Sewage sludge and digestates from anaerobic fermentation are increasingly considered soil amendments and organic fertilizers to close agricultural element cycles. Beside plant nutrients, organic materials may contain potentially toxic trace elements. Their application cause soil pollution and enhance plant–soil transfer of undesired elements. The processes involved could be potentially deployed for phytoextraction applications. In this study, Alyssum murale, Fagopyrum esculentum, Lupinus albus and Carthamus tinctorius were cultivated on heavy metal polluted soil from the post-mining area of Freiberg Germany, treated with 10% (dw basis) sewage sludge or 1% digestate. Effects of soil amendments on the accumulation of P, Fe, Mn, Zn, Cu, Cd, As, Pb in different plant species evaluated by comparing shoot element concentrations (ICP-MS) of treated plants with reference plants cultivated on the soil. Both sewage sludge and digestate had high concentrations of nutrients, especially of phosphorus (22 g/kg P) in sewage sludge and (9.6 g/kg P) in digestate) which were magnitude higher than in the soil (30 mg/kg P). Compared to soil, sewage sludge contained lower concentrations of Mn, Cu, As, higher concentrations (factor of two) Zn and similar concentrations of Cd, Pb, Ni. Compared to  soil, the digestate was significantly enriched in Cu, Zn, Ni, Cd and depleted in As and Pb. Plants treated with digestate showed adverse effects on growth (C. tinctorius) and significantly reduced biomass. Plants treated with digestate were characterized by significantly higher concentrations of Mn, Fe, Zn, Cu (Alyssum murale) and higher concentrations of Mn, Fe (F. esculentum). In contrast, concentrations of Cd, Pb As remained unchanged. Due to detrimental effects on plant growth, the treatment of plants with digestate significantly reduced amount of elements accumulated, irrespective of plant species. In contrast, sewage sludge amended plants showed increased shoot yield (factor 2), and elevated concentrations of P, Mg and Zn.In   addition sewage sludge significantly increased concentrations of Zn, Cu, Ni, Cd, Co in A. murale und F. esculentum (by a factor of 20) and to a less extend in L. albus and C. tinctorius (Factor 2). Considering the higher shoot yield of sewage sludge amended plants, the increased concentrations enhanced phytoaccumulation of Cu, Zn, Ni, Cd and Co, which decreased in the order F. esculentum > C. tinctorius > A. murale > L. albus. Specifically, the accumulation of Zn in F. esculentum increased from 394 µg to 6658 µg and from 111 µg to 590 µg in C. tinctorius. Similarly, the accumulation of Cd increased from 8 µg to 98 µg in F. esculentum and from 0.26 µg to 31 µg in A. murale when sewage sludge was added. The calculated mass balance of elements  in pots and elements transferred into plant biomass revealed that plants accumulated 1% of total P present in the pots. Concomitantly, a single plant of F. esculentum accumulated 16% and 5% of plant-available Zn and Cd by soil sequential extraction analysis. Our findings indicate that high biomass metal-accumulators like F. esculentum could be used for industrial pretreatment of sewage sludge while retaining their high fertilization value.

How to cite: Zaffar, N., Shirmer, D., and Wiche, O.: Impact of sewage sludge and digestate soil amendment on the phytoaccumulation of potentially toxic elements in Alyssum murale, Fagopyrum esculentum, and Carthamus tinctorius, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8902, https://doi.org/10.5194/egusphere-egu22-8902, 2022.

The inefficient management of fertilizers is dramatically impairing the soil, water, and atmosphere quality. Efficient alternative methodologies for granting adequate N availability to crops while reducing the nutrient losses in the environment are urgently needed. In this work, we present a column leaching experiment in which the amount and speciation of the N lost by different slow-release fertilizers were investigated, in comparison to traditional fertilizers (urea and liquid digestate). The slow-release alternatives are produced by recovering N from liquid digestate and represented by NH₄-enriched zeolite-rich tuff and struvite. Four treatments were tested consisting in sandy soil fertilized with urea, liquid digestate, NH₄-enriched zeolite tuff and struvite. N amount and speciation was accounted in eight flushing events over 38 days (Total Kjeldahl N, Organic-N, NH₄⁺-N, NO₃^--N, NO₂^--N).

Results showed that urea and liquid digestate fertilized columns lost the majority of N within the first 2 flushing events as organic N and NH₄⁺-N, respectively. On the contrary, struvite and NH₄-enriched zeolite fertilized columns lost homogeneously fewer N and with a more balanced speciation over the entire experiment length. The mass balance outlined that, native soil N was mined in urea and liquid digestate treatments while in the soil fertilized with slow-release alternatives a fraction of N from the fertilizers was still present. These two slow-release alternatives thus representing a way to recycle N from liquid digestate and to use it more efficiently, minimizing N losses.

How to cite: Ferretti, G., Galamini, G., Medoro, V., Faccini, B., and Coltorti, M.: Slow-release fertilizers from liquid digestate: amount and speciation of the N leached in a laboratory column experiment, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4489, https://doi.org/10.5194/egusphere-egu22-4489, 2022.

Anaerobic digestion technique and production of bioenergy from biogas is an important contribution to achieving the targets of climate protection. Concomitantly, the use of digestates as secondary raw material for the production of fertilizers and the extraction of economic valuable elements are increasingly considered. The latter requires profound knowledge on the element concentrations in digestates and how changes in process parameters affect their enrichment. In this study a lab scale continuous anaerobic digestion with different organic loading rates (ORL) were performed to explore effects of loading rate on biogas production and concentration of heavy metals (Zn, Cr, Ni) and valuable elements (Ge, REEs) in digestate. The pH was 6.8–7.2 throughout the whole process. In a 30 liter reactor with working volume of 25 liter grass (Phalaris arundinaceae) and manure (20/80, 30/70, 40/60, 50/50, 60/40 ) were added as a substrate at different OLR (1, 2, 2.5, 3, 3.5, 4 kg VS m-3 d-1). The digestate of each organic loading rate was analyzed by ICP-MS. Increasing the OLR significantly increased gas production by 64%, 12%, 8%, 16% and 20%, respectively. While biogas production increased, concentration of heavy metals (Zn, Cr, Ni) and valuable elements (Ge, REEs) decreased at each level of OLR increase except between OLR 2 and OLR 3.  The increased biogas production was most likely caused by higher amounts of readily degradable organics in the fermenter, while decreasing concentrations of elements in digestates result from a dilution of initially high element concentrations in the manure with low concentrated grass biomass. In fact, we could say that the concentrations of elements in manure were by far higher compared to the grass. However, there was OLR 3 where higher inputs of biomass did not negatively affect element concentrations in digestate. Surprisingly at this OLR highest relative increase in gas production was observed. This suggests that at this loading rate enrichment of elements through losses of carbon and dilution with increasing contents of low concentrated biomass was balanced. We could demonstrate that OLR fundamentally impacts gas production and mineral element concentrations in digestate. The effects depend initially on element concentrations in biomass and gas production which potentially offers novel perspectives for optimization of biogas process towards a phytomining of valuable elements and use of digestates as secondary raw materials.

How to cite: Zaffar, N., Ferchau, E., Heilmeier, H., and Wiche, O.: Effect of organic loading rate on biogas production and concentration of heavy metals and valuable elements in continuous anaerobic co-digestion of manure and reed canary grass, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-404, https://doi.org/10.5194/egusphere-egu22-404, 2022.

Various micropollutants (including pharmaceuticals, UV filters, cosmetics, cleansers, etc.), are increasingly being detected in the environment because of their partial or incomplete removal from wastewater in wastewater treatment plants (WWTPs). These compounds can be taken up by plants if treated wastewater is used for irrigation or if biosolids are used for soil amendment. Previous studies focused on this subject were usually performed under greenhouse conditions. Therefore, the aim of this study was to evaluate a behavior of studied compounds under natural climatic conditions. Experiment was carried out directly in the wastewater treatment plant, where nine raised beds were installed, which contained soils taken from topsoil of two soil types Arenosol (two beds) and Cambisol (seven beds). Either maize or a mixture of different vegetables (lettuce, carrot and onion) was grown in these beds. Of the seven beds with the Cambisol, one of the beds containing either maize or vegetables was irrigated with tap water and other pair of beds (maize or vegetables) was irrigated with treated wastewater (i.e., WWTP effluent). In another pair of beds (maize or vegetables), composted sludge from WWTP Three beds containing both types of biosolids were irrigated with tap water. Only vegetables were grown in the beds with the Arenosol, which were irrigated with either tap water or treated wastewater. Climatic data, irrigation doses, drainage water volumes, soil water contents and plant growth were monitored during the experiment. Selected compounds concentrations were measured in WWTP effluent, both biosolids, drainage water, soils, and plant tissues. Fifty five of 77 analyzed compounds were quantified in WWTP effluent. Main compounds were pharmaceuticals (e.g., telmisartan, gabapentin, diclofenac, carbamazepine, and its metabolites), UV filters (e.g., phenylbenzimidazole sulfonic acid) and compounds used in anticorrosive paints (e.g., 1H-benzotriazole). In the case of both biosolids, the dominant compounds were telmisartan, sertraline, trazodone, citalopram, diclofenac (i.e., pharmaceuticals) and 1H-benzotriazole. Uptake of different compounds by plants depended on a plant and properties of organic molecules, which affected their sorption in soils and mainly their ability to be taken up and translocated in plants. For instance, pharmaceuticals carbamazepine, gabapentin tramadol and venlafaxine were mainly found in lettuce leaves.

Acknowledgement: Study was supported by the Ministry of Agriculture of the Czech Republic, project "The fate of selected micropollutants, which occur in treated water and sludge from wastewater treatment plants, in soil" (No. QK21020080) and partly also by the European Structural and Investment Funds, projects NutRisk (No. CZ.02.1.01/0.0/0.0/16_019/0000845).  

How to cite: Kodešová, R., Švecová, H., Klement, A., Fér, M., Nikodem, A., Kočárek, M., Chroňáková, A., and Grabic, R.: Uptake of micropollutants from treated wastewater, sewage sludge and composted sewage sludge by plants, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6637, https://doi.org/10.5194/egusphere-egu22-6637, 2022.

Soil inoculation with plant growth promoting rhizobacteria (PGPR) promises benefits for agriculture as well as phytoremediation and phytomining of potentially toxic elements (PTEs) and critical raw materials (CRMs) in soil. Thus, we investigated on a field scale the effects of soil inoculation on biomass production as well as on phytoextraction of germanium (Ge), sum total of rare earth elements (REET), copper (Cu), lead (Pb), zinc (Zn), cadmium (Cd), cobalt (Co), nickel (Ni), Iron (Fe), calcium (Ca) and phosphorus (P). Zea mays (ZM) and Helianthus annuus (HA) were used as test plants and the commercially available PGPR RhizoVital®42 containing Bacillus amyloliquefaciens FZB42 as source of inoculum. Post-harvest, biomass/m², shoot element content/m², root concentration and water-soluble soil element fraction of root soils were compared for plants grown on inoculated versus uninoculated reference soil. Results indicated increase of 24 % and 26 % for ZM and HA grown on inoculated soils respectively, albeit insignificant at p ≤ 0.05. Inoculation with PGPR enhanced the ZM shoot content of P, K, Co, Cd and Ge by percentages between 20 and 80 % (significant only for Ge) and decreased shoot content of Pb, REET and Cu by 35 %, 28 % and 59 % respectively. For HA grown on inoculated soil, shoot content of Ca, Ni, Cu, Zn, Ge, REET and Pb increased by over 28 % with negligible decrease observed for Cd. Water soluble element concentrations revealed increased concentrations of more than 15 % for K, Fe, Zn, Cd, Pb, Ge and REET in inoculated post-harvest root soils of ZM with negligible changes of less than ≤ 5% observed for P, Ca, Co, Ni and Cu. For HA , increase of ≥ 28 % for water soluble element concentrations occurred only for P and Ca, with concentrations of Ni, Cu, Zn, Cd, Pb and REET decreasing by percentages between 11 and 41 %. Also, increased root concentrations of ≥ 22 % for ZM growing on inoculated soils occurred only for P, Ca, Cu and Cd while decreased concentration of ≥ 12 % occurred only for Fe, Co, Ni, Pb and REET. Summarily, results suggest that bioaugmentation with commercially available PGPR RhizoVital®42, containing Bacillus amyloliquefaciens FZB42 has the potential to enhance biomass production as well as enhance or inhibit phytoextraction of some elements. Also, effects of PGPR on phytomining and phytoremediation is plant specific for some elements, depending mostly on plant physiological  characteristics.

How to cite: Okoroafor, P. U., Ikwuka, G., Zaffar, N., Ngalle Epede, M., and Wiche, O.: Field Studies on Effects of Bioaugmentation on Phytoextraction of Germanium, Rare Earth Elements and Potentially Toxic Elements, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2074, https://doi.org/10.5194/egusphere-egu22-2074, 2022.

Pentachlorophenol (PCP) is a recalcitrant compound that could persist in the environment causing serious pollution concerns. Bioremediation of PCP is demonstrating to achieve encouraging results compared to the common physical and chemical techniques.

The aim of this work was to assess different bioremediation processes as biostimulation and/or bioaugmentation approaches of artificially PCP (100 mg kg^-1) contaminated forest soil (Sc). The biostimulation treatment provided phosphate and three different organic amendments, such as forest compost (FC), municipal solid waste compost (MC) or sewage sludge (SS). Two different microbial consortia B1 and B2 were used as bioaugmentation treatments. The combination of both biostimulation and bioaugmentation techniques was also assessed. Soil physical and chemical properties, PCP amount, soil microbial biomass carbon, soil respiration and some enzymatic activities at zero time (T0) and after 30 d incubation (T30) were evaluated.

No significant changes in terms of main chemical soil properties were observed, but an increment of organic carbon in all organic amendment-based treatments at T0 and T30 was observed. The PCP concentration at T0 was on average 82 mg kg^-1 in all soil samples. After 30 days natural attenuation was responsible for the reduced PCP extractable in Sc (68.5 mg kg^-1). The combined action of biostimulation and bioaugmentation led to a strong PCP reduction (71%) in Sc+B1+FC sample, whereas a depletion of only 52% and 41% occurred with the single application of FC or B1, respectively. The presence of PCP negatively affected soil microbial biomass carbon and the activity of dehydrogenase and fluorescein diacetate hydrolysis that recovered upon organic amendment also combined with microbial consortia B1 or B2. FC based biostimulation treatment also stimulated soil respiration. These results demonstrate that the simultaneous treatment of biostimulation and bioaugmentation showed a better performance in the PCP removal with more effectiveness than the single techniques.

How to cite: Di Rauso Simeone, G., Werheni Ammeri, R., Hidiri, Y., Salah Abassi, M., Mehri, I., Costa, S., Hassen, A., and Rao, M.: Remediation of pentachlorophenol contaminated forest soil by the combined action of biostimulation and bioaugmentation techniques, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6427, https://doi.org/10.5194/egusphere-egu22-6427, 2022.

Energy crop Miscanthus x giganteus (Mxg) is known for its ability to grow in contaminated soils and for its high biomass which can be transformed to various biobased products.

A two-year pot experiment (2019 – 2020) was set to determine impact of diesel pollution on Mxg growth and impact of Mxg on degradation of diesel pollution. Mxg was grown in pots with diesel-spiked soil with different concentrations (2 500 – 50 000 mg/kg dry soil). Four soil samplings (three in 2019 and one in 2020) were carried out. The soil parameters (available nutrients, humus, pH, TOC) and diesel concentration (C₁₀ – C₄₀ analysis) were monitored. At the end of each growing season the biomass parameters (height and number of stems) were measured.  After the second growing season rhizomes and roots weight was also determined. Plant fitness was quantified by measuring of leaf fluorescence. The changes of microbial communities were characterized by phospholipid fatty acids (PLFA) analysis, respiration and enzymatic activities.

Higher diesel concentration affected negatively the growth of Miscanthus x giganteus. Biodegradation of diesel followed the first-order kinetics. Achieved half-lives were significantly shorter in pots with developed planted (compared to unplanted control); at low and high diesel concentrations the differences was not significant. Microbial activity was mostly stimulated by diesel concentration, which indicates microbial biodegradation as the key process. The results implicate slight stimulation of biodegradation developed by Mxg.

How to cite: Burdová, H.: The impact of diesel pollution on Miscanthus x giganteus biomass- two-year pot experiment , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7083, https://doi.org/10.5194/egusphere-egu22-7083, 2022.

Ore-mining industry produces a waste, which belongs to the main sources of potentially toxic elements (PTEs). One of the initial steps necessary for remediation project of contaminated sites is the research of PTEs mobile forms that are very capable to enter trophic chain mainly through plants. Great abandoned copper deposit São Domingos (Portugal) was selected as a representative area since the presence of high PTEs contents was proved there in previous research activities.

The presented work is focused on efficiency of natural sorbents on the immobilisation of PTEs in copper-polluted soil developed on tailings taken from the mine district, and to compare the treated soils as habitats of vascular plants. Several natural sorbents were selected for the adequate realization of experimental part: bentonite, charcoal, calcium carbonate, phosphate, chicken manure, and organo-zeolitic substrate (mixture of perlite, chicken manure, and calcium carbonate; 5:1:3).

From the whole area of the mine-dump, 10 sites were chosen as the representatives of not-so-heterogenic soil conditions, where the sampling itself was realized. As the representative PTEs; Cr, Mn, Co, Ni, Cu, Zn, As, Cd, and Sb were chosen. The sorbents were added to composite soil sample. Ex situ experiments were realized from 1^st of June to 30^th of September 2020. At the end of experiments, a soil sample from each pot were taken, dried and grained into the fine powder. For assessment of total concentration of elements, microwave digestion was performed, with 100 mg of grained powder dissolution in aqua regia. For the purpose to assess the forms of PTEs with the ability to be assimilated by plant roots, the extraction from 1 g of sample was executed in the sequence: I. deionized water; II. 1M ammonium acetate solution by pH 7 (both mixed for 12 hours); 0.01M citric acid solution (mixed for 2 hours). First two fractions can be referred as mobile / exchangeable. The prcessed soil solutions were measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS).

The technosol was contamined mainly by As, Cu, and Zn. Obtained results show that neither As nor Sb are present in inverstigated francions, whereas the concentrations of Cr is also very low. The other PTEs are contained in significat concentrations, mostly in mobile fraction, especially Co (36 %); Mn (27 %); Cu (25 %); and Cd (15 %). Among the natural sorbents, the only ones efficient in reducting the mobile forms were charcoal and organo-zeolitic substrate. These pots were also the only suitable habitats for mixture of grass species. In both cases, the mobile contents of Ni, Cu, and Zn were practically reduced to zero since the mobile contents of Co, Mn and Cd decreased to minimum. For better understanding of habitat-suitability after application of those sorbents, the plant-nutrient characterisation should be included in further research. Based on those results, both natural sorbents could be considered for application in remediation techniques aimed on those PTEs.

How to cite: Midula, P., Wiche, O., Andráš, P., Ševčíková, J., Drimal, M., Matos, J. X., and Kuráň, P.: Immobilisation of potentially toxic elements by natural sorbents: case study of spolic technosol from São Domingos Cu-ore deposit (Portugal), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12395, https://doi.org/10.5194/egusphere-egu22-12395, 2022.

Arsenic is common toxic contaminant in soils, but tracking its mobility is difficult because microscale processes govern its speciation and affinity to minerals. We aimed to unravel such dynamics in contaminated soils of Harz brook using a novel approach. By combining diffusive equilibrium in thin-film (DET) gels, spectrophotometric methods and hyperspectral imagery we were able to determine the spatial variability of arsenite (As(III)), arsenate (As(V)) and phosphate at submillimeter resolution. Iron was imaged simultaneously using the established colorimetric mapping of dissolved iron. The 2D-DET gel probes combined with XRF based element mapping in the solid and liquid phase, revealed microstructures and distinct mm-scale lamination surrounding porewater channels. Small-scale correlation analyses of arsenic and iron hotspots in the gels suggested active iron-driven local redox cycling of arsenic. The local processes overall point towards net release of sorbed As(V) in the form of As(III) into the porewater. These results show that 2D-DETs can deepen our understanding of the differential leaching of As(V) vs As(III) from iron oxides under anaerobic conditions. This study is the first fine-scale 2D characterization of arsenic speciation in porewater and represents a crucial step towards understanding the redox cycling and transfer of arsenic in heavily contaminated sediment and soil ecosystems. These insights may further lead to in-depth characterization of arsenic transfer mechanisms into the food web.

How to cite: Castillejos Sepulveda, A., Metzger, E., Littmann, S., Taubner, H., Chennu, A., Gatti, L., de Beer, D., and Klatt, J. M.: Two-dimensional imaging of arsenic concentration and speciation with diffusive equilibrium in thin-film (DET) gels, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11816, https://doi.org/10.5194/egusphere-egu22-11816, 2022.

Affordable environmentally friendly solutions are essential for the remediation of waste sites globally. 
Phytoremediation is an increasingly popular environmentally friendly method to help remediate waste 
sites and offset costs of waste site remediation. A greenhouse experiment was set up using to determine 
uptake of metallic zinc (Zn) and copper (Cu) solution by known hyperaccumulator Brassica juncea. With
treatments (T)1- 4, having final added soil concentrations of 100, 200, 310, and 330 mg kg ^-1 elemental Zn 
and Cu respectively. At 8 weeks, samples were harvested, weighed, and measured for atomic emission 
spectrometry (Agilent Technologies 4210 MP-AES). Phytotoxicity was determined based on visual 
observation, biomass, and chlorophyll measurements. The results showed no significant difference 
between the root mass of control, T1, and T2, whereafter T3 and T4 showed a 52.6_%, and 73.7_% 
decrease in mean root mass. There was no observable significant difference in leaf or stem mass among 
control, T1-T3, though the mean average of leaf mass decreased across all treatments. T4 showed 
significant difference in average leaf mass from control with a 46.1% decrease in average mass. At the 
highest concentration levels, T4 showed a 62.3% decrease in stem mass when compared to the control. 
AES measurements revealed pools of Zn and Cu in root, leaf, and stem material. The highest 
concentrations of Zn and Cu were to be found in the stem material, with highest observed 
concentrations (T4) being 11,700 mg kg^-1 of Zn and 3,116 mg kg^-1 of Cu. AES measured leaf material also 
showed large pools of both Zn and Cu with highest observed values (T4) being 5,813 mg kg^-1
for Zn and 2,901 mg kg^-1 for Cu. It can be determined from this experiment that B. juncea shows the ability to grow 
in heightened levels of Zn and Cu, as well as associate excess free Zn and Cu ions into plant tissues. 

How to cite: Grimm, M.: Feasibility of Brassica juncea as a Hyperaccumulator in Phytomining of Cu and Zn, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2542, https://doi.org/10.5194/egusphere-egu22-2542, 2022.

The fate of Pharmaceutically Active Compounds (PhACs) in the environment may depend on a number of interrelated processes. Their environmental risk is mainly influenced by their adsorption and desorption processes in the soil. The present work aimed to study the adsorption and desorption of PhACs (17α-ethinyl estradiol (EE2), carbamazepine (CBZ), diclofenac sodium (DFC)) on various agricultural soils formed under different redox conditions: an Arenosol with fully aerobic conditions and a Histic Gleysol sample with suboxic and anoxic conditions. The objectives of the study were to investigate how the soil properties modify the sorption processes of the PhACs. Adsorption isotherms were applied to estimate the model parameters using Langmuir, Freundlich and Dubinin-Radushkevich model in a batch technique experiment. The different composition of the soil samples significantly affected the amount of adsorbed PhACs (CBZ, DFC, EE2). Top soil samples with a high organic matter content adsorbed higher amounts of PhACs, while the amount of adsorbed PhACs decreased gradually with depth. In desorption experiments, the amount of PhACs released also varied with depth. In contrast, the rate of desorption was lowest at the topsoil samples and increased with depth. In samples where the deeper levels were characterised by higher clay mineral content (e.g. the C-level of the Histic Gleysol), significantly less PhACs could be desorbed. The physico-chemical properties of the soil showed that the amount of the desorbed PhACs mainly influenced by the specific surface area and clay content of the soil. This study could be useful for understanding of the movement of PhACs in soils formed under different conditions. This study was funded by the Hungarian National Research, Development and Innovation Fund (2020-1.1.2-PIACI-KFI-2021-00309).

How to cite: Szabó, L., Vancsik, A., Bauer, L., Jakab, G., Kondor, A., Filep, T., and Szalai, Z.: Influencing factors on the adsorption-desorption processes of Pharmaceutically Active Compounds (PhACs) in various agricultural soils, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2593, https://doi.org/10.5194/egusphere-egu22-2593, 2022.

Wastewater treatment technologies worldwide use only marginally reduce the number of organic micropollutants (e.g. pharmaceuticals) in treated wastewater. Treated wastewater is used for irrigation in semi-arid and Mediterranean areas. Most of the treated wastewater is discharged into surface water bodies In European Countries. The use of these water bodies for irrigation results in the presence of PhACs into the agro-environment. The ever-changing environment in the soils influences the adsorption of these compounds. One of the ever-changing environmental factors is pH. The pH can highly fluctuate in the rhizosphere during the whole growing season. Consequently, the study of the effect of this environmental factor should also be considered when assessing the environmental risk of PhACs.

The main questions of our research were: (a) How do root acids affect adsorption-desorption interactions?; (b) Are there synergistic effects during competitive adsorption of 17α-ethinyl estradiol (EE2), carbamazepine (CBZ), and diclofenac sodium (DFC)?

Studied compounds were tested in both single-compound adsorption and competitive adsorption and batch experiments. The adsorbents were from a calcareous, humic sandy soil used to grow lucerne. The sorption experiments were carried out at three different depths of the soil profile, where at the ploughed layer (0-20 cm), soil pH was adjusted to model the effect of ambient acids on sorption processes. Competitive adsorption tests were performed at both the original and the modified pH values. Adsorption isotherms were applied to estimate the model parameters using Langmuir, Freundlich, and Dubinin-Radushkevich model. According to our results, the pH changes influenced the sorption processes, especially the desorption. The outcome of our study could be able to estimate the behaviour of PhACs at different soil horizons of sandy agricultural soil.

This study was funded by the Hungarian    National Research, Development, and Innovation Fund (2020-1.1.2-PIACI-KFI-2021-00309).

How to cite: Bauer, L., Szabó, L., Vancsik, A., Kondor, A., Jakab, G., and Szalai, Z.: The effects of pH on the adsorption and desorption mechanisms of Pharmaceutically Active Compounds (PhACs) in a tilled Arenosol, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3841, https://doi.org/10.5194/egusphere-egu22-3841, 2022.

The ever-increasing use of pharmaceuticals in the 21st century has led to growing concern about the environmental impact of pharmaceutical substances. In terms of their mechanism of action, antibiotics pose one of the most significant risks to the environment by altering microbiological conditions. Microbial degradation of organic matter in soil systems is the primary driver of the carbon cycle, so antibiotic pollution can significantly impact soil CO2 emissions. Soil organic matter is not a homogenous system; most soil organic carbon models separate different carbon pools with shorter and longer decomposition times. As previously published, different soil organic carbon pools may have different chemical properties, and therefore adsorption properties. This study focused on the adsorption properties of different soil carbon fractions.

Adsorption studies were performed on three fluoroquinolone antibiotics (ciprofloxacin, norfloxacin, ofloxacin) by batch and kinetic experiments on three Luvisol samples with different land use (arable, grassland, forest). The SOM fractionation was based on the Zimmermann procedure, and the batch and kinetic experiments have also been carried out on the fractions. The soil fractions were analysed by TOC, XRD, XRF, BET, FTIR during the adsorption. Langmuir and Freundlich models were applied on the equilibrium data. The kinetics data were analysed by pseudo-first and second-order kinetics models. The main parameters affecting adsorption were studied by principal component analysis. Our results suggest that the long-term carbon pools are most affected by the adsorption of antibiotics.

PREPARED WITH THE PROFESSIONAL SUPPORT OF THE DOCTORAL STUDENT SCHOLARSHIP PROGRAM OF THE CO-OPERATIVE DOCTORAL PROGRAM OF THE MINISTRY OF INNOVATION AND TECHNOLOGY FINANCED FROM THE NATIONAL RESEARCH, DEVELOPMENT AND INNOVATION FUND.

How to cite: Vancsik, A. V., Szabó, L., Pirger, Z., Bauer, L., Jakab, G., Kondor, A. C., and Szalai, Z.: Differences of antibiotic-adsorption properties on various soil organic carbon pools, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11554, https://doi.org/10.5194/egusphere-egu22-11554, 2022.

Phosphorus (P) and iron (Fe) are limiting nutrients in many (agro-)ecosystems. Due to P-sorption under most soil conditions, the current P-fertilization practices are inefficient, since large quantities of the P fertilizer applied remain in the soil as a residual part. Therefore, the development of sustainable agricultural practices urgently needs to improve nutrient-acquisition efficiencies of crop species through rhizosphere engineering and breeding of low-input strains. The availability of nutrients in the rhizosphere, especially that of P, is dependent on the activity of roots and associated microbes, particularly their ability to acidify the surrounding soil and release chelating compounds such as carboxylates. Therefore, there is a growing interest among plant ecologists, breeders and agronomists in “easily-measurable” tools to trace belowground functional traits in nutrient acquisition under soil conditions. Here, we explore the idea to use rare earth elements (REEs) in plant material to evaluate the nutrient-acquisition strategy, particularly under nutrient limitation. The rationale behind this hypothesis is that i) REEs are present in almost all soils at quantities similar to some plant nutrients such as Cu and Zn, ii) REEs interact with nutrient-bearing soil phases (phosphates, Fe-oxyhydroxides), iii) root exudates released under P/Fe deficiency strongly mobilize REEs in soil, and iv) the uptake of mobilized REEs in plants depends on their chemical form, which is a function of rhizosphere chemistry.  Preliminary results from greenhouse and large-scale field experiments indicate that P-inefficient species show different REE-concentrations in their leaves than P-efficient species, and that the pattern of REEs is related to the composition of root exudates. In ongoing experiments, this hypothesis will be rigorously tested by coupling a field sampling campaign of plant material from species with contrasting nutrient-acquisition strategies along soils with changing nutrient availability (Western Australian chronosequences) as well as controlled greenhouse experiments for mechanistic elucidation of processes involved.

How to cite: Wiche, O., Pourret, O., and Lambers, H.: Rare earth elements as potential tracers of carboxylate-based plant nutrition strategies , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3674, https://doi.org/10.5194/egusphere-egu22-3674, 2022.

Background:  Silicon (Si) is one of the elements whose role in plant nutrition and development is not fully defined and has become of great interest as of recent. The presence of Si, is, however, known to extend several benefits to plants, which include increased biomass production and tolerance against both biotic and abiotic stressors, furthermore, it improves plant rigidity.Aim: This study represents a greenhouse experiment that was designed to explore the effects of Si accumulation and its relationship with the uptake of essential and nonessential elements while alleviating toxicity in plants with different nutrition strategies.Methods: Four plant species, Brassica napus (B. napus, a hyperaccumulator), Lupinus albus (L. albus, an excluder), Cucumis sativus, and Zea mays (C. sativus and Z. mays, both Si accumulators), were cultivated on a semi hydroponic substrate under greenhouse conditions. The plants were treated with a variation between a solution made of a trace element mix (Al, Cd, Mn and REE) without Si (further denoted TE-mix) and a similar mix with Si- fertilizer as silicic acid (further denoted Si+). The solution concentrations were varied between 10 and 100 µM, to investigate the effect of Si. After harvest, the concentration of Ca, Mn, Fe, P, Al, Cd and REE were determined using IC-PMS. Results: Treatment with 10 µM TE-mix and Si+ showed a decrease in biomass on the biomass of B. napus and L. albus. The effect of Si on the biomass of Si accumulators (C. sativus and Z. mays) decreased with the increasing concentration of the TE application. Treating the plants with Si+ at both low and high concentrations resulted in low Ca concentration in B. napus and C. sativus when compared to the concentrations from TE-mix treatment which are up to fivefold higher. The influence of Si+ on the concentration of Mn, and Fe increased (≥150 % and ≥10% respectively) with increased Si+ concentration. The results further indicated that treating the plants with Si+ increased the concentration of Al and Cd accumulated in B. napus, C. sativus and Z. mays. Higher concentrations of LREE were accumulated when compared to LREE in all species when treated either with TE-mix or Si+ (at both 10 and 100 µM). The highest REE concentration was accumulated in B. napus (21.4 µg /g LREE and 17.4 µg /g HREE) when the plants were treated with 100µM Si+. Conclusion: The results from this study provide further insight into the benefits of supplementing Si as fertilizer, toward plant development and nutrition. Even when utilized on plants with different nutrition strategies, Si may assist the plants in biomass production and to acquire nutrients such as Fe and Mn. Furthermore, the use of Si can assist plants in resisting high concentrations of toxic trace elements such as Al and Cd while also accumulating nonessential but valuable elements such as rare earth elements when implementing phytoremediation. 

How to cite: Monei, N., Benyr, V., Hitch, M., Heilmeier, H., and Wiche, O.: Silicon Extends Beneficial Effects Towards the Accumulation of Micronutrients and Rare Earth Elements, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5812, https://doi.org/10.5194/egusphere-egu22-5812, 2022.

Silicon (Si), as the second most abundant element in the Earth's crust beyond oxygen, represents an essential part of the mineral world. Si is a crystalline semi-metal or metalloid belonging to the same periodic group as carbon, but with chemical performances dissimilar from all of its group counterparts. Despite sharing the bonding versatility of carbon, with its four valence electrons, Si is a relatively inert element. Besides its abundance (27.6%), Si is not usually found in its pure state, but rather its dioxide and hydrates. Silica (SiO₂) is the one stable oxide of silicon, and it is more energetically favorable for Si to create four single bonds with each oxygen rather than make two double bonds with each oxygen atom. This leads to a linking form of -Si-O-Si-O- networks called silicates. The core unit of silicates can bind together in a variety of ways, creating a wide array of minerals. As an inevitable soil constituent, Si is present at high concentrations in soil solutions ranging from 0.1-0.6 mM roughly two orders of magnitude higher than some macronutrients. Therefore, exposed to Si, plants developed mechanisms for its uptake, translocation, and deposition within the plant tissue. Mostly accumulated in cell walls (CW), the location and content of Si are being primed by the chemistry and structure of lignin. We investigated how Si interacts with the process of lignin formation in the CWs. In an in vitro system, we studied the interaction of SiO₂ with the peroxidase-catalyzed polymerization of a lignin monomer into a lignin model compound, imitating conditions of the last step in lignin formation. FTIR and fluorescence spectroscopy and microscopy showed that Si is bound to the final polymer and that the structure of the Si-DHP differs from pure DHP. Fluorescence spectroscopy showed that Si does not bind to the monomers, so Si probably inhibits the formation of the larger lignin fragments, as evidenced by HPLC-DAD, by binding to dimmers formed during DHP synthesis. The structural changes of the polymer are related to the changed proportion of the fractions of various MW. The enzyme catalyzing DHP synthesis was not inhibited by Si. This may indicate that the complex formed with Si and short oligomers activates the enzyme, and prevents the formation of the large fragments. Obtained results may influence further investigations of Si interactions with lignin and understanding of Si effects on the CW structure.

Acknowledgements. This work was financed by the Ministry of the Education, Science and Technological Development of the Republic of Serbia, the contract No 451-03-9/2021-14/200053.

How to cite: Dragišić Maksimović, J., Djikanović, D., Kalauzi, A., Tanasijević, G., Maksimović, V., and Radotić, K.: Role of silicon in polymerization process during lignin synthesis and cell wall properties, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10375, https://doi.org/10.5194/egusphere-egu22-10375, 2022.

Riparian zones, important hotspots for nitrogen retention, are at risk of losing ecosystem functioning by species invasion and chemical contaminants. Invasive Fallopia japonica is suspected of using polyphenolic compounds as a “novel weapon” to decrease nitrification which may be amplified by copper pollution. Inhibited nitrification results in lower nitrate availability for competing plants and is presumed to be part of Fallopia japonica´s competitive strategy. Polyphenols are known to enter the soil with leaf litter, but may also be exuded by roots. Yet, the entry pathway and the specific compounds hampering nitrification are not fully determined. Within the group of secondary metabolites produced by Fallopia japonica, emodin and resveratrol are frequently described, although their role in the invasion strategy via modification of nitrification has never been tested. As plants are likely to increase exudation and the production of polyphenols under stress, synergistic inhibition of nitrification may be expected under contaminant pollution. Hence, the following hypotheses were tested: (I) Resveratrol and emodin inhibit nitrification. (II) Under copper stress, Fallopia japonica increases the content of emodin and resveratrol. Therefore, both stressors act synergistically on nitrification inhibition. (III) As we assume polyphenols to enter the soil via root exudation, nitrification is more strongly inhibited in the rhizosphere compared to the non-rooted soil.

We ran a mesocosm experiment with Fallopia japonica and copper additions (0, 90, 270, 810 mg Cu kg^-1 soil) over two growing seasons. In September of the second year, we analyzed total polyphenol, resveratrol, and emodin concentration in roots, fresh leaves, and senescent leaves using LC-HRMS. Potential nitrification was measured in the rhizosphere and the non-rooted soil. All samples were analyzed in fivefold repetition across all copper concentrations. We further tested how the nitrification in soil responds to additions of resveratrol and emodin.

Resveratrol inhibited nitrification while for emodin no significant effect was found. Under copper stress, concentrations of resveratrol in roots and emodin in senescent leaves were elevated, while total polyphenolic content was not influenced. Copper contamination had a strong concentration-dependent inhibitive effect on potential nitrification. Independent of the copper concentration, Fallopia japonica decreased the potential nitrification slightly more than the highest copper concentration (by 75 % compared to control). Despite the increase of resveratrol in roots, the stressors had neither a synergistic nor additive effect, because of the overwhelming influence of Fallopia japonica alone. In contrast to hypothesis (III), nitrification inhibition was lower in the rhizosphere compared to the non-rooted soil, suggesting that nitrification was not primarily controlled by active root exudation but possibly more by aboveground leachates or litter decomposition. We link this to Fallopia japonica´s competition strategy hampering nitrification more in the soil that provides nitrate for competing plants.

Our data reveals that polyphenols produced by Fallopia japonica may act as a “novel weapon” to benefit the own nutrition and to outcompete other plants. By inhibiting nitrification outside the own rhizosphere, the nitrogen availability for the riparian plant community could be substantially reduced having potentially negative effects on the biodiversity of riparian ecosystems and their ecosystem functioning.

How to cite: Girardi, J., Korz, S., Muñoz, K., Jungkunst, H., and Brunn, M.: Phenolic compounds from invasive Fallopia japonica inhibit nitrification, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11809, https://doi.org/10.5194/egusphere-egu22-11809, 2022.

In this study we used the HAIR (HArmonized environmental Indicators for pesticide Risk) modelling tool _[1],[2] for estimating the risks of pesticide use in Irish grassland soils, as part of the PROTECTS research project _[3]. This project aims to provide baseline information in an Irish context to build towards mitigating the effects of pesticide use on terrestrial ecosystem services, focusing on pollinators and soils. Our study focused on estimating the potential terrestrial risks posed by pesticides on soils in the form of earthworm terrestrial risk-indicators (ETR_e) using the HAIR2014 _[2] for selected herbicide active substances (ASs). The work involved a refinement of the HAIR2014 tool for Irish conditions, as explained in Premrov et. al (2021) _[4]. In brief, this included upgrading the spatial (GEO) database, climate data inputs and ‘crop-regions’ for Ireland _[4]. An Irish grassland land-use (LU) map was derived from PERSAM data/maps _[5] and the remaining inputs (i.e. soil inputs) were obtained from the HAIR2014 default databases _[2] (assigned to the new grid _[4]). The pesticide application/usage inputs were derived from published national surveys on plant-protection product (PPP) usage for Ireland _[6]. Recent advancements include work on building a compound-database for HAIR2014 for the selected ASs of interest (e.g. glyphosate, MCPA, MCPP, 2,4-D, 2,4-DB, etc. ). This requires information for a number of physico-chemical and other parameters for these ASs, which are sourced from EU regulatory and evaluation data and EFSA publications, in addition to other relevant sources. We will present the generated HAIR2014 simulation outputs in the form of ETR_e risk indicator maps for selected herbicide ASs for Irish grasslands.  The aim of this work is to generate pesticide risk indicator output maps for soils in Irish grasslands that will inform an area-based risk assessment, as well as assist the development of recommendations for potential future national soil-monitoring and sampling needs.

Acknowledgements

Thanks go to Irish Department of Agriculture, Food and the Marine (DAFM) for funding the PROTECTS project.

Literature

[1] HAIR2014, (last assessed 2022). HArmonized environmental Indicators for pesticide Risk. URLs: https://www.pesticidemodels.eu/; https://www.pesticidemodels.eu/hair/hair2014.

[2] Kruijne, R., et al.  (2011). HAIR2014 Software Manual (2014);  Hair 2010 Documentation Alterra Wageningen UR.

[3] PROTECTS project, (2018). Protecting terrestrial ecosystems through sustainable pesticide use URL: https://protects.ucd.ie.

[4] Premrov, A., Saunders, M., Zimmermann, J., Stout, J., (2021). Insights into preliminary procedures for estimation of soil pesticide risks in Irish grasslands using HAIR2014 tool, IGRM2021, Limerick, Ireland. URL: https://www.mic.ul.ie/sites/default/files/uploads/624/Premrov%20IGRM%20poster.pdf.

[5] EFSA, (2015). Data PERSAM tool. URL:  https://esdac jrc ec europa eu/content/european food safety authority efsa data persam software tool (and there cited data sources)

[6] DAFM, (last assessed 2022) Pesticide Statistics Pesticide Usage Surveys. URL: https://www pcs agriculture gov ie/sud/pesticidestatistics/

How to cite: Premrov, A., Saunders, M., Stanley, D., White, B., Carolan, J. C., Quirke, J., Broderick, M., Conroy, K., Zimmermann, J., and Stout, J.: Insights into using HAIR2014 tool for estimating soil pesticide risks in Irish grasslands for selected herbicide active substances , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2989, https://doi.org/10.5194/egusphere-egu22-2989, 2022.

Annually, millions of tons of granular material such as excavated soil, asphalt, crushed rock and concrete are generated in the building and construction sector in Sweden alone. These materials often exhibit elevated concentrations of several potentially hazardous substances compared to background values. These materials are often being regarded and treated as waste due to a lack of appropriate and optimised environmental risk assessment for reuse purposes. Subsequently, this classification prevents materials technically suitable for reuse forming circular material flows. Standardized and scientifically based criteria for reclassifying these materials as products rather than waste are lacking.  

The goal of this project (co-financed by the Swedish Transport Authority and SBUF, the Swedish construction industry’s organisation for research and development) is to enable circular flow of surplus construction materials such as excavated soil, asphalt, crushed rock and concrete with regard to environmental and health risks.

To achieve this the project focuses on improving the knowledge on the environmental properties of those surplus materials as well as by developing methods to assess governing environmental risks associated with circular use on a scientific basis. These will form the backbone of criteria for when masses can seize to be considered waste and be turned into a product instead: the End-of-Waste criteria. As these materials are often in contact with soil or can potentially leak hazardous substances to soil, a working hypothesis for the project is that the protection of ecological soil functions is governing for environmentally sound reuse, and as such for End-of-Waste criteria. Aspects that need to be considered for End-of-Waste criteria for these materials are many, broad and complex: Chemical and physical properties of the materials, concentrations and properties of potentially hazardous substances, transport and alteration of potentially hazardous substances as a function of their use and suitability in constructions, aging of the material, soil properties, other environmental and human health risks but also and legal and societal aspects.

We will gather information about use, classification and management of these materials and assess knowledge gaps regarding their environmental properties and as well as their potential environmental effects in light of current risk assessment, on ecotoxicological effects in soil particularly. Moreover, we will test and develop methods to more accurately reflect environmental risks that recycling of these material entails. Results will be used to outline relevant End-of-Waste criteria with regard to environmental and health risks. These criteria will be tested and evaluated.

How to cite: Jennerheim, J., Hansson, M., Hammer, E., and van Praagh, M.: Circular material flow in construction – what to consider optimised mass management when waste is to become a resource , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12377, https://doi.org/10.5194/egusphere-egu22-12377, 2022.