Li Wei-Ming, Xu Lei, Zhang Li-Chang, Shi Cai-Ling, Xie Wen-Jun
School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, China.
Huan Jing Ke Xue. 2025 Aug 8;46(8):5325-5335. doi: 10.13227/j.hjkx.202407154.
Microplastics are widespread in terrestrial and marine environments. As a transition zone between land and ocean, coastal soils have unique microplastic pollution characteristics. To reveal the characteristics of microplastic pollution in coastal soils, soils with different salinization levels were collected from Wudi County toward the sea. The distribution characteristics of microplastics and their relationship with soil physical and chemical properties were analyzed through density separation, oxidative digestion, and micro-Raman spectroscopy techniques. The pollutant load index method was used to assess its ecological risk. The results showed that microplastics were detected in 51 sampling points of coastal soil in Wudi County, and the abundance of microplastics ranged from 550 to 3 950 n·kg. Polyethylene （PE）, polyethylene terephthalate （PET）, polypropylene （PP）, polystyrene （PS）, and polyvinyl chloride （PVC） accounted for 53.1%, 13.9%, 16.4%, 8.4%, and 8.2%, respectively. The shapes of microplastics mainly included film （accounting for 62.0%）, fiber （accounting for 13.7%）, sphere （accounting for 13.2%）, and sheet （accounting for 11.1%）. Microplastics with grain size less than 1 000 μm accounted for 85.0%. The lowest abundance of microplastics appeared in the bare land with the highest degree of salinization, and the highest abundance appeared in the non-salinized cotton soil. The abundance of microplastics was significantly correlated with soil salinization levels （< 0.05）. With saline level increasing, the total abundance of microplastics and the abundance of film, PE, and PET microplastics decreased significantly （< 0.05）. The proportion of microplastics with grain size greater than 1 000 μm decreased significantly （< 0.05）, but the proportion of microplastics with grain size less than 100 μm increased significantly （< 0.05）. This may be because of the different soil use types and different sources of microplastics in soils with varied saline levels. Soil organic carbon （SOC） was significantly positively correlated with the abundance of microplastics （< 0.05）. The risk load index （PLI） values of all soil samples ranged from 1.19 to 2.41, which were low risk level pollution. Among them, the PLI values of wasteland and bare land with high saline level were lower, and the PLI values of soils with low saline level were higher. The results of this study can provide an important basis for understanding the microplastic pollution and exploring the relationship between soil properties and microplastic distribution characteristics in coastal saline soils.
微塑料在陆地和海洋环境中广泛存在。作为陆地与海洋的过渡地带，海岸带土壤具有独特的微塑料污染特征。为揭示海岸带土壤微塑料污染特征，从无棣县向海采集了不同盐渍化程度的土壤。通过密度分离、氧化消解和显微拉曼光谱技术分析了微塑料的分布特征及其与土壤理化性质的关系。采用污染物负荷指数法评估其生态风险。结果表明，在无棣县海岸带土壤的51个采样点检测到微塑料，微塑料丰度范围为550～3950个·kg。聚乙烯（PE）、聚对苯二甲酸乙二酯（PET）、聚丙烯（PP）、聚苯乙烯（PS）和聚氯乙烯（PVC）分别占53.1%、13.9%、16.4%、8.4%和8.2%。微塑料形状主要包括薄膜（占62.0%）、纤维（占13.7%）、球体（占13.2%）和薄片（占11.1%）。粒径小于1000μm的微塑料占85.0%。微塑料丰度在盐渍化程度最高的裸地中最低，在非盐渍化棉田中最高。微塑料丰度与土壤盐渍化程度显著相关（<0.05）。随着盐渍化程度增加，微塑料总丰度以及薄膜、PE和PET微塑料丰度显著降低（<0.05）。粒径大于1000μm的微塑料比例显著降低（<0.05），但粒径小于100μm的微塑料比例显著增加（<0.05）。这可能是由于不同盐渍化程度土壤的土地利用类型和微塑料来源不同。土壤有机碳（SOC）与微塑料丰度显著正相关（<0.05）。所有土壤样品的风险负荷指数（PLI）值范围为1.19～2.41，属于低风险水平污染。其中，高盐渍化荒地和裸地的PLI值较低，低盐渍化土壤的PLI值较高。本研究结果可为了解海岸带盐渍土微塑料污染及探究土壤性质与微塑料分布特征之间的关系提供重要依据。
