HS8.1.7 | Emerging particles, biocolloids and PFAS in terrestrial and aquatic systems
EDI
Emerging particles, biocolloids and PFAS in terrestrial and aquatic systems
Convener: Constantinos Chrysikopoulos | Co-conveners: Thomas Baumann, Fritjof Fagerlund, Markus Flury, Tissa Illangasekare, Jürgen Mahlknecht
Orals
| Mon, 15 Apr, 08:30–12:30 (CEST)
 
Room 2.15
Posters on site
| Attendance Mon, 15 Apr, 16:15–18:00 (CEST) | Display Mon, 15 Apr, 14:00–18:00
 
Hall A
Orals |
Mon, 08:30
Mon, 16:15
Particles (inorganic particles, biocolloids, plastics) in environmental systems are of great concern because of their potential adverse effects on ecosystem functions, wildlife, and human health. They may also alter the transport properties of dissolved contaminants and change the hydraulic properties of subsurface systems. On the other hand, engineered particles and biocolloids play an important role in site remediation, aquifer restoration, and technical installations in the subsurface. Although there is extended experience in dealing with the colloidal domain in subsurface media, new particles pose new challenges and one has to acknowledge that the analytical window to the colloidal domain is nowadays wide open: some of the "old" concepts likely need to be reevaluated.

The unique properties of the "forever contaminants" per- and polyfluoroalkyl substances (PFAS) also pose many challenges for groundwater management, risk assessment and remediation. Partitioning of mixtures of many co-occurring chemicals between different matrices such as the soil, groundwater and air as well as the interfaces between these phases is key to their mobility and fate as well as strategies for mitigation. Abiotic and biotic transformations and degradation influence persistence, partitioning between phases, mobility and risks. Many processes in both the groundwater and vadose zones need to be better understood and there is an urgent need for improved remediation and mitigation methods.

This interdisciplinary session fosters the exchange among scientists from hydrogeology, microbiology, ecotoxicology, engineering, and analytical chemistry in order to provide a general picture of the occurrence and fate of natural and engineered particles and PFAS in aquatic and terrestrial systems. The presented papers will provide better process understanding through laboratory and field research, modeling, and site characterization to address new challenges and solutions associated with contamination of the soil-groundwater system by PFAS and particles as well as unsolved challenges related to other emerging or traditional contaminants. This session will have particular focus on the issue of moving from the laboratory to the field scale.

Orals: Mon, 15 Apr | Room 2.15

The oral presentations are given in a hybrid format supported by a Zoom meeting featuring on-site and virtual presentations. The button to access the Zoom meeting appears just before the time block starts.
Chairpersons: Thomas Baumann, Fritjof Fagerlund, Jürgen Mahlknecht
08:30–08:35
PFAS and other Emerging Contaminants
08:35–08:45
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EGU24-21370
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HS8.1.7
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Highlight
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On-site presentation
Denis O'Carroll, Diana Ackerman Grunfeld, Daniel Gilbert, Jennifer Hou, Matthew Lee, and Tohren Kibbey

Per- and polyfluoroalkyl substances (PFAS) have been used extensively in a range of consumer and industrial products since the 1950s, including in fire-fighting foam, given their exceptional interfacial properties and stability. However, concerns related to PFAS (eco)toxicity have only become widely known in the last 25 years. Passage of PFAS regulations and advisories has now proceeded at a much quicker rate than for many groups of anthropogenic chemicals, with the breadth of PFAS subject to regulation continually increasing and deemed acceptable levels continually decreasing. Here, we summarize global surface and groundwater PFAS data (n > 45,000) to quantify the extent to which PFAS water concentrations exceed drinking water advisories and regulations globally (e.g., European Union Directive 2020/2184, US EPA, Health Canda) as well as in the context of the Stockholm Convention for the protection of human health and the environment from persistent organic pollutants.  For example, our analysis suggests that 32% and 16% of sampled groundwater and surface water exceed the threshold of 1.0 for the unitless US PFAS hazard index for drinking water, respectively, when there is no known source of PFAS contamination, with the rate of exceedance increasing when there is a known source. The extent of exceedances for other jurisdictions will be discussed. Further, analysis of PFAS embodied in consumer products suggests that typical methods used to quantify PFAS in surface and groundwater likely underestimate total PFAS concentration.  Given this the future environmental burden posed by PFAS is likely underestimated.

How to cite: O'Carroll, D., Ackerman Grunfeld, D., Gilbert, D., Hou, J., Lee, M., and Kibbey, T.: An Assessment of the Global PFAS Burden to Our Waters, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21370, https://doi.org/10.5194/egusphere-egu24-21370, 2024.

08:45–08:55
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EGU24-2002
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HS8.1.7
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On-site presentation
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Joris Dijkstra, Noemi Brunschwiler, and Jasper Griffioen

Poly- and perfluoroalkyl substances (PFAS), among which are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), are common contaminants in Dutch soils, originating from fluorpolymer- factories (for PFOA), firefighting training grounds (for PFOS), or other often unknown sources. Previous research suggests that Municipal Waste-to-Energy (WtE) plants may be a source for diffuse PFAS contamination in the Netherlands, where 13 WtE plants are currently operational. Even though PFAS compounds should be eliminated at the temperatures at which WtE plants operate, the existence of “cold spots” in the oven is known and may imply that PFAS survive the combustion process. To investigate the potential contribution of WtE plants to diffuse PFAS contamination, a case study was set up in which topsoils surrounding a WtE plant in Alkmaar (Netherlands) were investigated. Ten locations were selected of which the soil profiles were undisturbed at least for 50 years and for which no other known PFAS sources are nearby. Eight locations were in the predominant wind direction (from SW to NE) and within a 5 km radius from the WtE plant. Two reference locations were located upwind. Each location was drilled to a depth of 80 cm and sampled with 10 cm intervals. Samples were analysed for 10 different PFAS and various bulk chemical and physical soil properties. In addition, PFAS was analysed in ashes from several modern WtE plants.

PFAS content is generally above national threshold values in the top layer of the soil (<30 cm) downwind of the WtE plant. In addition, considerable PFAS contents were detected in the ashes from WtE plants, indicating that PFAS are able to survive the combustion. The PFAS soil profiles follow a bell-shaped pattern with the highest content observed at 10-20 cm depth rather than directly at the surface. This indicates that most of the PFAS contamination originates from past emissions which have now decreased. A weak correlation between the distance from the waste incinerator and the measured PFAS content in the soil profile is found. Hydrus-1D, a reactive transport model code, was used to calculate content-depth profiles of PFOA and PFOS under three different emission/deposition scenarios to assess whether the emissions could account for the observed contamination depth patterns. The model calculations support the hypothesis that the observed PFAS content-depth profile can be explained by historical emissions and that the main source of contamination has decreased. This observation is consistent with the termination of a previous waste incineration plant, located on nearly the same spot, in 1996. The old incineration plant is likely to have had a less efficient combustion process. Based on the results of this study, a contribution of waste incineration to diffuse PFAS contamination is likely; additional research is needed to investigate the influence of other possible sources.

How to cite: Dijkstra, J., Brunschwiler, N., and Griffioen, J.: Tracing sources of diffuse PFAS pollution: PFAS contamination in soil near a Municipal Waste-to-Energy plant, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2002, https://doi.org/10.5194/egusphere-egu24-2002, 2024.

08:55–09:05
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EGU24-7899
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HS8.1.7
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On-site presentation
Claus Haslauer, Thomas Bierbaum, Simon Kleinknecht, and Tobias Junginger

Per- and polyfluoroalkyl substances (PFAS) are persistent organic chemicals. Within the diverse PFAS class with thousands of individual species, the perfluoroalkyl acids (PFAAs) are of environmental concern due to their pronounced stability, prevalent occurrence at contaminated sites globally, and their detrimental health impacts.

On contaminated sites, soil contamination often originates from sources like firefighting foams, industrial waste, or fertiliser from processed waste. This study is closely linked to the “Rastatt case”, where more than 1000 ha agricultural land are contaminated with PFAS due to the application of paper-fiber biosolids, and investigates PFAS immobilization as a strategy to mitigate the risk of groundwater contamination.

The current understanding of the fate and transport of PFAS within the subsurface is limited, largely due to the complex sorption processes and unidentified precursor compounds and transformation rates. The efficacy and long-term stability of PFAS immobilization are crucial parameters for field applications but have not been verified to date. Furthermore, a standardized experimental methodology for testing PFAS immobilization has not been established.

This presentation characterizes PFAS leaching behaviors, examines the efficacy and long-term stability of PFAS immobilization, and assesses the applicability of experimental methods in investigating PFAS immobilization. Mathematical models are employed to characterize various sorption processes.

We found that the complexity of PFAS leaching with rate-limited sorption and biotransformation contribute to long-term leaching. Sorption to air-water-interfaces (AWIs) was highlighted as a potentially dominant retention mechanism under variably-saturated conditions.

The influence of PFAS chain length on the immobilization efficacy was evident. Delayed breakthrough of short-chain PFAAs and prolonged leaching at low rates indicate that PFAS sorption to the immobilization agents is reversible. 

Long-term effects of PFAS immobilization were examined in column experiments with extended durations. The prediction of leaching based on this column data is compromised by indistinct precursor transformation and unaccounted AWI sorption. A thorough examination of PFAS leaching dynamics was achieved through lysimeter experiments, revealing the AWI sorption influence. However, moderate acceleration in PFAS leaching compared to field scenarios constrains long-term predictions.

This presentation sheds light on the benefits and constraints on the application of PFAS immobilization for a large non-point source.

How to cite: Haslauer, C., Bierbaum, T., Kleinknecht, S., and Junginger, T.: Immobilization of Per- and Polyfluoroalkyl Substances (PFAS) – Experimental and Model-based Analysis of Leaching Behavior, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7899, https://doi.org/10.5194/egusphere-egu24-7899, 2024.

09:05–09:15
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EGU24-10863
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HS8.1.7
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ECS
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On-site presentation
Jacopo Cogorno and Massimo Rolle

PFOS fate and transport in the subsurface are significantly impacted by the spatially and temporally variable hydrochemical conditions found in natural environments, which often exhibit strong ionic strength gradients and pH fluctuations [1,2]. Batch and flow-through column experiments are standard methods for characterizing PFOS adsorption and transport behaviors, and their outcomes are often quantitatively interpreted by defining empirically derived solid-water distribution coefficients (e.g., Langmuir and Freundlich equations) [3]. The limitation of these models is that they are strictly system-dependent and cannot precisely assess PFOS removal under varying water chemistry conditions. Thus, there is a need for mechanistic sorption prediction models able to account for varying electrostatic properties of the surface-solution interface in response to changes in pore water chemistry, and that could be implemented in reactive transport simulators for precisely assessing PFOS migration under dynamic hydrochemical conditions in multicomponent systems [4].

In this work, we initially conducted a comprehensive set of adsorption experiments and IR spectroscopy analyses with varying pH and ionic strength conditions to elucidate PFOS binding behavior on goethite surfaces as a function of solution chemistry. The experimental outcomes were quantitatively interpreted by developing a surface complexation model (CD-MUSIC) built on the results of the adsorption experiments and on the molecular-level understanding acquired through IR spectroscopy. Subsequently, a series of one-dimensional flow-through experiments were conducted in fully saturated goethite-coated silica sand columns by injecting a 2 mg/L PFOS pulse with varying NaCl background electrolyte concentrations and collecting PFOS and pH breakthrough curves at the outlet of the domain. PFOS uptake exhibited a complex behavior that was strongly dependent on solution pH and electrolyte concentration and that originated from the co-existence and speciation of two distinct PFOS-goethite surface complexation mechanisms: (i) a hydrogen-bonded complex (HB) and (ii) a weaker outer-sphere complex involving Na+ co-adsorption (OS-Na+). The non-trivial dependency of PFOS uptake on solution chemistry significantly impacted its transport behavior. Dynamic ionic strength gradients established during the flow-through experiments led to distinct retardation and transport behaviors which were not observed in the experiments performed with constant ionic strengths [5]. PFOS and pH breakthrough curves were quantitatively described by implementing the developed surface complexation model within the reactive transport simulator PHREEQC-3 coupled with MATLAB through the IPhreeqc module [6,7]. The simulations illuminated the key role of multicomponent transport effects on PFOS mobility and the importance of explicitly accounting for mineral surface charge adjustments in response to changes in water chemistry.

[1] Zhu et al. (2017) Chemosphere 168, 390-398. [2] Blowes et al. (2014) In Treatise on Geochemistry 2nd Edition Vol. 11, pp 131-190. [3] Johnson et al. (2007) J. Chem. Eng. Data 52, 1165-1170. [4] Cogorno and Rolle (2024) Env. Sci. Technol. https://doi.org/10.1021/acs.est.3c09501. [5] Cogorno and Rolle (2024) In prep. [6] Charlton and Parkhurst (2011) Comput. Geosci. 37, 1653-1663. [7] Muniruzzaman and Rolle (2016) Adv. Water Resour. 98, 1-15.

How to cite: Cogorno, J. and Rolle, M.: Impact of variable water chemistry on PFOS-goethite interactions under batch and flow-through conditions: experimental evidence and reactive transport modeling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10863, https://doi.org/10.5194/egusphere-egu24-10863, 2024.

09:15–09:25
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EGU24-11156
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HS8.1.7
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On-site presentation
Christopher Higgins, Tissa Illangasekare, John Stults, and Bo Guo

Background/Objectives: Per- and Polyfluoroalkyl substances (PFASs) are a group of highly recalcitrant, bioaccumulative, and toxic chemicals that are frequently introduced to groundwater through land surface exposure. As a result, the vadose zone has been identified as a significant long-term source zone for PFAS leaching into groundwater. This talk summarizes critical findings regarding PFAS transport in the vadose zone and introduces several emerging topics expected to develop over the next several years.

Approaches/Activities: Early efforts in understanding PFAS Fate & Transport processes focused on their multi-phase retention processes. Specifically, understanding the degree of equilibrium partitioning to the solid phase and the air-water interface have been intensely studied topics. Equilibrium partitioning to solid and air-water interfaces generally increases with increasing molecular volume, with exceptions for very long chain perfluoroalkyl acids (PFAAs), cationic and zwitterionic PFASs, perfluoroalkyl ethers, and PFASs with very large headgroups. Recent research and emerging field data suggest many sites are impacted by non‑ideal, non‑equilibrium processes. Evidence of PFAA generation from precursor transformation, physically driven non-ideal transport, and chemically driven non-idealities have emerged as environmentally relevant topics. A specific list of topics for discussion is presented below:

  • Precursor Transformation: Despite the name “forever chemicals”, there are many PFASs known as PFAA precursors. Precursors transform into PFAAs, which are more mobile and can serve as a centurial source of PFAS contamination to underlying aquifers.
  • Non-Ideal Transport Mechanisms Can Accelerate PFAS Leaching: Non-Ideal transport can be caused by physically driven non-equilibrium processes. Examples include flow path channelization, immobile water formation, sheet flow, and reduced accessibility of air-water interfaces. It is likely that these mechanisms drive rate-limited desorption from solid-phase materials. Non-Ideal transport appears to be more prevalent at lower saturations.
  • Additional Transport Processes: PFAS retention and retardation by the presence of other co-contaminants such as non-aqueous phase liquids (NAPLs) in media are starting to receive more research attention.
  • Evidence of Self-Assembly and Chemically Driven Rate-Limited Desorption: Molecular self-assembly refers to the potential of PFASs and other surfactants to form discrete microstructures at liquid interfaces. These thermodynamically stable microstructures may contribute to the consistently elevated PFAS concentrations observed in source zones.

Results/Conclusions: Many considerations are needed when assessing the fate & transport risks for PFASs at a given site. While there is early evidence that equilibrium models can predict long-term mass flux in some locations, these models may not predict large discharges from discrete storm events. Terminal PFAA discharge to groundwater from precursor transformation is of critical importance to understanding the long-term behavior of PFASs in the subsurface. The potential for Non-Ideal transport to accelerate PFAS transport may explain the conundrum of why some long chain PFAAs are found in groundwater systems despite their strong equilibrium retention properties. Another explanation for accelerated transport is the potential for competitive adsorption of mixtures to reduce the equilibrium partitioning potential of substances in mixtures. Additional retention (i.e., adsorption to NAPLs) requires additional study to determine appropriate partitioning parameters. Finally, PFASs may have unique transport and retention mechanisms which may be enhanced by their surfactant properties.

How to cite: Higgins, C., Illangasekare, T., Stults, J., and Guo, B.: Recent Advancements in Mechanistic Understandings of PFAS Fate & Transport in the Vadose Zone, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11156, https://doi.org/10.5194/egusphere-egu24-11156, 2024.

09:25–09:35
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EGU24-20496
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HS8.1.7
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Highlight
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On-site presentation
Jesús Carrera, Paula Rodriguez-Escales, Cristina Valhondo, Lurdes Martinez-Landa, Silvia Diaz-Cruz, Benjamín Piña, Albert Contreras, Gerard Quintana, and Laia Navarro-Martin

Soil Aquifer Treatment (SAT) consists of recharging the effluents of wastewater treatment plants across the soil (possibly reinforced with a reactive layer), unsaturated zone, and aquifer. It has been known since long that a dramatic water quality improvement occurs after soil and aquifer passage. However, the actual contaminant removal mechanisms remain open to discussion. Here, we summarize results observed at a number of sites displaying significant degradation of the most recalcitrant chemical compounds, as well as orders of magnitude reduction of antibiotic resistance and pathogen indicators. We have observed that the most toxic species, with significant partition coefficients, tend to accumulate in biofilms, where microorganisms accumulate. The accumulation of degrading microorganisms at the place where they can be degraded suggest natural selection. Further, a broad range of redox conditions, from aerobic to sulphate reduction (and, thus, a broad diversity of microbial communities), do occur during SAT. Together, these processes ensure a an extremely bioactive environment, which explains the dramatic reduction in toxicity we have observed after relatively modest (some 15 days) residence time in the aquifer. An implication from these observations is that the strict conditions imposed by the EU on SAT must be relaxed.

How to cite: Carrera, J., Rodriguez-Escales, P., Valhondo, C., Martinez-Landa, L., Diaz-Cruz, S., Piña, B., Contreras, A., Quintana, G., and Navarro-Martin, L.: A short review of the processes explaining water quality improvement during Soil Aquifer Treatment, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20496, https://doi.org/10.5194/egusphere-egu24-20496, 2024.

09:35–09:45
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EGU24-15559
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HS8.1.7
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Highlight
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On-site presentation
Kai Uwe Totsche

Structural dynamics, fluid flow, and reactive transport in permeable media are affected by the presence of and interactions with components of the total mobile inventory (TMI). With the term TMI we take into account the fact that the inventory of mobile substances in natural permeable media extends over an extremely wide range of sizes (spanning five orders of magnitude from the truly dissolved matter in the nanometre range to the large microaggregates and biota, around 250µm) and an almost incomprehensible diversity of proprietary and foreign materials (e.g., organic, inorganic, organo-mineral associations, microaggregates, biota, viruses, MGE, etc.; Lehmann et al. 2021 DOI:10.1016/j.scitotenv.2020.143774). Despite the essential role the larger particles of TMI up to a size of 250µm play for the functions, ecology, and intercompartment exchange in the subsurface and in between the surface and subsurface (Zerfaß et al. 2022 DOI:10.1016/j.watres.2022.118998; Herrman et al. 2023 DOI: 10.1016/j.soilbio.2023.109192), the majority of studies on the subsurface water resources and the biogeochemical cycling are dedicated to the operationally defined dissolved fraction, and, to a lesser extent, to the colloidal sized materials. Larger mobile materials beyond the 2µm size limit are vastly omitted. With increasing size beyond the “magical” 450nm size boundary, however, the understanding of the mechanisms that control the fate of TMI-components gets more demanding. With increasing size, morphology and surface properties control the interactions with the mobile and immobile surfaces and thus the transport behaviour. With increasing size, the effects of gravity on interactions and transport can no longer be neglected (Guhra et al. 2021 DOI: 10.1016/j.jcis.2021.03.153). And with increasing size, the pore-network structure, void-size-distribution, and connectivity constrain the accessibility to fractions of the void space by exclusion. The story does not end here: Interactions of TMI-components with the immobile solid phase change the structure of the void-network (Ritschel et al. 2023, DOI: 10.1016/j.geoderma.2022.116269). And TMI change the properties of the – frequently aqueous fluids in natural systems, e.g., the density, the viscosity, and the surface tension. In sum, fluid dynamics and reactive transport in natural systems like soils, sediments, the vadose and the phreatic zone are rather complex phenomena that are intimately intertwined with the physical and biogeochemical weathering and alteration in the subsurface and pedogenesis at the regolith-atmosphere interface. In view of the growing awareness of the subsurface as a mosaic of habitats and ecosystems (Lehmann and Totsche, 2020 DOI: /10.1016/j.jhydrol.2019.124291; Yan et al. 2020 DOI: 10.1016/j.watres.2019.115341), affected by land-use and climate change, this presentation pleads for a more general and synoptic understanding of fluid flow and reactive transport in natural permeable media and the consequences for their properties, functions and finally life sustaining ecosystem services. Given the power provided by multi-omics in combination with the wide spectrum of (non-invasive) spatio-temporal observational techniques, and the rapid progress in E-science and model-Big-data integration, the reconstruction of the “true” complexity of the subsurface compartments and their development in response to climate and land-use change is possible and allows to define the objectives for ambitious future coordinated research.

How to cite: Totsche, K. U.: Linking the dynamics of the total mobile inventory to the co-evolution of structure and function in the subsurface, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15559, https://doi.org/10.5194/egusphere-egu24-15559, 2024.

09:45–09:55
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EGU24-22435
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HS8.1.7
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On-site presentation
Manish Kumar, Rahul Silori, Durga Madhab Mahapatra, and Jurgen Mahlknecht

The present communication investigated the dynamics (prevalence, seasonality, and removal) of endocrine disruptive chemicals (EDCs) and seven target pharmaceuticals and personal care products (PPCPs) in the Himalayan city of Dehradun in Uttarakhand province of India. Two municipal and two academic institutions WWTPs were selected for wastewater (WW) sampling in the city during spring, summer, and monsoon seasons. The result showed Diclofenac and Caffeine occurrence in all influent samples of the WWTPs indicative of considerable intake in the city. During the study, Caffeine and Acetaminophen concentrations were consistently higher in the sampled WW influents. The total PPCPs concentration in the WWTPs ranged from 1K to 74K ngL-1 and 22 to 64K ngL-1in influent and effluents, respectively. Seasonal variations in influent wastewater samples indicated high mean PPCP levels during spring, followed by monsoon and summer seasons. Caffeine showed the highest PPCP concentration (71K ngL-1) during monsoon and while Ciprofloxacin concentration was high (16K ngL-1) during the spring season. The study also revealed high correlation between Acetaminophen with Diclofenac (r=+0.77) and Ketoprofen (r=+0.62). In addition, Diclofenac was firmly linked with Ketoprofen (r=+0.89), whereas Ciprofloxacin was strongly linked with Carbamazepine (r=+0.65).

While the estrone showed concentrations at μgL−1 levels in influent concerning ngL−1 levels of triclosan (TCS). The highest global concentration of ~124 μgL−1 is recorded for the estrone during our monitoring period. The tests for Normality showed a non-normal data distribution (p>0.05) for all WW PPCPs samples except for Caffeine influents. PPCP concentration showed a high statistically significant variation between the influent and effluent samples (p<<<0.001), indicating highly decisive evidence for unequal means. The PPCPs treatment rates in the WWTPs ranged from ~69 -100%. In terms of total PPCPs, average removal efficiencies of WWTPs were recorded in the range of 41.66-71.40%. The maximum removal was recorded for Acetaminophen and Ketoprofen, while increased concentrations in the effluents (negative removals) were witnessed for Ciprofloxacin, Carbamazepine, and Caffeine in the WWTPs. The WWTPs have been found to contribute to existing PPCP loads and are channelized toward the disposal sites, posing a severe threat to biodiversity, human health, and the ecological integrity of the region and its downstream. We critically highlighted the limitation of the WWTPs in the treatment, degradation, and assimilation of EDCs leading to several environmental & human health-based threats to one health in the region. This study is vital for setting up baseline data and setting a platform for future research surveillance and control of emerging contaminants (ECs) in ecologically sensitive hilly landscapes.

How to cite: Kumar, M., Silori, R., Madhab Mahapatra, D., and Mahlknecht, J.: Patterns of Prevalence, Seasonality, and Treatment Efficiencies of Endocrine Disruptive Chemicals, Pharmaceuticals, and Personal Care Products in the Wastewaters of the Himalayan City of Dehradun, India, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22435, https://doi.org/10.5194/egusphere-egu24-22435, 2024.

09:55–10:05
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EGU24-22399
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HS8.1.7
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On-site presentation
Kanika Dogra, Manish Kumar, and Vivek Agarwal

We present the interpretation of the Perfluorooctane sulfonate (PFOS) dataset spread over eighteen years between 2005 to 2023. The data explicitly depicts the essence of i) a growing monitoring network with growing concern i.e. ten to nearly 100 locations; ii) increasing resolution in knowing the chemical closely with advancing technologies i.e. inclusion of branched and linearity of PFOS rather than just ionic form; iii) increasing the diversity of systems being gradually included in the monitoring system to appreciate the environmental interactions, i.e. only groundwater to freshwater to even brackish water systems. This government-supported monitoring data tracks the curve of PFC-related concern for water sectors over the last two decades of the 21st century and thus provides the learnings for the future. The dataset also indicates that knowing a problem is the first step towards taking the right steps towards correcting that given system, as evident by decreasing PFOS concentrations between 2005 (ND to 0.5 µgL−1) to 2023 (ND to 0.012 µgL−1) in the groundwater environment of Yorkshire, UK. However, the data fails to provide confirmatory evidence of PFC pathways linking with surface-groundwater interactions. This work can be an eye-opener for policymakers of developing countries who are so reluctant to acknowledge the lack of regulations, and thus the associated need to monitor of chemicals of emerging concerns like PFAs, thus completely losing the opportunity of establishing stringent guidelines at the right time.

How to cite: Dogra, K., Kumar, M., and Agarwal, V.: Decadal Resolution of ‘Forever Chemical’ of PFOS in the groundwater of Yorkshire County, United Kingdom: The Future of the Past Learnings, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22399, https://doi.org/10.5194/egusphere-egu24-22399, 2024.

10:05–10:15
Nanoparticles and Micro- and Nanoplastics
Coffee break
Chairpersons: Constantinos Chrysikopoulos, Markus Flury, Tissa Illangasekare
10:45–10:50
10:50–11:00
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EGU24-6160
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HS8.1.7
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Highlight
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On-site presentation
Thilo Hofmann, Charlotte Henkel, Thorsten Hueffer, and Stephanie Castan

The impact of nanoplastics on the co-transport of emerging contaminants is a subject of ongoing debate. Agricultural soils face potential contamination from micro- and nanoplastics through diverse agricultural practices. Various authors argue that the substantial surface area of small particles and their high sorption potential may considerably augment the mobility of numerous contaminants within the critical zone. Concerns have been expressed regarding the role of micro- and nanoplastics as carriers for organic contaminants into deeper soil layers, posing a potential threat to groundwater resources, particularly in agricultural soils where sewage sludge and plant protection products are frequently applied.

In this study, we investigated the correlation between transport and desorption timescales by employing two diffusion models for micro- and nanoplastics ranging from 100 nm to 1 mm. To assess the transport of contaminants bound to these plastics, we examined the diffusion and partitioning coefficients of prominent agrochemicals and additives, along with commonly used polymers like polyethylene and tire material. Our modeling analysis reveals that the desorption rate of most organic contaminants is too rapid for micro- and nanoplastics to serve as effective transport facilitators in soil. Notably, the transport of contaminants facilitated by microplastics was observed to be significant only for highly hydrophobic contaminants under preferential fast-flow conditions.

While micro- and nanoplastics could potentially introduce harmful contaminants into agricultural soils, our study suggests they do not significantly enhance contaminant mobility. Importantly, we found that nanoplastics, in particular, do not promote contaminant relocation under conditions relevant to almost all contaminants of concern.

How to cite: Hofmann, T., Henkel, C., Hueffer, T., and Castan, S.: Why nanoplastics do not enhance the transport of contaminants in the critical zone, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6160, https://doi.org/10.5194/egusphere-egu24-6160, 2024.

11:00–11:10
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EGU24-1667
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HS8.1.7
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ECS
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On-site presentation
Andreas Cramer, Anders Kaestner, Pascal Benard, Mohsen Zarebanadkouki, Peter Lehmann, and Andrea Carminati

Microplastic (MP, ⌀ < 5 mm) can be found worldwide. Besides aquatic environments, terrestrial ecosystems are reported to contain large amounts of MP of different origin, polymer type, shape, size, and state of degradation. Furthermore, soil is considered the largest sink of MP in terrestrial ecosystems. Though, little is known about the effects of MP on soil and its interaction with water flow. Since MP is inherently hydrophobic, the transport of MP and the flow of water interact with each other. However, the extent of MP transport in soils and the interactions with water flow remain largely unexplored.

To approach these questions, neutron and x-ray imaging methods were applied. Simultaneous neutron and x-ray CT at the beamline ICON (Paul-Scherrer-Institute) during wetting and drying cycles of a model porous media mixed with MP in different contents were used to monitor MP in different contents (size between 20-75 μm) and water distribution during repeated wetting and drying cycle of a sandy substrate (particle size between 700-1200 μm). Here, the initial MP configuration as well as the configuration after each wetting and drying cycle were captured in three dimensions. During the wetting process, time-series neutron radiographies imaged the water infiltration patterns.

MP reduced water infiltration in soils. High MP contents caused local water reppellency and were by-passed by perculating water. MP impacted the verticle distribution of water, reducing the local soil water content and driving water to deeper soil layers. Significant transport of MP were not visible during the wetting and drying cycles, plausibly because water by-passed the pore space containing MP. Rapid and preferential infiltration into deeper areas of the sample as well as low local volumetric water contents during the course of infiltration are evident. The extent seems to be MP content dependent.

In conclusion, MP-water interactions in soils have a strong impact on water flow and MP transport and fate in soils. Transport processes like advection, which are significant for wettable particles, play only a minor role in transporting low wettability particles like MP under unsaturated conditions. Though, MP seems to be spatially re-configured. This might be due to hydrophobic interactions between water and MP. Hydrophobic MP has an affinity towards adsorbing to the air-water interface rather than being dispersed in water when in contact.

How to cite: Cramer, A., Kaestner, A., Benard, P., Zarebanadkouki, M., Lehmann, P., and Carminati, A.: Water flow and MP transport in sandy soils imaged with neutron radiography and X-ray CT, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1667, https://doi.org/10.5194/egusphere-egu24-1667, 2024.

11:10–11:20
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EGU24-227
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HS8.1.7
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ECS
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Highlight
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On-site presentation
Kara Müller, Martin Elsner, and Natalia P. Ivleva

Biodegradable polymers are considered one of the solutions to the plastic accumulation problem in terrestrial and aquatic systems. It is important to ensure complete degradation since residual micro- and nanoplastics influence soil health and its biota. During biodegradation, microorganisms first colonize the plastic surface, where they then excrete enzymes responsible for the depolymerization. Finally, the mono- and oligomers are utilized by the microorganisms as energy sources (mineralization into CO2) or for biomass formation. Only by studying the last step the final fate of the anthropogenic pollutant is revealed. Conventionally CO2 concentrations are measured to monitor microbial activity in samples exposed to plastics in comparison to plastic-free controls. However, this is in no direct relation to the polymer and priming effects or unknown processes due to bacteria adaptation might blur the analysis. Stable isotope labels can be traced from the polymer into 13CO2, D2O and microbial biomass to overcome those obstacles. While many publications covered 13CO2 monitoring, only Zumstein et al. additionally traced the carbon label into fungal biomass with nanoscale secondary ion mass spectrometry.[1] In our approach, we use deuterium instead of carbon labels due to reduced costs and enhanced availability of labeled compounds. Although we lose the ability to contribute to a closed mass balance, we use non-destructive Raman microspectroscopy to gain additional chemical information on a single cell level. Heavier isotopes lead to a red shift of the according Raman band due to their larger mass. Deuteration of microbial lipids, proteins, DNA, and carbohydrates leads to an extensive shift of C-H vibrations into the Raman-silent region. C-D vibrations can therefore be quickly detected with a facilitated data analysis.

We incubated the environmental bacterium Sphingomonas koreensis with deuterated polylactic acid (dPLA) in an aqueous medium at room temperature under aerobic conditions. After 3 weeks, we observed an additional biomass spectrum for about 50 % of the measured cells besides undeuterated biomass and dPLA particles. After 13 weeks, this spectrum was already recorded for all cells. While the biomass and C‑H str. vibrations clearly indicate microbial biomass, the C-D vibrations of the additional spectra differ from reference deuterated biomass spectra obtained with glucose-d12 and D2O labeling. After comparing these untypical C-D vibrations to self-obtained and literature reference spectra, they were interpreted to originate from deuterated biomass with strongly deuterated lipids and inhibited labeling of proteins. Now that we can trace deuterium from labeled plastics into microbial biomass, we want to extend the approach to terrestrial environments. Therefore, cell isolation from the soil matrix was successfully adapted from the literature[2] to gain adequate Raman spectra. In ongoing experiments, environmental samples will first be exposed to unlabeled PLA for bacteria adaptation and then used for incubation with dPLA in soil microcosms. 

References:

  • Zumstein, M.T., et al., Science Advances, 2018. 4(7): p. eaas9024.
  • Eichorst, S.A., et al., FEMS Microbiology Ecology, 2015. 91(10).

Acknowledgments: Deutsche Forschungsgemeinschaft (DFG) Project IV 110/2-2 and International Atomic Energy Agency (IAEA) for funding different parts of the research. Dr. Jürgen Allgaier (FZ Jülich) for providing the deuterated PLA.

How to cite: Müller, K., Elsner, M., and Ivleva, N. P.: Deuterium Labels to Study Biodegradation of Plastics with Raman Spectroscopy , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-227, https://doi.org/10.5194/egusphere-egu24-227, 2024.

11:20–11:30
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EGU24-3604
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HS8.1.7
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ECS
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On-site presentation
Yingxue Yu and Markus Flury

The increasing threat from plastic pollution has promoted the widespread application of biodegradable plastic. In agriculture, biodegradable plastic, mainly in the form of biodegradable plastic mulch, has received a lot of attention due to its in-situ degradability and satisfying agronomical performances. However, biodegradable plastic mulches do not degrade instantaneously but rather fragment into micro- and nanoplastics, and these micro- and nanoplastics could reside in soil or even migrate along soil profiles. Here, we investigated the mobility of pristine and weathered polybutylene adipate co-terephthalate (PBAT) nanoplastics in sand columns under unsaturated flow conditions. We further studied the effect of proteins on the mobility of PBAT nanoplastics with both negatively charged bovine serum albumin and positively charged lysozyme. We found that (1) the pristine and the weathered PBAT nanoplastics were mobile with or without the presence of proteins; (2) the positively charged lysozyme inhibited the transport of PBAT nanoplastics; and (3) lower water saturation inhibited the transport of PBAT nanoplastics via physical straining. These results suggest that biodegradable nanoplastics generated from biodegradable plastic mulches are mobile and may transport readily along soil profiles.

How to cite: Yu, Y. and Flury, M.: Transport of Biodegradable Nanoplastics Affected by Weathering and Proteins in Unsaturated Porous Media, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3604, https://doi.org/10.5194/egusphere-egu24-3604, 2024.

11:30–11:40
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EGU24-15458
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HS8.1.7
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ECS
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On-site presentation
Elvira Colmenarejo Calero, Manca Kovač Viršek, Tine Bizjak, and Nina Mali

Microplastics (MPs), are considered an emerging global pollutant and a significant contributor to environmental pollution. They are defined as plastic particles measuring less than 5 mm which can vary in chemical composition, color, shape, density, size, and other characteristics. MPs generated through urban, industrial, and agricultural activities have the potential to reach the environment, including groundwater. However, despite the significance of groundwater as a vital resource, there is a notable dearth of information regarding the occurrence, transport, and risk of MPs in this environment.

In Slovenia, groundwater resources are the primary source of drinking water for 98% of the population. A considerable number of these resources are affected by different anthropogenic activities that result in contamination by different pollutants, among which MPs are probably included. The present study aimed to investigate the presence of MPs in karst and alluvial aquifers of three different regions of Slovenia. Particular emphasis has been given to the improvement of sampling and detection of MPs in groundwater along with the evaluation of the impact of hydrogeological environment, land use and anthropogenic activities in the recharge zone of each sampling site on the occurrence of MPs in groundwater.

Groundwater samples were collected from a total of 19 locations, 8 were situated in alluvial aquifers and 11 in karst formations. In each location a total of 3 cubic meters of water was sampled using an in-situ filtration system with a filter pore size of 10 - 100 µm. The samples were then analyzed in the laboratory using a digital microscope with a magnification range of 100 - 5000x and stereomicroscope with magnification 12,5 – 100x. The chemical composition of particles was determined using FTIR microscope and ATR-FTIR. The results showed that MPs were present in all sampled sites, with fibers and fragments being the most common observed shapes. The study proves the presence of MPs in both, alluvial and karst aquifers of Slovenia and demonstrates the suitability of an in-situ filtration system for sampling MPs in groundwater.

How to cite: Colmenarejo Calero, E., Kovač Viršek, M., Bizjak, T., and Mali, N.: Microplastics pollution in groundwater: Case study - Slovenia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15458, https://doi.org/10.5194/egusphere-egu24-15458, 2024.

11:40–11:50
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EGU24-8778
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HS8.1.7
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On-site presentation
|
Frank von der Kammer, Helene Walch, Raisibe Florence Lehutso, and Thilo Hofmann

The assessment of nanoparticle NP transformation in the aquatic environment is essential for comprehending the fate of nanoparticles and conducting accurate risk assessments. Nanoparticles encompass a variety of materials, including manufactured nanomaterials, nanoplastics, and natural colloids. Environmental transformation comprises four main routes: dissolution/leaching, abiotic transformation/degradation, biotic transformation/degradation and (hetero-)agglomeration.

The kinetics of heteroagglomeration play a pivotal role in nanoparticle (NP) transport mechanisms in rivers. The parametrization of heteroagglomeration processes between NPs and suspended particulate matter (SPM) was hampered by the variability of SPM floc composition and conformation/size on spatial and temporal scales. Available analytical methods were either unsuitable or required unrealistic high NP concentrations. The SPM used in heteroagglomeration studies was either unrealistically simple (silica particles, clays) or exceptionally unique (specific natural SPM sample).

After a thorough analysis of mechanisms of floc formation and the relevant building blocks of natural, riverine SPM and the successful and reproducible laboratory synthesis of model SPM flocs, we designed a method to determine the heteroagglomeration attachment efficiency αhetero  under environmentally relevant conditions. This allows well controlled laboratory experiments as well as standardization for risk assessment purposes. The heteroagglomeration attachment efficiency () constitutes the most suitable parametrization of particle-particle interactions. The presented test matrix combines synthetic model SPM flocs with the model freshwater composition suggested in OECD TG 318, both designed to represent agglomeration-relevant characteristics of natural systems. The test matrix was employed in a newly developed stirred-batch method addressing the shortcomings of existing strategies to determine αhetero. Time-resolved inductively coupled plasma mass spectrometry allowed to work at realistic concentrations of NP (5 ppb) and SPM flocs (20 and 40 ppm).

The approach was evaluated by testing the heteroagglomeration of CeO2 nanoparticles in four different combinations of SPM and water chemistry.

  • Natural flocs in natural water
  • Natural flocs in synthetic (TG318) water
  • Synthetic flocs in natural water
  • Synthetic flocs in synthetic water

The results show the applicability and precision of the invented test system and the synthetic SPM but also reveal some differences between results from natural and synthetic water chemistry which can be explained by the type and quality of the NOM. Calculated transport distances for 50% unassociated NPs reached up to 370 km, what is unexpectedly high.

How to cite: von der Kammer, F., Walch, H., Lehutso, R. F., and Hofmann, T.: Nanoparticle Heteroagglomeration with Natural and Synthetic Suspended Particulate Matter, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8778, https://doi.org/10.5194/egusphere-egu24-8778, 2024.

11:50–12:00
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EGU24-13533
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HS8.1.7
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ECS
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Virtual presentation
Luis Ullauri, William Johnson, Diogo Bolster, and Bashar Al-Zghoul

The cause of non-exponential decreases in colloid concentrations with distance from source was posited to derive from the emergence of fast- and slow- attaching populations from identical individuals (Johnson, 2018).  Fast-attachers were posited to attach according to a rate coefficient corresponding to favorable conditions, whereas the remainder of the population were posited to attach according to a slower rate coefficient.  This talk demonstrates the emergence of fast- and slow- attaching populations in pore network transport experiments under unfavorable conditions.  We explain the segregation into two subpopulations as being driven by colloid-surface repulsion, topological impacts of the flow field (incomplete pore scale mixing), and consequent impacts on the number of interceptions incurred prior to attachment. 

How to cite: Ullauri, L., Johnson, W., Bolster, D., and Al-Zghoul, B.: Experimental Confirmation of Emergence of Fast- and Slow- Attaching Subpopulations from Identical Individuals Produces Non-Exponential Decreases in Colloid Concentrations with Distance from Source under Unfavorable Conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13533, https://doi.org/10.5194/egusphere-egu24-13533, 2024.

12:00–12:10
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EGU24-2071
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HS8.1.7
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On-site presentation
Gukhwa Hwang and Hyunjung Kim

The importance of nanoscale roughness factors on the fate and transport of colloidal particles has been well emphasized in recent literature; however, most of the works either only used modeling tools or had limitations on unravelling the effect experimentally due to the lack of well-defined systems to solely capture the role of the nanoscale roughness. Therefore, this study aimed to “experimentally” observe the adhesion characteristics of environmental colloidal particles on a surface with nanoscale roughness (NR) factors (i.e., height and fraction) under environmentally relevant solution chemistry conditions. Prior to analyzing the effect of the NR, the solid surface was first fabricated. AFM was employed to confirm the adhesion force between the target material and the uniformly fabricated rough surface, which can influence the contact area. To the best of our knowledge, our study is the first to experimentally quantify the sole effect of the NR with well-controlled NR-surfaces via the adhesion force measurement in aqueous system. The findings are important to verify the role of NR in the interaction of particles with different shapes (i.e., sphere and plateau) and sizes (i.e., 2 μm to 15 μm in length or diameter), which the authors believe will provide new insights to the society on better understanding the role of NR in the interaction of environmental colloidal particles.

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. RS-2022-00166099).

How to cite: Hwang, G. and Kim, H.: Adhesion forces measured between colloids and nanoscale surface roughness in aqueous solution, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2071, https://doi.org/10.5194/egusphere-egu24-2071, 2024.

12:10–12:20
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EGU24-11500
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HS8.1.7
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On-site presentation
Tiziana Tosco, Monica Granetto, Silvia Fogliatto, and Francesco Vidotto

Pesticide use plays a crucial role in achieving high crop yields in the context of a global population growth scenario. However, the extensive application of pesticides has progressively led to the contamination of environmental matrices, particularly soils and groundwater, posing potential risks to human health, flora, and fauna. Nanopesticides can be instrumental in mitigating pesticide pollution, especially for highly soluble and volatile active ingredients. They are formed by nanoparticles (nanocarriers) containing an active ingredient, sometimes shielded by a coating, and dispersed in a colloidal suspension. The nanoformulations proposed in this study utilize low-cost mineral materials (such as montmorillonite, zeolite, kaolin) and food-grade biopolymers to incorporate two distinct herbicides, namely dicamba and S-metolachlor, characterized by high solubility (and thus high migration potentian in the subsoil) and, for dicamba only, moderate volatility.

The efficacy of the newly developed nanoherbicides in terms of reduced mobility in porous media, reduced persistency, and efficacy toward target weeds was assessed in the laboratory against the pure herbicide and commercial formulations containing the same active ingredients. Specifically, the mobility in porous media was tested through column transport experiments under both saturated and unsaturated conditions, using sand and standard soils (representative, respectively, of top soil and aquifers). These tests were conducted at various scales, ranging from small columns (1.6 cm diameter, 10 cm length) to a laboratory lysimeter (30 cm diameter, 70 cm length). Batch degradation tests in soils indicated comparable DT50 values for the nanoformulation and the commercially available product. The efficacy of the nanopesticides was also examined against conventional products in greenhouse settings through dose-response tests on selected sensitive weeds. The greenhouse tests revealed that clay-based nanoformulations do not impede the effectiveness of dicamba against target weeds, showing efficacy comparable to the commercial competitor for both dicamba and S-Metolachlor, although variations were observed depending on the treated species.

Despite the small scale of the tests conducted in the laboratory and greenhouse, these initial results suggest the promising efficacy of the proposed nanoformulation approach in controlling the environmental spread of soluble herbicides without compromising efficacy against target species.

This research was conducted within the Nanograss project, co-funded by the Compagnia di San Paolo Foundation.

 

Reference

Granetto M., Serpella L., Fogliatto S., Re L., Bianco C., Vidotto F., Tosco T. (2022). Natural clay and biopolymer-based nanopesticides to control the environmental spread of a soluble herbicide. Science of The Total Environment 806(3),151199, https://doi.org/10.1016/j.scitotenv.2021.151199

How to cite: Tosco, T., Granetto, M., Fogliatto, S., and Vidotto, F.: Managing the leaching of water-soluble herbicides in soils using eco-compatible nanocarriers, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11500, https://doi.org/10.5194/egusphere-egu24-11500, 2024.

12:20–12:30

Posters on site: Mon, 15 Apr, 16:15–18:00 | Hall A

The posters scheduled for on-site presentation are only visible in the poster hall in Vienna. If authors uploaded their presentation files, these files are linked from the abstracts below, but only on the day of the poster session.
Display time: Mon, 15 Apr 14:00–Mon, 15 Apr 18:00
Chairpersons: Constantinos Chrysikopoulos, Fritjof Fagerlund, Markus Flury
Nanoparticles and Micro- and Nanoplastics
A.55
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EGU24-4290
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HS8.1.7
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ECS
Vasileios Katzourakis and Constantinos Chrysikopoulos

         In order to investigate the migration of nanoparticles in porous media, the model developed by Katzourakis and Chrysikopoulos (2021) is applied  to simulate the transport of aggregating nanoparticles under various initial conditions. In the aforementioned model, nanoparticles may collide with each other and form larger particle structures with different mobility and reactivity characteristics. Individual particles as well as aggregates can be found suspended in aqueous phase or attached, reversibly and/or irreversibly, on the solid matrix. The aggregation process modelled after the Smoluchowski population balanced equation (PBE), is coupled with the conventional advection-dispersion-attachment (ADA) equation to form a system of coupled equations that govern the transport of aggregating nanoparticles. Particle collisions are expected to increase exponentially with increasing initial number of injected particles (N0). Therefore, substantially pronounced aggregation is expected when N0 is increased. Similarly, the initial particle diameter distribution of the injected particles is expected to affect the average size of aggregates and in turn influence their mobility in a porous medium. Several model simulations were performed with different N0 and particle diameter distributions. The results indicated the strong importance of taking into account the initial particle concentration and realistic particle diameter population distribution into consideration.

How to cite: Katzourakis, V. and Chrysikopoulos, C.: Investigating the effects of initial concentration and population distribution on the transport of aggregating nanoparticles in porous media, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4290, https://doi.org/10.5194/egusphere-egu24-4290, 2024.

A.56
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EGU24-2545
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HS8.1.7
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ECS
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|
Anastasios Malandrakis, Kyriaki Varikou, Νektarios Kavroulakis, Antonis Nikolakakis, Irene Dervisi, Chrysavgi Reppa, Stefanos Papadakis, Maria Holeva, and Constantinos Chrysikopoulos

The effectiveness of copper containing nanoparticles (Cu/CuO-NPs) against insecticide-resistant olive fruit flies (Bactrocera oleae) and their impact on the insect’s reproductive and endosymbiotic parameters were evaluated. The insecticidal activity of both nano and bulk copper [Cu(OH)2] was comparable or greater than that of the reference insecticide deltamethrin at recommended doses as revealed by feeding experiments. A significant synergistic effect between Cu-NPs or CuO-NPs and deltamethrin was observed in terms of adult mortality. Furthermore, the deltamethrin + Cu-NPs combination decreased the total number of offspring as compared with the untreated control. The above combination also significantly decreased the mean number of stings, pupae, female and total number offspring of the surviving female, compared to deltamethrin applied alone. The abundance of the Candidatus Erwinia dacicola- a B. oleae larvae bacterial gut endosymbiont- was adversely affected by bulk and nanosized copper. Concluding, Cu-NPs have a great potential to control insecticide-resistant B. oleae populations by reducing adult and larval survival and fecundity, and provide the means for reducing the environmental footprint of pesticides by minimizing their required doses.

This study was co-financed by the European Regional Development Fund of the European Union and Greek national funds through the Rural Development Program (RDP/ΠΑΑ) 2014 – 2020, under the call "Cooperation for environmental projects, environmental practices and actions for climate change“ (project code: Μ16SΥΝ2-00354).

How to cite: Malandrakis, A., Varikou, K., Kavroulakis, Ν., Nikolakakis, A., Dervisi, I., Reppa, C., Papadakis, S., Holeva, M., and Chrysikopoulos, C.: Copper nanoparticles: Insecticidal action, resistance management  and effect on  endosymbiont abundance in olive fruit fly Bactrocera oleae , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2545, https://doi.org/10.5194/egusphere-egu24-2545, 2024.

A.57
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EGU24-9087
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HS8.1.7
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Nektarios Kavroulakis, Myrto Tsiknia, Maria Kissandraki, Constantinos Chrysikopoulos, and Anastasios Malandrakis

This study investigated the impact of metallic nanoparticles (NPs) containing copper, silver, copper oxide, and zinc oxide, recognized as potential pollutants, on the structural and compositional aspects of soil microbial communities in comparison to their bulk counterparts. The influence of these nanoparticles was examined at two distinct accumulation levels within the soil ecosystem.

The potential effects of metallic nanoparticles in comparison to their bulk counterparts were evaluated in a pot experiment under controlled environmental conditions. High-throughput sequencing of PCR-amplified 16S rRNA and ITS2 marker genes was employed to analyze the impact of NPs and counterparts on bacterial and fungal rhizospheric communities using two dosage levels.

Bioinformatic analysis of the obtained sequencing results revealed a distinct metal-dependent differentiation in bacterial and fungal soil community structures. Silver-containing treatments exhibited an enhanced ability to induce changes in both bacterial and fungal communities compared to other metals. Furthermore, treatment dose had a profound differentiation effect on the two microbial communities. The low dose notably influenced bacterial communities to a greater extent compared to the high dose, whereas fungal communities exhibited significant alterations under high-dose conditions rather than under low-dose conditions.

This study was co-financed by the European Regional Development Fund of the European Union and Greek national funds through the Rural Development Program (RDP/ΠΑΑ) 2014 – 2020, under the call "Cooperation for environmental projects, environmental practices and actions for climate change” (project code: Μ16SΥΝ2-00354) and by the European Union- Next Generation EU, Greece 2.0 National Recovery and Resilience plan (project code: TAEDR-0535675)

How to cite: Kavroulakis, N., Tsiknia, M., Kissandraki, M., Chrysikopoulos, C., and Malandrakis, A.: Metallic Nanoparticles: Differential  impact on Fungal vs Bacterial Soil Communities , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9087, https://doi.org/10.5194/egusphere-egu24-9087, 2024.

A.58
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EGU24-16845
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HS8.1.7
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Highlight
Manca Kovač Viršek, Tine Bizjak, Elvira Colmenarejo Calero, Katarina Zabret, Anja Koroša, Miloš Miler, and Nina Mali

Microplastics are recognised as an emerging pollutant. Microplastics describe plastic particles between 1 µm and 5 mm, which may be produced in this size (primary microplastics) or originate from bigger plastic debris subjected to decay or wear in the environment (secondary microplastics). Research in the field of microplastics started in the marine environment over 60 years ago but has been focusing on other environments only for the past 25 years. Microplastic particles have been observed almost everywhere – in oceans, rivers, wetlands, groundwater, lakes, air, plants, animals and people. Water is identified as the main transport medium of microplastics, however, only a few more recent studies identified microplastics in groundwater. Groundwater is an important drinking water resource in many parts of the world, e.g., in Slovenia, 98 % of drinking water demands are covered by groundwater resources.

This contribution gives the main subject of the ongoing research project GWMicroPlast, within which we will investigate the entire pathway of the microplastics and other pollutants linked with plastics pollution through the aquifer, starting from potential sources to the transport in the unsaturated zone and saturated zone and focusing on the evaluation of the presence of microplastics in different groundwater zones and on the improvement of understanding of microplastics migration through the aquifer. Within the scope of the proposed project, we aim to check the status of microplastic pollution in all three types of drinking water aquifers, intergranular, karst and fissured, in Slovenia. Special attention will be paid to developing methods for sampling and analysing microplastics in groundwater for different aquifers. The transport processes of microplastics in the gravel unsaturated zone will be investigated in more detail by a tracing experiment in the lysimeter. 

 

Acknowledgement: This contribution is part of the ongoing research project entitled “Improved methods for determination of transport processes and origin of microplastics in groundwater resources – (GWMicroPlast)” supported by the Slovenian Research and Innovation Agency (J1-50030).

How to cite: Kovač Viršek, M., Bizjak, T., Colmenarejo Calero, E., Zabret, K., Koroša, A., Miler, M., and Mali, N.: GWMicroPlast project – researching microplastics in groundwater, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16845, https://doi.org/10.5194/egusphere-egu24-16845, 2024.

A.59
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EGU24-19579
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HS8.1.7
Raisibe Florence Lehutso, Lorenzo Sanjuan Navarro, Melanie Vital, and Frank Von der Kammer

The last decade has seen a tremendous increase in research efforts to develop and apply analytical techniques with the aim of investigating the environmental behavior of colloids (1-1000 nm in diameter) and nanoparticles (NPs, 1-100 nm in diameter). Many of these studies were triggered by the wide application of manufactured nanomaterials, as well as the implications of these products as potentially dangerous, particulate pollutants [1]. During their live cycle, these materials are transported to or within environmental compartments, potentially leading to adverse effects that need to be fully studied and understood. In the environment, NPs are subject to processes such as dissolution, transformation, (over-)coating and (hetero-)agglomeration. These changes can occur in variable time frames, from minutes to geological time scales, causing certain changes in the intrinsic properties that need to be monitored [2]. In this work, new methodologies to evaluate NPs dissolution, transformation and heteroagglomeration for the purpose of standardization are developed.

To develop standardized methods for NP dissolution batch experiments, different parameters such as the impact of pH, types of buffers, types of pH control, initial concentrations, types of agitation, and types of natural organic matter have been investigated. For NP transformation, assessments were undertaken in conditions simulating aquatic environments with realistic sulfide and phosphate concentrations in batch and flow-through reactors. For heteroagglomeration, a model suspended particulate matter (SPM) was designed for interaction with particulate contaminants (e.g., NP, colloids etc.). Furthermore, a system to investigate model SPM and NP heteroagglomerationto determine attachment efficiency was developed.

Methods to investigate NPs dissolution, transformation and heteroagglomeration were successfully developed for later standardization. The batch experiment set-up is practical and efficient for determining NP solubility and dissolution rates. Transformation of NPs via formation of protective layer which significantly decreased NP dissolution was observed. However, in some cases an increase in ion concentration could be related to the formation of amorphous compound in the nanoparticle surface showing a higher apparent solubility compared with high ordered phases. The versatility of results obtained corroborate the methodology effectiveness. For heteroagglomeration, the model SPM was generated, and the designed protocol is highly reproducible and is independent of the SPM component source. NP and model SPM heteroagglomeration attachment efficiencies were determined in different environmental conditions, illustrating system applicability and robustness in different matrix. The methods developed herein edges efforts towards standardizing methods to investigate the behavior and fate of NP in aquatic system.  

[1] Bathi et al., Science of the Total Environment 793 (2021) 148560.

[2] Stetten et al., Nanomaterials 12 (2022) 519.

How to cite: Lehutso, R. F., Sanjuan Navarro, L., Vital, M., and Von der Kammer, F.: DISSOLUTION, TRANSFORMATION AND (HETERO-)AGGLOMERATION OF NMs: NEW METHODOLOGIES TO ALLOW FOR STANDARDIZATION., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19579, https://doi.org/10.5194/egusphere-egu24-19579, 2024.

PFAS and other Emerging Contaminants
A.60
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EGU24-16852
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HS8.1.7
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ECS
Nicola Messinger, Lutz Ahrens, Stefan Bertilsson, Dan Berggren Kleja, and Fritjof Fagerlund

The extensive use of Aqueous Film Forming Foam (AFFF) has led to substantial contamination by per- and polyfluoroalkyl substances (PFAS) of soils and groundwater at many firefighting training sites in Sweden and worldwide. PFAS is a group of extremely persistent anthropogenic substances that pose risk for adverse effect even at low levels. There is consequently a need to understand the potential for natural degradation of these compounds and the controlling environmental factors. Understanding the microbial capacity to degrade and transform PFAS is also crucial for comprehending their transport in soil and groundwater and for the development of a potential bioremediation technique. Despite commonly referred to as “forever chemicals”, there is emerging evidence of PFAS being microbially degraded in laboratory settings. The aim of this study is to investigate the microbial degradation capacity of the natural bacteria at two firefighting training sites (FFTS) contaminated with PFAS. Utilizing a sonic drill, soil samples were collected from both above and below the water table from FFTS near Örnsköldsvik and Sundsvall Timrå airports in Sweden. Enrichment cultures were initiated by mixing these soil samples with four different growth media—two for aerobic and two for anaerobic incubations. The incubation conditions, aerobic or anaerobic, were determined dependent on if the sample was taken above or below the groundwater level. All incubations were spiked with perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), 6:2 fluorotelomer sulfonic acid (6:2FTSA) and perfluorooctane sulfonaminde (FOSA) to reach a concentration of 9ppm. Samples from the incubations were taken at monthly intervals to screen for fluoride production, as an indicator for PFAS degradation, using ion chromatography. Using this approach, we aim to uncover the capability of the natural microbial community at these sites to degrade PFAS. In the second phase of this study, this will be followed by careful analysis of degradation products with the aim to identify degradation pathways.

How to cite: Messinger, N., Ahrens, L., Bertilsson, S., Berggren Kleja, D., and Fagerlund, F.: Exploring microbial PFAS degradation at two contaminated firefighting training sites in Sweden, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16852, https://doi.org/10.5194/egusphere-egu24-16852, 2024.

A.61
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EGU24-10687
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HS8.1.7
Fritjof Fagerlund, Mason Johnson, and Robert Earon

Per- and polyfluoroalkyl substances (PFAS) are extremely persistent contaminants that constitute an increasing problem for drinking water resources worldwide. Modelling tools to predict the subsurface transport of PFAS are important both for risk assessment and for design and evaluation of in-situ PFAS stabilization using activated carbon (AC) or other sorbent amendments. At highly contaminated hotspots, such as fire-fighting training sites, a mixture of many PFAS are typically present in the contaminated groundwater. The different PFAS can interact in the sorption process and e.g. compete for sorption sites, which may affect both the risks associated with PFAS transport and the efficacy of remediation strategies such as sorbent amendments.

The aim of this study was to develop a user-friendly modelling approach to account for competitive sorption of PFAS in a solute transport package that can be applied in combination with groundwater flow modelling with MODFLOW, and to illustrate the effect of competition on the transport of different PFAS for a field site scenario. A competitive sorption model for PFAS was implemented in MODFLOW/MT3DMS and can be run in combination with a graphical user interface for MODFLOW such as GMS. The new model is aimed for practical applications of site modelling and PFAS risk assessment when competition effects may be important. Modelling of a field site scenario based on a fire-fighting training site at a Swedish airport illustrates that competitive sorption affects the transport of PFAS in the groundwater and can provide valuable site-specific insight for remediation efforts.

How to cite: Fagerlund, F., Johnson, M., and Earon, R.: Modelling approach to account for competitive sorption of PFAS in MODFLOW-based solute transport simulations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10687, https://doi.org/10.5194/egusphere-egu24-10687, 2024.

A.62
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EGU24-16892
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HS8.1.7
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ECS
Mineral oil, movement and monitoring ecosystem health 
(withdrawn)
Katie Reilly and Iseult Lynch
A.63
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EGU24-10544
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HS8.1.7
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ECS
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Highlight
Dominik Renner, Hermann Rügner, Martin Ebner, Joel Fabregat-Palau, and Peter Grathwohl

The pressure on natural water resources and aquatic ecosystems will increase in the future, particularly in urban areas, as a result of climate change and population and economic growth. Rapid rates of urbanization may lead to an increase in impervious surfaces, resulting in higher runoff volumes and pollutant loads. While wastewater treatment technology made significant progress over time, it is reported that a significant part of runoff is still discharged directly into rivers. Besides dissolved compounds, many toxic compounds are associated with natural and anthropogenic particles and some small particles themselves have to be considered pollutants such as microplastics (MP) and tire wear particles (TWP).

In the scope of this study, suspended river sediments are examined towards type and amount of transported anthropogenic particles as well as for the contaminant loading with organic pollutants such as per- and polyfluoroalkyl substances (PFAS) and polycyclic aromatic hydrocarbons (PAH). The overall aim of the study is to identify correlations between the different classes of contaminants (i.e., MP, TWP, PFAS, PAH) and physio-chemical parameters (e.g., total suspended solids (TSS), turbidity, total organic carbon (TOC)) or catchment-specific properties such as land use and geology, as well as event- and/or seasonal related features (e.g., rain intensity, 1st flush effects).

The samples are collected during high discharge events in rivers with contrasting catchments regarding land use and geology in southwest Germany. PFAS analysis includes the monitoring of 40 different PFAS and the direct total oxidizable precursor (dTOP) assay to investigate the levels of precursor compounds that are not included in the target analysis. Preliminary results suggest a predominant transport of long-chain PFAS precursors on suspended sediments in rivers compared to targeted PFAS. Microscopic analyses of the collected particles after standard filtration, chemical treatment, and separation steps imply amounts of MP and TWP in the range of 0.1‰ of the total suspended sediment mass.

How to cite: Renner, D., Rügner, H., Ebner, M., Fabregat-Palau, J., and Grathwohl, P.: Particle-Associated Contaminant Transport in Rivers during High Discharge Events, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10544, https://doi.org/10.5194/egusphere-egu24-10544, 2024.

A.64
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EGU24-17825
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HS8.1.7
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ECS
María Alejandra Cruz Bolaños, Jan Willem Foppen, Enric Vázquez-Suñé, and Marc Teixidó

Next-generation stormwater drainage systems (e.g., green infrastructure) are increasingly implemented to enable runoff infiltration into the subsoil for aquifer recharge. Unfortunately, urban runoff can act as a major transport vector of pollution, and conventional infrastructure fails to remove polar organic contaminants. We studied the transport and removal of novel polar (mobile) stormwater vehicle-related organic contaminants of emerging concern, utilizing batch experiments and laboratory sand biofilters amended with granulated activated carbon (GAC) and biochar. Rapid small-scale column breakthrough curves and a 1D transport model demonstrated geomedia amendments can enhance target organic contaminant removal via sorption. However, contaminant transport was subject to kinetic effects, making it sensitive to infiltration flow rates and hydraulic retention times. To overcome these challenges, we developed pilot-scale 1-m length biofilters operating at relevant environmental conditions. These columns included a water retention zone equipped with various sensors to keep track of hydraulic and contaminant removal performance. Overall, our research contributes to understanding pollutant fate and transport during passive infiltration and enhancing conventional removal technologies for polar organic contaminants.

How to cite: Cruz Bolaños, M. A., Foppen, J. W., Vázquez-Suñé, E., and Teixidó, M.: Passive Removal of Stormwater Polar Organic Contaminants in Geomedia-Amended Biofilters, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17825, https://doi.org/10.5194/egusphere-egu24-17825, 2024.

A.65
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EGU24-18027
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HS8.1.7
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ECS
Jiaqi Xu, Jordi Cama, and Marc Teixido

Chemical pollution is recognized as a global problem, arising from trace organic contaminants (TOrCs), such as the emerging persistent mobile, and toxic (PMT) and very persistent, very mobile (vPvM) organic compounds. Rapid urbanization has increased impervious surfaces, facilitating the deposition and accumulation of pollutants. Additionally, stormwater acts as a transportation conduit for this PMT/vPvM substances, functioning as a surface pollutant wash-off, discharges into water bodies, and decreases the urban water quality. Green infrastructure, mainly designed to mitigate flood risk and recharge aquifers, may contaminate the soil-groundwater system. It is therefore crucial to develop cost-effective remediation technologies to enhance the removal of polar contaminants before reaching the aquifer.

In this study, a laboratory-based removal evaluation for 20 cost-effective PCMs (e.g., activated carbons and standard biochars) towards 34 PMT/vPvM target compounds (covering a wide range of uses, e.g., biocides, additives, herbicides) has been conducted. Preliminary results show that activated carbon (GAC), regenerated activated carbon (RAC) and MSP700 biochar exhibit strong adsorption capabilities for PMT compounds. The pyrolysis temperature, surface area, and aromaticity of the PCM play a crucial role in the adsorption process. The sorption kinetics for a suite of eight representative PMT compounds (covering a broad range of physicochemical properties) is better reproduced using a pseudo-second order (PSO) model, indicating a diffusion-controlled process. Sorption equilibrium for most adsorbates is achieved within 48 h. GAC, with the highest specific surface area, exhibits rapid adsorption, whereas MSP700 biochar shows the slowest adsorption rates. Furthermore, the sequence of adsorption capacity for the studied adsorbates is: neutral > positive > negative. Finally, the identification of GAC, RAC, and MSP700 as effective adsorbents for PMT/vPvM substances offers valuable insights for next-generation urban water management.

How to cite: Xu, J., Cama, J., and Teixido, M.: Sorption of Persistent, Mobile, and Toxic (PMT) and very persistent, very mobile (vPvM) substances onto pyrogenic carbonaceous materials, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18027, https://doi.org/10.5194/egusphere-egu24-18027, 2024.

A.66
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EGU24-4260
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HS8.1.7
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ECS
Mohammed Benaafi, Bassam Tawabini, Ahmed M. Al-Areeq, and Isam Aljundi

PFAS (per- and polyfluoroalkyl compounds) have emerged as prevalent pollutants in groundwater due to their vast past utilization in consumer products and industrial applications, coupled with their remarkable persistence. The current research investigated 17 PFAS chemicals in 10 groundwater samples from coastal multi-layered aquifer systems in Eastern Saudi Arabia, with seven samples from shallow aquifers (2-30 m) and three samples from deep aquifers (>70 m). The analysis utilized solid phase extraction and liquid chromatography-tandem mass spectrometry (LC-MS/MS) in accordance with EPA Method 537 and ISO 25101, with a detection limit of 10 ng/L. The results show that four PFAS substances were detected with values above the detection limits in shallow groundwater samples: perfluorobutane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorooctanoic acid (PFBA), and perfluorobutane sulfonic acid (PFBS). In contrast, no PFAS compound was found in the deep wells. PFOS was found in 29% of the samples (2 out of 7) with a maximum value of 23.6 ng/L. PFBA and PFBS were found in 14% of samples at 11 and 53 ng/L, respectively. PFOA was found to have a concentration of 10.9 ng/L and a detection frequency of 14%. The occurrence of PFAS, although currently at minimal levels, suggests potential pollution of the coastal aquifer that requires continuous monitoring and assessment to determine the source, the extent of the contamination, and its potential impact on human health and the environment. Additionally, while the highest PFOS concentration remained below the EPA's lifetime health advisory of 70 ng/L, it exceeded Vermont's PFOS drinking water standard of 20 ng/L. Recent research has linked PFOS exposure through drinking water to immune effects in infants at levels as low as ten ng/L. Further research is needed to investigate the potential spreading of PFAS plumes, identify potential sources of contamination, assess the extent of environmental and human health impacts, and develop effective remediation strategies. The findings add to the global contribution of PFAS contamination, underscoring the importance of having a proactive approach to monitoring and managing these persistent environmental pollutants.

How to cite: Benaafi, M., Tawabini, B., M. Al-Areeq, A., and Aljundi, I.: Occurrence and Distribution of Per- and Polyfluoroalkyl Substances (PFAS) in the Coastal Groundwater of Eastern Saudi Arabia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4260, https://doi.org/10.5194/egusphere-egu24-4260, 2024.