Meeting Report #EnvChem2025

#EnvChem is a biannual two-day international meeting that spans across environmental chemistry. In 2025, it was held at the University of Portsmouth on June 12th and 13th and featured 4 keynote speakers, 19 oral and 13 poster presentations. The meeting was jointly organised by the Royal Society of Chemistry’s Environmental Chemistry Group and Water Science Forum, and hosted ~50 delegates. Shimadzu sponsored the event. Described as “a really nice conference for your first presentation”, #EnvChem participants are considered “encouraging, and don’t grill you too hard.”

Talks

Our first session, Bioremediation and Biosensing Technologies, was chaired and introduced by Professor Gary Fones (University of Portsmouth). The opening keynote speaker, Head of Conservation and Collections Care for the Mary Rose Trust and Interdisciplinary RSC Award Winner, Dr Eleanor Schofield (Imperial College London), spoke on work ‘Towards an environmentally sustainable Mary Rose Museum’. Commissioned by Henry VIII, the Mary Rose sank, not on its maiden voyage, but as a result of a water line raised by renovations coinciding with a turn during a storm. When the Mary Rose was raised in 1982, archaeologists excavated over 19,000 objects, including infrastructure, clothes, coins, jewellery, and human and animal remains. The recovered half of the wooden ship, aged using its cellulose, lignin and hemicellulose ratio, was so well preserved because it had been buried in silt, preventing oxygen corrosion and limiting microbial decay; further efforts were made to ensure minimal and reversible preservation via immersion in two grades of polyethylene glycol (PEG) and subsequent freeze drying.

However, sulphate presented further problems with sulfur-reducing microbes active during drying and oxidation upon air exposure; this was monitored via X-ray absorption spectroscopy (XAS), X-ray fluorescence spectroscopy (XRF) and Fourier transform infra-red (FT-IR) analyses. Salt crystallisation and dissolution cycles resulted in breakdown of the vessel’s galley and ballast bricks prior to controlled environment storage. The rapid corrosion of metal cannon balls was investigated sacrificially by taking segments from some artefacts to learn more about the process. This conservation work is energy-intensive, but by securing sustainability grants and with support from 3ADAPT, they have successfully reduced their energy consumption and carbon footprint.

In the first session, Sanugi Dassanyake (University of Warwick) presented ‘Exploring the ability of various plants to bioremediate OSPW-derived compounds using FT-ICR MS’. In laboratory experiments, the biological uptake of complex toxic mixtures including compounds such as naphthenic acid that derive from oil sands process-affected water (OSPW) was investigated in incubated native slender wheat grass roots. Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was selected due to its selectivity. THEMIS was used to reduce background noise signals in spectra and improve quality of the spectra for analysis by averaging. Results showed that compounds may have migrated to the roots, as similar compounds were obtained in the OSPW solution and were not present in control samples.

Carla Comadran Casas (University of Glasgow) delivered ‘Bioremediation of multiple heavy metals through microbial-induced calcite precipitation’. Whilst ~100% carbon dioxide trapping occurs in urea solution, co-application with calcium is less effective, with microbial emission of carbon dioxide due to a buffering effect that lowers storage capacity. However, calcium is essential for calcium carbonate formation. Therefore, timing is critical, with the two-step introduction of urea and then calcium achieving 7.1% storage, an improvement over 0.5% for simultaneous introduction. Growth curves and activity of model bacteria in hydrocarbon polluted environments were investigated to test the in-field system robustness. Sufficient cell populations compensated for the hydrocarbon pollution disruption of the urease enzyme.

‘Electrochemical detection of chitin using the Schales assay’ was brought to us by Adam Hughes-Buchanan (University of Strathclyde). Part of a study into mitigating rain-induced landslides via fungal treatment of sands, it focused on the development of an electrochemical biosensor to identify the persistence of fungal inoculum and of the desired effect. The Schales assay was used to reduce ferricyanide to ferrocyanide. Electrochemical rather than colorimetric measures were tested as a detection. Optimisation showed enzyme incubation times of 60 mins and concentrations of 50 mU of chitinase/NAGase (to hydrolyse chitin) performed best. Strong correlations between both substrates were obtained with R2 = 0.93 and 0.96 for raw chitin and colloidal chitin, respectively. Colloidal chitin showed stronger assay response, but greater variation.

The second session, Cutting-Edge Approaches for Pollutant Recovery, was chaired by Dr Helena Rapp-Wright (Imperial College London), where Kasim Sani Musa (Newcastle University) spoke on ‘Optimising adsorption systems for complex produced water treatment’. These complex systems include organic and inorganic contaminants, requiring different treatment methods (physical, chemical and biological) depending on particle size. Focussing on adsorption treatments, evaluation explored effectiveness, applicability, versatility, scalability and efficiency. Three types of pollutants were selected to represent the extreme range found in produced water: polycyclic aromatic hydrocarbons (PAHs), phenolics and trace heavy metals. Results showed differences in adsorption for the compounds analysed, as well as removals using the P400 protein. Plastic and glass vials were used as a further control, and glass found to interfere with the lead concentration.

Sophie Singer (University of Glasgow) addressed ‘Supramolecular gelation of pharmaceuticals towards recovery and remediation’ from the environment. This study aimed to trigger gelation in pharmaceuticals such as carbamazepine and 17αα-ethynylestradiol (EE2) via processes such as pH switching (lowering) and reversible electrolysis to tune solubility. Three kinds of gel were formed, depending on the nature of their interactions: polymer gels (e.g. PDMS in contact lenses), molecular polymers (e.g. jelly), and low-molecular-weight-gelators (LMWG). LMWG have been used for remediation for oil spills, heavy metals, and dyes, but research on pharmaceuticals is limited. Glucono-δδ-lactate was used to form more uniform gels than HCl, allowing gel characterisation. SEM images also showed differences in fibres depending on the acid ratio.

The next talk, ‘Green nano-based solution for emerging and traditional contaminants in the largest mangrove ecosystem’ by Santanu Majumder (IISER Kolkata) took us to the hard-to-access Indian Sundarbans in the Ganges Delta, a highly enriched biodiverse environment, one of the world’s top carbon sinks. However, it also suffers from high deposition of anthropogenic pollutants. This project quantitatively profiled pollutants, and selected fungi as a potential local and green mitigation solution. Sampling from less visited sites showed high heavy metal contamination and difference in fungal biodiversity. One fungi associated with high removals of metals, was found for the first time in India, and efforts made to optimise uptake. However, recoveries were highest at pH 2, unrealistic in the environment, and research continues.

Elmira Khaksar Najafi (University of Glasgow) spoke next on ‘Effect on calcium source and concentration on mineral carbonation for heavy metals immobilisation of contaminated soils’. The focus of the investigation was to determine if there is an optimum concentration of calcium (Ca2+) for carbonation removal of heavy metals. Experiments used a wet (rapid reaction, suspended precipitation) method over dry (slow) or semi-dry (localised precipitation), working on the third level of soil, a reddish clay. Because the concrete washout solution contains a solid portion, testing was conducted to determine sample homogeneity. Whilst low concentrations of calcium did not immobilise heavy metals, medium/high calcium content did not give significantly different results. FTIR was used for analysis.

Posters

A diversity of posters were presented on themes of counting contaminants, their consequences, and how to control/remediate them. Counting contaminants focussed on improvements in the resolution and cost-effectiveness of detection methods. Three posters on passive samplers explored organic contaminant monitoring for substances such as PFAS and oestradiol, with aims to increase resolution on short timescales, giving time weighted averages, and identifying short term spikes via sampling snapshots. Other PFAS work in Scottish pastures developing and optimising extraction as well as analysis. The impact of source water was correlated with the occurrence of nitrogenous disinfection byproducts (DBS) in drinking water, and particulate matter emission loads linked to cooking type and product type, showing that pan cooking and supposedly healthier air frying had higher emissions than oven cooking, and that emissions from fresh products took three weeks to equal emissions from manufactured products. Lead(II) concentrations detected using Gii pure carbon sensors (a 3D nanomaterial) resolved down to 0.1 ppm.

Consequences analysed included those of 60 unique chemical and biological stressors in freshwater, contributing 90% of the contaminant load to macroinvertebrates communities as predictive ecotoxicology models. Data demonstrated the decline of sensitive taxa and increases in pollutant-tolerant taxa.

Existing and novel remediation techniques were evaluated. Counts of microplastics in Saudi Arabia sewage treatment plants dropped below 20% after any of five tested treatment technologies, with the remaining particles mostly < 250 μμm. Foam fractionation and granular sorbent downflow of filtration systems were modelled as a cost-effective methods for removing PFAS. Novel photochromic iron-based ionic liquid catalysts removed up to 70% of BPA via oxidative degradation in just 15 minutes at room temperature and pH 6.6, and demonstrated 4 cycles of use. Finally, a novel extracellular, less technical and less expensive method for estimating microbial carbon use efficiency (CUE) (how efficiently they convert carbon into biomass) was proposed, which involves tracking respiration.

Talks

Session three, Characterising and Responding to Environmental Pollution, was chaired by Professor Caroline Gauchotte-Lindsay (University of Glasgow). Alexandra Richardson (Imperial College London) presented ‘Measurement and removal of per- and polyfluoroalkyl substances (PFAS) in London tap water’. Miles of piping between water treatment plants and drinking water outlets (taps) may impact the chemicals delivered. Volunteer samples from 12 London boroughs indicated 13 PFAS compounds, 10 of which could be quantified. All concentrations were below the safe limit set by the drinking water inspectorate (DWI) of 10ng/l and the European food safety authority (EFSA) 4.4ng/kg(body mass)/week (samples were 0.9-3.3ng/kg/week), and results were shared with the citizen scientists. This work highlighted the challenges of citizen science data collection, including sample sizes (84% of kits were returned), communication, and potential contamination.

Katie McKenzie (Robert Gordon University) presented ‘Assessment of road pollution in retention ponds’. Whilst there has been recognition that roads are a source of environmental pollution, it has, until recently, been focussed on vehicle engine exhausts. Abrasion of tyres on the road surface creates microplastics which present complex pollutants. Rain and road run-off is a primary route of these pollutants into the wider environment. Two seasons of sampling campaigns captured across two sites (a dual carriage way and slip road, where increased braking and turning occurs) examined particles and chemical additives from tyre and roadwork particles (TRWPs) to evaluate the effectiveness of sustainable drainage systems (SuDS), many of which mimic natural drainage systems.

Jana-Sophie Appelt (University of Southampton) spoke on ‘Occurrence and fate of trace metals, PAHs and hormones in Southampton Water, UK’. With unique physical and chemical properties, estuarine sediments act as filters for some pollutants in water environments. This study investigated the role of these in contaminant retention, since antimicrobials like flumequine have been found in cores that pre-date market approval, indicating mobility. Salting out did not demonstrate a significant effect on contaminant retention, as the adsorption was not significantly different between seawater and brackish water. Freeze dried, extracted, and derivatised samples were analysed by GC-MS, which demonstrated differences across matrices and contaminants; for example, trace metals clustered together closer to the port.

The closing keynote presentation of day one by Stephanie Metzger, Policy Advisor for the Royal Society of Chemistry, outlined recent work on ‘PFAS and CECs: policy outlook and opportunities for action (Royal Society of Chemistry)’, which evaluated how mobile contaminants of emerging concern (CECs) end up in the environment via sources such as run off, WWTP, or agricultural lands, and may bioaccumulate in organisms, even at very low concentrations. Policy implementation is challenging, not least because MPs are very time poor. To address this, the RSC published some recommendations on how to tackle CECs in water, a broad piece of work highlighting four key themes: monitoring, risk assessment and management, tackling sources of pollution, and global collaboration. WWTPs, as a main source of CECs in the environment, will be explored. New rules for more thorough and cost-effective urban waste management will ensure 80% of the waste management cost should be covered by “responsible industries” such as pharmaceuticals and cosmetics manufacturers.

PFAS encompasses 5-15,000 chemicals, several of which are banned. Likely source sites of contamination are locations where fire-fighting foam is more commonly used, as well as wastewater treatment plants, landfill sites (from leachate) and incinerators - most of which do not burn hot enough to fully break down PFAS. The drinking water inspectorate’s (DWI) January 2025 update now requires a limit of 100ng/L cumulative PFAS concentration. Whilst not all PFAS are expected to be toxic, substitution of one for another may worsen a situation, but present a different mechanism for action, and phase-out needs to be carefully managed.

Day two was opened by the Environmental Chemistry Group Committee Chair, Professor Caroline Gauchotte-Lindsay (University of Glasgow) who presented the new ECG Just Transition Strategy (see pp. 12-15).

Next, Graham Merrington, Director at WCA Environment Ltd delivered a talk on ‘Undertaking environmental risk assessment: does the quality of the measured chemical data matter?’, highlighting challenges managing exposure data, and providing a roadmap for ensuring your data is usable. Admitting the conflation of hazard and risk keeps him up at night, he expressed how the effects and levels of chemicals both matter. In particular, he called for comprehensive data inclusion in supplementary information for transparency, consistency, and judgement over its reliability and relevance for purpose. Depending on the specific application, data will need to look at different parameters and comply with the specific standards required. Time period, sensitivity, and analytical methods will affect these. More on this and the CREED evaluation system may be found on pp. 18-21.

Session four was opened and chaired by Symiah Barnett (Loughborough University), on Evidence-Based Approaches for Regulation. In this session, Zulin Zhang (James Hutton Institute) began with ‘Which compounds should be listed as priority control: classical or emerging contaminants?’ To answer this question, he investigated the prevalence of persistent organic pollutants (POPs) and metal organic pollutants (MOPs) in Yangtze river sediments. Phthalate esters (PAEs) and polycyclic aromatic hydrocarbons (PAHs) resulted in 88% of the total cumulative load averaging 403.2 ng/g (higher downriver than upriver). Risk assessment determined 10 compounds at high risk (i.e., 7 x PAHs, 2 x PAEs and 1 x antibiotic) for future research attention.

Charlotte Linley (WCA Environment Ltd) followed, presenting ‘Evaluating bioavailability-based approaches for setting aluminium discharge limits in the UK’. The UK currently has a 50 ug/L limit on aluminium in environmental waters, but this may be over-protective. Water chemistry conditions are inherently different everywhere around the country, making a complex model, where the toxicity of aluminium varies geographically. Since speciation is too complex to develop a biotic ligand model (BLM), a multi-linear regression model was used to generate species and genus mean, acute and chronic concentration values. This involved data cleansing to remove unreliable and less relevant studies and determine a site-specific guidelines for safe concentrations of aluminium. After a break, Dr Rowena Fletcher-Wood (Freelance) opened the fifth session, on the subject of ‘Bioavailability, and Toxicokinetics in Complex Matrices’. This session began with a talk by Adam Peters (WCA Environment Ltd) on ‘Metal bioavailability: the rocky road from academic model to routine regulatory implementation’. His talk began with a summary of the history of in-use regulatory models, such as the use of hardness as a key controller since the 1980s. He went on to discuss how the BLM combines three biotic models (gill surface interaction (GSIM), free ion activity (FIAM) and Windermere humic aqueous (WHAM) models) to link complex matrices to biological accumulation and toxicity. These allow the cross-species validation of data from different species that flourish in different environments and generate a sensitivity spectrum.

Jasmin Uhlhorn (Brunel University) spoke next on ‘Characterisation of mixture toxicokinetic profiles of pharmaceuticals in Daphnia magna’. The extent to which bioactive pharmaceuticals are reaching aquatic species remains limited. In this study, Daphnia magna was used as a model invertebrate species to investigate exposure from a mixture of pharmaceuticals. Following a complex matrix solid-phase extraction (SPE), LC-MS/MS was used for analysis. Carbamazepine showed an uptake in ~48h and a depuration finishing around 100h. These measurements gave bioconcentration factors (BCFs) for all the pharmaceuticals investigated. Higher BCFs values were obtained for compounds with higher logP values, giving a medium linear correlation (R2=0.57). However, some compounds showed variability, such as fluoxetine and amitriptyline, probably due to different functional groups, and pH impacted results. Data will be used to perform a machine learning model in order to predict BCFs in daphnia, enabling the generation of toxicokinetic data.

‘A plasmonic nano-tastebud sensor for the detection and discrimination of organic micropollutants in drinking water’ was introduced by Baptiste Poursat (University of Glasgow), who evaluated the progress of a new sensor to save time and lower costs monitoring and categorising waters through fingerprinting. Each sensor is engineered to react to different components in the sample, turning to a different colour. A total of 12 micropollutants were tested at different concentrations. Results showed that certain compounds such as hormones (e.g., oestrogens) had higher detection levels, not being detectable at lower concentrations. Whilst the detector successfully detected all compounds overall, it showed sensitivity to chlorine, and often mis-categorised its findings, requiring expert human input.

After lunch, the final keynote speaker for the event, Fay Couceiro Professor of Environmental Pollution at University of Portsmouth, discussed ‘Microplastics, the environment and us’. Research into microplastic impact on human health and solutions is in its infancy. Yet microplastics are vectors for harmful chemicals and biota due to their absorbance – for which they are designed. Conditions are exacerbated via physical, (irritation) chemical (toxicity), and biological (microorganism) vectors.

Atmospheric fallout of microplastics is the least understood, but plastic in the atmosphere now outweighs that in the oceans. Smaller in size, these more significantly toxic microplastics are receiving less publicity, and primarily originate from indoor air. Addition to arable land comes from plastic sheets used as mulch to retain moisture, and treated sewage sludge used as fertiliser. Microplastic ingestion is persistent but hard to measure. However, Professor Couceiro’s group have attempted to – from activities in a home to road runoff compounds and their impact on algae, and wastewater treatment site studies. In one incredible experiment, women rowing unsupported round the UK were asked to collect water samples for microplastic analysis. To conclude, Professor Couceiro asked whether post wastewater treatment of sludge should be better, or whether we should we should be responsible for reducing our input of microplastics to wastewater streams and, therefore, the environment?

Dr Stephanie Powley (BAT) chaired Advanced NMR and Mass Spectrometry for Environmental Contaminant Characterisation. Meredith Cave (Petrostat) presented ‘Geological techniques in a microplastic world’ – using past geological periods

to give insights in future scenarios due to climate change. Work involved capturing natural soil samples. However, these were challenging, since some samples exploded following standard literature techniques due to relatively high acidities, and demonstrated high primary and secondary (degraded) microplastic contents (up to 95% of marine litter). Whilst prior extinction events took place over thousands or millions of years, current changes in soil composition are taking place over only centuries.

Niamh Gurrin (University of Edinburgh) brought us ‘Ironing out issues with comparative 1H-NMR of peat dissolved organic matter’. Peat is a large carbon store, however around 30% of CO2 lost from damaged peatlands is emitted into water, and damaged peat can contribute carbon to the atmosphere. NMR may provide a snapshot of the organic matter in water systems, suppressing the water peak via presaturation and NOESY. Significant differences in signals were found with different mixing times, falling outside the acceptable tolerance of reproducibility. Making experiments as comparable as possible was essential before multivariable analysis was used to tease out the origin of this. Paramagnetic iron was identified as the most likely culprit.

Mark P. Barrow (University of Warwick) gave a talk on ‘Characterisation of pollution within Nairobi River sediments using high field Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS)’. Two highly populated high-waste locations were selected (Kawangware and Kiambio). FTICR MS analysis was used to characterise sediments in an untargeted scoping study, and allowed tens of thousands of compositions from a single sample, even for complex mixtures. Markers found were linked with sewage and engine oil lubricants and kerosine used in cooking. APPI preparation was found to cause fragmentation of some sample components, including cholesterol.

Closing the event, Alexander Zherebker (University of Cambridge) presented ‘Hidden molecular signatures in organic aerosols revealed by mass spectrometry and formulae difference statistics’. This study aimed to compare organic aerosols (OA) collected in summer from marine, forest, and urban environments. Samples were characterised by the number of formulae and % of intensity, and fingerprints investigated. 1,198 aerosols were found in common compared to unique components for urban, rural and marine; 1205, 2508 and 1527, respectively. Individual statistical analysis was performed using principal component analysis (PCA), followed by using FDS space, whereupon the variance explained a greater proportion of the data (~80%). Marine FDSs contributed higher to PCA results.

Prizes

Poster presentation award winners were Zakia Tebetyo (‘Detection of oestradiol using a competitive lateral flow device’) and Madelyn Murphy (‘Extraction and analysis of perfluoroalkyl substances in biosolids’). Posters were judged by a panel of Early Career environmental chemists, including Symiah Barnett, Sophie Singer, Katie McKenzie, and Lauren Yarrow-Wright (Assistant Editor of the RSC’s Environmental Science series of journals and RSC Sustainability). The oral prize winner was Jasmin Uhlhorn. The judging panel were made up of three past and present ECG Chairs: Professor Caroline Gauchotte-Lindsay, Dr Rowena Fletcher-Wood, and Dr Tom Sizmur.