Nanoplastics in forests: Exploring the effects of nanoplastics on forest soils and tree physiology (NanoPlast)

The fate of plastic in the environment is of global concern, because its production recently has increased strongly and it accumulates in terrestrial and aquatic ecosystems. Although some knowledge on its role in aquatic and terrestrial ecosystems was gained in the recent decade, hitherto very little is known about the impact of micro and nanoplastics in forest ecosystems. The aim of this pioneering project was to explore if nanoplastics are taken up by forest trees species through leaves or roots. In greenhouse experiments, we exposed leaves or roots of seedling of two forest trees species to solutions with highly 13C-labelled polystyrene nanoparticles (13C-nPS, 99 atom%) and examined if they were incorporated in different above- and belowground tissues. Treated part of the trees for both species showed significant 13C-enrichment, indicating that trees take up nanoparticles. However, the overall 13C signal strength in tissues that were not exposed to the 13C label remained low (Δδ13C-1‰) and was confined to a few seedlings, leaving it ambiguous whether nanoplastic transport occurs or not. We acknowledge that the new method developed might be not sensitive enough to unequivocally detect mechanisms of nanoplastic uptake and transport at environmentally realistic concentrations.

塑料在环境中的归趋是全球关注的热点问题，近年来其产量大幅增长，并在陆地与水生生态系统中持续累积。近十年来，学界对塑料在水生和陆地生态系统中的作用已积累了一定认知，但迄今为止，关于微塑料和纳米塑料（micro and nanoplastics）对森林生态系统的影响，相关研究仍极为匮乏。本开创性研究项目旨在探究森林树木物种是否可通过叶片或根系吸收纳米塑料。在温室实验中，我们将两种林木幼苗的叶片或根系暴露于高浓度碳13标记的聚苯乙烯纳米塑料（13C-labelled polystyrene nanoparticles, 13C-nPS，99 atom%）溶液中，并检测其是否被整合至不同的地上与地下组织内。两个树种的处理组树木均呈现出显著的13C富集现象，表明树木能够吸收纳米塑料。然而，未暴露于13C标记物的组织中，整体13C信号强度仍处于较低水平（Δδ13C-1‰），且仅在少数幼苗中可被检测到，因此无法明确纳米塑料是否发生了跨组织运输。本研究承认，所开发的新方法灵敏度或不足以在环境现实浓度下，明确检测纳米塑料的吸收与运输机制。