HS8.2.9

Managed Aquifer Recharge (MAR) is a technology to deal with water stress and water scarcity worldwide. Depending on the origin and degree of prior treatment, the water inflow in MAR facilities contains measurable concentrations of Emerging Organic Compounds (EOCs). Understanding the processes that influence the fate of EOCs in the aquifer is therefore a key point for evaluating and predicting contaminant plumes and risk assessment. Such fate is clearly linked to the presence of biofilms that develop mainly in the first centimeters of the aquifer. Yet, the link between microorganisms, the development of biofilm and the fate of contaminants is not well understood. The spatial distribution into different redox states and thus the taking place of the different redox reactions, which significantly influence the degradation of pollutants as well as the sorption of these substances, is an important point. Sorption takes place in two different phases, the sediment and the biofilm. We have used the results of some conducted column experiments to create a numerical model, with which the processes taking place can be viewed in a differentiated manner and investigated further. The results show that biofilm plays an important role as a sorption phase and should therefore not be neglected when investigating and evaluating the fate of pollutants.

How to cite: Behle, V., Rodríguez-Escales, P., and Sanchez-Vila, X.: The Role of Biofilm on the Fate of Emerging Organic Compounds: Numerical Modelling of Column Experiments, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1779, https://doi.org/10.5194/egusphere-egu22-1779, 2022.

Ultraviolet filters (UVFs) are emerging organic contaminants that are present in personal care (sunscreens and many cosmetics) and numerous industrial products. Among UVFs, the group of benzophenone derivatives are the most used worldwide. Benzophenone-3 (PB-3, oxybenzone) is one of the most common UVF. BP-3 is considered as an endocrine disruptor with estrogenic activity, it is photo-stable, lipophilic and bioaccumulates in different organisms. The widespread use of BP-3 has led to its release into aquatic ecosystems mainly via discharge of wastewater treatment plant effluents. Common sources of water for Managed Aquifer Recharge (MAR) are affected, to some extent, by effluents of wastewater treatment plants and therefore, MAR has been proposed as a potential source of these compounds to the environment. Understanding the fate of UVFs but also of their transformation products (TPs) in MAR is relevant because some of them can be more ecotoxic than the parent compound. We evaluated the fate of selected UVFs and its TPs at different compartments (water, soil and biofilm) in two field pilot scale MAR systems; one of them operated with a permeable reactive barrier based on compost and the other with sand (without reactive barrier). We compared the temporal and spatial evolution of these UVFs before and after a slug injection of lithium acetate, as organic carbon source, in the two MAR systems. Quantification of selected UVFs and TPs showed that the two MAR systems promoted the removal of UVFs. Extended removal was enhanced by the compost reactive barrier, in which lower concentrations of all selected UVFs and TPs were measured. The fact that they were detected and quantified more often sorbed onto the biofilm and organic fraction of sediment than in the aqueous phase suggested that degradation takes place in the two solid compartments.

Acknowledgements

This work was financially supported by the Catalan Research Project RESTORA (ACA210/18/00040), by the Spanish Ministry of Science and Innovation through MONOPOLIOS (RTI2018-101990-B-100, MINECO/FEDER) and Project CEX2018-000794-S), as well as the EU project MARADENTRO (PCI2019-103425 and PCI2019-103603). We also thank the Consorci de la Costa Brava Girona (CCBGi) for the unlimited access to the WWTP.

How to cite: Jou-Claus, S., Rodríguez-Escales, P., Martínez-Landa, L., Diaz-Cruz, M. S., Carrera, J., Sunyer-Caldú, A., Quintana, G., and Valhondo, C.: Evaluating the fate of UV filters and transformation products during managed aquifer recharge: the role of reactive barriers, biofilms and varying redox., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7511, https://doi.org/10.5194/egusphere-egu22-7511, 2022.

Titanium dioxide nanoparticles (TiO₂ NPs) are increasingly used as photocatalysts, or as additives in personal care products, paints or food packaging, owing to their specific and individual properties. TiO₂ NPs can enter the environment through corrosion and degradation of end-of-life products and surfaces bearing these entities. Additionally, the agricultural application of sewage sludge, presumed to be the primary sink for engineered TiO₂ through the treatment of wastewater, has become a widespread fertilizing practice. The primary environmental medium receiving unwanted TiO₂NPs as pollutants is the soil environment. Hence, studying the behavior and interactions of such NPs with the soil and the soil solution is a prerequisite for apprehending the ecological risk related to such emerging pollutants. The interactions of TiO₂ NPs with the soil solution and solid phases -adsorption, aggregation, dissolution and sedimentation- are governed by the physicochemical characteristics of the nanoparticles (size, shape, surface properties, crystal structures) as well as the properties of the soil (pH, salt and organic matter contents).

            Our study focuses on performing laboratory experiments in soil extracts, as model soil solutions, of a neutral phaeozem, an acidic regosol and a solonetz (pH>9) with engineered TiO₂ NPs: 89% anatase (20-25 nm) and 11% rutile (50 nm), pure rutile and pure anatase. The goal is twofold i) investigating the changes of the photocatalytic activity of TiO₂ NPsfollowing their interactions with the different soil solutions, and ii) studying the degradation of the dissolved natural organic material in the soil solution due to the addition of TiO₂ catalysts. Three different types of soils have been selected for the experiments displaying variable pH and salt contents (acidic and neutral soils with low salt contents, and alkaline soils with high salt contents) to examine the effect of the pH, ionic strength and salt concentrations in the soil extracts on the outcome of the experiments. The reacted NPs will be characterized by SEM for potential changes in the particle morphology, XRD for analyzing the changes induced in its crystal structure, and IR spectroscopy for examining the changes occurred on the surface of the NPs (adsorption of organic molecules from the soil solution, changes in hydrophylicity) and DRS (changes in their optical properties). The photocatalytic activity following NP interactions with the soil solutions will be evaluated by monitoring phenol degradation in a reactor. The impact of the TiO₂ NPs on the degradation of natural organic matter will be assessed by total organic carbon measurements. Our preliminary results show that depending on the crystal structure of the applied TiO₂ NP, the pH of the soil solution may significantly change and there are visible changes of the NPs' properties. These results will promote our understanding of potential environmental risks related to engineered nanoparticles released into soils and groundwater.

How to cite: Solymos, K., Ariya, B., Babcsányi, I., Farsang, A., and Pap, Z.: Investigating the behavior and catalytic activity of TiO2 nanomaterials in soil extracts, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11191, https://doi.org/10.5194/egusphere-egu22-11191, 2022.

Remediation of sites contaminated with per- and polyfluoroalkyl substances (PFASs) is a significant step towards protecting drinking water sources and limiting human exposure. PFAS production and use is increasingly being restricted worldwide with a reduction of point sources; however, legacy plumes are still posing a threat due to the persistence of these chemicals against degradation. One of the most widely applied soil remediation techniques for PFASs is stabilisation, aiming to long-term entrapment of the contaminants with the addition of fixation agents in the subsurface, which prevent their leaching from soil to groundwater. In relation to this, the aim of this study was to identify the leaching behaviour of various PFASs in a treatment scenario using colloidal activated carbon (CAC). The effect of dissolved organic carbon (DOC), one of the major groundwater constituents in Sweden, on sorption was evaluated. Silt loam soil sampled from central Sweden was used, as well as a mixture of the soil with CAC at 0.1% w/w. Spiked artificial groundwater was prepared with a mixture of 21 PFASs, at a total concentration of 1.4 μg mL^-1. The sorption of PFASs to the solid phase was investigated using 15 cm long column experiments under saturated conditions, with and without DOC at 10 mg L^-1. Non-reactive tracer tests with NaCl were used to evaluate hydrological parameters. The desorption behaviour after treatment was also investigated, by switching the inflow from contaminated to clean water after steady state was achieved. Analysis of the compounds was conducted using ultra performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). Preliminary results showed retardation of PFASs with the addition of CAC, primarily for long-chain PFASs, exhibiting a correlation between sorption strength capacity and perfluorocarbon chain length. Some short-chain compounds, like perfluorobutanoate (PFBA) and perfluoropentanoate (PFPeA), exhibited immediate breakthrough. Slightly higher retardation of long-chain PFASs was noticed in the presence of DOC, for both treated and reference soil, indicating a potential increase of adsorption sites. Conversely, short-chain PFASs appeared to be outcompeted by DOC and showed faster breakthrough in its presence. These results indicate that humus content can have variable effect on PFAS sorption to soil and CAC, depending on perfluorocarbon chain length. Further experiments aim to the quantification of the sorption capacity.

How to cite: Niarchos, G., Liebenehm-Axmann, A. M., Berggren Kleja, D., Ahrens, L., and Fagerlund, F.: Evaluating the effect of DOC on PFAS sorption to soil and colloidal activated carbon using column tests, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7877, https://doi.org/10.5194/egusphere-egu22-7877, 2022.

Evidence of pesticides leaching due to intense rainfall events was found in two wellhead protection areas (WHPAs) located in the wine-growing areas of the Veneto piedmont area, in Italy. In this territory, the extensive agricultural activities related to the Prosecco production are developed often using pesticides-based vine protection practices. In the same area, numerous wells extract from the phreatic aquifers the drinking water needs of most of the province of Treviso, rising concern on the possibility of groundwater contamination from pesticides and risks for human health. Further experimental surveys – infiltration tests and soil samplings – were developed in the same WHPAs to study the spatial variability of the chemical-physical properties of the soil governing the pesticides leaching. The experimental data collected on areas of 2 hectares comprising both vineyards and non-agricultural areas, highlighted a larger variability of the soil properties inside the vineyards. Moreover, soil infiltration capacity, assumed in our case as the main property governing the pesticide leaching capacity, showed values up to one order of magnitude higher within the areas destined to wine-growing activities than the non-agricultural ones. This information, obtained at the local and at the field scale, were included in a geospatial analysis related to the distribution of vine-specific pesticides at the scale of the Treviso province, to obtain a vulnerability map for all the wells located in area. The geospatial analysis, developed in a geographical information system (GIS), is based on the sale data of pesticides for agricultural activities - also referred to as plant protection products (PPPs) – registered in the province in the period 2012-2019. The units of PPPs (kilograms or liters) collected at the municipal scale (the province of Treviso counts 94 municipalities) were analyzed by: i) identification of the vine-specific products based on the local guidelines for the vine-protection practices, ii) hazard classification of the vine-specific PPPs based on the CLP pictograms and statements (Classification, Labelling and Packaging Regulation, EC/1272/2008). This information, combined with the extension of the wine-growing areas from land use geographical data (Corine Land Cover 2018), allowed to outline, by assuming the use of the PPP in the municipality of sale, a map showing the hazard level of the wine-growing areas. The geospatial analysis based on the level of superimposition obtained between the extension of the wellhead protection areas and the wine-growing areas, led to a vulnerability map for wells. The map, resulting from the definition in different scenarios of the WHPAs extensions based on a geometrical criterion and the PPPs-based hazard of the vineyards, gives a clear picture of the wells that require PPPs-specific actions to minimize the risk for the quality of the water supplied for human consumption. 

How to cite: Costa, L. and Salandin, P.: Vulnerability of wells supplying drinking water and use of pesticides in wine-growing areas: the Treviso province case study, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11391, https://doi.org/10.5194/egusphere-egu22-11391, 2022.

Nitrate (NO₃^–) is the final product of the microbial nitrification process in the subsurface environment and can play a significant factor in potential contamination, causing seasonal hypoxia or eutrophication in the aquatic ecosystem. Excessive nitrogen (N) input by anthropogenic activities is well known as one of the major nitrogen sources such as dissolution of organic or synthetic (NH₄⁺, NO₃^–) fertilizer, leakage of the municipal and industrial landfill, and manure or septic wastewater. This study implemented dual nitrate isotopes approach to investigate the spatial distribution of nitrate contamination and its relative contribution of multiple nitrate sources in Daejeong region, Jeju island, South Korea. A total of 26 groundwater samples were collected from Sangmo, Hamo, and Dongil areas in Daejeong region and their nitrate concentrations were measured. The isotope ratios of N (δ¹⁵ N_NO3) and O (δ¹⁸ O_NO3) were analyzed using a denitrifier which converts the dissolved nitrate in the groundwater sample into gaseous nitrous oxide (N₂O). The NO₃-N concentration above the DWS (drinking water standard, 10 mg/L) was found in 11 out of 19 wells only in Sangmo, while the average NO₃-N concentrations of Hamo and Dongil were 2.95 and 2.58 mg/L, respectively. More than 80% of land use in Daejeong region was reported as agricultural farming, and massive synthetic fertilizer usage was expected. However, the δ¹⁵ N_NO3 ranged from 8.3‰ to 10.2‰, with an average of 9.22‰ and δ¹⁸ O_NO3 ranged from 3.2 to 6.9‰ with an average of 5.58‰, which are similar values of manure and septic wastewater. Thus, further investigation on land use changes, historical fertilizer consumption and its isotopic shifting in Daejeong region need to be considered for the relative contribution of nitrate sources.

How to cite: Kim, C., Lee, J., Kim, S., and Yang, M.: Dual isotopes evaluation of nitrate contamination and their relative contribution of multiple sources in Daejeong, Jeju island, South Korea, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1581, https://doi.org/10.5194/egusphere-egu22-1581, 2022.

A water quality problem exists in populated areas along the flanks of Mt. Meru in northern Tanzania, with excessively high fluoride (F-) concentrations exceeding the WHO drinking water standards (1.5 mg/L). Little is known about the potential sources of F^-among the various rocks types forming the Meru aquifers. Nineteen samples (Debris avalanche deposits (DAD n=4), lava flows n=6, brecciated lava n=4, pumice n=2, scoria n=1, ash n=1, carbonitic n=1) representative of the materials covering the slopes of Mt. Meru were characterized for their mineralogical, chemical, and total and water-soluble F^- compositions. Mt. Meru is mainly composed of alkaline volcanic rocks of basaltic to phonolitic composition. The total F^- analysis indicated that F^-occurs in all rock types with a mean value varying per rock type from 0.6 to 3.2 g/kg. The DAD in the east and northwest of Mt.Meru contained the highest amount of F^- (mean 3.1±0.17 g/kg), whilst the lava flow samples had the lowest mean value (0.6±0.25 g/kg). Water rock-interaction experiments further revealed the highest release of F^- in the analyzed DAD samples, possibly associated with their weathering status that progressively converted the primary minerals into secondary clay-bearing minerals assemblage, and favoring F^- release into the interacting water. Unlike DAD, pumice and ash have a moderately high level of total F^- (1.76±0.04 g/kg) yet; release a minimal amount of it through leaching. Petrographic observations showed that the analyzed volcanic rocks consist of volcanic glass and rare F^--bearing accessory minerals (amphibole, titanite, biotite, and apatite), among others. Using electron microprobe analysis, the F^- concentrations were found to be as high as 3- 6.5 g/kg in the glassy groundmass and up to 4 g/kg, 5 g/kg, and 45 g/kg in accessory phases of titanite, amphibole, and fluorapatite, respectively. Comparing the abundance and the composition of the glassy groundmass with the mineral phases, the former harbors most of the total F^-content. The findings of leaching experiments are congruent with past water quality which show that, low F^- is found in water from lava and tephra-dominated areas at higher altitudes and Mt. Meru west, respectively. This new information could guide future explorations for safer locations to place wells for water consumption. Itcould also be of interest for other East African Rift sectors and similar volcanic settings.

Keywords: Northern Tanzania, East African Rift, Meru volcano, fluoride contamination, volcanic rocks, leaching

How to cite: Kisaka, M., Tomašek, I., Bennett, G., Shemshanga, C., Devidald, J.-L., Fontijn, K., Mahene, W., Walraevens, K., Delmelle, P., and Kervyn, M.: Characterization of volcanic deposits along the slopes of Mount Meru, Northern Tanzania: insights into the potential sources and release of fluoride, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2659, https://doi.org/10.5194/egusphere-egu22-2659, 2022.

How to cite: Fernandez-Rojo, L., Rovira, M., Jubany, I., and Martí, V.: Effect of size reduction and calcite impurities on the adsorption of arsenic onto a ferric (hydr)oxide-calcite by-product, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4348, https://doi.org/10.5194/egusphere-egu22-4348, 2022.

Waste water treatment using chemicals reagents are effective but pose serious environmental and health problems.Public demand for renewable and biodegradable products grows with awareness of environmental protection, materials of biological origin appear to offer solutions. In our present work, we have synthetized matrix membranes based on different compositions of granulated actived carbonne (GAC),kaolin,Zinc Oxide (ZnO) and Iron Oxyde (Fe₂O₃). The membrane samples  were characterized by different analytical methods such as FTIR spectroscopy and XRD .The matrix membranes were tested for the removal of toxic metals such as chromium from aqueous solutions  The experimental test were caried on filtration unit .After each filtration test ,the concentraton of the heavy metals were be determined by analytical method . The rejection rate ratio was calculatad refering to the values of the copper and chromium concentration on Feed and permeate .solutions .The results shows the important contribution of natural inorganic matter on the copper and chromium ions from water.

How to cite: Chabane, M., Rahoui, K., Melkaoui, C., Dahmani, B., and Ferrah, N.: Removal of copper and chromnium from water by mixed matrix membranes loaded with natural inorganic fillers, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11168, https://doi.org/10.5194/egusphere-egu22-11168, 2022.