Abstract

Sanitary landfills and uncontrolled dumpsites are plastic wastes (PWs) reservoirs containing ∼60% of all the plastics ever made, amounting to 5,000 × 10⁶ tons as of 2017. The distribution, long-term behavior, and release of macro- and microplastics (MPs) from disposal sites are critical to global plastics pollution, but are poorly understood and lack systematic assessments. We review comprehensively the available knowledge in the three aspects herein. The spatial and temporal distribution of PW in 616 municipal solid waste (MSW) samples retrieved from 275 disposal sites in 56 countries are summarized. The weight percentages of PW (%PW) generally decrease with increasing year of disposal and disposal depth. Other influential factors are disposal duration and country income level. The %PW values in different disposal sites show high regionality and spatial variability and heterogeneity. Disposal sites mostly have harsh temperature and stress, reactive liquids, and microbial activities, which are conducive to long-term processes of PW and MPs. The major processes are chemical degradation, dissolution, leaching and adsorption, biological degradation, mechanical wearing, pneumatic and hydrological transport and deposition, and conglomeration. PW leaves disposal sites via recycling, scavenging, mining, wind and surface runoff, coastal erosion and flooding, and slope failure. The release and removal pathways of PW from disposal sites have been recognized only qualitatively. In addition, the sources, presences, and secondary generation of MPs in disposal sites have been studied occasionally, whereas the transport and fate of MPs within and from disposal sites remain largely unstudied.

摘要

卫生垃圾填埋场和不受控制的垃圾场是塑料废物 (PW) 库，其中包含 60% 的所有塑料，总计 5,000 × 10 ⁶吨，截至 2017 年。处理场的宏观和微塑料 (MPs) 的分布、长期行为和释放对全球塑料污染至关重要，但人们对此知之甚少，缺乏系统评估。我们全面回顾了本文三个方面的可用知识。总结了从 56 个国家的 275 个处置场回收的 616 个城市固体废物 (MSW) 样品中 PW 的时空分布。PW 的重量百分比（%PW）一般随着处置年份和处置深度的增加而降低。其他影响因素是处置期限和国家收入水平。不同处置场的%PW值表现出较高的区域性和空间变异性和异质性。处置场所大多具有严酷的温度和压力、反应性液体和微生物活动，这有利于PW和MPs的长期进程。主要过程是化学降解、溶解、浸出和吸附、生物降解、机械磨损、气力和水文输送和沉积以及团聚。PW 通过回收、清除、采矿、风和地表径流、海岸侵蚀和洪水以及斜坡破坏离开处置场。PW 从处置场释放和清除的途径仅在定性上得到认可。此外，偶尔研究过处置场内 MPs 的来源、存在和二次生成，而处置场内和来自处置场的 MPs 的运输和归宿在很大程度上仍未研究。机械磨损、气力和水文输送和沉积以及聚集。PW 通过回收、清除、采矿、风和地表径流、海岸侵蚀和洪水以及斜坡破坏离开处置场。PW 从处置场释放和清除的途径仅在定性上得到认可。此外，偶尔研究过处置场内 MPs 的来源、存在和二次生成，而处置场内和来自处置场的 MPs 的运输和归宿在很大程度上仍未研究。机械磨损、气力和水文输送和沉积以及聚集。PW 通过回收、清除、采矿、风和地表径流、海岸侵蚀和洪水以及斜坡破坏离开处置场。PW 从处置场释放和清除的途径仅在定性上得到认可。此外，偶尔研究过处置场内 MPs 的来源、存在和二次生成，而处置场内和来自处置场的 MPs 的运输和归宿在很大程度上仍未研究。PW 从处置场释放和清除的途径仅在定性上得到认可。此外，偶尔研究过处置场内 MPs 的来源、存在和二次生成，而处置场内和来自处置场的 MPs 的运输和归宿在很大程度上仍未研究。PW 从处置场释放和清除的途径仅在定性上得到认可。此外，偶尔研究过处置场内 MPs 的来源、存在和二次生成，而处置场内和来自处置场的 MPs 的运输和归宿在很大程度上仍未研究。