THE PLASTIC UNDERGROUND – EXPLORING THE MECHANISMS CONTROLLING THE FATE AND TRANSPORT OF MICROPLASTICS IN THE SUBSURFACE

While there have been advances in understanding the above ground plastic cycle, there is still a substantial lack of understanding the sources and activation mechanisms of plastic pollution affecting the entry, fate, transport, transformation and impact of microplastics into soils, riverbeds, sediment and groundwater aquifers. We here present the initial outcomes of integrated field and laboratory analytical experimental approaches and mathematical modelling studies to provide mechanistic understanding of the overall magnitude as well as hot spots (and hot moments) of microplastic entry into subsurface ecosystems and their transport and transformation pathways. Our model results highlight that a large proportion (>95%) of all mismanaged plastic waste emitted since the 1950s is temporarily stored in river basins and able to enter subsurface ecosystems in the long-term. Using multi-scale modelling studies in combination with artificial river simulators (flumes) we evidence that hyporheic exchange represents a preferential input mechanism for smaller and lighter microplastics into streambed sediments and underlying groundwater ecosystems. This finding maps directly onto field experimental findings from our global monitoring programme which identified streambed distinct streambed hotspots of microplastic accumulation. Soil and streambed sediment columns were deployed to explore the controls on microplastic transport once they have entered the subsurface, highlighting that in particular intermittent, pulsed hydraulic forcing increases the potential for fast particle transport. 

Presentation Preference: Oral

Primary Presenter: Stefan Krause, University of Birmingham, UK (s.krause@bham.ac.uk)

Authors:

Stefan Krause, University of Birmingham, UK  (s.krause@bham.ac.uk)

Uwe Schneidewind, University of Birmingham  (u.schneidewind@bham.ac.uk)

Jaswant Singh, Indian Institute of Technology Roorkee  (jaswant_s@hy.iitr.ac.in)

Brijesh Yadav Kumar, Indian Institute of Technology Roorkee  (brijesh.yadav@hy.iitr.ac.in)

Laurent Simon, University of Lyon, LEHNA, France  (laurent.simon@univ-lyon1.fr)

Florian Mermillod-Blondin, University of Lyon, France  (florian.mermillod-blondin@univ-lyon1.fr)

Fuad Alqrinawi, University of Birmingham, UK  (f.y.m.alqrinawi@bham.ac.uk)

Bruon Fraga, University of Birmingham, UK  (b.fraga@bham.ac.uk)

Liam Kelleher, University of Birmingham, UK  (l.kelleher@bham.ac.uk)

Lee Haverson, University of Birmingham. UK  (l.haverson@bham.ac.uk)

Iseult Lynch, University of Birmingham, UK  (i.lynch@bham.ac.uk)

Sophie Comer-Warner, University of Birmingham, UK, University of Illinois Urbana Champaign, US  (s.comer-warner@bham.ac.uk)

Jesus Gomez-Velez, Oak Ridge National Lab, US  (gomezvelezjd@ornl.gov)

Laurent Lassabatiere, Ecole Nationale des Travaux Publics de l'Etat, LEHNA, France  (Laurent.LASSABATERE@entpe.fr)

Brice Mourier, Nationale des Travaux Publics de l'Etat, LEHNA, France  (Brice.MOURIER@entpe.fr)

Laurence Volatier, Nationale des Travaux Publics de l'Etat, LEHNA, France  (Laurence.VOLATIER@entpe.fr)

Petros Mecaj, University of Lyon, LEHNA, France  (petros.mecaj@univ-lyon1.fr)

Zoraida Quinones, University of Lyon, LEHNA, France  (zoraida.quinones@univ-lyon1.fr)

Bjoern Wissel, University of Lyon, LEHNA, France  (bjoern.wissel@univ-lyon1.fr)

Lizeth Cardoza Pedroza, Nationale des Travaux Publics de l'Etat, LEHNA, France  (Lizeth.CARDOZAPEDROZA@entpe.fr)

Reza Dehbandi, University of Birmingham, UK  (r.dehbandi@bham.ac.uk)