Research article - Peer-reviewed, 2021
Nanoplastic Transport in Soil via Bioturbation by Lumbricus terrestris
Heinze, Wiebke Mareile; Mitrano, Denise M.; Lahive, Elma; Koestel, John; Cornelis, GeertAbstract
Plastic pollution is increasingly perceived as an emerging threat to terrestrial environments, but the spatial and temporal dimension of plastic exposure in soils is poorly understood. Bioturbation displaces microplastics (>1 mu m) in soils and likely also nanoplastics (<1 mu m), but empirical evidence is lacking. We used a combination of methods that allowed us to not only quantify but to also understand the mechanisms of biologically driven transport of nanoplastics in microcosms with the deep-burrowing earthworm Lumbricus terrestris. We hypothesized that ingestion and subsurface excretion drives deep vertical transport of nanoplastics that subsequently accumulate in the drilosphere, i.e., burrow walls. Significant vertical transport of palladium-doped polystyrene nanoplastics (diameter 256 nm), traceable using elemental analysis, was observed and increased over 4 weeks. Nanoplastics were detected in depurated earthworms confirming their uptake without any detectable negative impact. Nanoplastics were indeed enriched in the drilosphere where cast material was visibly incorporated, and the reuse of initial burrows could be monitored via X-ray computed tomography. Moreover, the speed of nanoplastics transport to the deeper soil profile could not be explained with a local mixing model. Earthworms thus repeatedly ingested and excreted nanoplastics in the drilosphere calling for a more explicit inclusion of bioturbation in nanoplastic fate modeling under consideration of the dominant mechanism. Further investigation is required to quantify nanoplastic re-entrainment, such as during events of preferential flow in burrows.Keywords
Microplastic; transport; fate; exposure; X-ray computed tomography; earthwormsPublished in
Environmental Science and Technology2021, volume: 55, number: 24, pages: 16423-16433
Publisher: AMER CHEMICAL SOC
Authors' information
Swedish University of Agricultural Sciences, Department of Soil and Environment
Mitrano, Denise M.
ETH Zurich
Lahive, Elma
UK Centre for Ecology and Hydrology (UKCEH)
Koestel, John (Koestel, Johannes)
Swedish University of Agricultural Sciences, Department of Soil and Environment
Koestel, John (Koestel, Johannes)
Agroscope
Swedish University of Agricultural Sciences, Department of Soil and Environment
UKÄ Subject classification
Environmental Sciences
Soil Science
Publication Identifiers
DOI: https://doi.org/10.1021/acs.est.1c05614
URI (permanent link to this page)
https://res.slu.se/id/publ/116578