Liu Mengting, Song Yang, Lu Shibo, Qiu Rong, Hu Jiani, Li Xinyu, Bigalke Moritz, Shi Huahong, He Defu
School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China.
Institute of Geography, University of Bern, Hallerstrasse 12, 3012 Berne, Switzerland.
Sci Total Environ. 2019 Nov 15;691:341-347. doi: 10.1016/j.scitotenv.2019.07.144. Epub 2019 Jul 11.
Microplastics (MP) have been recently found in soil environments. These MP might have adverse effects at high concentrations and thus efficient extraction and analysis of MP from soil is needed. Here we propose a new method of NaBr solution circulation for extracting soil MP. A device for the circular extraction of soil MP was developed. This device included a separation, vacuum filtration, and solution recovery system. It was then utilized to test separation efficiency of soil MP with three economic and environmentally friendly extraction reagents: NaCl, CaCl and NaBr solutions. The separation was tested with ten different types of polymers, three different size classes and three different shapes of MP. Extraction with NaBr showed the highest recovery rates ranging from 85% to 100%. After extraction the samples were treated with HO and analyzed by micro-Fourier transform infrared spectroscopy. The developed method was assessed for its potential influence on MP and no significant changes in the integrity of multiple MP were found. Finally, the established method was used to analyze MP in four types of soil: farmland, yellow-brown, paddy and floodplain soil from the suburb of Shanghai. Results showed that the mean abundance of MP was 136.6-256.7 item kg. Various MP including PP (40%), PE (35.5%), Acrylic (15.6%), PET (6.7%) and PA (2.2%) were found. With this paper, we provide an alternative method through NaBr solution circulation for the extraction of soil MP.
最近在土壤环境中发现了微塑料（MP）。这些微塑料在高浓度时可能会产生不利影响，因此需要从土壤中高效提取和分析微塑料。在此，我们提出一种用于提取土壤微塑料的溴化钠溶液循环新方法。开发了一种用于循环提取土壤微塑料的装置。该装置包括分离、真空过滤和溶液回收系统。然后利用它用三种经济且环保的提取试剂（氯化钠、氯化钙和溴化钠溶液）测试土壤微塑料的分离效率。用十种不同类型的聚合物、三种不同尺寸等级和三种不同形状的微塑料进行了分离测试。用溴化钠提取显示出最高回收率，范围为85%至100%。提取后，样品用双氧水进行处理，并通过微傅里叶变换红外光谱进行分析。评估了所开发方法对微塑料的潜在影响，未发现多种微塑料的完整性有显著变化。最后，使用所建立的方法分析了四种类型土壤中的微塑料：上海郊区的农田土、黄棕壤、水稻土和河漫滩土。结果表明，微塑料的平均丰度为136.6 - 256.7个/千克。发现了各种微塑料，包括聚丙烯（40%）、聚乙烯（35.5%）、丙烯酸（15.6%）、聚对苯二甲酸乙二酯（6.7%）和聚酰胺（2.2%）。通过本文，我们提供了一种通过溴化钠溶液循环提取土壤微塑料的替代方法。
