Environmental Technology Division, CSIR-National Botanical Research Institute, Lucknow, India; Institute of Environment and Sustainable Development, Banaras Hindu University, Varanasi, India.
Institute of Environment and Sustainable Development, Banaras Hindu University, Varanasi, India.
NanoImpact. 2024 Jul;35:100525. doi: 10.1016/j.impact.2024.100525. Epub 2024 Aug 10.
The ubiquitousness of microplastics (<5 mm) has become a pressing environmental concern globally due to the extensive use of plastics. Microplastics have been well-studied in aquatic environments but not well-characterized in soils. Present analytical processes to quantify microplastics accurately in soil samples are quite challenging and require improved and validated analytical steps to eliminate the obscurities and biases. We aimed to develop an effective method for the extraction and quantification of microplastics from soil samples. Different ratios of low-(NaCl) and high-density solutions (ZnCl/ NaBr) were tested to determine the most efficient combination for density-dependent separation of microplastics from soil. The combination of low- (1:6) and high-density (1:3) solutions {as weight of soil(g)/volume of density solution(ml)} accounted for 95% recovery of the spiked microplastic particles from soil samples. Likewise, different soil-to-solution ratios of HO were tested for the removal of soil organic matter with heating and non-heating steps. Prior removal of organic matter from soil samples achieved a clear supernatant that facilitated 99% recovery of microplastic particles. The validation of individually spiked microplastic particles of small (10-100 μm) and large scale (100-5000 μm) resulted in recovery ranging from 88 to 99%. A validated modified method with prior digestion followed by density-dependent separation was further tested using the field samples with microplastic contamination. The microplastics of different shapes, sizes, colours and polymeric compositions were reported efficiently and well characterized in the field-collected soil samples using this method.
由于塑料的广泛使用，无处不在的微塑料（<5 毫米）已成为全球紧迫的环境关注点。微塑料在水生环境中已经得到了很好的研究，但在土壤中却没有得到很好的描述。目前，准确量化土壤样品中微塑料的分析过程极具挑战性，需要改进和验证分析步骤，以消除不确定性和偏差。我们旨在开发一种从土壤样品中提取和量化微塑料的有效方法。测试了不同比例的低盐（NaCl）和高密度溶液（ZnCl/NaBr），以确定从土壤中分离微塑料的密度依赖性最有效的组合。低浓度（1:6）和高浓度（1:3）溶液（按土壤重量（g）/密度溶液体积（ml）的比例）的组合可从土壤样品中回收 95%的添加微塑料颗粒。同样，测试了不同的土壤与 HO 的比例，以在加热和非加热步骤中去除土壤中的有机质。在从土壤样品中预先去除有机质后，可获得清澈的上清液，从而实现 99%的微塑料颗粒回收率。单独添加的小（10-100μm）和大（100-5000μm）微塑料颗粒的验证结果表明回收率在 88%至 99%之间。在进一步使用受微塑料污染的现场样品测试经过预先消化和密度依赖性分离的经过验证的改良方法后，可有效地报告并很好地描述了不同形状、大小、颜色和聚合物组成的微塑料。
