The Grand Challengers Podcast Episode #34

A world of plastics from macro and micro to nano – should zero plastics be the long-term goal?

Guest: Denise Mitrano

October 29th, 2024

Episode Teaser

Introduction

“…environmental science needs to beyond just describing the problem and also help working towards solutions…”

Denise Mitrano is Assistant Professor in the Environmental Systems Science Department at ETH Zurich. Trained as an environmental, analytical chemist, Denise focuses on the impacts of anthropogenic materials in technical and environmental systems, in particular, the analytics, transport, fate and legislation around plastic pollution. She is passionate about finding new creative ways to protect the environment against pollutants of emerging concern by understanding the how and finding out where we can replace and reduce their sources in our day to day lives.

On today’s show, Denise and I touch upon the topic of plastic pollution, from macro and micro to nano. We discuss the sources, some initiatives to reduce plastics entering the environment and the challenges that the science will face in the coming years. We also reflect whether a plastic free world is possible and what realistic scenarios we can expect for both environmental and human health protection and the role of science in future legislation.

Biography

Denise M. Mitrano is an Assistant Professor at ETH Zurich in the Environmental Systems Science Department. As an environmental analytical chemist, her research focuses on the distribution and impacts of anthropogenic materials in technical and environmental systems. She is particularly interested in developing analytical tools to systematically understand the mechanisms and processes driving the fate, transport and biological interactions of particles, such as engineered nanomaterials and nano- and microplastics. In this context, her research group uses these results to assess risks of anthropogenic materials across various ecosystems and scales.

An interest in a “safer by design” approach for both nanomaterials and plastics is exemplified by working on the boundaries of environmental science, materials science and policy to promote sustainability and environmental health and safety of new materials. Her work has recently been recognized by the Swiss National Science Foundation Marie Heim Vögtlin Prize for Outstanding Young Woman Researcher of the Year (2022), the 2022 James J. Morgan Early Career Award for Outstanding Contributions to Environmental Science from ES&T and the ACS Division of Environmental Chemistry, and the 2022 Emerging Investigator in Atomic Spectroscopy Award.

Resources Related to the Episode

  • Yes… we recorded this at the height of summer and I am glad that I can release this in time for the autumn weather!
  • I alluded to Denise on Jon Hathaway’s episode (Episode 24) – check out Jon’s episode for more on cycling and outdoor adventures
  • Denise recommends Veloland.ch for cycling routes across Switzerland. For other cycling routes around Zurich region, also check out Bikemap
  • Stoic philosophy from ancient Greece, for more info, check out the works of Epictetus and Seneca (Roman times)
  • For more information about legacy issues around mines, we cover this topic on Episode 17 with Mohan Yellishetty
  • What are engineered nanomaterials?
  • What are contaminants of emerging concern (CECs)? [US EPA] [Wikipedia] [ScienceDirect]
    • 6PPD-Quinone leaching out of tyre wear particles, a famous study: Tian, Z., Gonzalez, M., Rideout, C.A., Zhao, H.N., Hu, X., Wetzel, J., Mudrock, E., James, C.A., McIntyre, J.K. and Kolodziej, E.P., 2022. 6PPD-quinone: Revised toxicity assessment and quantification with a commercial standard. Environmental Science & Technology Letters, 9(2), pp.140-146. [Link]
    • What are PFAS? – some further details
  • The topic of greenwashing has showed up on several episodes in the past including Episode 3 with Martijn Kuller and Episode 16 with Mattheos Santamouris.
  • EMPA – the Swiss Federal Laboratories for Material Science & Technology
  • Microplastics:
    • The spherical macroplastic publication, also good for terminology and defining what microplastics are: Hartmann, N.B., Huffer, T., Thompson, R.C., Hassellov, M., Verschoor, A., Daugaard, A.E., Rist, S., Karlsson, T., Brennholt, N., Cole, M. and Herrling, M.P., 2019. Are we speaking the same language? Recommendations for a definition and categorization framework for plastic debris. [Link]
    • Mitrano, D.M., Wick, P. and Nowack, B., 2021. Placing nanoplastics in the context of global plastic pollution. Nature Nanotechnology, 16(5), pp.491-500. [Link]
      • The issue of microplastics from tyre wear: Wagner, S., Hüffer, T., Klöckner, P., Wehrhahn, M., Hofmann, T. and Reemtsma, T., 2018. Tire wear particles in the aquatic environment-a review on generation, analysis, occurrence, fate and effects. Water research, 139, pp.83-100. [Link]
    • The famous example worldwide of exfoliation beads
    • The famous example on single-use plastic bags
  • Organic chemistry 101 [Khan academy]
  • Denise’s work on microplastics removal:
    • Frehland, S., Kaegi, R., Hufenus, R. and Mitrano, D.M., 2020. Long-term assessment of nanoplastic particle and microplastic fiber flux through a pilot wastewater treatment plant using metal-doped plastics. Water Research, 182, p.115860. [Link]
    • Pulido-Reyes, G., Magherini, L., Bianco, C., Sethi, R., von Gunten, U., Kaegi, R. and Mitrano, D.M., 2022. Nanoplastics removal during drinking water treatment: Laboratory-and pilot-scale experiments and modeling. Journal of hazardous materials, 436, p.129011. [Link]
    • Parrella, F., Brizzolara, S., Holzner, M. and Mitrano, D.M., 2024. Impact of heteroaggregation between microplastics and algae on particle vertical transport. Nature Water, pp.1-12. [Link]
  • Denise’s work on metal-doped plastics: Mitrano, D.M., Beltzung, A., Frehland, S., Schmiedgruber, M., Cingolani, A. and Schmidt, F., 2019. Synthesis of metal-doped nanoplastics and their utility to investigate fate and behaviour in complex environmental systems. Nature nanotechnology, 14(4), pp.362-368. [Link]
  • Denise’s work on microplastics regulation:
    • Mitrano, D.M. and Wohlleben, W., 2020. Microplastic regulation should be more precise to incentivize both innovation and environmental safety. Nature communications, 11(1), p.5324. [Link]
    • Mitrano, D.M. and Wagner, M., 2022. A sustainable future for plastics considering material safety and preserved value. Nature Reviews Materials, 7(2), pp.71-73. [Link]
    • The UN Plastics Treaty and the scientific coalition working on the treaty
  • Bernd Nowack, Denise’s postdoc supervisor
  • The Marie Heim Vögetlin Prize that Denise received

Episode Chapters

(Chapters are embedded in the episode for quick access, click this to expand and view all chapters and time stamps)
  • 0:00 Intro
  • 1:59 Guest Intro and getting out of your comfort zone
  • 6:25 Discovering environmental chemistry and nanomaterials
  • 13:17 Contaminants of emerging concern
  • 16:16 Denise’s journey to Switzerland
  • 18:00 Plastics 101
  • 24:53 Two historical examples of plastics management
  • 27:23 Can we create a plastic-free world?
  • 30:36 Denise’s Research Pillar 1 – Analytical
  • 34:40 Denise’s Research Pillar 2 – Transport and Fate
  • 41:23 Metal-doped Microplastics
  • 47:39 Denise’s Research Pillar 3 – Policy and Regulation
  • 51:43 Denise’s Future Research Trajectory
  • 57:43 Q&A Start
  • 58:00 What inspires you?
  • 58:56 If you had a magic wand?
  • 1:01:16 Key event, person, book
  • 1:02:59 Time management
  • 1:05:07 Biggest challenge in career to date
  • 1:07:44 Advice for young researchers
  • 1:08:44 Where can people reach you?
  • 1:09:07 Final Message
  • 1:09:45 Outro

Connect with Denise Mitrano

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Credits