HS8.1.1 | Consequences of anthropogenic activities, emerging particles, biocolloids and organic contaminants on the physico-chemical conditions of aquatic and terrestrial systems.
EDI
Consequences of anthropogenic activities, emerging particles, biocolloids and organic contaminants on the physico-chemical conditions of aquatic and terrestrial systems.
Co-organized by ERE1
Convener: Estanislao Pujades | Co-conveners: Constantinos Chrysikopoulos, Anna Jurado Elices, Thomas Baumann, Markus Flury, Meiping Tong, Christophe Darnault
Orals
| Mon, 24 Apr, 16:15–18:00 (CEST)
 
Room 2.15
Posters on site
| Attendance Mon, 24 Apr, 14:00–15:45 (CEST)
 
Hall A
Posters virtual
| Attendance Mon, 24 Apr, 14:00–15:45 (CEST)
 
vHall HS
Orals |
Mon, 16:15
Mon, 14:00
Mon, 14:00
The conservation and restoration of aquatic systems is essential to cover the growing demand of drinking water, especially in urban areas. However, the physico-chemical conditions of aquatic systems can be altered by a wide range of factors such as (i) the release of pollutants as a result of human activities (organic and inorganic contaminants), (ii) the presence of natural and engineered particles (inorganic particles, biocolloids and plastics), or (iii), the impacts of anthropogenic activities developed in urban areas (geothermal energy, constructions or landfills). All of these factors are of great concern because of their potential adverse effects on ecosystem functions, wildlife and human health.
The session is divided according with two main topics: (i) the effects of the presence of particles in environmental systems, and (ii), the consequences of anthropogenic activities on the physico-chemical conditions of urban water resources.
Main contributions will be focused on:
• The occurrence and fate of chemicals compounds of anthropogenic origin and particles in aquatic and terrestrial systems.
• The impacts of human related activities and actions on the physico-chemical conditions of water resources, especially in urban environments.
• Methods to detect, characterize, quantify and test the behaviour of particles in aquatic and terrestrial systems.
• Interactions between biocolloids, particles and solids
• Toxicity of products generated from biological disruption of pollutants in the presence of biocolloids and adverse effects of nanoparticles on microorganisms
• The effects of climate change on biocolloids and nanoparticles migration
• Public health risks associated with water and air polluted with biocolloids and nanoparticles.

Orals: Mon, 24 Apr | Room 2.15

Chairpersons: Thomas Baumann, Constantinos Chrysikopoulos, Estanislao Pujades
Emerging particles and biocolloids in terrestrial and aquatic systems
16:15–16:25
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EGU23-1651
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Highlight
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Virtual presentation
Haifeng Rong and Meiping Tong

The wide application of industrial and consumer product leads to the ubiquitous presence of PFOA (an anionic surfactant) in natural environments. PFOA could interact with microplastics (one emerging pollutants abundant in environments) and the transport of both PFOA and microplastics thus might be altered. The cotransport behaviors of PFOA with micron-sized plastic particles (MPs) with different surface charge (both negative and positive surface charge) in porous media in both 10 and 50 mM NaCl solutions were investigated in present study. Both types of MPs (negatively charged carboxylate-modified MPs (CMPs) and positively charged amine-modified MPs (AMPs)) could adsorb PFOA onto MPs surfaces which decreased PFOA transport with MPs co-present in suspensions under both solution conditions examined. PFOA had diverse impact on the transport behaviors of CMPs and AMPs. Specifically, PFOA decreased the transport of CMPs, while increased the transport of AMPs when PFOA was copresent in suspensions. The mechanisms driving to the changed transport of two types of MPs induced by PFOA were found to be different. The decreased electrostatic repulsion of CMPs due to the adsorption of PFOA onto CMPs surfaces led to the decreased transport of CMPs when PFOA was copresent. The increased electrostatic repulsion due to the adsorption of PFOA onto AMPs surfaces as well as the steric repulsion induced by suspended PFOA caused the enhanced AMPs transport with PFOA in solutions. The results of this study show that when PFOA and microplastics are copresent in natural environments, their interaction with each other will alter their transport behaviors in porous media, and the alteration is highly correlated with the surface charge of MPs.

How to cite: Rong, H. and Tong, M.: Cotransport of PFOA with Different Electrically Charged Plastic Particles in Saturated Porous Media, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1651, https://doi.org/10.5194/egusphere-egu23-1651, 2023.

16:25–16:35
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EGU23-12562
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ECS
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On-site presentation
Nadia Bouzid, Remi Bizeul, Anthony Foucher, Sophie Ayrault, Olivier Evrard, Rachid Dris, Bruno Tassin, and Jonnhy Gasperi

Depending on hydrodynamic conditions, river sediments act as a sinks or a sources of microplastics through deposition and remobilisation processes. During flood events, the increase of river flow leads to an increase in the resuspension of bottom sediments and bank erosion processes and favoring the microplastic transportation. Previous work conduced in the Seine river catchment in 2018 has shown that floods, which occur for only 15% of the annual time, contributed to 40% of the total microplastic flux. Therefore, at the end of a flood period, with the decreasing in water level, some flow regimes allow the deposition of contaminated sediments carried by the river on the banks.

This study presents the characterization and quantification of microplastics in ten samples lag deposits collected along the Seine river after the February 2021 flood event. Microplastics from 10 to 500 µm were analysed in replicate samples using two methods (FTIR microspectroscopy and Pyr-GC/MS). In order to characterize the origin of the sampled sedimentary deposits a fingerprinting approach based on the measurement of radionuclides activity (137Cs, 210Pbex and 7Be) was carried out. A mixing model was applied to discriminate old and recent sediments and their origin from the surface (e.g. soil erosion) or subsurface (e.g. bank erosion). High concentration levels of microplastics, ranging from 8,000 to 50,000 items/kg, were observed mainly characterised by FTIR microspectroscopy as PP, PE, PS and PVC. All the samples analysed show a similar size distribution with a majority of particles below 100 µm. PP is the most abundant polymer found. The quantification by Pyr-GC/MS provided masses consistent with microspectroscopy results ranging from 200 to 14,000 µg PP/kg of dry sediment.  An increase in microplastic contamination between the upstream and the downstream part of the Paris area was observed. In this study, the relationships between sediment characteristics and microplastic contamination could not be demonstrated. Further work is needed to verify whether a more marked relationship can be observed in major events where a clearer variation in sediment sources is observed between the upper and lower parts of the Paris area.

How to cite: Bouzid, N., Bizeul, R., Foucher, A., Ayrault, S., Evrard, O., Dris, R., Tassin, B., and Gasperi, J.: Microplastics in sediment deposited along the Seine River after a major flood event (February 2021), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12562, https://doi.org/10.5194/egusphere-egu23-12562, 2023.

16:35–16:45
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EGU23-2570
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ECS
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On-site presentation
Anastasios Malandrakis, Nektarios Kavroulakis, and Constantinos Chrysikopoulos

The potential of ZnO nanoparticles (NPs) to control Alternaria alternata isolates resistant to the succinate dehydrogenase inhibitor (SDHI) boscalid was evaluated both in vitro and in vivo. ZnONPs could effectively inhibit mycelial growth and suppress disease symptoms in both boscalid sensitive (BOSC-S) and resistant (BOSC-R) isolates. A high synergistic effect against BOSC-S and BOSC-R isolates was observed when ZnO-NPs was combined with boscalid both in vitro and when applied in artificially inoculated tomato fruit. The positive correlation between nanoparticles and their ionic counterpart ZnSO4 and the neutralization of the ZnO-NPs fungitoxic action in the presence of EDTA suggested that zinc ion release is the most probable fungitoxic mechanism of ZnO-NPs. The disruption of cellular ion homeostasis mechanisms by zinc NPs could account for the enhanced effectiveness of ZnO-NPs against A. alternata  compared to ZnSO4. ATP-dependent ion efflux and ROS production could contribute to the fungitoxic action of ZnO-NPs as indicated by bioassays with ATP- and antioxidant-inhibitors. Boscalid acting as a “capping” agent for ZnO-NPs, significantly reducing NPs mean size, probably accounted for the synergy observed against BOSC-S and BOSC-R isolates. Concluding, ZnO-NPs are effective against A. alternata both alone or in mixtures with boscalid, and can be used as an effective, eco-compatible anti-resistance tool for reducing the environmental footprint of synthetic fungicides.

How to cite: Malandrakis, A., Kavroulakis, N., and Chrysikopoulos, C.: Zinc nanoparticles combat boscalid-resistance in Alternaria alternata, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2570, https://doi.org/10.5194/egusphere-egu23-2570, 2023.

16:45–16:55
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EGU23-7878
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Highlight
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On-site presentation
Jan Willem Foppen and Thom Bogaard

Artificial DNA as a tracer in environmental applications has received increased attention in environmental science. In the last few years, we have been looking at the transport of silica encapsulated DNA particles (SiDNA), which we injected instantaneously or as a function of time in various saturated groundwater and surface water laboratory set-ups. These included batches, columns, sand tanks, open pipes, trenches, flumes, etc. The overarching aim of all these experiments was to understand SiDNA transport behaviour, to quantify the mass balance and to assess tracer-like capabilities of SiDNA. Our work indicated that in most applications, the shape of the breakthrough curve in terms of time to rise and time to peak were similar to the breakthrough curve of a conservative tracer. Specifically, SiDNA could be used to quantify dispersion in surface water transport, and to determine aquifer parameters, like hydraulic conductivity and porosity in multi-tracer experiments. However, this was accompanied by some uncertainty as in most applications, injected mass recoveries were less than 100% due to losses as a result of settling, river bed interactions, interactions with particulate matter (in surface water applications), straining, kinetic attachment and detachment (in groundwater applications). 
We conclude that SiDNA can be used when mass balance issues are relatively unimportant, for instance in case of complex flow path analyses or source tracking applications, whereby encapsulated artificial DNA with different DNA strands can be injected in several locations or can be added to the source. Currently, we think large scale field applications of SiDNA are still limited, due to required specific knowledge and analytical infrastructure, relatively high costs and limited SiDNA production scale. Once these issues are tackled, a truly unique multi-tracer will enrich the toolbox of hydrologists.

How to cite: Foppen, J. W. and Bogaard, T.: Potential and limitations of silica encapsulated DNA particles for hydro(geo)logy, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7878, https://doi.org/10.5194/egusphere-egu23-7878, 2023.

16:55–17:05
Quality and quantity issues of urban hydrogeology
17:05–17:15
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EGU23-8241
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ECS
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Highlight
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On-site presentation
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Julia Garagnon, Yves Perrette, Emmanuel Naffrechoux, and Edwige Pons-Branchu

The preservation of water resources and the limitation of pollution are an environmental central issue in the current intense anthropization context. Considered as sensitive recorders of past changes, speleothems offer an under investigated natural archive for the reconstruction of water quality. Urban speleothems have recently been used to show the impact of urbanization over the water quality using inorganic trace elements. Speleothems thus represent a promising archive of water quality on short and long-time scales. However, they have never been used to trace organic pollution. Within the organic and anthropogenic proxies, polycyclic aromatic hydrocarbons (PAHs) are commonly used in water quality analysis. These persistent organic pollutants (POPs) are mainly due to anthropogenic emissions. The use of speleothem to trace the variations in quantity and quality of organic matter, including organic pollutant as PAHs, over the last centuries, is unprecedented.

For this purpose, high resolution (10 µm) solid phase UV fluorescence imaging analyses were crossed with chemical analyses (PAHs, Non Purgeable Organic Carbon (NPOC)) carried out on low weight samples (a few mg to g) from a Parisian aqueduct flowstone. Solid-phase fluorescence imaging, although poorly applied yet to speleothems, is a non-destructive technique. To obtain quantitative information, solid phase spectroscopy is coupled with liquid phase compound analysis and NPOC analysis. Due to their low concentration, the analysis of PAHs required a long development phase. The protocol consists of an extraction and analysis process using high performance liquid chromatography coupled with a fluorescence detector. The first results reveal the presence of PAHs for 300 years in runoff water with an increase, in particular in heavy molecular weight PAHs, over the last two decades. These data will be crossed with modelled imaging of quantitative variations in organic matter. This work opens the way to a better long term understanding of the impact of anthropization on transfer of pollutants in subsurface waters.

How to cite: Garagnon, J., Perrette, Y., Naffrechoux, E., and Pons-Branchu, E.: 300 years of organic pollution recorded in an urban speleothem (Paris, France), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8241, https://doi.org/10.5194/egusphere-egu23-8241, 2023.

17:15–17:25
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EGU23-16939
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On-site presentation
María Alejandra Cruz Bolaños, Jiaqui Xu, Jan Willem Foppen, and Marc Teixidó Planes

Stormwater runoff capture can provide means of flood control and augmentation of local water supplies. However, urban stormwater is considered a major transport vector of contaminants, primarily from vehicle-related sources. Unfortunately, conventional green infrastructures fail to consistently remove the contaminant dissolved fraction – in particular persistent, mobile, and toxic (PMT) organic pollutants. We investigated the transport and removal of stormwater vehicle-related trace organic contaminants, such as 1H-benzotriazole, N'N-diphenylguanidine, and hexamethoxymethylmelamine utilizing continuous-flow sand columns amended with granulated activated carbon (GAC) and wheat-straw produced biochar (WSP550). All the pollutants were subjected to nonequilibrium interactions in sand-only (control) and GAC/biochar-amended sand columns, with kinetic effects on transport. The Langmuir sorption kinetics model could well describe the observed breakthrough curves, which assumes the saturation of sorption sites that might occur in infiltration systems with DOM fouling. Furthermore, we found that GAC amendments can attenuate the contaminants significantly better with faster adsorption kinetics and higher sorption capacity than the biochar. Based on the optimized sorption parameters, we concluded that HMMM had the lowest affinity in both carbonaceous adsorbents. These column results corroborated observations from preliminary batch experiments. Based on the case study simulation, the amendments of pyrogenic carbonaceous adsorbents could improve vehicle-related organic contaminant removal and exhibit a service life of more than a decade in a green infrastructure. Overall, our research contributes to improving polar organic pollutant removal technologies in environmental applications.

How to cite: Cruz Bolaños, M. A., Xu, J., Foppen, J. W., and Teixidó Planes, M.: Transport and Removal of Stormwater Vehicle-Related Contaminants in Laboratory Columns, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16939, https://doi.org/10.5194/egusphere-egu23-16939, 2023.

17:25–17:35
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EGU23-7356
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On-site presentation
Andrea Erhardt, Elizabeth Avery, Olena Samonina, Lidiia Kryshtop, Iryna Vyshenska, and Alan Fryar

The water supply for Kyiv (Ukraine) is a seasonally and spatially variable mixture of both ground and surface water. This water supply is vulnerable to the effects of climate change, pollution, and geopolitical conflict. Climate change has resulted in changing precipitation patterns, potentially altering the balance between ground and surface water utilization. Additionally, the ongoing conflict makes a holistic understanding of water resources and pathways critical for water management. This study uses water stable isotopes as tracers for water sources and the importance of different reservoirs in water management.

For this study tap water, surface water, groundwater, and precipitation were collected over 14 months (2019-2020) in Kyiv and nearby Boryspil, Brovary, and Boyarka and measured for hydrogen (𝛿2H) and oxygen (𝛿18O) stable isotope ratios. Precipitation data was used to capture seasonal variability in storm trajectories and create a meteoric water line. These results were then compared to surface, ground, and tap water to capture water sources and residence times.

The stable isotope values from the tap water for each district show a general seasonal trend in water sources, with more groundwater used in the supply in the winter for most districts. Spatially, groundwater use increases from south to north in the left-bank districts in Kyiv city and groundwater use generally decreases from south to north in the right-bank districts. As precipitation patterns shift and temperatures increase, the reliance on particular water sources may need to shift as well.

 Overall, 𝛿2H and 𝛿18O data provide a baseline expectancy for current water use throughout the year and, from this, deviations can be assessed early. A holistic view of the water system will be critical to assess changes due to infrastructure damage and/or other impact on water management in the Kyiv region.

How to cite: Erhardt, A., Avery, E., Samonina, O., Kryshtop, L., Vyshenska, I., and Fryar, A.: A holistic view of water sources in Kyiv, Ukraine using tap water, surface water, groundwater, and precipitation hydrogen (𝛿2H) and oxygen (𝛿18O) stable isotope ratios, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7356, https://doi.org/10.5194/egusphere-egu23-7356, 2023.

17:35–17:45
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EGU23-2785
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ECS
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On-site presentation
Maximilian Noethen, Hannes Hemmerle, Susanne Benz, Kathrin Menberg, Jannis Epting, Philipp Blum, and Peter Bayer

In addition to the continuous increase of groundwater temperatures due to global warming, heat losses from infrastructure, (underground) buildings and geothermal use lead to thermal anomalies on regional to local scales. Often, these local heat accumulations (hot spots) of groundwater temperatures are associated with underground car parks (UCP). They represent sizeable infrastructures that are typical for densely built-up areas and are numerous in many cities. Unlike regular basements, they often reach beneath the groundwater table and heat up due to frequent traffic. They therefore act as heat sources for groundwater. By analysing long-time data from 31 sites in Germany, Austria, and Switzerland, we discovered seasonally varying heat flux intensities and even directions. While all UCPs heat the groundwater during the warm period, most UCPs cool the groundwater in the cold period. Only few act as continuous heat source all year round. We also discuss characteristics and their influence on the temperature such as the type of use (public/private) and the depth of the UCP. Furthermore, we present the results of a spatial analysis of heat fluxes and flows from over 5000 UCPs in Berlin, Germany. By discussing the range of heat fluxes and the hydrogeological conditions that lead to regional differences, we demonstrate the role of UCPs for subsurface urban warming. The results show that about 40 % of Berlin’s total heat flow from UCPs occurs in the “Mitte” district, where the density of UCPs is highest and the distance to the groundwater table is typically below 4 m. Finally, the knowledge gained about subsurface heat sources can help improve urban thermal groundwater management and highlights the potential for recovering waste heat from UCPs through geothermal applications.

How to cite: Noethen, M., Hemmerle, H., Benz, S., Menberg, K., Epting, J., Blum, P., and Bayer, P.: Thermal impact of underground car parks on groundwater, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2785, https://doi.org/10.5194/egusphere-egu23-2785, 2023.

17:45–17:55
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EGU23-7715
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On-site presentation
Alain Dassargues and Philippe Orban

Abandoned mines can play a new role in renewable energy production and storage in combination with fifth-generation heating and cooling networks. Obviously, the underground potential must be matched with the uses/productions of heat and cold by surface activities. Therefore, this will be considered here only in highly urbanized areas or in economic and industrial areas.

Flooded abandoned mines form highly heterogeneous aquifers that are artificially and locally highly permeable around former underground works (i.e., tunnels, galleries, mined extraction zones, wells, shafts). Thermal energy storage (ATES) systems, using heat pumps and an open loop with a groundwater pumping and re-injection doublet, are thus challenging and uncertain in such a variable underground environment. Hot water is pumped in the deepest parts of the open network, and cold water can be re-injected in the shallower parts (i.e. in shallower galleries or fractured rocks). A seasonal inversion could be planned for cooling the buildings during the summer season. However, the true geometry of the interconnected network made of old open galleries and shafts can be highly complex and partially unknown. Indeed, high-velocity water flow and heat transport are expected in this network inducing potentially a full or partial bypass of the fractured and porous rock massif.

A hydrogeological characterization of the old mined zones for detailed simulations of the groundwater flow and associated heat transport is thus a needed step allowing to assess the actual feasibility of a given project. The simulated short-, mid-, and long-term temperature evolution in pumping and injection zones will consist of key information for designing and dimensioning the whole geothermal project and assessing future efficiency and impact. Depending on the degree of precision required, which is dependent on the level of reduction of uncertainties associated with the geothermal project, the hydrogeological baseline issues can be very significant, challenging scientists in different areas of quantitative hydrogeology:

  • conceptualization in a simple model of the often unknown complexity/heterogeneity of the galleries network conjugated to those of the mined geological formations;
  • simulation of temperature-dependent variable-density groundwater flow and coupled heat transport;
  • combining high-velocity ‘pipe-like’ water flows (in the shafts and galleries) and porous/fractured groundwater flow (in the rock matrix);
  • simulation of different transient scenarios to assess evolutions in the long term.

As an illustration, a simplified but realistic situation is simulated showing the influence of the highly different heat/cold transport in the galleries and shafts, compared to the propagation in the porous/fractured rocks. Indeed, the different temperature evolutions allow anticipating the temperature changes affecting the future (short-, mid-, and long-term) efficiency of a geothermal system as well as possible environmental impacts.

Real cases in relation to future projects should ideally be simulated using the most detailed approaches, with true data. Those baseline hydrogeological data are not easy to obtain but they are the guarantee of reliable predictions and therefore that the financial risk is reasonable.

Dassargues A., 2018. Hydrogeology: groundwater science and engineering, 472p. Taylor & Francis CRC press, Boca Raton.

How to cite: Dassargues, A. and Orban, P.: Hydrogeological baselines for geothermal energy and heat storage in old flooded coal mines in urban areas, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7715, https://doi.org/10.5194/egusphere-egu23-7715, 2023.

17:55–18:00

Posters on site: Mon, 24 Apr, 14:00–15:45 | Hall A

Chairpersons: Markus Flury, Constantinos Chrysikopoulos, Estanislao Pujades
Emerging particles and biocolloids in terrestrial and aquatic systems
A.135
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EGU23-2118
Constantinos V. Chrysikopoulos, Anthi S. Stefanarou, Vasileios E. Katzourakis, and Anastasios A. Malandrakis

This study investigates the transport of pesticide thiophanate methyl (TM) as well as the co-transport of TM and titanium dioxide (TiO2) nanoparticles in a water saturated column packed with quartz sand under various water conditions. Several ionic strengths (Is) (1, 10, 50 and 100 mM) and pH (3, 5, 7, 10) values were examined. The results from the transport experiments  were fitted and analyzed with the use of the ColloidFit software, while the results from cotransport experiments were fitted with a modified mathematical model of Katzourakis and Chrysikopoulos (2015). The results suggested that the lowest mass recovery rate was for the co-transport experiments with the addition of NaCl. It was shown that TM has a weak affinity for sand but a relatively strong affinity for TiO2 at high Is and acidic pH. Furthermore, salinity was shown to have significant effects on TM removal.

How to cite: Chrysikopoulos, C. V., Stefanarou, A. S., Katzourakis, V. E., and Malandrakis, A. A.: Transport of thiophanate methyl in porous media in the presence of titanium dioxidenanoparticles, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2118, https://doi.org/10.5194/egusphere-egu23-2118, 2023.

A.136
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EGU23-142
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ECS
Yingxue Yu, Markus Flury, Anton Astner, Douglas Hayes, Tahsin Zahid, and Indranil Chowdhury

Plastic pollution caused by conventional plastics has promoted the development and application of biodegradable plastics. However, biodegradable plastics do not degrade readily in water, instead, they can generate countless micro- and nanoplastics. Compared to microplastics, nanoplastics are more likely to cause negative impacts to the aquatic environment due to their smaller size. The impacts of biodegradable nanoplastics highly depend on their aggregation behavior and colloidal stability, which still remain unknown. Here, we studied the aggregation kinetics of polybutylene adipate co-terephthalate (PBAT) nanoplastics in both NaCl and CaCl2 solutions before and after artificial weathering. We further studied the effect of proteins on aggregation kinetics with both negatively charged bovine serum albumin (BSA) and positively charged lysozyme (LSZ). We found that divalent cations (Ca2+) destabilized PBAT nanoplastics more aggressively than monovalent cations (Na+); weathering stabilized PBAT nanoplastics profoundly, with no aggregation observed in NaCl nor in CaCl2; both BSA and LSZ promoted the aggregation of pristine PBAT nanoplastics, with LSZ showing more pronounced effect. These results suggest that biodegradable nanoplastics, especially weathered biodegradable nanoplastics, are highly stable in the aquatic environment.

How to cite: Yu, Y., Flury, M., Astner, A., Hayes, D., Zahid, T., and Chowdhury, I.: Aggregation Kinetics and Stability of Biodegradable Nanoplastics: Effects of Weathering and Proteins, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-142, https://doi.org/10.5194/egusphere-egu23-142, 2023.

A.137
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EGU23-196
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ECS
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Reshmi Das, Chanakya Hoysall, and Lakshminarayana Rao

Foaming of surface water bodies is a common concern of many major metropolitan cities globally. These hideous and persistent foams disturb aquatic ecosystems and also emit an obnoxious stench. These foams also overflow onto the surrounding roads, causing pedestrians discomfort and traffic disruption. Even though foaming of the aquatic system is a widespread phenomenon, it is not entirely scientifically understood yet. The central unexplored question in this domain is - what compounds make up a foam? To answer this question, it is vital to understand the physics of foaming, the properties of a compound that helps in foaming, and its chemical/physical influence on the distribution of other compounds and species in a water body.

 Foam is caused by surface-active compounds called surfactants. In aquatic environments, the surfactants may be either endogenous or anthropogenic in origin. In nutrient-rich waterbodies, decaying plants and microorganisms can be a potential endogenous source of surfactants. Commercially used surfactants in households and industries find their way into the aquatic ecosystem through untreated effluents discharged after anthropogenic activities. These foams, by the mechanism of foam fractionation, also tend to enrich many organic and inorganic compounds into the foam phase. Enrichment might lead to precariously high concentrations of surface-active contaminants in the foam phase, which would otherwise be within acceptable levels in bulk lake water. Thus, foam not only has surfactants but also has other enriched chemical compounds in it.

This work aims to identify those compounds in foam, focusing on sewage-fed Bellandur lake in India, which has been infamous for foaming for the past decade and understand their environmental implications. Bellandur Lake has anionic surfactant concentrations reaching up to 20 mg/l and surface tension as low as 45 mN/m. The Lake is eutrophied, with chlorophycean algae concentration reaching up to 13.8×107 cells/mL of Lake water. The scope of this study is as follows:

  • to assign relative flux to surfactants from various sources and identify the most significant contributor to foaming events;
  • to estimate the relative difference in concentrations of contaminants in bulk liquid and foam phase and predict the possibility of an impending threat, if any.

This study thus provides an opportunity for a better understanding of the foaming pattern, which is essential to prevent the occurrence of such foaming events in future.

How to cite: Das, R., Hoysall, C., and Rao, L.: Foam Composition and Surfactant Sources in an Urban Foaming Lake: A Comprehensive Analysis, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-196, https://doi.org/10.5194/egusphere-egu23-196, 2023.

A.138
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EGU23-10883
Hannes Laermanns, Markus Rolf, Susanne Forche, Elena Castrucci, Alexander Stelzer, and Christina Bogner

Most studies focus on the detection of microplastic particles in different compartments of the environment. While impacts of microplastics on aquatic systems have already a wide acceptance in public, the research on microplastics in terrestrial systems is quite young. Our study aims to decipher the consequences of microplastics on the soil-water retention curve beyond the wilting point. Using a dew point WP4C hygrometer, we measured water retention curves of loess and sand samples with added microplastics, namely amorphous biopolymer, polystyrene in two sizes and three different types of UV-aged particles. All the different microplastics were added in concentrations of 0.1 wt.%, 0.5 wt.%, and 4.5 mg/kg. Reference samples without microplastics were prepared as well. For the analysis, we fitted the Webb model and calculated the water content at the wilting point and the slope of the soil-water retention curve. Our preliminary results did not show any significant differences between the different microplastics and their concentrations, however, the lowest slope and highest water content at pF 4.2 were observed in the samples without microplastics. Furthermore, the results indicated a greater variability with increasing size of microplastic particles.

How to cite: Laermanns, H., Rolf, M., Forche, S., Castrucci, E., Stelzer, A., and Bogner, C.: The influence of microplastics on the dry end of the soil-water retention curve, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10883, https://doi.org/10.5194/egusphere-egu23-10883, 2023.

Quality and quantity issues of urban hydrogeology
A.139
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EGU23-12881
Estanislao Pujades, Carmen Sáez, Olha Nikolenko, Laura Scheiber, Arianna Bautista, Marinella Farré, and Anna Jurado

Riverbank filtration (RBF) consists in forcing surface water to infiltrate and flow through an aquifer by means of a pumping well located near a surface water body. RBF aims to take advantage of the filtration capacity of aquifers to improve the water quality by removing a wide range of pollutants, including contaminants of emerging concern, by combining of physical, chemical and biological processes. However, the efficacy of RBF for eliminating substances that are considered persistent, mobile, and toxic (PMT), or very persistent and very mobile (vPvM), is expected to be low due to the high mobility of these substances. PMT and vPvM compounds, which are accumulated in the water cycle, are harmful to humans and the environment. For this reason, the processes affecting PMT and vPvM substances during RBF processes deserve to be deeply investigated.

This study aims at investigating the processes affecting PMT and vPvM substances in a site that behaves similarly to a RBF system. The study site is located in Sant Adriá del Besòs (Barcelona, Spain), where a constant pumping to drain an underground parking lot forces the water from the Besòs river to infiltrate and travel up to 230 m through the aquifer. Groundwater samples were collected from the river, and a set of piezometers aligned along the groundwater flow line between the Besòs river, and the underground parking lot allowed monitoring of the water at different stages after its infiltration. The samples were analysed by liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) and PMT and vPvM were determined by a suspected screening approach.

This investigation provides new insights into the processes affecting PMT and vPvM substances and will have tremendous implications for determining groundwater quality in managed aquifer recharge contexts.

How to cite: Pujades, E., Sáez, C., Nikolenko, O., Scheiber, L., Bautista, A., Farré, M., and Jurado, A.: Processes affecting the behaviour of persistent, mobile, and toxic substances in a riverbank filtration system, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12881, https://doi.org/10.5194/egusphere-egu23-12881, 2023.

A.140
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EGU23-12959
Anna Jurado, María Alejandra Villa, Marc Teixidó, Nicola Montemurro, Sandra Pérez, Jan Willem Foppen, and Estanislao Pujades

Water shortage is expected to exacerbate because of the increase pressure on water resources due to climate change and the growing population. It is deemed necessary to take advantage of all the available freshwater resources to cover the growing demand, especially in urban areas. However, urban aquifers are commonly contaminated by a wide range of organic contaminants of emerging concern (OCECs). OCECs, which comprise natural and synthetic compounds, are potentially hazardous to the environment and human health. Therefore, the processes controlling the behaviour of OCECs must be investigated to determine when and how the urban resources can be used safely and to design remediation strategies against them. The removal rate of OCECs depends on the temperature and redox conditions of groundwater that may be affected by anthropogenic activities like the exploitation of the geothermal potential of aquifers. The behaviour of some OCECs has been investigated in the context of managed aquifer recharge (MAR). However, the water range in MAR is lower than that expected around geothermal exploitations, and the behaviour of OCECs under similar conditions to that found around geothermal facilities should be evaluated. We have investigated the removal of 12 OCECs reported in the aquifers of Barcelona (Spain) by using batch experiments under different redox conditions and temperatures (25°C and 35°C). The results show that the removal rate of OCECs depends on the temperature, suggesting that the impact of geothermal exploitations must be considered when investigating the fate and evolution of OCECs in urban aquifers. Unexpectedly, it was observed that the removal rate could also decrease with the temperature, which may be related to the proliferation of different communities of bacteria depending on the temperature. Overall, this investigation supports the idea that it is possible to design geothermal facilities to promote the removal of OCECs.

How to cite: Jurado, A., Villa, M. A., Teixidó, M., Montemurro, N., Pérez, S., Foppen, J. W., and Pujades, E.: Organic contaminants of emerging concern (OCECs) in urban aquifers affected by geothermal exploitations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12959, https://doi.org/10.5194/egusphere-egu23-12959, 2023.

A.141
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EGU23-3082
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ECS
Franco Coscia, Enric Vázquez-Suñè, and Estanislao Pujades

Phosphogypsum is a waste that results when fertilizer is obtained from phosphate through a wet chemical process. Phosphogypsum waste can entail negative consequences for the environment and human health since it is enriched in radionuclides from U-decay series and metal impurities. Phosphogypsum wastes are commonly accumulated in large stockpiles that are exposed to weathering processes. These stockpiles are located near the plants where phosphate is processed, which are usually located in coastal areas. This is the case of a phosphogypsum stack on the western side of the Tinto River estuary (Huelva, SW Spain), where the piles were directly settled on the marshland without using any isolation from 1968 to 2010. Here, in addition to the potential environmental impacts, the effect of the phosphogypsum wastes on human health are a source of concern since the piles are located near the city of Huelva (Spain). In this context, it is of paramount importance to assess the phosphogypsum leachate percolation into underlaid aquifer systems and the release of pollutants to the Tinto River.

This investigation aims at building a complex coupled hydro-chemical numerical model accounting with variable density to quantify how the pollutants are released to the environment. The first step has consisted in developing the flow numerical model that has been calibrated by fitting the piezometric head oscillations as a result of recharge processes and sea tide oscillations. The good fitting obtained during the calibration process (normalized RMS when comparing simulated and observed piezometric heads is less than the 10%) allows affirming that the estimated hydraulic parameters are accurate, and are consistent with the literature reviewed. Furthermore, the numerically calculated mass balance is consistent with the conceptually estimated one, the differences were as expected. Thus, the model allows simulating the flow processes and modelling predictive scenarios. The next steps will consist in implementing variable density and hydro-chemical, and possibly, hydromechanical processes.

This study, which uses numerical modelling, is intended to be useful for future work related to restoration measures and provides new insights into the water balance along with the complex processes occurring at the site.

How to cite: Coscia, F., Vázquez-Suñè, E., and Pujades, E.: Numerical modeling of flow in a phosphogypsum stack. Case of salt-marshes, Huelva, SW Spain., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3082, https://doi.org/10.5194/egusphere-egu23-3082, 2023.

A.142
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EGU23-4754
Luiz Leal, Carlos Purificação, Harald Klammler, and Kirk Hatfield

Groundwater located in peri-urban areas may be impacted by many pollutants from different types of point or diffuse sources. About 40% of Brazil's waste is disposed of inappropriately in open dumps and constitutes a risk of contamination for aquifers. In the metropolitan region of the city of Salvador in northeastern Brazil, approximately 9,800 tons of solid waste are generated daily. This research aimed to delineate areas for the implementation of landfills and protection of peri-urban groundwater in Salvador and other catchments in northeastern Brazil. An integration of Boolean and fuzzy logic was performed using GIS, while the Analytic Hierarchy Process was used in a Multi Criteria Decision Analysis technique to generate the weights of the factors and criteria for the fuzzy model. From this methodology, two preliminary models were generated, one using the Boolean logic and the other the fuzzy logic. The first used restrictive criteria established by Brazilian legislation applied to fifteen factors/themes. In the second model, non-restrictive criteria were applied to eleven factors/themes based on technical knowledge and literature. The integration of the maps and the crossing of the models demonstrates that 6% of the studied areas are classified as highly adequate; 16% as adequate; 8% not suitable; and 70% are areas with total restrictions for locations of landfills and protection of aquifers.

How to cite: Leal, L., Purificação, C., Klammler, H., and Hatfield, K.: GIS‐based multi-criteria decision analysis for suitable locations of landfills and protection of peri-urban groundwater catchments: a case study in northeastern Brazil, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4754, https://doi.org/10.5194/egusphere-egu23-4754, 2023.

A.143
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EGU23-813
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Highlight
Shubham Kumar, Indra Mani Tripathi, and Pranab Kumar Mohapatra

Emerging contaminants are becoming more prevalent in the environment. The consequences of emerging contaminants on the urban environment and living being's health are poorly understood by society. Pharmaceutical compound removal is not considered in designing a conventional sewage treatment facility. Instead, they were primarily concerned with organic and bacterial removal. Molecules containing xenobiotics whose physicochemical characteristics, such as small molecular size, water solubility, ionizability and volatility, make it challenging to identify, quantify, and degrade these complex chemicals. In the present study, we will take samples from Surface Water (SW) and Wastewater Treatment Plants (WTP) in the fast-growing Indian secondary cities (Bhopal, Bhuj and Kozhikode). We use analytical methods, including High-Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC) coupled with Mass Spectrometry (MS) to identify these compounds. The mentioned techniques have the potential to characterise complex environmental chemicals at low concentrations. In addition, Wetlands Construction can be an alternative and affordable technology for emerging compound treatment that performs satisfactorily for a variety of sewage types, including domestic sewage and wastewater. Our study identifies the contaminants present in the environment and the most popular analytical techniques for identifying and quantifying these compounds. We also present some potential solutions for the treatment of compounds by fusing several other technologies. This shows that in order to lessen or stop the deposition of these compounds into the environment, sewage treatment technologies need to be investigated and combined.

How to cite: Kumar, S., Tripathi, I. M., and Mohapatra, P. K.: Identifying wastewater pollutants from pharmaceutical residues and xenobiotic contaminants in Indian secondary cities, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-813, https://doi.org/10.5194/egusphere-egu23-813, 2023.

A.144
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EGU23-5588
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ECS
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Highlight
Eva Kaminsky, Constanze Englisch, Christian Griebler, Cornelia Steiner, Gregor Götzl, Kay Knoeller, Hans Sandén, Gregor Laaha, and Christine Stumpp

Urban shallow groundwater is highly impacted in terms of hydrogeology and water quality by anthropogenic activities and infrastructure, such as heating and cooling, surface sealing, leaking sewage pipes, and underground buildings. For a sustainable management of urban water resources, a better understanding of biogeochemical processes and its dynamics on a spatial and temporal scale in the urban subsurface is needed. So far, data sets including a critical minimum number of key parameters and an appropriate resolution in space and time have often been missing. Here, we introduce a multi-tracer approach applied to assess the shallow aquifers in Vienna. Water samples were collected twice, in autumn 2021 and spring 2022, respectively, from 150 groundwater wells in the city limits of Vienna. A comprehensive set of parameters (e.g. major ions, nutrients, heavy metals, water and nitrate stable isotopes) were analyzed to evaluate the spatial and seasonal variations in water origin and quality. Statistical analysis revealed that driving factors influencing groundwater quality include aquifer properties, interactions between groundwater-surface water, and redox conditions. A combined interpretation of conservative tracers indicated zones influenced by surface water - groundwater interactions that also influenced the water chemistry. Microbial anaerobic processes govern groundwater quality. In particular, contamination of nitrate from septic water and manure is locally reduced by denitrification, as proven by compound-specific isotope analysis, improving water quality. At the same time, other anaerobic processes, such as iron and manganese reduction, sulfate reduction, and methanogenesis deteriorate water quality. Finally, groundwater temperatures, up to 27°C, were observed close to urban underground infrastructure, hinting at subsurface buildings and surface sealing as stressors in shallow groundwater. In conclusion, our high resolution spatial sampling with the large set of parameters will not only allow a better understanding of groundwater quality dynamics, but also allows to evaluate effects to groundwater biodiversity and develop predictive mathematical models.

How to cite: Kaminsky, E., Englisch, C., Griebler, C., Steiner, C., Götzl, G., Knoeller, K., Sandén, H., Laaha, G., and Stumpp, C.: What are the driving factors affecting urban groundwater quality? A multi-tracer approach for the assessment of Vienna’s shallow aquifers, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5588, https://doi.org/10.5194/egusphere-egu23-5588, 2023.

A.145
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EGU23-11717
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ECS
Martin Binder, Felicia Kossek, Christian Engelmann, and Jannis Epting

Adequate management strategies are critically required to increase the resilience and long-term availability of groundwater resources in the light of progressive climate change and accelerating urbanization. Here, robustly parameterized numerical models, designed for simulating water flow as well as solute and heat transport processes in the hydrogeological subsurface, are powerful and widely established tools supporting decision making and planning.

Among other applications related to more general quantity- and quality-related questions, these numerical tools can be also used, e.g., for investigating the current thermal state of the subsurface and occurring changes due to artificial and natural influences. Models designed for this very specific task should include at least all major artificial objects (e.g., underground car parks, tunnels, buildings, sewer networks) which thermally contribute to the overall groundwater heat regime. For instance, the heat exchange between the subsurface and sewer systems may significantly contribute to the subsurface urban heat island effect and should, therefore, be implemented. However, fully three-dimensional implementations of sewer networks (typically with hundreds of kilometers of pipes) are mostly out of question when applying such numerical models, since it would be associated with large computational demands and increasing numerical instabilities.

To overcome this limitation, the focus of our ongoing research is to evaluate the suitability of an adaptive surrogate method to be coupled to existing numerical heat transport models. This method is based on linking expected thermal exchange rates between small subsurface objects (e.g., sewer pipes) and their surrounding area, which depend on site-specific parameters (e.g., surface-groundwater table distance, pipe dimensions, shapes and materials), with the spatial elements of an existing model mesh, e.g., as area-averaged heat sources or sinks. Numerical heat conduction simulations performed on pipe scale while employing seasonally changing ambient and sewer conditions point towards the importance of considering both stationary (such as materials) and transient input datasets (such as temperature fluctuations) in this linking process. The collection and pre-processing of both dataset types is performed in separate workflows employing standardized geographic information system (GIS) software. Based on these input datasets, heat flux calculations can be done either employing the numerical code itself (if the model code allows user-defined calculations) or, again, in a GIS-assisted step (in order to further reduce the computational demand during the runs of the numerical model).

The conceptual workflow, first results as well as expected advances and limitations of this surrogate approach will be critically discussed using the example of the well-documented heat transport case study of ‘Basel-City’. Among others, the aforementioned stationary and transient input datasets, and based on that, processed vertical heat fluxes will be presented for selected areas of the Swiss canton.

How to cite: Binder, M., Kossek, F., Engelmann, C., and Epting, J.: Surrogate-based implementation of sewer network structures into numerical heat transport models: First results of the Basel-City case study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11717, https://doi.org/10.5194/egusphere-egu23-11717, 2023.

A.146
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EGU23-14782
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ECS
Moushumi Hazra, Himanshu Joshi Joshi, and Bhanu P. Vellanki

With time, a lot of change in the nature of impurities, especially a surge in emerging contaminants in urban wastewater has been observed due to changing lifestyle, uncontrolled and mismanaged urban sprawl, increasing pollution and disease burden, and easy access to antibiotics. Conventional sewage treatment plants have thus faced challenges in treating emerging pollutants such as antibiotics, with variable success as reported in few studies.  Antibiotics are persistent in the environment and result into development of antimicrobial resistance. The concentration of antibiotics reportedly varies from µg/L to ng/L in raw/treated sewage which is generally dependent upon differences in environmental/social factors as well as treatment technology. The present study was conducted with the purpose of identifying the role of activated sludge process (ASP) in a standalone mode as well as in a hybrid mode duly integrated with upflow anaerobic sludge blanket reactor (UASB) in removal of antibiotics from the raw sewage. The antibiotics were analysed with a Liquid Chromatography Mass Spectrometer (LCMS), and the removal efficiencies were compared for both the treatment systems. The concentration of selected antibiotics in raw/treated sewage of the hybrid UASB-ASP varied in the range of 0.92-79025.9µg/L and 0.03-3439µg/L respectively. It was observed that the concentration of erythromycin was very less inspite of being used as a wide spectrum antibiotic against gram positive/gram-negative bacteria causing upper and lower respiratory diseases. An apparent reason could be that it is mainly metabolised by human liver and only 5% is excreted in active form. Also, low concentration of sulfamethoxazole and enrofloxacin were detected in the ranges 0.04-0.92µg/L and 0.03-0.94µg/L respectively in the raw/treated sewage. Notably, even these concentrations could also inhibit bacterial growth by altering microbial production of folic acid and induce antimicrobial resistance at sub lethal concentration. The removal efficiency for UASB-ASP for selected antibiotic was between 51.09% to 95.87% indicating an efficient reduction. Low concentration of sulfamethoxazole and enrofloxacin was observed within the range of 0.15 – 0.21 g/L and 0.007 – 0.01 µg/L in the raw/treated sewage of ASP. Negative removal (increased concentration in the treated sewage) was observed for erythromycin and ciprofloxacin, apparently because of resistance to degradation. The reduction of sulfamethoxazole, enrofloxacin, tetracycline was 27%, 52%, 65% where trimethoprim demonstrated maximum removal of 88% in ASP.  The hybrid UASB-ASP performed better than the standalone ASP with respect to reduction of all antibiotics, indicating that ASP can perform more efficiently when integrated with other technologies alongwith addition of a proper dosing of chlorination. Risk associated with the selected antibiotics from sewage treatment plant to the receiving environment (both water/soil) was quantified employing hazard quotient (HQ) using predicted no effect concentration (PNEC) values derived from literature. HQ for sulfamethoxazole was calculated to be above 1, and higher values were observed for trimethoprim (in the range of 589-628), and tetracycline (in the range of 405-722) indicating potential environmental concern for aquatic environment/soil, whichever may be of concern. No risk seemed to appear for indirect human exposure to enrofloxacin as indicated by the calculated values of HQ (0.004-0.02).

 

How to cite: Hazra, M., Joshi, H. J., and Vellanki, B. P.: Efficiency of activated sludge process for reduction of antibiotics from municipal wastewater , EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14782, https://doi.org/10.5194/egusphere-egu23-14782, 2023.

Posters virtual: Mon, 24 Apr, 14:00–15:45 | vHall HS

Chairpersons: Anna Jurado Elices, Meiping Tong, Christophe Darnault
Emerging particles and biocolloids in terrestrial and aquatic systems
vHS.19
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EGU23-10830
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Highlight
Christophe Darnault

Nanoscience and nanotechnology have revolutionized many sectors of the industry with the development of novel materials and technologies. With the increasing use of nanomaterials in products and applications, the presence of nanoparticles in the environment, such as in soil, sediments, water, air, and biota, is inevitable. Understanding of the physical and chemical processes and environmental conditions that govern the fate and behavior of nanomaterials in the environment is essential to strengthen the environmental and human health security. This study discusses the role of physical and chemical processes and environmental conditions on the fate, transport, behavior, transformation, and toxicity of metal based nanoparticles and their environmental impacts, with a focus on terrestrial and aquatic systems, as well as plants and microorganisms. Research on the interactions of nanomaterials with the environment and biological systems will allow the development of models contributing to advancing knowledge on the behavior and fate of nanoparticles in the environment and assessing their potential risk in the environment.

How to cite: Darnault, C.: Nanomaterial Interactions with the Environment and Biological Systems: Implications for Soil, Water, Plants, and Microorganisms, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10830, https://doi.org/10.5194/egusphere-egu23-10830, 2023.

vHS.20
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EGU23-16985
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ECS
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Highlight
Fengxian Chen, Bin Zhou, Liqiong Yang, Xijuan Chen, and Jie Zhuang

Escherichia coli, as an indicator of fecal contamination, can move from manure-amended soil to groundwater under rainfall or irrigation events. Predicting its vertical transport in the subsurface is essential for the development of engineering solutions to reduce the risk of microbiological contamination. In this study, we collected 302 datasets from 39 published papers addressing E. coli transport through saturated porous media and trained an automated machine learning model (H2O AutoML) to predict bacterial transport. Bacterial concentration, porous medium type, particle size, ionic strength, pore water velocity, and column length were used as input variables while the first-order attachment coefficient and spatial removal rate were set as target variables. The six input variables have low correlations with the target variables, namely, they cannot predict target variables independently. However, with the automated machine learning model, input variables can effectively predict the target variables. Among 20 candidate models, Gradient Boosting Machine showed the best performance. Among the six input variables, pore water velocity, ionic strength, particle size, and column length were more important than bacterial concentration and porous medium type. This method of using historical literature data to train automated machine learning models provides a new avenue for predicting the transport of other contaminants in the environment.

How to cite: Chen, F., Zhou, B., Yang, L., Chen, X., and Zhuang, J.: Predicting bacterial transport through saturated porous media using an automated machine learning model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16985, https://doi.org/10.5194/egusphere-egu23-16985, 2023.

vHS.21
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EGU23-1194
Bing Bai, Haiyan Wu, and Fan Bai

With the increasing research on particles and biocolloids in terrestrial and aquatic systems, the transport and deposition of particles and biocolloids in porous media has become an important research topic. Based on the transport and deposition experiments of heavy metal pollutants and suspended-colloidal particles (SPs) in porous media, a nonlinear attachment-detachment model with adsorption hysteresis is proposed, which uses an adsorption function and scanning desorption isotherms to model the deposition effect of SPs. The reaction rate constant related to hysteretic characteristics essentially reflects the nonequilibrium hydrodynamic process during the transport of SPs. Static deposition tests and column experiments with pulse injection are used to calibrate the transport parameters. Column penetration experiments are performed under variable injection concentrations and seepage velocities. The results show that there is good agreement between simulated and experimental breakthrough curves (BTCs).

This model shows that increasing or decreasing the seepage velocity results in substantial changes in the penetration concentration of SPs, which is closely related to the adsorption hysteresis and the deposition dynamics of SPs. When the injection concentration is increased, the effluent concentration clearly increases, which reflects a nonlinear deposition process. In contrast, with a decrease in the injection concentration, the release effect of the already deposited SPs prolongs the penetration process, which is also related to the hysteresis. Previously proposed linear attachment-detachment models probably result in an overestimation of the adsorption capacity of porous media.

How to cite: Bai, B., Wu, H., and Bai, F.: A nonlinear attachment-detachment model with adsorption hysteresis for suspension-colloidal transport, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1194, https://doi.org/10.5194/egusphere-egu23-1194, 2023.

vHS.22
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EGU23-1771
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ECS
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Lichun Hsieh and Meiping Tong

The release of microplastics (MPs) especially those with sizes less than 10 μm from effluent of wastewater treatment plants (WWTPs) is one of the major sources of plastics into aquatic environment. To reduce the discharge of MPs into environment, it is essential to further enhance their removal efficiencies in WWTPs. In present study, to boost the removal performance of MPs in sand filtration systems (units that commonly employed in WWTPs to remove colloidal pollutants), six types of biochar fabricated from three raw biomass materials (i.e. lignin, cellulose, and woodchips) at two pyrolysis temperatures (400 °C and 700 °C) was respectively amended into sand columns as thin permeable layer. We found that adding all six types of biochar into sand columns as thin permeable layer could greatly improve the retention of MPs with the diameter of 1 μm under either slow (4 m/d) or fast flow rates (160 m/d) due to the high adsorption capability of biochar. Woodchip-derived biochar exhibited the highest MPs retention performance, which was followed by cellulose-derived biochar and then lignin-derived biochar. Moreover, for biochar derived from three raw biomasses, increasing pyrolysis temperature could improve MPs retention performance. The direct observation of real-time plastics retention processes on different types of biochar via a visible flow chamber showed that woodchip-derived biochar especially that fabricated at 700 °C exhibited more MPs trapping processes relative to lignin and cellulose-derived biochar due to their more complex surface morphology. Thus, the highest MPs retention performance was achieved in sand columns with amendment by 1 wt% woodchip-derived biochar fabricated at 700 °C. More importantly, we found that for these modified sand filtration column systems, complete MPs removal could be achieved in real river water and actual sewage water, in multiple filtration cycles, longtime filtration process (100 pore volumes injection) as well as with interval flow conditions. Moreover, biochar could be regenerated and reused as thin permeable layer to effectively remove MPs. The results of this study clearly showed that biochar especially woodchip-derived biochar fabricated at 700 °C had the potential to immobilize MPs especially those with small sizes in WWTPs.

How to cite: Hsieh, L. and Tong, M.: Addition of biochar as thin preamble layer into sand filtration columns could improve the microplastics removal from water, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1771, https://doi.org/10.5194/egusphere-egu23-1771, 2023.