School of Environmental Science and Engineering, Tianjin University, Tianjin, 300354, PR China.
Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Resources, Fuzhou University, Fuzhou, 350108, PR China.
Environ Pollut. 2021 Jan 15;269:116199. doi: 10.1016/j.envpol.2020.116199. Epub 2020 Dec 1.
Microplastic (MP) pollution poses a huge threat to agroecosystems, but the distribution characteristics of MPs in different types of farmland are still largely unknown. In this work, samples from six land-use types were collected from Chinese farmlands in five provinces. It was found that MP abundances were in the range of 2783-6366 items/kg in all samples. MP distribution results showed that over 80% of particles were less than 1 mm, and that MP sizes ranging between 0.02 and 0.2 mm represented the greatest proportion. The particle shape classified as fragment (with edges and angular) was the most frequent shape, with an abundance of approximately 54.05%. Polyethylene (PE) and polyamides (PA) were the most abundant polymers in cropped lands; 20.88% and 20.31%, respectively. Statistical analyses showed that lands used for plastic mulching (mulch film and greenhouse crops) had a significantly higher particle abundance, hence identifying plastic mulching as a major contributor to MP pollution in agricultural lands. Furthermore, paddy lands had a significantly higher MP abundance than wheat lands. Variation analyses of MP characteristics revealed that cereal crop farmlands (wheat, paddy land) were more likely to contain fibrous shapes and large MP particles (1-5 mm). Economically important tree lands (orchards, woodlands) were likely to contain fragment shapes and pony-size MPs (0.02-0.2 mm). Discrepancies among farmlands may depend on various reasons, such as mulching plastic application, irrigation, atmospheric fallout, etc. This study provides firsthand evidences about the characteristics of MP pollution in farmlands and explores some predominant MP sources in agroecosystems.
微塑料（MP）污染对农业生态系统构成了巨大威胁，但不同类型农田中 MP 的分布特征仍知之甚少。本研究从中国五个省份的农田中采集了六种土地利用类型的样本。结果发现，所有样本中 MP 的丰度范围为 2783-6366 个/千克。MP 分布结果表明，超过 80%的颗粒小于 1 毫米，粒径在 0.02-0.2 毫米之间的 MP 占比最大。碎片形状（有棱有角）的颗粒是最常见的形状，丰度约为 54.05%。在种植地中，最丰富的聚合物是聚乙烯（PE）和聚酰胺（PA），分别为 20.88%和 20.31%。统计分析表明，用于塑料覆盖（地膜和温室作物）的土地颗粒丰度显著更高，因此鉴定出塑料覆盖是农业用地中 MP 污染的主要来源。此外，稻田的 MP 丰度明显高于麦田。MP 特征的变化分析表明，谷物农田（小麦、稻田）更有可能含有纤维状和较大的 MP 颗粒（1-5 毫米）。经济重要的林地（果园、林地）更可能含有碎片状和小马大小的 MP（0.02-0.2 毫米）。农田之间的差异可能取决于各种原因，如覆盖塑料的应用、灌溉、大气沉降等。本研究提供了农田中 MP 污染特征的第一手证据，并探讨了农业生态系统中一些主要的 MP 来源。
