April 10, 2025 – An important research progress has been recently published online in the internationally authoritative academic journal Nature. This research was jointly completed by the research groups of Professor Wang Lei and Professor Sun Hongwen from the College of Environmental Science and Engineering at Nankai University, the research group of Professor Baoshan Xing from the University of Massachusetts Amherst in the United States, in collaboration with the Research Center for Eco – Environmental Sciences of the Chinese Academy of Sciences, Northeastern University, and the Beijing Academy of Agriculture and Forestry Sciences.
The title of this research paper is “Leaf absorption contributes to accumulation of microplastics in plants”. For a long time, there has been a lack of conclusive evidence regarding the potential absorption behavior of atmospheric microplastics by plant leaves. The research team tackled this challenge head – on. By leveraging advanced detection techniques such as mass spectrometry, hyperspectral imaging, and atomic force microscopy – infrared spectroscopy (AFM – IR) combination, they successfully overcame the research difficulties of the size limitation of microplastics in environmental samples and the difficulty in quantitatively characterizing the level of bio – accumulation. They not only successfully observed the absorbed microplastic particles within the leaves of plants in real – world environments but also revealed the correlation between the microplastics enriched in leaves and those in the atmosphere. Moreover, through simulated exposure experiments, they elaborated in detail the absorption and enrichment mechanism by which microplastics can be absorbed through leaf stomata, enter the vascular bundle along the apoplast pathway, and accumulate in trichomes.
According to AsiaMB, this study for the first time clearly indicates that the absorption of atmospheric microplastics by leaves is a key pathway for microplastics to enter the food chain and even the human body. This achievement has significantly advanced the understanding in the field of microplastic pollution research. It is another leading achievement in the research field of new pollutants in China, which can provide a solid scientific basis for the formulation of pollutant management policies. Plant absorption is an important way for many pollutants to enter the food chain. Although plants can absorb microplastics from the soil through their roots, the upward transportation efficiency is not high, and the impact on the above – ground edible parts is limited. However, with the widespread presence of microplastic pollution in the atmosphere, if it can be directly absorbed by plant leaves, it will undoubtedly bring more direct ecological risks of pollution. The new pollutant research team at Nankai University, with environmental science as the core, integrates methods and cutting – edge technologies from geosciences, ecology, and analytical chemistry. They conducted field investigations and laboratory simulation studies on the potential absorption behavior of atmospheric microplastics by plant leaves.
The research team selected typical areas such as polyester production enterprises and landfills. By using techniques such as “chemical depolymerization – monomer compound mass spectrometry detection” independently developed by the team, they accurately and quantitatively characterized the pollution levels of polyethylene terephthalate (PET) and polystyrene (PS) microplastics as well as plastic oligomers in tree leaves. The study found that the concentrations of PET and PS polymers in some plant leaves can reach up to 10^4 ng/g at the highest, and are significantly correlated with leaf growth duration, leaf gas exchange capacity, and the level of air pollution. With the help of hyperspectral imaging (HSI) and atomic force microscopy – infrared spectroscopy (AFM – IR) combination technology, the researchers observed absorbed PET, PS, PA (nylon), and PVC (polyvinyl chloride) microplastic particles in the leaves of on – site plants.
The research team also carried out various forms of exposure experiments using on – site collected microplastic dust as well as fluorescent – labeled and europium – labeled microplastic particles. Through HSI, laser confocal microscopy, and laser ablation inductively coupled plasma mass spectrometry characterization methods, they clearly revealed the behavioral pattern of microplastics being absorbed by the stomata of corn leaves, transported to the vascular tissue through the apoplast pathway, and accumulated in the leaf trichomes. The study also reported the concentration levels of microplastics in vegetables, highlighting the significant impact of open – field – grown leafy vegetables on human exposure to microplastics and revealing the key role of plants in the potential risks to the ecosystem and human health during the process of environmental microplastics entering the food chain. Nankai University is the first corresponding unit, and Professor Wang Lei, Professor Baoshan Xing, and Professor Sun Hongwen are the corresponding authors of this paper. Li Ye, a 2021 – level doctoral student majoring in environmental science at the College of Environmental Science and Engineering, is the first author of the paper. This research work was funded by the National Key Research and Development Program of China, the General Program of the National Natural Science Foundation of China, and the International Cooperation Project of the Asia – Pacific Network for Global Change Research (APN).