Accelerated soil diuron mineralisation by microbial consortia inoculation and enhancing bioavailability with cyclodextrin.

The deleterious effects of pollution on human health, the functioning of biogeochemical cycles, erosion of biodiversity and more broadly on the entire biosphere, have become a major concern for modern societies. Diuron is considered a “Priority Hazardous Substance”.In the case of diuron, biodegradation appears to be the major cause of diuron dissipation, although due to its high persistence, and hence, the likely formation of aged residues, these can be found in many environment such as soil, sediments and water. Especially in the case of diuron, where its principal metabolite, 3,4 dichloroaniline (3,4-DCA) is considered as highly toxic to different organisms.Agricultural soils possess large and often highly diverse microbial communities that potentially can exhibit many degradative properties, and when these capacities are expressed fully and rapidly, organic chemicals are readily destroyed.To date, all the efforts invested in research on soil bioremediation have been applied to optimizing microbial activity by adding nutrients (bioestimulation), or adding microbial consortia (bioaugmentation). This techniques belong to the green technologies that are used to remove organic contaminants from environments. Another technique used to increase solubility was to add cyclodextrins which increase bioavailability of pollutant.Different results were found for each of the consortium employed in this study, which were previously isolated using an enrichment technique from five agricultural soils that had been managed with pesticides for more than 10 years (C1,C2,C3,C4,C5). In solution medium, C2 consortium was able to mineralize a 88.6% of the diuron initially added to solution (10 ppm + 450 Bq). In the soil used in slurries conditions, time in days needed to reach a 50% of diuron mineralisation was drastically reduced,except when was inoculated C4. Afterwards, in a more realistic scenario under static conditions was observed 23.2% of global herbicide mineralisation with C1. By last, under static condition when cyclodextrin (CD) was used in combination with bioaugmentation (C1) a 42.2% of the extent of mineralisation was rised.In conclusion, the combination of bioaugmentation and bioestimulation resulted in a successful strategy to speed up soil diuron biorremediation. CD, provoked a substantial improvement in diuron mineralisation due to the formation of an inclusion complex with diuron,which increased its solubility and hence bioavailability and mineralisatio

Assisted attenuation of a soil contaminated by diuron using hydroxypropyl-β-cyclodextrin and organic amendments

7 páginas.-- 1 Grafico.-- 3 figuras.-- 2 tablas.-- 59 referenciasDiuron desorption and mineralisation were studied on an amended and artificially contaminated soil. The amendments used comprised two different composted organic residues i.e., sewage sludge (SS) mixed with pruning wastes, and urban solid residues (USR), and two different solutions (with inorganic salts as the micronutrients and hydroxypropyl-β-cyclodextrin (HPBCD)). After applying micronutrients to activate the soil flora, 15.5% mineralisation could be reached after 150 days, indicating that the soil has a potential capacity to mineralise the herbicide through biostimulation-assisted attenuation. Diuron mineralisation was also improved when HPBCD solutions were applied. Indeed, the extent of herbicide mineralisation reached 29.7% with this application. Moreover, both the lag phase and the half-life time (DT50) were reduced to 33 and 1778 days, respectively, relative to the application of just micronutrients (i.e., 39 and 6297 days, respectively). Organic amendments were also applied (i.e., USR and SS) on the contaminated soil: it was found that the diuron mineralisation rate was improved as the amendment concentration increased. The joint application of all treatments investigated at the best conditions tested was conducted to obtain the best diuron mineralisation results. The micronutrient amendment plus 4% USR or SS amendment plus HPBCD solution (10-fold diuron initially spiked) caused an extent of diuron mineralisation 33.2 or 46.5%, respectively.This work was supported by the Spanish Ministry of Science and Innovation (co-funded by the Fondo Europeo de Desarrollo Regional, FEDER) under the research project CTM2009-07335 and Junta de Andalucía (RNM 894).Peer reviewe

Studying the behavior of diuron in soil-water system. Use of cyclodextrins for soil remediation

Con el objetivo de estudiar el comportamiento del herbicida Diurón en el sistema suelo-agua, se realizaron ensayos de adsorción- desorción y de lixiviación en columnas de suelos. Para la adsorción del herbicida diurón en los suelos con propiedades físico-químicas diferentes, las variables significativas fueron la materia orgánica (MO), óxidos amorfos totales y la fracción arcilla. La desorción de los suelos presentó histéresis en todos los casos, aunque una histéresis positiva cuando se extrajo con Ca (NO3)2 y una histéresis negativa cuando se utilizó ciclodextrina (HPBCD). El porcentaje de diurón eluido en las columnas de suelos seleccionados alcanzó casi el 83,1% en un suelo arenoso con contenido en MO <1%, por el contrario, en el suelo con mayor contenido en MO, la cantidad eluida del herbicida fue sólo del 6,65%.In order to study the behavior of the herbicide Diuron in the soil-water system, adsorption- desorption tests and leaching in soil columns were performed. For the adsorption of diuron in soils with different physicochemical properties, significant variables were the organic matter (OM), total amorphous oxides and clay fraction. Soil desorption hysteresis was observed in all cases a positive hysteresis when extracted with Ca(NO3)2 and a negative hysteresis when cyclodextrin (HPBCD) was used. The percentage of diuron eluted from sore columns reached almost 83.1% in a sandy soil with OM <1%; on the contrary, in a soil with higher OM content, the amount of the herbicide eluted was 6.65%

ESTUDIOS DE BIODEGRADACIÓN Y MINERALIZACIÓN A ELEVADAS CONCENTRACIONES DEL HERBICIDA DIURON, EMPLEANDO CEPAS BACTERIANAS DEGRADADORAS ESPECÍFICAS EN CONDICIONES DE ESTRÉS

El uso extendido en todo el mundo de herbicidas de origen químico, ha favorecido la difusión de estos a suelos y aguas, tanto superficiales como subterráneas, convirtiendo a estos compuestos tóxicos en potencialmente peligrosos para el medio ambiente y la salud de las personas. El herbicida diurón está considerado como sustancia peligrosa prioritaria para la Directiva Marco del Agua de la Comisión Europea. Igualmente está incluido en una lista de sustancias prioritarias para el establecimiento de políticas para el agua, y está incluido en la lista 3 de contaminantes candidatos de los Estados Unidos. España y Bélgica son los únicos países de la Unión Europea donde se hace uso de este herbicida. Por ello se han realizado estudios con el objetivo de degradarlo por completo y/o hacerlo no biodisponible para seres humanos y otros organismos vivos. Estos estudios sitúan a la biodegradación como la opción más eficiente y fiable para llevar a cabo este cometido.En el presente estudio, se lleva a cabo el analisis de los resultados obtenidos en los ensayos de biodegradación y mineralización del herbicida diuróna diferentes concentraciones y de su principal metabolito, la 3,4-dicloroanilina (3,4-DCA), cuya toxicidad hace que el diurón sea tan peligroso para la salud y el medio ambiente, utilizando cepas bacterianas degradadoras específicas, las cuales han sido sometidas a elevadas concentraciones de Diurón. Por último, se sealizaron experimentos de biodisponibilidad del herbicida, a elevadas concentraciones, haciendo uso de ciclodextrinas. Estos agentes químicos biodegradables pueden optimizar la capacidad biodegradadora de los microorganismos hacia el contaminante, y se presentan como una alternativa más amigable con el medio ambiente, ya que debido a la naturaleza de disolventes y otros agentes químicos no biodegradables, estos pueden acabar suponiendo otro problema ambiental o de salud, que se añadiría al existente causado por el contaminante que se pretendía eliminar en primera instancia

Cambios biométricos y refractivos asociados a las iridotomías con láser Nd-YAG.

El glaucoma se define como una neuropatía óptica progresiva cuya característica principal consiste en la degeneración de las células ganglionares de la retina, produciendo daños a nivel del nervio óptico y campo visual. Hoy en día, la iridotomía láser periférica (LPI) con láser Nd-YAG es uno de los tratamientos de elección ante una crisis aguda del glaucoma de ángulo cerrado (GPAC) necesario para revertir el cuadro, así como técnica de prevención en pacientes con sospecha de cierre angular (PACS).En esta revisión bibliográfica de la técnica, se pretende analizar los cambios en la biometría ocular (amplitud de la cámara anterior y otros parámetros) así como en la refracción de los pacientes tras la realización de LPI con láser Nd-YAG.<br /

Demographic, clinical and antibody characteristics of patients with digital ulcers in systemic sclerosis: data from the DUO Registry

OBJECTIVES: The Digital Ulcers Outcome (DUO) Registry was designed to describe the clinical and antibody characteristics, disease course and outcomes of patients with digital ulcers associated with systemic sclerosis (SSc). METHODS: The DUO Registry is a European, prospective, multicentre, observational, registry of SSc patients with ongoing digital ulcer disease, irrespective of treatment regimen. Data collected included demographics, SSc duration, SSc subset, internal organ manifestations, autoantibodies, previous and ongoing interventions and complications related to digital ulcers. RESULTS: Up to 19 November 2010 a total of 2439 patients had enrolled into the registry. Most were classified as either limited cutaneous SSc (lcSSc; 52.2%) or diffuse cutaneous SSc (dcSSc; 36.9%). Digital ulcers developed earlier in patients with dcSSc compared with lcSSc. Almost all patients (95.7%) tested positive for antinuclear antibodies, 45.2% for anti-scleroderma-70 and 43.6% for anticentromere antibodies (ACA). The first digital ulcer in the anti-scleroderma-70-positive patient cohort occurred approximately 5 years earlier than the ACA-positive patient group. CONCLUSIONS: This study provides data from a large cohort of SSc patients with a history of digital ulcers. The early occurrence and high frequency of digital ulcer complications are especially seen in patients with dcSSc and/or anti-scleroderma-70 antibodies

Effect of addition of HPBCD on diuron adsorption-desorption, transport and mineralization in soils with different properties

8 páginas.-- 2 figuras.-- 6 tablas.-- 52 referencias.-- Supplementary data associated with this article can be found in the online version at http://dx.doi.org/10.1016/j.geoderma.2015.11.022. These data include one table with the solution nutrients (SNs). Additionally, two figures have been also included. One of them with diuron adsorption–desorption isotherms on soils, using Ca(NO3)2 or HPBCD as extractant solutions, and the other with diuron breakthrough curves in soils 7 and 1 in the presence or absence of HPBCD.The influence of different soil properties on diuron adsorption and the effect of hydroxypropyl-β-cyclodextrin (HPBCD) on its desorption, leaching, and mineralization have been investigated. The significant variables on adsorption were organic matter (OM) content, aluminum oxides, and clay fraction. Diuron desorption from soils presents negative hysteresis when HPBCD solutions were used as an extractant, in comparison to the positive hysteresis when using Ca(NO3)2 solutions. Therefore, higher amounts of diuron were desorbed by HPBCD due to the formation of an inclusion complex that causes an increase in its solubility. However, the application of HPBCD in columns of selected soils did not cause increased leaching of the herbicide. Finally, the presence of HPBCD shows clearly an increase in the rate of mineralization of diuron in contaminated soils and a drastic reduction of DT50 values due to its increasing bioavailability. HPBCD is proposed as an efficient tool for diuron soil bioremediation.The authors are indebted to Presmar S.L. for providing the technical diuron, This work was supported by the Spanish Ministry of Economiy and Competitiveness (co-funded by the Fondo Europeo de Desarrollo Regional, FEDER), under the research project CTM2013-42599-R and Junta de Andalucía Proyect RNM 894Peer reviewe

Effect of hydroxypropyl-β-cyclodextrin on diuron desorption and mineralisation in soils

2 figures, 4 tables, 52 references.Purpose The herbicide diuron has the unfortunate property of being strongly adsorbed onto soil organic matter particles, and hence, is slowly degraded in the environment because of its reduced bioavailability. The aim of this work was to gain insight into the fate and behaviour of diuron in the soil–water system, and develop and test an environmentally friendly soil decontamination technique that could give rise to an enhancement of diuron mineralisation by sensitive soil endogenous microorganisms, by means of increasing the bioavailability of the pollutant employing cyclodextrin (CD) solutions what would represent an improvement from both economic and environmental standpoints. Materials and methods Selected soil colloidal components: montmorillonite, a synthetic humic acid and a synthetic acicular goethite, and two different soils were employed in this study to perform batch adsorption–desorption experiments. Desorption experiments were performed using a 0.01 M Ca(NO3 ) 2 solution with and without hydroxypropyl-β- cyclodextrin (HPBCD) 50 mM. Assays to study the mineralisation of 14C-labelled diuron were performed in respirometers, into which 10 g of soil and 50 mL of mineral salts medium (MMK) were placed, obtaining a final concentration of 50 mg kg−1 and a radioactivity of approximately 900 Bq per flask. Results and discussion Humic acid could be clearly discerned as the major colloidal component responsible for adsorption. HPBCD was used in diuron desorption experiments from soil, showing a strong extracting power on its removal. The mineralisation of diuron in the presence and absence of HPBCD was tested in a soil managed with diuron for several years, involving therefore the presence of microorganisms that have some specificity for diuron. Natural soil attenuation for diuron was improved when a HPBCD solution was used in the presence of micronutrients as a bioavailability enhancer, obtaining 66 % of mineralisation in comparison to that obtained with only micronutrients addition (44 %). Conclusions The use of HPBCD solution at a very low concentration of only 10 times the diuron equimolar concentration in soil, acts as a bioavailability enhancer, accelerating the passage of the diuron-desorbing fraction from the soil particle surface to the soil solution, and hence, improving the accessibility of the microorganisms to the herbicide. Diuron mineralisation rate and the extent of its mineralisation were improved when the HPBCD solution was employed in the presence of micronutrients.Marina Rubio thanks the Spanish Research Council (CSIC) for her Predoctoral Research grant (JAE-Pre). We are indebted to Presmar S.L. for providing the technical diuron. This work was supported by Spanish Ministry of Science Innovation (co-funded by Fondo Europeo de Desarrollo Regional, FEDER), CTM2006-04626 and CTM2009-07335.Peer reviewe

Accelerated diuron mineralisation in soil using cyclodextrin solutions

Póster 111, en la Sesión: In situ bioremediation of contaminated soil and groundwater.-- Simposio celebrado del 24-28, junio, 2012, en Praga, República Checa.Tbe phenylurea herbicide diuron is widely used in a broad range of berbicide formulations, and it is frequently detected as a major water contaminant in areas where its use is extensive. Diuron has the unfortunate combination of being both, slowly degraded in the environment and mobile, what makes this herbicide potentially leachable to groundwaters.Peer reviewe

Efecto de ciclodextrinas en la biodegradación natural de diurón en un suelo contaminado

4 páginas.-- 3 figuras.-- 1 tabla.-- 4 referencias.-- Comunicación presentada en el VI Simposio nacional de control de la degradación y restauración de suelos, Almería (2013)La estructura química del herbicida diurón le confiere un importante carácter hidrofóbico que está relacionado con su elevada persistencia en el suelo, además de la presencia de cloro que hace de este herbicida un compuesto con propiedades tóxicas y de difícil eliminación en suelos contaminados a través de la flora autóctona del mismo. Además, la biodegradación de diurón da lugar a la formación, principal metabolito, un compuesto altamente tóxico y persistente en el suelo, como es la 3,4-dicloroanilina. Con el fin de encontrar procedimientos que podrían resultar en una mejora de la biodisponibilidad de diurón, se han utilizado moléculas biodegradabales como las ciclodextrinas capaces de formar complejos de inclusión en solución con compuestos hidrofóbicos. En los estudios de solubilidad del plaguicida con las diferentes ciclodextrinas seleccionadas se obtuvieron los mejores parámetros de complejación con hidroxipropil-BCD (HPBCD) con un valor de la constante de complejación de 207.70 M-1. La biodisponibilidad del diurón fue probada en un suelo franco arenoso. Se confirmó mediante el control de la producción de 14 CO2 que la propia flora endógena junto a una solución de micronutrientes (oligoelementos) fue capaz de mineralizar hasta un 44%. Sin embargo, se mejoró cuando se empleó una solución de HPBCD como potenciador de la biodisponibilidad, y los micronutrientes como bioestimulantes, obteniendo un 66% de mineralización.Peer Reviewe