PS等. 光氧化会导致游离单体[96]、低相对分子质量片段（乙烷、丙烷和乙烯）[97, 98]以及氧合低相对分子质量片段（羧酸、醇和醛）[27, 99]等释放, 其中大多数具有生物毒性[25]. PS老化可能会释放致癌物（苯乙烯单体）, 引起生物神经功能紊乱. Vitrac等[100]研究表明, 由于PS酸奶罐的使用, 人体可能会摄入12 µg左右的PS单体. PS单体还会在环境中发生氧化而产生一种突变诱导化合物（苯基环氧乙烷）, 对人类健康构成严重威胁[101]. Ahmad等[102]研究发现, 将热水倒入EPS和PS杯后, 热水受到PE和其他芳香族化合物的污染. PVC树脂本身无毒无害, 但其老化后会释放出对人体有麻醉和致畸致癌作用的残留单体氯乙烯[103]；当温度超过50℃时, PVC甚至还会释放氯化氢气体, 这种气体会对人体造成急性毒性. 此外, 塑料还会释放出其他气态产物, 如二氧化碳、甲烷和乙烯等温室气体[29, 30], 以及挥发性有机化合物（VOC）[26]. 聚碳酸酯（PC）因极强的耐水性和本身无色无味而被广泛使用, 但老化后双酚A组分的浸出使其存在较高的生物毒性风险[96]. 塑料在氧化作用下会释放出一系列含氧产物. Gewert等[27]将4种塑料（PE、PP、PS和PET）暴露于紫外线（UV）, 5 d后检测出22种具有氧化端基的同源低相对分子质量降解产物, 其中主要是二羧酸.

4 塑料老化过程的环境危害

老化过程中的塑料以多种形态存在, 从宏观碎片到纳米级颗粒均会对生态系统造成不利影响. 宏观塑料碎片主要通过缠结和摄入这两种物理方式对生物体造成损伤[104]. 缠结可导致生物窒息、进食障碍、败血症以及行动能力受限[105], 摄入则可能引发消化道堵塞、穿孔及溃疡, 甚至死亡[106]. 以上大型碎片在长期老化过程中会逐渐分解为直径小于5 mm的微塑料, 成为微塑料污染的主要来源之一[107, 108].

与宏观塑料相比, 微塑料更易被生物摄取[109, 110]并通过食物链进行传播[111]. 微塑料进入生物体后会直接影响其摄食行为[112]和消化系统[113, 114]. Romas等[114]发现摄入塑料碎片（<5 mm）后的巴西鲈鱼肠道内容物的平均总重量较低, 这归因于微塑料摄入导致的虚假饱足感. 微塑料在不同组织及器官中的积聚可能诱发炎症、氧化应激和细胞凋亡, 导致代谢紊乱、发育和生殖健康受损以及神经系统毒性[115, 116]. Deng等[117]使用两种直径（5 µm和20 µm）PS研究其在小鼠体内的分布后发现, 微塑料颗粒在肝脏、肾脏和肠道中的积累与其粒径密切相关, 且颗粒的体内积累会引起能量和脂质代谢紊乱. Jin等[118]将小鼠暴露于不同粒径的PS微塑料28 d后发现, 其精子质量和睾酮水平下降, 组织学分析显示小鼠的生精细胞排列无序, 生精小管内出现多核淋巴细胞, 且诱发了睾丸炎症和血睾屏障损伤. 微塑料可通过食物网进行转移. 如研究发现海鸟可通过食用含微塑料的鱼类间接摄入微塑料[119]. 除了与生物体直接作用外, 微塑料还可能通过与非生物环境的相互作用间接影响生物群落或生态系统[120], 如改变化学物质在环境中的分布、影响光在水柱中的穿透或改变沉积物特性[121, 122].

纳米塑料（<1 µm）由于更小的尺寸和更大的比表面积而展现出与微塑料不同的环境行为[123], 造成更为直接和严重的生物毒性[124, 125]. Rist等[126]研究发现, 100 nm颗粒对蓝贻贝幼虫的变形效应是2 µm颗粒的6~10倍. Jeong等[127]同样观察到, 50 nm的PS微珠对线虫的毒性远超6 µm颗粒. 纳米颗粒的毒性还体现在其对污染物的强吸附能力[128], Singh[129]发现金属氧化物与纳米塑料的共同作用会严重损害斑马鱼DNA. 微塑料和纳米塑料对环境和生物的影响较为复杂, 涉及物理积累、生化干扰、添加剂浸出和污染物吸附等.

老化过程中各个尺寸级别的塑料颗粒都会释放出塑料添加剂、单体以及低聚物等溶解性物质[130, 131]. 如表 3, 以上物质会干扰生物的内分泌系统, 引起生殖、发育等问题, 还可能致畸、致癌及引起神经毒性等不良反应[31]. 以上有毒物质可利用微塑料作为载体将其转移至生物体内[132, 133]. 相关研究表明, PVC可将吸附的壬基酚、菲和三氯生等有毒物质转移至瓢虫的肠道组织中, 导致免疫功能受损和生理应激增加, 提高瓢虫的死亡率[134].

表 3 塑料释放产物名称、用途与危害 Table 3 Names, uses and hazards of plastic release products

5 展望

在塑料老化过程中, 微纳米颗粒、塑料添加剂及其他溶解性化合物的释放会对生态系统和人类健康构成威胁, 需要更深入地研究来全面评估其长期影响. 当前研究在考虑环境复杂性、精确监测微纳米塑料以及塑料添加剂环境行为等方面存在不足, 未来的研究可以从以下4个方面开展：

（1）在自然环境条件下对塑料污染物进行实时监测和长期跟踪, 以揭示其真实行为模式.

（2）开发高效的微纳米塑料检测技术, 提升在环境样本中的识别和定量能力, 并深入研究微纳米塑料与其他污染物的相互作用.

（3）加深对塑料添加剂在环境中行为的理解, 开发预测模型和风险评估方法, 并探索无毒或低毒的添加剂替代品.

（4）重点研究未聚合游离单体、裂解物和降解物等溶解性化合物的环境毒性和生物累积性, 同时探索更环保的塑料设计和生产方式, 减少有害化合物生成.

6 结论

在塑料老化过程中, 其表面物理特性和化学性质发生显著变化, 如表面粗糙度增加和新官能团形成, 以上改变增强了塑料与环境中其他物质的相互作用, 包括有害化学物质的吸附及生物体的附着. 光氧化与外界作用力的联合是塑料非生物降解的关键, 不仅促进了微纳米颗粒的释放, 还加剧了添加剂和其他有毒化合物的浸出, 以上物质会导致生物毒性. 此外, 微纳米塑料还可以作为环境中污染物的载体, 与污染物一起被生物摄入, 并通过生物积累作用影响食物链的各个层级. 总之, 塑料的老化过程复杂, 其产生的环境影响需引起后续研究者的重视.

参考文献
[1] Wang J D, Tan Z, Peng J P, et al. The behaviors of microplastics in the marine environment[J]. Marine Environmental Research, 2016, 113: 7-17. DOI:10.1016/j.marenvres.2015.10.014
[2] Cao Y R, Lin H J, Zhang K, et al. Microplastics: a major source of phthalate esters in aquatic environments[J]. Journal of Hazardous Materials, 2022, 432. DOI:10.1016/j.jhazmat.2022.128731
[3] Geyer R, Jambeck J R, Law K L. Production, use, and fate of all plastics ever made[J]. Science Advances, 2017, 3(7). DOI:10.1126/sciadv.1700782
[4] Cai L Q, Wang J D, Peng J P, et al. Observation of the degradation of three types of plastic pellets exposed to UV irradiation in three different environments[J]. Science of the Total Environment, 2018, 628-629: 740-747. DOI:10.1016/j.scitotenv.2018.02.079
[5] Ramasamy B S S, Palanisamy S. A review on occurrence, characteristics, toxicology and treatment of nanoplastic waste in the environment[J]. Environmental Science and Pollution Research, 2021, 28(32): 43258-43273. DOI:10.1007/s11356-021-14883-6
[6] Osman A I, Hosny M, Eltaweil A S, et al. Microplastic sources, formation, toxicity and remediation: a review[J]. Environmental Chemistry Letters, 2023, 21(4): 2129-2169. DOI:10.1007/s10311-023-01593-3
[7] Gewert B, Plassmann M M, MacLeod M. Pathways for degradation of plastic polymers floating in the marine environment[J]. Environmental Science: Processes & Impacts, 2015, 17(9): 1513-1521.
[8] Jakubowicz I. Evaluation of degradability of biodegradable polyethylene (PE)[J]. Polymer Degradation and Stability, 2003, 80(1): 39-43. DOI:10.1016/S0141-3910(02)00380-4
[9] Ng E L, Huerta Lwanga E, Eldridge S M, et al. An overview of microplastic and nanoplastic pollution in agroecosystems[J]. Science of the Total Environment, 2018, 627: 1377-1388. DOI:10.1016/j.scitotenv.2018.01.341
[10] Zhang K, Hamidian A H, Tubić A, et al. Understanding plastic degradation and microplastic formation in the environment: a review[J]. Environmental Pollution, 2021, 274. DOI:10.1016/j.envpol.2021.116554
[11] Pirsaheb M, Hossini H, Makhdoumi P. Review of microplastic occurrence and toxicological effects in marine environment: experimental evidence of inflammation[J]. Process Safety and Environmental Protection, 2020, 142: 1-14. DOI:10.1016/j.psep.2020.05.050
[12] Kamweru P K, Ndiritu F G, Kinyanjui T K, et al. Study of temperature and UV wavelength range effects on degradation of photo-irradiated polyethylene films using DMA[J]. Journal of Macromolecular Science, 2011, 50(7): 1338-1349. DOI:10.1080/00222348.2010.516172
[13] Chen Z, Zhao W Q, Xing R Z, et al. Enhanced in situ biodegradation of microplastics in sewage sludge using hyperthermophilic composting technology[J]. Journal of Hazardous Materials, 2020, 384. DOI:10.1016/j.jhazmat.2019.121271
[14] Chen X C, Xiong X, Jiang X M, et al. Sinking of floating plastic debris caused by biofilm development in a freshwater lake[J]. Chemosphere, 2019, 222: 856-864. DOI:10.1016/j.chemosphere.2019.02.015
[15] Auta H S, Emenike C U, Jayanthi B, et al. Growth kinetics and biodeterioration of polypropylene microplastics by Bacillus sp. and Rhodococcus sp. isolated from mangrove sediment[J]. Marine Pollution Bulletin, 2018, 127: 15-21. DOI:10.1016/j.marpolbul.2017.11.036
[16] Yuan Y B, Liu P, Zheng Y, et al. Unique Raoultella species isolated from petroleum contaminated soil degrades polystyrene and polyethylene[J]. Ecotoxicology and Environmental Safety, 2023, 263. DOI:10.1016/j.ecoenv.2023.115232
[17] Miranda M N, Sampaio M J, Tavares P B, et al. Aging assessment of microplastics (LDPE, PET and uPVC) under urban environment stressors[J]. Science of the Total Environment, 2021, 796. DOI:10.1016/j.scitotenv.2021.148914
[18] Song Y K, Hong S H, Eo S, et al. Rapid production of micro- and nanoplastics by fragmentation of expanded polystyrene exposed to sunlight[J]. Environmental Science & Technology, 2020, 54(18): 11191-11200.
[19] Julienne F, Delorme N, Lagarde F. From macroplastics to microplastics: role of water in the fragmentation of polyethylene[J]. Chemosphere, 2019, 236. DOI:10.1016/j.chemosphere.2019.124409
[20] Tang C C, Chen H I, Brimblecombe P, et al. Morphology and chemical properties of polypropylene pellets degraded in simulated terrestrial and marine environments[J]. Marine Pollution Bulletin, 2019, 149. DOI:10.1016/j.marpolbul.2019.110626
[21] Suhrhoff T J, Scholz-Böttcher B M. Qualitative impact of salinity, UV radiation and turbulence on leaching of organic plastic additives from four common plastics-A lab experiment[J]. Marine Pollution Bulletin, 2016, 102(1): 84-94. DOI:10.1016/j.marpolbul.2015.11.054
[22] Meides N, Menzel T, Poetzschner B, et al. Reconstructing the environmental degradation of polystyrene by accelerated weathering[J]. Environmental Science & Technology, 2021, 55(12): 7930-7938.
[23] Qin J H, Zeng S Q, Wang X, et al. Generation of micro(nano)plastics and migration of plastic additives from poly(vinyl chloride) in water under radiation-free ambient conditions[J]. Chemosphere, 2022, 299. DOI:10.1016/j.chemosphere.2022.134399
[24] Pfohl P, Wagner M, Meyer L, et al. Environmental degradation of microplastics: how to measure fragmentation rates to secondary micro-and nanoplastic fragments and dissociation into dissolved organics[J]. Environmental Science & Technology, 2022, 56(16): 11323-11334.
[25] Sait S T L, Sørensen L, Kubowicz S, et al. Microplastic fibres from synthetic textiles: environmental degradation and additive chemical content[J]. Environmental Pollution, 2021, 268. DOI:10.1016/j.envpol.2020.115745
[26] Wu X Y, Chen X L, Jiang R F, et al. New insights into the photo-degraded polystyrene microplastic: effect on the release of volatile organic compounds[J]. Journal of Hazardous Materials, 2022, 431. DOI:10.1016/j.jhazmat.2022.128523
[27] Gewert B, Plassmann M, Sandblom O, et al. Identification of chain scission products released to water by plastic exposed to ultraviolet light[J]. Environmental Science & Technology Letters, 2018, 5(5): 272-276.
[28] Fairbrother A, Hsueh H C, Kim J H, et al. Temperature and light intensity effects on photodegradation of high-density polyethylene[J]. Polymer Degradation and Stability, 2019, 165: 153-160. DOI:10.1016/j.polymdegradstab.2019.05.002
[29] Ward C P, Armstrong C J, Walsh A N, et al. Sunlight converts polystyrene to carbon dioxide and dissolved organic carbon[J]. Environmental Science & Technology Letters, 2019, 6(11): 669-674.
[30] Royer S J, Ferrón S, Wilson S T, et al. Production of methane and ethylene from plastic in the environment[J]. PLoS One, 2018, 13(8). DOI:10.1371/journal.pone.0200574
[31] Paluselli A, Fauvelle V, Galgani F, et al. Phthalate release from plastic fragments and degradation in seawater[J]. Environmental Science & Technology, 2019, 53(1): 166-175.
[32] Singh P, Lau C S S, Siah S Y, et al. Microbial degradation of low-density polyethylene, polyethylene terephthalate, and polystyrene by novel isolates from plastic-polluted environment[J]. Archives of Microbiology, 2024, 206(4). DOI:10.1007/s00203-024-03895-8
[33] Singh P, Nagarajan A, Chua K O, et al. Biodegradation of low-density polyethylene by novel halophilic bacteria from mangrove ecosystem[J]. Bioremediation Journal, 2023. DOI:10.1080/10889868.2023.2297181
[34] Brandon J, Goldstein M, Ohman M D. Long-term aging and degradation of microplastic particles: comparing in situ oceanic and experimental weathering patterns[J]. Marine Pollution Bulletin, 2016, 110(1): 299-308. DOI:10.1016/j.marpolbul.2016.06.048
[35] Veerasingam S, Saha M, Suneel V, et al. Characteristics, seasonal distribution and surface degradation features of microplastic pellets along the Goa coast, India[J]. Chemosphere, 2016, 159: 496-505. DOI:10.1016/j.chemosphere.2016.06.056
[36] Lv Y D, Huang Y J, Kong M Q, et al. Multivariate correlation analysis of outdoor weathering behavior of polypropylene under diverse climate scenarios[J]. Polymer Testing, 2017, 64: 65-76. DOI:10.1016/j.polymertesting.2017.09.040
[37] Cooper D A. Effects of chemical and mechanical weathering processes on the degradation of plastic debris on marine beaches[D]. London: The University of Western Ontario, 2012.
[38] 范秀磊, 常卓恒, 邹晔锋, 等. 可降解微塑料对铜和锌离子的吸附解吸特性[J]. 中国环境科学, 2021, 41(5): 2141-2150.
Fan X L, Chang Z H, Zou Y F, et al. Adsorption and desorption properties of degradable microplastic for Cu2+ and Zn2+ [J]. China Environmental Science, 2021, 41(5): 2141-2150.
[39] Song Y K, Hong S H, Jang M, et al. Combined effects of UV exposure duration and mechanical abrasion on microplastic fragmentation by polymer type[J]. Environmental Science & Technology, 2017, 51(8): 4368-4376.
[40] Jabarin S A, Lofgren E A. Photooxidative effects on properties and structure of high‐density polyethylene[J]. Journal of Applied Polymer Science, 1994, 53(4): 411-423. DOI:10.1002/app.1994.070530404
[41] Rouillon C, Bussiere P O, Desnoux E, et al. Is carbonyl index a quantitative probe to monitor polypropylene photodegradation?[J]. Polymer Degradation and Stability, 2016, 128: 200-208. DOI:10.1016/j.polymdegradstab.2015.12.011
[42] Ojeda T, Freitas A, Birck K, et al. Degradability of linear polyolefins under natural weathering[J]. Polymer Degradation and Stability, 2011, 96(4): 703-707. DOI:10.1016/j.polymdegradstab.2010.12.004
[43] de la Orden M U, Montes J M, Martínez Urreaga J, et al. Thermo and photo-oxidation of functionalized metallocene high density polyethylene: effect of hydrophilic groups[J]. Polymer Degradation and Stability, 2015, 111: 78-88. DOI:10.1016/j.polymdegradstab.2014.10.023
[44] Adelhafidi A, Babaghayou I M, Chabira S F, et al. Impact of solar radiation effects on the physicochemical properties of polyethylene (PE) plastic film[J]. Procedia-Social and Behavioral Sciences, 2015, 195: 2210-2217. DOI:10.1016/j.sbspro.2015.06.302
[45] 蒋凤华, 谢林青, 孙承君, 等. 常见塑料薄膜制品在UV作用下的性能变化特征[J]. 科学通报, 2021, 66(13): 1571-1579.
Jiang F H, Xie L Q, Sun C J, et al. The characteristic change of plastic film from common used packing bags under UV photodegradation[J]. Chinese Science Bulletin, 2021, 66(13): 1571-1579.
[46] Iñiguez M E, Conesa J A, Fullana A. Recyclability of four types of plastics exposed to UV irradiation in a marine environment[J]. Waste Management, 2018, 79: 339-345. DOI:10.1016/j.wasman.2018.08.006
[47] Lv Y D, Huang Y J, Yang J L, et al. Outdoor and accelerated laboratory weathering of polypropylene: a comparison and correlation study[J]. Polymer Degradation and Stability, 2015, 112: 145-159. DOI:10.1016/j.polymdegradstab.2014.12.023
[48] Yang R, Liu Y, Yu J, et al. Thermal oxidation products and kinetics of polyethylene composites[J]. Polymer Degradation and Stability, 2006, 91(8): 1651-1657. DOI:10.1016/j.polymdegradstab.2005.12.013
[49] Liu G Z, Zhu Z L, Yang Y X, et al. Sorption behavior and mechanism of hydrophilic organic chemicals to virgin and aged microplastics in freshwater and seawater[J]. Environmental Pollution, 2019, 246: 26-33. DOI:10.1016/j.envpol.2018.11.100
[50] Wu J, Xu P C, Chen Q H, et al. Effects of polymer aging on sorption of 2, 2', 4, 4'-tetrabromodiphenyl ether by polystyrene microplastics[J]. Chemosphere, 2020, 253. DOI:10.1016/j.chemosphere.2020.126706
[51] 李婉逸, 刘智临, 苗令占, 等. 淡水系统中4种塑料颗粒的老化过程及DOC产物分析[J]. 环境科学, 2021, 42(8): 3829-3836.
Li W Y, Liu Z L, Miao L Z, et al. Aging process and DOC analysis of four different types of plastic particles in freshwater systems[J]. Environmental Science, 2021, 42(8): 3829-3836.
[52] Mao R F, Lang M F, Yu X Q, et al. Aging mechanism of microplastics with UV irradiation and its effects on the adsorption of heavy metals[J]. Journal of Hazardous Materials, 2020, 393. DOI:10.1016/j.jhazmat.2020.122515
[53] Arnaud R, Moisan J Y, Lemaire J. Primary hydroperoxidation in low-density polyethylene[J]. Macromolecules, 1984, 17(3): 332-336. DOI:10.1021/ma00133a012
[54] Gardette M, Perthue A, Gardette J L, et al. Photo-and thermal-oxidation of polyethylene: comparison of mechanisms and influence of unsaturation content[J]. Polymer Degradation and Stability, 2013, 98(11): 2383-2390. DOI:10.1016/j.polymdegradstab.2013.07.017
[55] ter Halle A, Ladirat L, Martignac M, et al. To what extent are microplastics from the open ocean weathered?[J]. Environmental Pollution, 2017, 227: 167-174. DOI:10.1016/j.envpol.2017.04.051
[56] Alimi O S, Claveau-Mallet D, Lapointe M, et al. Effects of weathering on the properties and fate of secondary microplastics from a polystyrene single-use cup[J]. Journal of Hazardous Materials, 2023, 459. DOI:10.1016/j.jhazmat.2023.131855
[57] Wilkes R A, Aristilde L. Degradation and metabolism of synthetic plastics and associated products by Pseudomonas sp.: capabilities and challenges[J]. Journal of Applied Microbiology, 2017, 123(3): 582-593. DOI:10.1111/jam.13472
[58] Lapointe M, Farner J M, Hernandez L M, et al. Understanding and improving microplastic removal during water treatment: impact of coagulation and flocculation[J]. Environmental Science & Technology, 2020, 54(14): 8719-8727.
[59] Fotopoulou K N, Karapanagioti H K. Surface properties of beached plastic pellets[J]. Marine Environmental Research, 2012, 81: 70-77. DOI:10.1016/j.marenvres.2012.08.010
[60] Liu J, Zhang T, Tian L L, et al. Aging significantly affects mobility and contaminant-mobilizing ability of nanoplastics in saturated loamy sand[J]. Environmental Science & Technology, 2019, 53(10): 5805-5815.
[61] Müller A, Becker R, Dorgerloh U, et al. The effect of polymer aging on the uptake of fuel aromatics and ethers by microplastics[J]. Environmental Pollution, 2018, 240: 639-646. DOI:10.1016/j.envpol.2018.04.127
[62] Fu Q M, Tan X F, Ye S J, et al. Mechanism analysis of heavy metal lead captured by natural-aged microplastics[J]. Chemosphere, 2021, 270. DOI:10.1016/j.chemosphere.2020.128624
[63] Zhang H B, Wang J Q, Zhou B Y, et al. Enhanced adsorption of oxytetracycline to weathered microplastic polystyrene: kinetics, isotherms and influencing factors[J]. Environmental Pollution, 2018, 243: 1550-1557. DOI:10.1016/j.envpol.2018.09.122
[64] Kaiser D, Kowalski N, Waniek J J. Effects of biofouling on the sinking behavior of microplastics[J]. Environmental Research Letters, 2017, 12(12). DOI:10.1088/1748-9326/aa8e8b
[65] Waldschläger K, Born M, Cowger W, et al. Settling and rising velocities of environmentally weathered micro-and macroplastic particles[J]. Environmental Research 2020, 191. DOI:10.1016/j.envres.2020.110192
[66] Johansen M P, Cresswell T, Davis J, et al. Biofilm-enhanced adsorption of strong and weak cations onto different microplastic sample types: use of spectroscopy, microscopy and radiotracer methods[J]. Water Research, 2019, 158: 392-400. DOI:10.1016/j.watres.2019.04.029
[67] Weinstein J E, Crocker B K, Gray A D. From macroplastic to microplastic: degradation of high-density polyethylene, polypropylene, and polystyrene in a salt marsh habitat[J]. Environmental Toxicology and Chemistry, 2016, 35(7): 1632-1640. DOI:10.1002/etc.3432
[68] Lambert S, Wagner M. Characterisation of nanoplastics during the degradation of polystyrene[J]. Chemosphere, 2016, 145: 265-268. DOI:10.1016/j.chemosphere.2015.11.078
[69] Mattsson K, Björkroth F, Karlsson T, et al. Nanofragmentation of expanded polystyrene under simulated environmental weathering (thermooxidative degradation and hydrodynamic turbulence)[J]. Frontiers in Marine Science, 2021, 7. DOI:10.3389/fmars.2020.578178
[70] Lambert S, Wagner M. Formation of microscopic particles during the degradation of different polymers[J]. Chemosphere, 2016, 161: 510-517. DOI:10.1016/j.chemosphere.2016.07.042
[71] Lambert S, Sinclair C J, Bradley E L, et al. Effects of environmental conditions on latex degradation in aquatic systems[J]. Science of the Total Environment, 2013, 447: 225-234. DOI:10.1016/j.scitotenv.2012.12.067
[72] Song Y K, Hong S H, Eo S, et al. The fragmentation of nano-and microplastic particles from thermoplastics accelerated by simulated-sunlight-mediated photooxidation[J]. Environmental Pollution, 2022, 311. DOI:10.1016/j.envpol.2022.119847
[73] Yousif E, Haddad R. Photodegradation and photostabilization of polymers, especially polystyrene: review[J]. SpringerPlus, 2013, 2(1). DOI:10.1186/2193-1801-2-398
[74] White J R, Shyichuk A V. Effect of stabilizer on scission and crosslinking rate changes during photo-oxidation of polypropylene[J]. Polymer Degradation and Stability, 2007, 92(11): 2095-2101. DOI:10.1016/j.polymdegradstab.2007.07.013
[75] Kutz M. Applied Plastics Engineering Handbook: Processing and Materials[M]. Oxford: William Andrew Publishing, 2011.
[76] Khaled A, Rivaton A, Richard C, et al. Phototransformation of plastic containing brominated flame retardants: enhanced fragmentation and release of photoproducts to water and air[J]. Environmental Science & Technology, 2018, 52(19): 11123-11131.
[77] Bridson J H, Gaugler E C, Smith D A, et al. Leaching and extraction of additives from plastic pollution to inform environmental risk: a multidisciplinary review of analytical approaches[J]. Journal of Hazardous Materials, 2021, 414. DOI:10.1016/j.jhazmat.2021.125571
[78] Do A T N, Ha Y, Kwon J H. Leaching of microplastic-associated additives in aquatic environments: a critical review[J]. Environmental Pollution, 2022, 305. DOI:10.1016/j.envpol.2022.119258
[79] Hermabessiere L, Dehaut A, Paul-Pont I, et al. Occurrence and effects of plastic additives on marine environments and organisms: a review[J]. Chemosphere, 2017, 182: 781-793. DOI:10.1016/j.chemosphere.2017.05.096
[80] Guney M, Zagury G J. Heavy metals in toys and low-cost jewelry: critical review of U.S. and Canadian legislations and recommendations for testing[J]. Environmental Science & Technology, 2012, 46(8): 4265-4274.
[81] Pan Y F, Liu S, Li H X, et al. Expanded polystyrene buoys as an important source of hexabromocyclododecanes for aquatic ecosystem: evidence from field exposure with different substrates[J]. Environmental Pollution, 2023, 318. DOI:10.1016/j.envpol.2022.120920
[82] Cheng H F, Luo H, Hu Y A N, et al. Release kinetics as a key linkage between the occurrence of flame retardants in microplastics and their risk to the environment and ecosystem: a critical review[J]. Water Research, 2020, 185. DOI:10.1016/j.watres.2020.116253
[83] Kwon J H, Chang S, Hong S H, et al. Microplastics as a vector of hydrophobic contaminants: importance of hydrophobic additives[J]. Integrated Environmental Assessment and Management, 2017, 13(3): 494-499. DOI:10.1002/ieam.1906
[84] Saini A, Thaysen C, Jantunen L, et al. From clothing to laundry water: investigating the fate of phthalates, brominated flame retardants, and organophosphate esters[J]. Environmental Science & Technology, 2016, 50(17): 9289-9297.
[85] Verla A W, Enyoh C E, Verla E N, et al. Microplastic⁃toxic chemical interaction: a review study on quantified levels, mechanism and implication[J]. SN Applied Sciences, 2019, 1(11). DOI:10.1007/s42452-019-1352-0
[86] Viljoen S J, Brailsford F L, Murphy D V, et al. Leaching of phthalate acid esters from plastic mulch films and their degradation in response to UV irradiation and contrasting soil conditions[J]. Journal of Hazardous Materials, 2023, 443. DOI:10.1016/j.jhazmat.2022.130256
[87] Sun B B, Hu Y A N, Cheng H F, et al. Releases of brominated flame retardants (BFRs) from microplastics in aqueous medium: kinetics and molecular-size dependence of diffusion[J]. Water Research, 2019, 151: 215-225. DOI:10.1016/j.watres.2018.12.017
[88] 李爱峰, 闫晨, 邱江兵. 微塑料浸出液的主要成分、检测方法及环境效应研究进展与展望[J]. 中国海洋大学学报, 2022, 52(10): 1-14.
Li A F, Yan C, Qiu J B. Progress on the main components, analytical methods and adverse effects of microplastic leachate[J]. Periodical of Ocean University of China, 2022, 52(10): 1-14.
[89] Luo H W, Liu C Y, He D Q, et al. Effects of aging on environmental behavior of plastic additives: migration, leaching, and ecotoxicity[J]. Science of the Total Environment, 2022, 849. DOI:10.1016/j.scitotenv.2022.157951
[90] Luo H W, Liu C Y, He D Q, et al. Interactions between polypropylene microplastics (PP-MPs) and humic acid influenced by aging of MPs[J]. Water Research, 2022, 222. DOI:10.1016/j.watres.2022.118921
[91] Liu P, Zhan X, Wu X W, et al. Effect of weathering on environmental behavior of microplastics: properties, sorption and potential risks[J]. Chemosphere, 2020, 242. DOI:10.1016/j.chemosphere.2019.125193
[92] Li B, Lan Z H, Wang L, et al. The release and earthworm bioaccumulation of endogenous hexabromocyclododecanes (HBCDDs) from expanded polystyrene foam microparticles[J]. Environmental Pollution, 2019, 255. DOI:10.1016/j.envpol.2019.113163
[93] Al-Malack M H. Migration of lead from unplasticized polyvinyl chloride pipes[J]. Journal of Hazardous Materials, 2001, 82(3): 263-274. DOI:10.1016/S0304-3894(00)00366-6
[94] Calò E, Greco A, Maffezzoli A. Effects of diffusion of a naturally-derived plasticizer from soft PVC[J]. Polymer Degradation and Stability, 2011, 96(5): 784-789. DOI:10.1016/j.polymdegradstab.2011.02.012
[95] Sørensen L, Groven A S, Hovsbakken I A, et al. UV degradation of natural and synthetic microfibers causes fragmentation and release of polymer degradation products and chemical additives[J]. Science of the Total Environment, 2021, 755. DOI:10.1016/j.scitotenv.2020.143170
[96] Nam S H, Seo Y M, Kim M G. Bisphenol A migration from polycarbonate baby bottle with repeated use[J]. Chemosphere, 2010, 79(9): 949-952. DOI:10.1016/j.chemosphere.2010.02.049
[97] Amamiya K, Saido K, Chung S Y, et al. Evidence of transport of styrene oligomers originated from polystyrene plastic to oceans by runoff[J]. Science of the Total Environment, 2019, 667: 57-63. DOI:10.1016/j.scitotenv.2019.02.383
[98] Saido K, Koizumi K, Sato H, et al. New analytical method for the determination of styrene oligomers formed from polystyrene decomposition and its application at the coastlines of the North-West Pacific Ocean[J]. Science of the Total Environment, 2014, 473⁃474: 490-495.
[99] Feng H M, Zheng J C, Lei N Y, et al. Photoassisted fenton degradation of polystyrene[J]. Environmental Science & Technology, 2011, 45(2): 744-750.
[100] Vitrac O, Leblanc J C. Consumer exposure to substances in plastic packaging. I. Assessment of the contribution of styrene from yogurt pots[J]. Food Additives & Contaminants, 2007, 24(2): 194-215.
[101] 薛山, 赵国华. 食品包装材料中有害物质迁移的研究进展[J]. 食品工业科技, 2012, 33(2): 404-409.
Xue S, Zhao G H. Research progress on migration of harmful substances from food packaging materials[J]. Science and Technology of Food Industry, 2012, 33(2): 404-409.
[102] Ahmad M, Bajahlan A S. Leaching of styrene and other aromatic compounds in drinking water from PS bottles[J]. Journal of Environmental Sciences, 2007, 19(4): 421-426.
[103] 李波平, 林勤保. PVC包装材料中化学物向食品迁移的研究[J]. 食品工业科技, 2007, 28(8): 197-200.
Li B P, Lin Q B. Review on the migration of chemicals from PVC plastic packaging materials to foodstuffs[J]. Food Industry Science and Technology, 2007, 28(8): 197-200.
[104] Alexiadou P, Foskolos I, Frantzis A. Ingestion of macroplastics by odontocetes of the Greek Seas, eastern Mediterranean: often deadly![J]. Marine Pollution Bulletin, 2019, 146: 67-75.
[105] Derraik J G B. The pollution of the marine environment by plastic debris: a review[J]. Marine Pollution Bulletin, 2002, 44(9): 842-852.
[106] Bjorndal K A, Bolten A B, Lagueux C J. Ingestion of marine debris by juvenile sea turtles in coastal Florida habitats[J]. Marine Pollution Bulletin, 1994, 28(3): 154-158.
[107] Imhof H K, Ivleva N P, Schmid J, et al. Contamination of beach sediments of a subalpine lake with microplastic particles[J]. Current Biology, 2013, 23(19): R867-R868.
[108] Free C M, Jensen O P, Mason S A, et al. High-levels of microplastic pollution in a large, remote, mountain lake[J]. Marine Pollution Bulletin, 2014, 85(1): 156-163.
[109] Zhao S Y, Zhu L X, Li D J. Microscopic anthropogenic litter in terrestrial birds from Shanghai, China: not only plastics but also natural fibers[J]. Science of the Total Environment, 2016, 550: 1110-1115.
[110] Thompson R C, Olsen Y, Mitchell R P, et al. Lost at sea: where is all the plastic?[J]. Science, 2004, 304(5672). DOI:10.1126/science.1094559
[111] Setälä O, Fleming-Lehtinen V, Lehtiniemi M. Ingestion and transfer of microplastics in the planktonic food web[J]. Environmental Pollution, 2014, 185: 77-83.
[112] Wright S L, Rowe D, Thompson R C, et al. Microplastic ingestion decreases energy reserves in marine worms[J]. Current Biology, 2013, 23(23): R1031-R1033.
[113] Gall S C, Thompson R C. The impact of debris on marine life[J]. Marine Pollution Bulletin, 2015, 92(1-2): 170-179.
[114] Ramos J A A, Barletta M, Costa M F. Ingestion of nylon threads by Gerreidae while using a tropical estuary as foraging grounds[J]. Aquatic Biology, 2012, 17(1): 29-34.
[115] von Moos N, Burkhardt-Holm P, Köhler A. Uptake and effects of microplastics on cells and tissue of the blue mussel Mytilus edulis L. after an experimental exposure[J]. Environmental Science & Technology, 2012, 46(20): 11327-11335.
[116] Rochman C M, Hoh E, Kurobe T, et al. Ingested plastic transfers hazardous chemicals to fish and induces hepatic stress[J]. Scientific Reports, 2013, 3(1). DOI:10.1038/srep03263
[117] Deng Y F, Zhang Y, Lemos B, et al. Tissue accumulation of microplastics in mice and biomarker responses suggest widespread health risks of exposure[J]. Scientific Reports, 2017, 7(1). DOI:10.1038/srep46687
[118] Jin H B, Ma T, Sha X X, et al. Polystyrene microplastics induced male reproductive toxicity in mice[J]. Journal of Hazardous Materials, 2021, 401. DOI:10.1016/j.jhazmat.2020.123430
[119] Tanaka K, Takada H, Yamashita R, et al. Accumulation of plastic-derived chemicals in tissues of seabirds ingesting marine plastics[J]. Marine Pollution Bulletin, 2013, 69(1-2): 219-222.
[120] Bakir A, Rowland S J, Thompson R C. Transport of persistent organic pollutants by microplastics in estuarine conditions[J]. Estuarine, Coastal and Shelf Science, 2014, 140: 14-21.
[121] Andrady A L. Microplastics in the marine environment[J]. Marine Pollution Bulletin, 2011, 62(8): 1596-1605.
[122] Claessens M, Meester S D, Landuyt L V, et al. Occurrence and distribution of microplastics in marine sediments along the Belgian coast[J]. Marine Pollution Bulletin, 2011, 62(10): 2199-2204.
[123] Murty B S, Shankar P, Raj B, et al. Unique properties of nanomaterials[A]. In: Murty B S, Shankar P, Raj B, et al (Eds.). Textbook of Nanoscience and Nanotechnology[M]. Berlin, Heidelberg: Springer, 2013. 29-65.
[124] Ray P C, Yu H T, Fu P P. Toxicity and environmental risks of nanomaterials: challenges and future needs[J]. Journal of Environmental Science and Health, Part C, 2009, 27(1): 1-35.
[125] Ma Y N, Huang A N, Cao S Q, et al. Effects of nanoplastics and microplastics on toxicity, bioaccumulation, and environmental fate of phenanthrene in fresh water[J]. Environmental Pollution, 2016, 219: 166-173.
[126] Rist S, Baun A, Almeda R, et al. Ingestion and effects of micro-and nanoplastics in blue mussel (Mytilus edulis) larvae[J]. Marine Pollution Bulletin, 2019, 140: 423-430.
[127] Jeong C B, Won E J, Kang H M, et al. Microplastic size-dependent toxicity, oxidative stress induction, and p-JNK and p-p38 activation in the monogonont rotifer (Brachionus koreanus)[J]. Environmental Science & Technology, 2016, 50(16): 8849-8857.
[128] Triebskorn R, Braunbeck T, Grummt T, et al. Relevance of nano-and microplastics for freshwater ecosystems: a critical review[J]. TrAC trends in Analytical Chemistry, 2019, 110: 375-392.
[129] Singh N, Bhagat J, Tiwari E, et al. Metal oxide nanoparticles and polycyclic aromatic hydrocarbons alter nanoplastic's stability and toxicity to zebrafish[J]. Journal of Hazardous Materials, 2021, 407. DOI:10.1016/j.jhazmat.2020.124382
[130] Teuten E L, Rowland S J, Galloway T S, et al. Potential for plastics to transport hydrophobic contaminants[J]. Environmental Science & Technology, 2007, 41(22): 7759-7764.
[131] Hüffer T, Praetorius A, Wagner S, et al. Microplastic exposure assessment in aquatic environments: learning from similarities and differences to engineered nanoparticles[J]. Environmental Science & Technology, 2017, 51(5): 2499-2507.
[132] Velzeboer I, Kwadijk C J A F, Koelmans A A. Strong sorption of PCBs to nanoplastics, microplastics, carbon nanotubes, and fullerenes[J]. Environmental Science & Technology, 2014, 48(9): 4869-4876.
[133] Eerkes-Medrano D, Thompson R C, Aldridge D C. Microplastics in freshwater systems: a review of the emerging threats, identification of knowledge gaps and prioritisation of research needs[J]. Water Research, 2015, 75: 63-82.
[134] Browne M A, Niven S J, Galloway T S, et al. Microplastic moves pollutants and additives to worms, reducing functions linked to health and biodiversity[J]. Current Biology, 2013, 23(23): 2388-2392.