The Grand Challengers Podcast Episode #45

“A list that keeps getting longer” – understanding pollutants of emerging concern for healthier aquatic environments

Guest: Lena Mutzner

June 17th, 2025

Episode Teaser

Introduction

“…Pollutants we like to focus on, they change… because we cannot focus on the ones we thought are the most important ones ten years ago!…”

Lena Mutzner, Group Leader at the Swiss Federal Institute of Aquatic Science & Technology Eawag. Lena specializes in quantifying organic contaminants in urban stormwater, grey and blue-green infrastructures systems using novel measurement techniques such as passive samplers. She has been actively pursuing a better understanding of a seemingly endless and growing list of contaminants of emerging concern, developing measurement and modelling methods to help quantify and mitigate their adverse effects in support of better and healthier environments for humans, ecology and our waterways.

On today’s show, Lena and I delve into the time and space complexity of environmental water quality and go deep on how different methods of measurement and modelling can yield valuable insights to better manage several common pollutants that we encounter in our day to day lives. We critically reflect on the repetition cycles in water quality research and discuss how she is embracing holistic approaches to tackle this ongoing challenge.

Biography

Dr. Lena Mutzner is an environmental engineer whose academic journey began with a BSc (2005-2008), MSc (2009-2012) and PhD (2015-2019) degrees in Environmental Engineering at the Swiss Federal Institute of Technology (ETH Zurich). She is currently Tenure Track Group Leader at Eawag, in the Department of Urban Water Management, focussing on urban water stormwater quality and developing tailored solutions for stormwater use. Lena also undertook a postdoctoral fellowship, funded by the Swiss National Science Foundation (SNSF) at Stanford University (2020) and the Technical University of Denmark (DTU) (2020-2022), where she gained international experience and further built up her extensive research network.

Lena is recognized for her contributions to novel monitoring approaches, such as passive sampling and modelling of organic micropollutants in both traditional (grey) and nature-based (blue-green) infrastructure. Lena is currently developing new approaches to monitoring, understanding and mitigating water pollution in urban catchments, adopting a more integrated, holistic approach to tackling the challenge. She is the current co-chair of the IWA Emerging Contaminants Working Group and takes an active role in supporting women in STEM.

Resources Related to the Episode

  • Check out Mashael Yazdanie on Episode 42 for more insights on meditation!
  • The discussion about Nordic countries just happened in the previous Episode 44 with Jarrod Luxton, you can check his out to add Finland to the list of comparisons
  • My first flush research was published in two papers, here is the detailed one: Bach, P.M., McCarthy, D.T. and Deletic, A., 2010. Redefining the stormwater first flush phenomenon. Water research, 44(8), pp.2487-2498. [Link]
  • We discussed contaminants of emerging concern and covered the group of microplastics previously on Episode 34 with Denise Mitrano
  • Some examples of water quality sampling techniques that we covered in our 101 discussion on water quality studies include: Grab samples, Composite samples, Passive Samplers, here are some links to water quality sampling [USGS] [OlympianWaterTesting]
  • 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
  • Organic chemistry 101 [Khan academy]
  • Lena’s key early publications:
    • Mutzner, L., Staufer, P. and Ort, C., 2016. Model-based screening for critical wet-weather discharges related to micropollutants from urban areas. Water research, 104, pp.547-557. [Link]
    • Mutzner, L., Vermeirssen, E.L., Mangold, S., Maurer, M., Scheidegger, A., Singer, H., Booij, K. and Ort, C., 2019. Passive samplers to quantify micropollutants in sewer overflows: accumulation behaviour and field validation for short pollution events. Water research, 160, pp.350-360 [Link]
    • Mutzner, L., Vermeirssen, E.L. and Ort, C., 2019. Passive samplers in sewers and rivers with highly fluctuating micropollutant concentrations–better than we thought. Journal of hazardous materials, 361, pp.312-320. [Link]
  • Her recent work on where we are at with monitoring of micropollutants: Mutzner, L., Furrer, V., Castebrunet, H., Dittmer, U., Fuchs, S., Gernjak, W., Gromaire, M.C., Matzinger, A., Mikkelsen, P.S., Selbig, W.R. and Vezzaro, L., 2022. A decade of monitoring micropollutants in urban wet-weather flows: What did we learn?. Water Research, 223, p.118968. [Open Access Link]
  • Lena’s recent work on Blue-Green Infrastructures for mitigating pollution: Poggioli, M., Cavadini, G.B., Zheng, Z., Rodriguez, M. and Mutzner, L., 2024. The impact of blue-green infrastructure on trace contaminants: A catchment-wide assessment. Water Research X, 25, p.100261. [Open Access Link]
  • The early study I mentioned from the 1980s adopting a holistic and integrated view of the catchment: Gujer, W., Krejci, V., Schwarzenbach, R. and Zobrist, J., 1982. Von der Kanalisation ins Grundwasser–Charakterisierung eines Regenereignisses im Glattal. Gas-Wasser-Abwasser, 62(7), pp.298-311. [in German]
  • What the PhD means in the context of innovation:
  • Key People Lena Mentioned:
  • Just because it was promised in the outro… become a Yoga Teacher! Here are 7 teaching tips!

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 & Meditative Activities
  • 4:16 Nordic Countries vs. Switzerland
  • 7:36 Lena’s Mission in Water Quality
  • 10:53 How it all started – engineering or psychiatry?
  • 13:18 Contaminants of emerging concern
  • 16:48 Studying Water Quality 101
  • 26:28 Which contaminants does Lena focus on?
  • 29:28 Tyre wear leachate and 6PPD-Quinone
  • 33:01 Data issues towards building water quality understanding
  • 36:45 Different types of common micropollutants
  • 40:55 Interplay of Modelling and Water Quality Data Collection
  • 46:18 Effect-based measurements
  • 48:19 The holistic view – integration as a the way forward
  • 51:05 Mitigation of pollution through Blue-Green Infrastructures
  • 54:00 Lena’s Future Research Trajectory
  • 56:49 Q&A Start
  • 57:24 What does innovation mean to you?
  • 1:00:30 Key Moment, Person, Event
  • 1:03:52 Women in STEM – Lena’s drive to be a role model
  • 1:06:40 Time Management
  • 1:10:24 Favourite childhood memory
  • 1:12:55 Biggest challenge to date
  • 1:18:17 Advice for young researchers
  • 1:20:00 What would you most like to be remembered for?
  • 1:21:15 Where can people find you?
  • 1:21:57 Final Message
  • 1:22:15 Outro

Connect with Lena Mutzner

Related Episodes

Episode #9 – Ana Deletic
From first flush and manholes to pendulums of stormwater, engineering and life
(Related Topics: First flush, stormwater quality)
Episode #10 – Daniele La Cecilia
Backyard balsamic vinegar, a pizza oven and technological progress in agriculture
(Related Topics: water quality, glyphosate)
Episode #20 – Belinda Hatt
Stormwater control measures, healthy waterways, battleships and karate at the riverside camp
(Related Topics: hydrology, water quality, waterways protection)
Episode #34 – Denise Mitrano
A world of plastics from macro and micro to nano – should zero plastics be the long-term goal?
(Related Topics: water quality, tyre wear particles, contaminants of emerging concern)
Episode #42 – Mashael Yazdanie
“Doing the right things the right way” – how to holistically plan for sufficiency and renewable energy
(Related Topics: meditative practices, planning, nature-based solutions)

Credits