Caracterización y modelización teórica de nuevos agentes quelantes análogos al EDDHE para su uso como fertilizantes

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento Química Agrícola, Geología y Geoquímica, Fecha de lectura 18-07-200

Bioremediation of multi-polluted soil by spent mushroom (Agaricus bisporus) substrate: Polycyclic aromatic hydrocarbons degradation and Pb availability

This study investigates the effect of three spent Agaricus bisporus substrate (SAS) application methods on bioremediation of soil multi-polluted with Pb and PAH from close to a shooting range with respect natural attenuation (SM). The remediation treatments involve (i) use of sterilized SAS to biostimulate the inherent soil microbiota (SSAS) and two bioaugmentation possibilities (ii) its use without previous treatment to inoculate A. bisporus and inherent microbiota (SAS) or (iii) SAS sterilization and further A. bisporus re-inoculation (Abisp). The efficiency of each bioremediation microcosm was evaluated by: fungal activity, heterotrophic and PAH-degrading bacterial population, PAH removal, Pb mobility and soil eco-toxicity. Biostimulation of the native soil microbiology (SSAS) achieved similar levels of PAH biodegradation as SM and poor soil detoxification. Bioaugmented microcosms produced higher PAH removal and eco-toxicity reduction via different routes. SAS increased the PAH-degrading bacterial population, but lowered fungal activity. Abisp was a good inoculum carrier for A. bisporus exhibiting high levels of ligninolytic activity, the total and PAH-degrading bacteria population increased with incubation time. The three SAS applications produced slight Pb mobilization (<0.3%). SAS sterilization and further A. bisporus re-inoculation (Abisp) proved the best application method to remove PAH, mainly BaP, and detoxify the multi-polluted soilThis work was financially supported by the Ministry of Economy and Competitiveness of Spain (Project CTM2013-47874-C2-R

Implications of polluted soil biostimulation and bioaugmentation with spent mushroom substrate (Agaricus bisporus) on the microbial community and polycyclic aromatic hydrocarbons biodegradation

Different applications of spent Agaricus bisporus substrate (SAS), a widespread agro-industrial waste, were investigated with respect to the remediation of a historically polluted soil with Polycyclic Aromatic Hydrocarbons (PAH). In one treatment, the waste was sterilized (SSAS) prior to its application in order to assess its ability to biostimulate, as an organic amendment, the resident soil microbiota and ensuing contaminant degradation. For the other treatments, two bioaugmentation approaches were investigated; the first involved the use of the waste itself and thus implied the application of A. bisporus and the inherent microbiota of the waste. In the second treatment, SAS was sterilized and inoculated again with the fungus to assess its ability to act as a fungal carrier. All these treatments were compared with natural attenuation in terms of their impact on soil heterotrophic and PAH-degrading bacteria, fungal growth, biodiversity of soil microbiota and ability to affect PAH bioavailability and ensuing degradation and detoxification. Results clearly showed that historically PAH contaminated soil was not amenable to natural attenuation. Conversely, the addition of sterilized spent A. bisporus substrate to the soil stimulated resident soil bacteria with ensuing high removals of 3-ring PAH. Both augmentation treatments were more effective in removing highly condensed PAH, some of which known to possess a significant carcinogenic activity. Regardless of the mode of application, the present results strongly support the adequacy of SAS for environmental remediation purposes and open the way to an attractive recycling option of this wasteThis work was financially supported by the Ministry of Science and Innovation of Spain (Project CTM2009-13140-C02-02

Synthesis and characterization of nano Fe and Mn (hydr)oxides to be used as natural sorbents and micronutrient fertilizers

Fe and Mn (hydr)oxides are widely used as contaminant sorbents in water/wastewater systems but their potential use as micronutrient fertilizers is still poorly known. In this research, four nano-metal (hydr)oxides (amorphous Mn oxide (AMO), Fe-Mn binary oxide (FMBO), two-line ferrihydrite (2L-Fh) and goethite) were successfully synthesized and completely characterized (infrared and Mössbauer spectroscopy, X-ray diffraction particle size, specific surface area, point of zero charge). AMO, FMBO and 2L-Fh were introduced to interact with AgNO3 (20.0 µM) and TlNO3 (100.0 µM) diluted solutions for three days to check their potential capability as potential Ag+ and Tl+ adsorbents. AMO and FMBO (4% w/w) were tested as nanofertilizers by arranging a hydroponic bioassay for 35 days on white lupin culture as a Mn-hyperaccumulator plant model. AMO structure was identified as an amorphous mixture of Mn oxides while FMBO was an Fe dopped birnessite. Both materials were efficient in extracting Ag+ and Tl+ although large Mn concentration was released from FMBO to the solutions. AMO and FMBO promoted Fe and Mn nutrition in plants. Synthetic iron chelate (Fe-EDDHA), present in the nutrient dissolution, could be adsorbed onto AMO surface by producing Fe and Mn accumulation in roots and increasing Mn uptake rate without toxicity symptoms. Therefore, AMO and FMBO not only demonstrated their efficiency as adsorbents, but also displayed they would be promising nanomaterials as micronutrient fertilizer

Evaluation of the sorption potential of mineral materials using tetracycline as a model pollutant

Tetracycline (TC) is among the most used antibiotics in animal feedstock in the EU. Antibiotics’ persistence as emerging pollutants in the environment is evidenced by their long half-life in residual organic-mineral sediments and waters. The risk associated with this persistence favours antibiotic-resistant microbiota, affecting human health and ecosystems. The purpose of the present work is to assess the adsorption of TC into natural clay minerals, synthetic iron hydroxides and calcined sewage sludge. TC adsorption isotherms were performed in three replicated batch tests at three di erent pH values (4, 6, 8) and TC concentrations (33–1176 mg.L−1). X-Ray di raction (XRD) mineralogy, cation exchange capacity (CEC), Brunauer, Emmett and Teller specific surface area (BET-SSA) and point of zero charge salt effect (PZSE) were determined for the characterization of materials. Sorption was analysed by means of fitting Langmuir and Freundlich adsorption models, which showed good fitting parameters for the studied materials. Low-charge montmorillonite (LC Mnt) is displays the best sorption capacity for TC at maximum TC concentration (350–300 mgTC.g−1) in the whole range of pH (4–8). Sepiolite and smectites adsorbed 200–250 mgTC.g−1, while illite, calcined sludge or iron hydroxides present the lowest adsorption capacity (<100 mgTC.g−1). Nevertheless, illite, sepiolite and ferrihydrite display high adsorption intensities at low to medium TC concentrations (<300 mg.L−1), even at pH 8, as is expected in wastewater environmental conditionsThis work has been economically supported by the Ministry of Economy and Competitiveness of Spain (CTM2013-47874-C2-2-R and AGL2016-78490-R)

Modeling arsenic in European topsoils with a coupled semiparametric (GAMLSS-RF) model for censored data

Arsenic (As) is a versatile heavy metalloid trace element extensively used in industrial applications. As is carcinogen, poses health risks through both inhalation and ingestion, and is associated with an increased risk of liver, kidney, lung, and bladder tumors. In the agricultural context, the repeated application of arsenical products leads to elevated soil concentrations, which are also affected by environmental and management variables. Since exposure to As poses risks, effective assessment tools to support environmental and health policies are needed. However, the most comprehensive soil As data available, the Land Use/Cover Area frame statistical Survey (LUCAS) database, contains severe limitations due to high detection limits. Although within International Or- ganization for Standardization standards, the detection limits preclude the adoption of standard methodologies for data analysis. The present work focused on developing a new method to model As contamination in European soils using LUCAS soil samples. We introduce the GAMLSS-RF model, a novel approach that couples Random Forests with Generalized Additive Models for Location, Scale, and Shape. The semiparametric model can capture non-linear interactions among input variables while accommodating censored and non-censored observations and can be calibrated to include information from other campaign databases. After fitting and validating a spatial model, we produced European-scale As concentration maps at a 250 m spatial resolution and evaluated the patterns against reference values (i.e., two action levels and a background concentration). We found a significant variability of As concentration across the continent, with lower concentrations in Northern countries and higher concentrations in Portugal, Spain, Austria, France and Belgium. By overcoming limitations in existing databases and methodologies, the present approach provides an alternative way to handle highly censored data. The model also consists of a valuable probabilistic tool for assessing As contamination risks in soils, contributing to informed policy-making for environmental and health protection

Stevensite-based geofilter for the retention of tetracycline from water

The antibiotic tetracycline, is considered a contaminant of emerging concern due to its presence in wastewater effluents, surface waters and groundwaters. Adsorption of tetracycline on soils and clays has been extensively studied to remove the contaminant from the water. A decreasing adsorption as the pH increases is normally reported in the pH range 3–9. However, adsorption isotherms performed on a commercial stevensite presented increasing adsorption with the increasing pH, in the pH range 2–8. This is very interesting since the pH in natural and wasterwaters are normally in the range 6–8. A laboratory design of a geofilter using a mixture of sand and stevensite was tested against an inflow solution of tetracycline 1 g/L, NaNO3 0.1 M and pH = 7 in an advective transport cell experiment. The number of tetracycline molecules exceed by >3 times the number exchangeable positions in the stevensite geofilter. Under these conditions, the TC adsorption on the geofilter reaches 590 mg/g, surpassing the retention capacity of most adsorbents found in literature. Besides, the tetracycline is completely desorbed by the inflow of a saline solution (Mg(NO3)2 0.5 M, at pH = 2) with capacity to replace the exchangeable positions, thus, recovering the geofilter and the tetracyclineThis work has been financially supported by the Spanish Ministry of Economy and Competitiveness through the AGL2016-78490-R projec

Thermodynamic Database Update to Model Synthetic Chelating Agents in Soil Systems

Poliaminocarboxylate and polyaminophenolcarboxylate chelating agents, being the most representatives EDTA and o,o-EDDHA, have been profusely studied by our research team during the last 25 years because they are synthetized to be mainly used as micronutrient fertilizers to correct nutritional disorders affecting largely on crop yields placed under Mediterranean conditions. In the last years new chelating agents were designed and synthesized and the most of them were proposed to be included in the current European Directive on Fertilizers. Overall chelating agent properties, including equilibrium in soil by modeling, should be taken in account in order to check the iron chlorosis correction ability. Chemical speciation programs such as MINTEQA2, and most recently VMinteq, are being successfully used as tools to predict the behavior of each novel chelating agent in soil-plant system. Nowadays just one polyaminophenolcarboxylate chelating agent (o,o-EDDHA) is available into a VMinteq-compatible database (Lindsay's database) whereas more than seven of these type of products are authorized by European fertilizers normative to be used as micronutrient fertilizers. Therefore the aim of this work was the database updating to include all chelating agents related to o,o-EDDHA and EDTA whose complete characterization is performed and published elsewhere. Once database is updated, further modelization studies such as equilibrium reactions and adsorption isotherms with solid phase may be readily performed to get fundamental information and understand the reactivity of these recalcitrant polyaminophenolcarboxylates in soils

Iron Chelates Supplied Foliarly Improve the Iron Translocation Rate in Tempranillo Grapevine

Iron (Fe) chlorosis is a widespread nutritional disorder in grapevine, particularly in vineyards developed on calcareous soils. Despite the effective application of highly efficient Fe chelates such as Fe¿ethylenediamine di-o-hydroxyphenylacetic acid (EDDHA) to the soil to solve the problem, the cost of the treatments and the loss of effectiveness of the chelate in the soil in rainfed crops limit their use. An alternative could be the utilization of Fe fertilizers directly supplied through foliar spray. Two Fe chelates [Fe¿ethylenediaminetetraacetate (EDTA) and Fe¿ethylenediamine disuccinic acid (EDDS)], an Fe complex (Fe-lignosulfonate), and an Fe salt (Fe-sulfate) were foliarly applied to mature Tempranillo tinto (Vitis vinifera L.), grown on a soil with a high active lime (most reactive calcium carbonate phase in soils) content (92.5 g kg¿1 at 30¿60 cm deep), and compared to an untreated control. Three shoots per vine and five vines per treatment were selected. One hundred mL of each Fe treatment (5 mM) were sprayed on mature leaves (treated), and young leaves (covered) were covered so Fe translocation could be studied. Treatments were repeated once after 2 weeks. Leaf blades were sampled before the first spray application and at the end of the assay, 4 weeks later, and 2 weeks after the second spray application. Micronutrient content [(Fe, manganese (Mn), copper (Cu), and zinc (Zn)] in leaf blades was determined and Fe/Mn ratio was calculated as a Fe nutrition index. Leaf chlorophyll content was measured weekly using a noninvasive Minolta SPAD chlorophyll meter. As expected, all Fe treatments resulted in greater leaf Fe concentration than in the untreated control; however, leaves sprayed with Fe-EDTA and Fe-sulfate showed the greatest Fe concentration. As consequence, the largest Fe/Mn ratio was found for Fe-EDTA and Fe-sulfate treatments, although no differences with Fe-EDDS treatment were found. Leaves sprayed with Fe-EDTA chelate showed not only the greatest SPAD readings at the end of the field experiment but also the greatest SPAD readings when measured on covered leaves from the 15th day after treatment application when compared to untreated control. Covered leaves from all vines sprayed with Fe treatments showed greater Fe concentrations than untreated control but only the Fe/Mn ratio for Fe-EDTA was significantly greater than that of untreated control. The inconsistency between total Fe concentration from the sprayed leaves and SPAD readings in both sprayed and covered leaves suggests that the proposed methodology is valid for assessing the Fe translocation rate from mature to young leaves when foliar fertilization was appliedFinancial support was provided by the AGL2010-18048 Project, funded by the Ministerio de Ciencia e Innovación (Spain).Peer Reviewe