Incorporation of microplastics from litter into burrows of Lumbricus terrestris

Microplastic transport in soil by earthworms

“…We showed, as one of the first studies of this type 15 , that PE microplastic particles can clearly be transported relatively quickly by anecic earthworms downward into a soil profile from the surface to a depth of 10 cm, where the number of particles transported appears to be influenced by particle size: the smallest particles were found most in the deepest layer. Our approach here was to use a controlled experiment in pots in the greenhouse with surface-added microplastic particles, which could afterwards be retrieved from the experimental soils at various depths.…”

“…For example, Huerta Lwanga et al . 15 , having compared different concentrations of PE microplastic (rather than sizes, as we have done), find concentration-dependent incorporation of microplastic material into burrow walls (data normalized to worm biomass). Additionally, it will be important to next design studies under field conditions to capture transfer rates under more realistic conditions.…”

“…Earthworms have also been implicated in the vertical transport of biochar particles in the field 25 . Additionally, Lumbricus terrestris was also recently shown to incorporate PE microplastic particles in its burrows during a 14-day mesocosm study 15 .…”

“…Previously, Huerta Lwanga et al . 15 have shown that Lumbricus terrestris L. could in fact incorporate microplastic particles into burrows.…”

Towards an ecology of soil microplastics

“…In addition, their interactions with the soil ecosystem are more complex than those of a chemical pollutant that harms some soil organisms through direct toxicity, while perhaps being metabolized or otherwise rendered inert by others (Díaz, ; Nannipieri & Bollag, ). Even heavy metals, for which interactions with organic matter have implications for their mobility in soil (Kalbitz & Wennrich, ), or which, in the case of mercury, can be microbially altered into a more bioavailable form (Trevors, ), do not interact with the soil ecosystem in ways as diverse as microplastics can or with as diverse an array of organisms (Huerta Lwanga, Gertsen, et al, ; Huerta Lwanga et al, ; Maaß, Daphi, Lehmann, & Rillig, ). Microplastics are in some ways more reminiscent of invasive species than inanimate chemical toxins, with effects on soil biota that can be mediated through effects on the physicochemical environment (Alerding & Hunter, ; Eisenhauer, Partsch, Parkinson, & Scheu, ).…”