As Clear as Mud: Resolving Chemical Complexity in the UK Water Cycle

April 16, 2026, 4.00 pm - 5.00 pm

Eawag Dübendorf, FC-C20 & online

Speaker
Prof Dr. Leon Barron, MRC Centre for Environment and Health, Environmental Research Group, Faculty of Medicine, Imperial College London

The seminar is open to the public.
To join online, please contact seminars@cluttereawag.ch for access details.

With over 350,000 chemicals currently estimated to be available commercially, the role of the analytical chemist has become increasingly challenging to detect, monitor and assess any associated environmental and human risks. Chemical pollution in the UK water cycle represents a complex situation which has been fuelled by water industry privatisation, ineffective regulation and policy, and lack of a chemicals strategy compounded by its EU-exit. For example, no English river now has good chemical status and only 14 % have good ecological status. This presentation will discuss recent research that focussed on chemicals of emerging concern (CECs) across drinking water, surface water and wastewater. In particular, the use of novel, scalable and sustainable methodologies will be discussed to enable higher spatio-temporal resolution analysis and risk assessment, including new multimodal sampling technologies (including 3D printed multimodal passive samplers), automated sample preparation robotics for large scale complex water analysis, and new opportunities in chemical analysis using mass spectrometry-based methods. The first application focuses on household drinking water, particularly for per- and poly-fluorinated chemicals (PFAS) and disinfectant by products analysis using both non-targeted and targeted mass spectrometry. The second application focusses on fresh water, particularly on the identification of new high risk pesticide source signatures as well as some lessons learned from engagement in local-national scale ‘citizen science’ activities for CECs. The third application focusses on national wastewater-based epidemiology, particularly to estimate community drug consumption patterns at high temporal resolution.

Professor Barron leads the Emerging Chemical Contaminants team within the Environmental Research Group at Imperial College London. His laboratory explores environmental issues in the UK ranging from sources, risks and impacts on environmental and public health, closely related to activities at Eawag. His work spans across all environmental spheres (soil, water, air and biological materials) and pollutant classes from pharmaceuticals and personal care products to pesticides, 'forever chemicals' (PFAS), and disinfectant by-products. He recently co-authored an article with Christoph Ort on international wastewater monitoring for spatio-temporal illicit drug use (link). His holistic scientific approach and case studies that are relatable to our everyday lives should makes this seminar exiting to a broad audience at Eawag and beyond.

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         .&nbsp;C.; Kasprzyk-Hordern,&nbsp;B.; Ort,&nbsp;C.; Simeoni,&nbsp;E.; Heath,
         &nbsp;E.; Pridotkiene,&nbsp;E.; Lai,&nbsp;F.&nbsp;Y.; Béen,&nbsp;F.; Oberac
         her,&nbsp;H.; Bodík,&nbsp;I.; Valenčić,&nbsp;I.; Slobodnik,&nbsp;J.; Stra
         ndberg,&nbsp;J.; Sheeran,&nbsp;K.; Smit-Rigter,&nbsp;L.&nbsp;A.; Barron,&nbs
         p;L.&nbsp;P.; Bijlsma,&nbsp;L.; Psichoudaki,&nbsp;M.; Savvidou,&nbsp;M.; Edl
         and-Gryt,&nbsp;M.; Busch,&nbsp;M.; Jandl,&nbsp;M.; Bertram,&nbsp;M.&nbsp;G.;
          de Alda,&nbsp;M.&nbsp;L.; Berndt,&nbsp;N.; Daglioglu,&nbsp;N.; Thomaidis,&n
         bsp;N.; Fabien,&nbsp;L.; Chomynova,&nbsp;P.; Oertel,&nbsp;R.; Castiglioni,&n
         bsp;S.; Mercan,&nbsp;S.; Akgür,&nbsp;S.&nbsp;A.; Schneider,&nbsp;S.; Gunnar
         ,&nbsp;T.; ter Laak,&nbsp;T.&nbsp;L.; Thiebault,&nbsp;T.; Matias,&nbsp;J.&nb
         sp;P.' (917 chars)      title => protected'Bridging the gap between research and decision making: A European survey to 
         enhance cooperation in wastewater-based epidemiology (WBE) for illicit drugs' (152 chars)      journal => protected'Public Health' (13 chars)      year => protected2025 (integer)      volume => protected241 (integer)      issue => protected'' (0 chars)      startpage => protected'158' (3 chars)      otherpage => protected'163' (3 chars)      categories => protected'wastewater-based epidemiology; illicit drugs; public health; new psychoactiv
         e substances; Europe; policy; cooperation' (117 chars)      description => protected'Objectives: Illicit drug use presents a significant challenge to global heal
         th and public safety, requiring innovative and effective monitoring strategi
         es. This study aimed to evaluate the current landscape of wastewater-based e
         pidemiology (WBE) for monitoring illicit drugs in Europe, focusing on collab
         oration, current practices, and barriers, while identifying opportunities fo
         r improvement. Study design: Cross-sectional survey-based study. Methods: Co
         ordinated by the Sewage Analysis CORe Group Europe (SCORE) and the European 
         Union Drugs Agency (EUDA), two surveys were conducted in 2023 targeting rese
         archers and stakeholders using WBE for illicit drugs. Data were analysed to 
         identify trends, gaps, and opportunities for improving WBE implementation. R
         esults: The findings indicate a robust research infrastructure and diverse a
         nalytical methods among European institutions. Two-thirds of the participati
         ng countries reported using WBE data to inform policy. However, challenges p
         ersist, particularly in securing funding and coordination, as well as genera
         ting national estimates from multiple locations and addressing specific loca
         l policy needs. Conclusions: WBE has proven to be a valuable tool for monito
         ring illicit drug trends and informing drug policies. To unlock its full pot
         ential, sustained funding, methodological standardization, and enhanced coop
         eration are essential. This study provides critical insights into the Europe
         an WBE landscape, offering a roadmap for strengthening the integration of ac
         tionable WBE data into public health and policy frameworks.' (1579 chars)      serialnumber => protected'0033-3506' (9 chars)      doi => protected'10.1016/j.puhe.2025.02.009' (26 chars)      uid => protected34016 (integer)      _localizedUid => protected34016 (integer)modified      _languageUid => protectedNULL      _versionedUid => protected34016 (integer)modified      pid => protected124 (integer)   1 => Snowflake\Publications\Domain\Model\Publicationprototypepersistent entity (uid=19517, pid=124)      originalId => protected19517 (integer)      authors => protected'González‐Mariño,&nbsp;I.; Baz‐Lomba,&nbsp;J.&nbsp;A.; Alygizakis,&nbsp
         ;N.&nbsp;A.; Andrés‐Costa,&nbsp;M.&nbsp;J.; Bade,&nbsp;R.; Barron,&nbsp;L
         .&nbsp;P.; Been,&nbsp;F.; Berset,&nbsp;J.‐D.; Bijlsma,&nbsp;L.; Bodík,&nb
         sp;I.; Ort,&nbsp;C.' (247 chars)      title => protected'Spatio‐temporal assessment of illicit drug use at large scale: evidence fr
         om 7 years of international wastewater monitoring' (125 chars)      journal => protected'Addiction' (9 chars)      year => protected2020 (integer)      volume => protected115 (integer)      issue => protected'1' (1 chars)      startpage => protected'109' (3 chars)      otherpage => protected'120' (3 chars)      categories => protected'amphetamine; cocaine; ecstasy/MDMA; illicit drugs; methamphetamine; wastewat
         er-based epidemiology' (97 chars)      description => protected'<em>Background and aims</em> Wastewater‐based epidemiology is an additiona
         l indicator of drug use that is gaining reliability to complement the curren
         t established panel of indicators. The aims of this study were to: (i) asses
         s spatial and temporal trends of population‐normalized mass loads of benzo
         ylecgonine, amphetamine, methamphetamine and 3,4‐methylenedioxymethampheta
         mine (MDMA) in raw wastewater over 7 years (2011-17); (ii) address overall 
         drug use by estimating the average number of combined doses consumed per day
          in each city; and (iii) compare these with existing prevalence and seizure 
         data. <em>Design </em>Analysis of daily raw wastewater composite samples col
         lected over 1 week per year from 2011 to 2017. <em>Setting and Participants
          </em>Catchment areas of 143 wastewater treatment plants in 120 cities in 37
          countries. <em>Measurements </em>Parent substances (amphetamine, methamphet
         amine and MDMA) and the metabolites of cocaine (benzoylecgonine) and of Δ<s
         
         
         hy-tandem mass spectrometry. Daily mass loads (mg/day) were normalized to ca
         tchment population (mg/1000 people/day) and converted to the number of combi
         ned doses consumed per day. Spatial differences were assessed world‐wide, 
         and temporal trends were discerned at European level by comparing 2011-13 dr
         ug loads versus 2014-17 loads. <em>Findings </em>Benzoylecgonine was the sti
         mulant metabolite detected at higher loads in southern and western Europe, a
         nd amphetamine, MDMA and methamphetamine in East and North-Central Europe. I
         n other continents, methamphetamine showed the highest levels in the United 
         States and Australia and benzoylecgonine in South America. During the report
         ing period, benzoylecgonine loads increased in general across Europe, amphet
         amine and methamphetamine levels fluctuated and MDMA underwent an intermitte
         nt upsurge. <em>Conclusi...' (2160 chars)      serialnumber => protected'0965-2140' (9 chars)      doi => protected'10.1111/add.14767' (17 chars)      uid => protected19517 (integer)      _localizedUid => protected19517 (integer)modified      _languageUid => protectedNULL      _versionedUid => protected19517 (integer)modified      pid => protected124 (integer)   2 => Snowflake\Publications\Domain\Model\Publicationprototypepersistent entity (uid=16913, pid=124)      originalId => protected16913 (integer)      authors => protected'van Nuijs,&nbsp;A.&nbsp;L.&nbsp;N.; Lai,&nbsp;F.&nbsp;Y.; Been,&nbsp;F.; And
         res-Costa,&nbsp;M.&nbsp;J.; Barron,&nbsp;L.; Baz-Lomba,&nbsp;J.&nbsp;A.; Ber
         set,&nbsp;J.-D.; Benaglia,&nbsp;L.; Bijlsma,&nbsp;L.; Burgard,&nbsp;D.; Cast
         iglioni,&nbsp;S.; Christophoridis,&nbsp;C.; Covaci,&nbsp;A.; de Voogt,&nbsp;
         P.; Emke,&nbsp;E.; Fatta-Kassinos,&nbsp;D.; Fick,&nbsp;J.; Hernandez,&nbsp;F
         .; Gerber,&nbsp;C.; González-Mariño,&nbsp;I.; Grabic,&nbsp;R.; Gunnar,&nbs
         p;T.; Kannan,&nbsp;K.; Karolak,&nbsp;S.; Kasprzyk-Hordern,&nbsp;B.; Kokot,&n
         bsp;Z.; Krizman-Matasic,&nbsp;I.; Li,&nbsp;A.; Li,&nbsp;X.; Löve,&nbsp;A.&n
         bsp;S.&nbsp;C.; Lopez de Alda,&nbsp;M.; McCall,&nbsp;A.-K.; Meyer,&nbsp;M.&n
         bsp;R.; Oberacher,&nbsp;H.; O'Brien,&nbsp;J.; Quintana,&nbsp;J.&nbsp;B.; Rei
         d,&nbsp;M.; Schneider,&nbsp;S.; Sadler Simoes,&nbsp;S.; Thomaidis,&nbsp;N.&n
         bsp;S.; Thomas,&nbsp;K.; Yargeau,&nbsp;V.; Ort,&nbsp;C.' (891 chars)      title => protected'Multi-year inter-laboratory exercises for the analysis of illicit drugs and 
         metabolites in wastewater: development of a quality control system' (142 chars)      journal => protected'Trends in Analytical Chemistry' (30 chars)      year => protected2018 (integer)      volume => protected103 (integer)      issue => protected'' (0 chars)      startpage => protected'34' (2 chars)      otherpage => protected'43' (2 chars)      categories => protected'illicit drugs; wastewater; inter-laboratory testing; wastewater-based epidem
         iology; quality assurance' (101 chars)      description => protected'Thirty-seven laboratories from 25 countries present the development of an in
         ter-laboratory testing scheme for the analysis of seven illicit drug residue
         s in standard solutions, tap- and wastewater. Almost 10 000 concentration va
         lues were evaluated: triplicates of up to five samples and 26 laboratories p
         er year. The setup was substantially improved with experiences gained across
          the six repetitions (e.g. matrix type, sample conditions, spiking levels). 
         From this, (pre-)analytical issues (e.g. pH adjustment, filtration) were rev
         ealed for specific analytes which resulted in formulation of best-practice p
         rotocols for inter-laboratory setup and analytical procedures. The results i
         llustrate the effectiveness of the inter-laboratory setup to assess laborato
         ry performance in the framework of wastewater-based epidemiology. The exerci
         se proved that measurements of laboratories were of high quality (&gt;80% sa
         tisfactory results for six out of seven analytes) and that analytical follow
         -up is important to assist laboratories in improving robustness of wastewate
         r-based epidemiology results.' (1093 chars)      serialnumber => protected'0165-9936' (9 chars)      doi => protected'10.1016/j.trac.2018.03.009' (26 chars)      uid => protected16913 (integer)      _localizedUid => protected16913 (integer)modified      _languageUid => protectedNULL      _versionedUid => protected16913 (integer)modified      pid => protected124 (integer)

Baz-Lomba, J. A.; van Nuijs, A. L. N.; Lenart-Boroń, A.; Péterfi, A.; de l'Eprevier, A.; Löve, A. S. C.; Kasprzyk-Hordern, B.; Ort, C.; Simeoni, E.; Heath, E.; Pridotkiene, E.; Lai, F. Y.; Béen, F.; Oberacher, H.; Bodík, I.; Valenčić, I.; Slobodnik, J.; Strandberg, J.; Sheeran, K.; Smit-Rigter, L. A.; Barron, L. P.; Bijlsma, L.; Psichoudaki, M.; Savvidou, M.; Edland-Gryt, M.; Busch, M.; Jandl, M.; Bertram, M. G.; de Alda, M. L.; Berndt, N.; Daglioglu, N.; Thomaidis, N.; Fabien, L.; Chomynova, P.; Oertel, R.; Castiglioni, S.; Mercan, S.; Akgür, S. A.; Schneider, S.; Gunnar, T.; ter Laak, T. L.; Thiebault, T.; Matias, J. P. (2025) Bridging the gap between research and decision making: A European survey to enhance cooperation in wastewater-based epidemiology (WBE) for illicit drugs, Public Health, 241, 158-163, doi:10.1016/j.puhe.2025.02.009, Institutional Repository

Background and aims Wastewater‐based epidemiology is an additional indicator of drug use that is gaining reliability to complement the current established panel of indicators. The aims of this study were to: (i) assess spatial and temporal trends of population‐normalized mass loads of benzoylecgonine, amphetamine, methamphetamine and 3,4‐methylenedioxymethamphetamine (MDMA) in raw wastewater over 7 years (2011-17); (ii) address overall drug use by estimating the average number of combined doses consumed per day in each city; and (iii) compare these with existing prevalence and seizure data. Design Analysis of daily raw wastewater composite samples collected over 1 week per year from 2011 to 2017. Setting and Participants Catchment areas of 143 wastewater treatment plants in 120 cities in 37 countries. Measurements Parent substances (amphetamine, methamphetamine and MDMA) and the metabolites of cocaine (benzoylecgonine) and of Δ⁹‐tetrahydrocannabinol (11‐nor‐9‐carboxy‐Δ⁹‐tetrahydrocannabinol) were measured in wastewater using liquid chromatography-tandem mass spectrometry. Daily mass loads (mg/day) were normalized to catchment population (mg/1000 people/day) and converted to the number of combined doses consumed per day. Spatial differences were assessed world‐wide, and temporal trends were discerned at European level by comparing 2011-13 drug loads versus 2014-17 loads. Findings Benzoylecgonine was the stimulant metabolite detected at higher loads in southern and western Europe, and amphetamine, MDMA and methamphetamine in East and North-Central Europe. In other continents, methamphetamine showed the highest levels in the United States and Australia and benzoylecgonine in South America. During the reporting period, benzoylecgonine loads increased in general across Europe, amphetamine and methamphetamine levels fluctuated and MDMA underwent an intermittent upsurge. Conclusions The analysis of wastewater to quantify drug loads provides near real‐time drug use estimates that globally correspond to prevalence and seizure data.

González‐Mariño, I.; Baz‐Lomba, J. A.; Alygizakis, N. A.; Andrés‐Costa, M. J.; Bade, R.; Barron, L. P.; Been, F.; Berset, J.‐D.; Bijlsma, L.; Bodík, I.; Ort, C. (2020) Spatio‐temporal assessment of illicit drug use at large scale: evidence from 7 years of international wastewater monitoring, Addiction, 115(1), 109-120, doi:10.1111/add.14767, Institutional Repository

van Nuijs, A. L. N.; Lai, F. Y.; Been, F.; Andres-Costa, M. J.; Barron, L.; Baz-Lomba, J. A.; Berset, J.-D.; Benaglia, L.; Bijlsma, L.; Burgard, D.; Castiglioni, S.; Christophoridis, C.; Covaci, A.; de Voogt, P.; Emke, E.; Fatta-Kassinos, D.; Fick, J.; Hernandez, F.; Gerber, C.; González-Mariño, I.; Grabic, R.; Gunnar, T.; Kannan, K.; Karolak, S.; Kasprzyk-Hordern, B.; Kokot, Z.; Krizman-Matasic, I.; Li, A.; Li, X.; Löve, A. S. C.; Lopez de Alda, M.; McCall, A.-K.; Meyer, M. R.; Oberacher, H.; O'Brien, J.; Quintana, J. B.; Reid, M.; Schneider, S.; Sadler Simoes, S.; Thomaidis, N. S.; Thomas, K.; Yargeau, V.; Ort, C. (2018) Multi-year inter-laboratory exercises for the analysis of illicit drugs and metabolites in wastewater: development of a quality control system, Trends in Analytical Chemistry, 103, 34-43, doi:10.1016/j.trac.2018.03.009, Institutional Repository

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As Clear as Mud: Resolving Chemical Complexity in the UK Water Cycle

Abstract

Prof Leon Barron

Joint publications