Changsha Research Station for Agricultural and Environmental Monitoring, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; College of Agriculture, Yangtze University, Jingzhou 434025, China.
Changsha Research Station for Agricultural and Environmental Monitoring, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China.
Ecotoxicol Environ Saf. 2021 Oct 1;222:112480. doi: 10.1016/j.ecoenv.2021.112480. Epub 2021 Jun 30.
The potentially negative effects of microplastics (MP) on agroecosystems have raised worldwide concerns. However, little is known about the negative effects of MP exposure on the soil-plant system. To fill up this knowledge gap, a pot experiment was set up, and two different MP types [high density polyethylene (HDPE) and general purpose polystyrene (GPPS)] were used, which had four particle sizes (<25, 25-48, 48-150, and 150-850 µm) at four application rates (2.5, 5, 10, and 20 g MP kg soil). Some soil properties and the growth of Chinese cabbage (Brassica chinensis L.) were monitored. The results showed that (1) MP application with high application rates and relatively small particle sizes significantly enhanced the soil urease activity, which accompanied with enhanced soil pH and decreased soil available concentrations of phosphorus and potassium in some cases. (2) The exposure of MP did not significantly affect the activity of soil catalase regardless of their application rates and sizes. MP with different application rates and small sizes significantly reduced the soil sucrase activity, but the largest size of MP enhanced the activity of soil sucrase. (3) GPPS at 10-20 g kg or with the sizes of <25 and 48-150 µm significantly reduced the fresh weight of Chinese cabbage, but the addition of HDPE had no remarkable effects on the fresh weight regarding of its application rates or sizes. (4) MP with high application rates and large sizes enhanced but small sizes of MP reduced the leaf soluble sugar concentration. The increasing application rates of MP and small size HDPE significantly reduced the starch concentration in the leaves of Chinese cabbage, however, the different sizes of GPPS showed limited effects on the leaf starch. The addition of MP with increasing application rates and different sizes always reduced the concentration of leaf chlorophyll. These parameters regarding to plant and soil could be used to assess the risks of MP pollution in the soil-plant systems. We found that the risks resulting from MP pollution were MP type-dependent and particle size-dependent. These findings indicate that overaccumulation of MP in the agriculture may possess an ecology risk and will negatively affect the agricultural sustainability and the food safety.
微塑料（MP）对农业生态系统可能产生的负面影响引起了全球关注。然而，对于 MP 暴露对土壤-植物系统的负面影响知之甚少。为了填补这一知识空白，进行了一项盆栽实验，使用了两种不同类型的 MP [高密度聚乙烯（HDPE）和通用聚苯乙烯（GPPS）]，它们有四种粒径（<25、25-48、48-150 和 150-850μm），四种施用量（2.5、5、10 和 20g MP kg 土壤）。监测了一些土壤特性和白菜（Brassica chinensis L.）的生长情况。结果表明：（1）高施用量和相对较小粒径的 MP 显著增强了土壤脲酶活性，同时在某些情况下还会提高土壤 pH 值并降低土壤有效磷和钾浓度。（2）无论施用量和粒径大小如何，MP 暴露对土壤过氧化氢酶活性均无显著影响。不同施用量和小粒径的 MP 显著降低了土壤蔗糖酶活性，但最大粒径的 MP 增强了土壤蔗糖酶活性。（3）10-20g kg 的 GPPS 或粒径为<25 和 48-150μm 的 MP 显著降低了白菜的鲜重，但添加 HDPE 对鲜重没有明显影响，不论其施用量或粒径大小。（4）高施用量和大粒径的 MP 会增强，但小粒径的 MP 会降低白菜叶片可溶性糖浓度。随着 MP 施用量的增加和小粒径 HDPE 的增加，叶片中淀粉浓度显著降低，而不同粒径的 GPPS 对叶片淀粉浓度的影响有限。随着 MP 施用量的增加和不同粒径的增加，叶片叶绿素浓度总是降低。这些关于植物和土壤的参数可用于评估土壤-植物系统中 MP 污染的风险。我们发现，MP 污染的风险取决于 MP 类型和粒径大小。这些发现表明，农业中 MP 的过度积累可能存在生态风险，并会对农业可持续性和食品安全产生负面影响。
