Evolution and assessment of a nitrate vulnerable zone over 20 years: Gallocanta groundwater body (Spain)

Nitrate pollution from agricultural sources is one of the biggest issues facing groundwater management in the European Union (EU). During the last three decades, tens of nitrate vulnerable zones (NVZ) have been designated across the EU, aiming to make the problem more manageable. The Gallocanta Groundwater Body in NE Spain was declared as an NVZ in 1997, and after more than 20 years, significant improvements in water quality were expected to be observed. In the present study, the spatiotemporal trend of nitrate concentration within the Gallocanta NVZ in the last 38 years was assessed, and the effectiveness of the NVZ implementation was tested. Data from the official Ebro Basin Confederation monitoring network from 1980 to 2018 were used, and the results showed an increasing but fluctuating trend in nitrate concentration since 1980. Although a slight improvement was detected after the NVZ designation in 1997, the low rate of improvement would take decades to reach desirable levels in most of the area. The lack of update and control of action programmes, the inappropriate NVZ delimitation, and the influence of natural factors seem to be the reasons for the failure of the nitrate reduction measures. Currently, nitrate pollution and groundwater management are a matter of concern for the EU, so given the recurring problems in water supply in the area and the nonfulfillment of the goal of good quality status, more demanding measures are needed to be implemented in the short term

Evaluation of alternatives for flood irrigation and water usage in Spain under Mediterranean climate

Evaluation of water management has been progressively more necessary to determine the availability of water resources, especially in the Mediterranean environment where competition for these resources is maximum. This work evaluates the irrigation management and evolution of hydric needs for the main crops implemented in the Ebro basin (Spain), through the monitoring of a pilot experimental basin between 1998 and 2012. This 15-year period comprehends changes in irrigation implemented by the Irrigation District as well as climate and agronomic variabilities of the region. Changes in water management (implementation of an on-demand irrigation system with annual water allowances and payment per surface and consumption, in opposition to an irrigation system in shifts) and crops contributed to reduce irrigation by 40% and drainage by 72%. This occurred due to better adjustments between the water volumes applied and the hydric needs of the crops, achieving flood irrigation efficiencies of 80%. However, small negative trends were detected in the water deficit evolution of corn and sunflower, which should be addressed and improved. Improvements in water management by farmers have enabled the increase of irrigation efficiency up to values found in pressurized irrigation systems, especially in initial stages of the irrigation campaigns. However, specific water deficit episodes were detected that should be remediated

Salinity contamination response to changes in irrigation management. Application of geochemical codes

Salinity contamination caused by irrigation has been widely studied but the analysis of geochemical processes regarding agronomic variables has not adequately been considered yet. The research presented here analyzes the influence of changes in irrigation management on salinity contamination, through the use of geochemical modeling techniques, in an agricultural basin during the hydrological year of 2001 and within the period 2005-2008. The results indicate that the changes implemented in irrigation management reduced the masses of salts exported in 72%, although water salinity increased by 25% (this salinity level does not restrict its use for irrigation). The different ionic ratios in drainage water, the results of the salinity balances, and the results of geochemical calculations (mass balances and speciation-solubility) indicate, mainly, precipitation of calcite, dissolution of gypsum and halite and cation exchange. The salt contamination index decreased from approximately 70% to levels close to those presented in modern irrigation areas, indicating that the changes in irrigation management were effective. Petrocalcic genesis and punctual sodification of soils can constitute an agroenvironmental problem that requires adequate management of irrigation and drainage considering future modernization of irrigation areas

Influence of hail suppression systems over silver content in the environment in Aragón (Spain). II: Water, sediments and biota

The silver content in soils in the area in the surroundings of the Gallocanta Lake (Aragón, NE Spain) is lower than expected considering the estimated silver emission during the last 50 years by hail suppression systems. To understand the silver accumulation processes, selected water (4 surface, 3 groundwater), biota and sediment (6 surface sediments and 3 cores from Gallocanta and Campillo de Dueñas Lakes and Used Reservoir) samples have been analysed. An essay comparing the growth of wheat in pots with different silver iodide concentrations has been carried out. Finally, silver content in 7 tissues from two sheep that graze in areas both with and without hail suppression systems during 6–8 years were analysed. Our results show that after 50 years of silver iodide emissions to the atmosphere, silver accumulation in the waters and sediments of the lowlands, including some wetlands of high ecological value, has not been significant. Sediment cores did not show any peaks associated to silver emission. We propose that constant absorption of silver by plants could explain the low concentration in water and sediments. Crops and grass could accumulate the excess silver, as both wheat and sheep are able to absorb significant amounts of silver. These bio - accumulation processes could have helped to avoid a progressive environmental deterioration of the surroundings of the Gallocanta Lake. However, this hypothesis should be corroborated and quantified by further research on the analysis of natural and agricultural areas under the influence of hail suppression systems

Feasibility of using rural waste products to increase the denitrification efficiency in a surface flow constructed wetland

A surface flow constructed wetland (CW) was set in the Lerma gully to decrease nitrate (NO3 -) pollution from agricultural runoff water. The water flow rate and NO3 - concentration were monitored at the inlet and the outlet, and sampling campaigns were performed which consisted of collecting six water samples along the CW flow line. After two years of operation, the NO3 - attenuation was limited at a flow rate of ~2.5 L/s and became negligible at ~5.5 L/s. The present work aimed to assess the feasibility of using rural waste products (wheat hay, corn stubble, and animal compost) to induce denitrification in the CW, to assess the effect of temperature on this process, and to trace the efficiency of the treatment by using isotopic tools. In the first stage, microcosm experiments were performed. Afterwards, the selected waste material was applied in the CW, and the treatment efficiency was evaluated by means of a chemical and isotopic characterization and using the isotopic fractionation (e) values calculated from laboratory experiments to avoid field-scale interference. The microcosms results showed that the stubble was the most appropriate material for application in the CW, but the denitrification rate was found to decrease with temperature. In the CW, biostimulation in autumn-winter promoted NO3 - attenuation between two weeks and one month (a reduction in NO3 - between 1.2 and 1.5 mM was achieved). After the biostimulation in spring-summer, the attenuation was maintained for approximately three months (NO3 - reduction between 0.1 and 1.5 mM). The e15NNO3/N2 and e18ONO3/N2 values obtained from the laboratory experiments allowed to estimate the induced denitrification percentage. At an approximate average flow rate of 16 L/s, at least 60% of NO3 - attenuation was achieved in the CW. The field samples exhibited a slope of 1.0 for d18O-NO3 - versus d15N-NO3 -, similar to those of the laboratory experiments (0.9–1.2). Plant uptake seemed to play a minor role in NO3 - attenuation in the CW. Hence, the application of stubble in the CW allowed the removal of large amounts of NO3 - from the Lerma gully, especially when applied during the warm months, but its efficacy was limited to a short time period (up to three months). © 2019 Elsevier B.V

EVALUACIÓN DE UN NUEVO REGADÍO A LO LARGO DE 10 AÑOS: BALANCES HÍDRICOS, CALIDAD DEL RIEGO Y CONTAMINACIÓN POR SALES Y NITRATOS

[ES] La transformación al regadío es frecuente en zonas semiáridas a lo largo del mundo por sus numerosas ventajas, pero el regadío también es considerado como el principal consumidor de recursos hídricos y la principal fuente de contaminación difusa. En este trabajo se presenta una evaluación de la calidad del riego y del lixiviado de sales y nitratos en una cuenca hidrológica (7,38 km2 ) representativa de los regadíos presurizados de la cuenca del Ebro. El estudio abarca 10 años hidrológicos: antes (2004-2005), durante (2006- 2008) y después (2009-2013) de la transformación de secano a regadío. Para este periodo, se realizaron balances hídricos y se obtuvieron indicadores de la calidad del riego a partir de éstos. Con la medida de la concentración de sales y nitratos en los diferentes componentes, se estimó la masa de estos contaminantes procedentes de la zona regable (352 ha), y se obtuvieron índices de contaminación. La eficiencia de riego alcanzó un 76,1%, mientras que las pérdidas de eficiencia se debieron a la evaporación y arrastre del riego por aspersión (13,5%) y al drenaje del riego (10,4%). La eficiencia de riego aumentó (1,05% año-1 ) y la fracción de drenaje disminuyó (0,95% año-1 ). Sin embargo, no se garantizó un incremento en la calidad del riego ya que el déficit hídrico también se incrementó (0,95% año-1 ) situándose en 17,8% al final del periodo de estudio. Tanto las masas exportadas como los índices de contaminación se incrementaron significativamente con la transformación al riego. Sin embargo, los valores obtenidos se encuentran por debajo del umbral de los regadíos considerados como más sostenibles. Mejoras en el manejo del riego, que tengan en cuenta la humedad del suelo y la velocidad del viento podrían incrementar de forma considerable la calidad del riego y disminuir el lixiviado y los índices de contaminación.Merchán, D.; Causapé, J.; Abrahao, R.; García-Garizabal, I. (2015). EVALUACIÓN DE UN NUEVO REGADÍO A LO LARGO DE 10 AÑOS: BALANCES HÍDRICOS, CALIDAD DEL RIEGO Y CONTAMINACIÓN POR SALES Y NITRATOS. En XXXIII CONGRESO NACIONAL DE RIEGOS. Valencia 16-18 junio de 2015. Editorial Universitat Politècnica de València. https://doi.org/10.4995/CNRiegos.2015.1440OC

Feasibility of using rural waste products to increase the denitrification efficiency in a surface flow constructed wetland

A surface flow constructed wetland (CW) was set in the Lerma gully to decrease nitrate (NO3−) pollution from agricultural runoff water. The water flow rate and NO3− concentration were monitored at the inlet and the outlet, and sampling campaigns were performed which consisted of collecting six water samples along the CW flow line. After two years of operation, the NO3− attenuation was limited at a flow rate of ~2.5 L/s and became negligible at ~5.5 L/s. The present work aimed to assess the feasibility of using rural waste products (wheat hay, corn stubble, and animal compost) to induce denitrification in the CW, to assess the effect of temperature on this process, and to trace the efficiency of the treatment by using isotopic tools. In the first stage, microcosm experiments were performed. Afterwards, the selected waste material was applied in the CW, and the treatment efficiency was evaluated by means of a chemical and isotopic characterization and using the isotopic fractionation (ε) values calculated from laboratory experiments to avoid field-scale interference. The microcosms results showed that the stubble was the most appropriate material for application in the CW, but the denitrification rate was found to decrease with temperature. In the CW, biostimulation in autumn-winter promoted NO3− attenuation between two weeks and one month (a reduction in NO3− between 1.2 and 1.5 mM was achieved). After the biostimulation in spring-summer, the attenuation was maintained for approximately three months (NO3− reduction between 0.1 and 1.5 mM). The ε15NNO3/N2 and ε18ONO3/N2 values obtained from the laboratory experiments allowed to estimate the induced denitrification percentage. At an approximate average flow rate of 16 L/s, at least 60% of NO3− attenuation was achieved in the CW. The field samples exhibited a slope of 1.0 for δ18O-NO3− versus δ15N-NO3−, similar to those of the laboratory experiments (0.9-1.2). Plant uptake seemed to play a minor role in NO3− attenuation in the CW. Hence, the application of stubble in the CW allowed the removal of large amounts of NO3− from the Lerma gully, especially when applied during the warm months, but its efficacy was limited to a short time period (up to three months)

Evaluación de los riegos de la Comunidad de Regantes V del Canal de las Bardenas

14 Pag., 2 Tabl., 1 Fig.[ES] En este artículo se presentan los resultados de las evaluaciones de riego que se han llevado a cabo dentro de la segunda fase del trabajo denominado “Mejora de la Gestión Integral del Agua de Riego en la Comunidad de Regantes V del Canal de Bardenas”. El 80 % de la superficie de esta comunidad está ocupado por suelos de plataformas residuales, mientras que el resto son suelos de aluvial. Para caracterizar la capacidad de retención de agua de los suelos (CRA) se realizó un muestro en el que se describieron 50 perfiles. Para determinar la infiltración de los suelos y los índices de calidad del riego por superficie se realizaron 50 evaluaciones de riego. Un adecuado manejo del agua a nivel de parcela y unas texturas francas-franco arenosas permiten alcanzar niveles de eficiencia medios en las parcelas de las plataformas (53 % de media), cuyos suelos se caracterizan por una baja CRA (60 mm de media). En aluviales la eficiencia llega hasta un 80 % de media, gracias a las elevadas capacidades de retención de agua de estos suelos (182 mm de media). Actualmente se está realizado un reaprovechamiento de las aguas de desagüe que posiblemente provoque que la eficiencia a nivel de comunidad sea mayor que la obtenida a nivel de parcela. Estos resultados permiten pensar que la modernización de los regadíos, mediante el cambio a un sistema de riego presurizado, tendría un fuerte impacto sobre la eficiencia en parcela, aunque el impacto sobre la eficiencia en la comunidad sería menor. La modernización tendría resultados muy beneficiosos social y económicamente para los agricultores, además de mejorar la calidad de las aguas de los ríos que atraviesan la comunidad.[EN] Results of the irrigation evaluations performed in the second phase of the project “Improvement of the Water Irrigation Integral Management in the Comunidad de Regantes V del Canal de Bardenas” are presented in this paper. An 80 % of the area of the Irrigation District is occupied by soils of residual platforms, and the rest of the soils are alluvial. A soil survey was performed for characterising the water holding capacity (WHC) of the soils, using 50 soil profiles. A total of 50 irrigation evaluations was performed for determining soil infiltration and the performance indexes of surface irrigation in the study area. An adequate water management in border irrigation and loam-sandy loam textures permit to attain 53 % application efficiency in platforms, whose soils are characterized by a low WHC (with an average of 60 mm). In alluvial soils the application efficiency is higher, with an average of 80 %, due to the high water holding capacity of these soils (an average of 182 mm). Currently, The district is enforcing a program for irrigation return flows reuse. This program surely results in an irrigation district efficiency substantially higher that the average application efficiency. With these results is possible to think that an irrigation modernization, through a change to a pressurized irrigation system will severely improve the application efficiency, but the effect on the irrigation district efficiency will only be moderate. However, this modernisation would have great social and economical benefits for farmers, and also, the water quality of rivers crossing the irrigation district will be improved.Este proyecto de investigación ha sido cofinanciado por la CICYT, por Fondos FEDER, por el CONSI+D y por la Comunidad de Regantes V de Bardenas.Peer reviewe

Mutation Analysis in Regulator DNA-Binding Regions for Antimicrobial Efflux Pumps in 17,000 Pseudomonas aeruginosa Genomes

Mutations leading to upregulation of efflux pumps can produce multiple drug resistance in the pathogen Pseudomonas aeruginosa. Changes in their DNA binding regions, i.e., palindromic operators, can compromise pump depression and subsequently enhance resistance against several antibacterials and biocides. Here, we have identified (pseudo)palindromic repeats close to promoters of genes encoding 13 core drug-efflux pumps of P. aeruginosa. This framework was applied to detect mutations in these repeats in 17,292 genomes. Eighty-nine percent of isolates carried at least one mutation. Eight binary genetic properties potentially related to expression were calculated for mutations. These included palindromicity reduction, mutation type, positioning within the repeat and DNA-bending shift. High-risk ST298, ST308 and ST357 clones commonly carried four conserved mutations while ST175 and the cystic fibrosis-linked ST649 clones showed none. Remarkably, a T-to-C transition in the fourth position of the upstream repeat for mexEF-oprN was nearly exclusive of the high-risk ST111 clone. Other mutations were associated with high-risk sublineages using sample geotemporal metadata. Moreover, 1.5% of isolates carried five or more mutations suggesting they undergo an alternative program for regulation of their effluxome. Overall, P. aeruginosa shows a wide range of operator mutations with a potential effect on efflux pump expression and antibiotic resistance.This research was funded by Acción Estratégica en Salud from the ISCIII, grant MPY 509/19. This research was also supported by Personalized and Precision Medicine grant from the Instituto de Salud Carlos III (MePRAM Project, PMP22/00092), Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación and Unión Europea-NextGenerationEU.S