The ubiquitous distribution of microplastics (MP) is a serious environmental issue in Asian countries. In this study, 54 open-dumping site soils collected from Cambodia, India, Indonesia, Laos, the Philippines, and Vietnam were analyzed for MP. Soil samples were also divided into light (floating) and heavy (sedimentation) fractions by density separation and analyzed for plastic additives. The highest abundance of MP was found in a soil from Cambodia at 218,182 pieces/kg. The median of MP in soils ranged from 1411 pieces/kg in India to 24,000 pieces/kg in the Philippines, suggesting that dumping sites are a major source of MP into the environment. Polyethylene, polypropylene, and polyethylene terephthalate were dominant polymers in soil samples analyzed. This indicates that daily-used plastic products are main sources of MP in dumping site soils in Asian countries. The high concentrations and burdens of phthalates and an antioxidant were detected in floating fraction accounting for 40 to 60% of the total additives in soils. Previous studies on soil pollution have assumed that the organic hydrophobic chemicals analyzed are adsorbed on the surface of soil particles. However, this result indicates that approximately half of the additives in dumping site soils were derived from MP, not soil particle. Monitoring study on soil pollution should be considered the occurrence of MP in the matrices.

微塑料 (MP) 无处不在的分布是亚洲国家一个严重的环境问题。在这项研究中，对从柬埔寨、印度、印度尼西亚、老挝、菲律宾和越南收集的 54 个露天倾倒场土壤进行了 MP 分析。土壤样品也通过密度分离分为轻（漂浮）和重（沉淀）部分，并分析塑料添加剂。在柬埔寨的土壤中发现的 MP 含量最高，为 218,182 件/公斤。土壤中 MP 的中位数从印度的 1411 件/公斤到菲律宾的 24,000 件/公斤不等，表明倾倒场是 MP 进入环境的主要来源。聚乙烯、聚丙烯和聚对苯二甲酸乙二醇酯是分析的土壤样品中的主要聚合物。这表明日用塑料制品是亚洲国家垃圾倾倒场土壤中 MP 的主要来源。在占土壤总添加剂 40% 至 60% 的漂浮部分中检测到邻苯二甲酸酯和抗氧化剂的高浓度和负荷。先前对土壤污染的研究假设所分析的有机疏水性化学物质吸附在土壤颗粒表面。然而，这一结果表明倾倒场土壤中大约一半的添加剂来自 MP，而不是土壤颗粒。土壤污染监测研究应考虑基质中MP的发生情况。先前对土壤污染的研究假设所分析的有机疏水性化学物质吸附在土壤颗粒表面。然而，这一结果表明倾倒场土壤中大约一半的添加剂来自 MP，而不是土壤颗粒。土壤污染监测研究应考虑基质中MP的发生情况。先前对土壤污染的研究假设所分析的有机疏水性化学物质吸附在土壤颗粒表面。然而，这一结果表明倾倒场土壤中大约一半的添加剂来自 MP，而不是土壤颗粒。土壤污染监测研究应考虑基质中MP的发生情况。