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Las Palmas de Gran Canaria, Spain

Loague K.,Stanford University | Blanke J.S.,RMC Water and Environment | Mills M.B.,Stanford University | Diaz-Diaz R.,Instituto Tecnologico Of Canarias | Corwin D.L.,U.S. Department of Agriculture
Journal of Environmental Quality | Year: 2012

Precious groundwater resources across the United States have been contaminated due to decades-long nonpoint-source applications of agricultural chemicals. Assessing the impact of past, ongoing, and future chemical applications for large-scale agriculture operations is timely for designing best-management practices to prevent subsurface pollution. Presented here are the results from a series of regional-scale vulnerability assessments for the San Joaquin Valley (SJV). Two relatively simple indices, the retardation and attenuation factors, are used to estimate near-surface vulnerabilities based on the chemical properties of 32 pesticides and the variability of both soil characteristics and recharge rates across the SJV. Th e uncertainties inherit to these assessments, derived from the uncertainties within the chemical and soil data bases, are estimated using fi rst-order analyses. Th e results are used to screen and rank the chemicals based on mobility and leaching potential, without and with consideration of data-related uncertainties. Chemicals of historic high visibility in the SJV (e.g., atrazine, DBCP [dibromochloropropane], ethylene dibromide, and simazine) are ranked in the top half of those considered. Vulnerability maps generated for atrazine and DBCP, featured for their legacy status inthe study area, clearly illustrate variations within and across the assessments. For example, the leaching potential is greater for DBCP than for atrazine, the leaching potential for DBCP is greater for the spatially variable recharge values than for the average recharge rate, and the leaching potentials for both DBCP and atrazine are greater for the annual recharge estimates than for the monthly recharge estimates. Th e data-related uncertainties identifi ed in this study can be signifi cant, targeting opportunities for improving future vulnerability assessments. © 2012 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. Source


Ould Mohamedou E.,University of Nouakchott | Ould Mohamedou E.,University of Nantes | Penate Suarez D.B.,Instituto Tecnologico Of Canarias | Vince F.,Ecole Polytechnique Federale de Lausanne | And 2 more authors.
Desalination | Year: 2010

The overall objective of the present work was to estimate by membrane autopsy the level of performances degradation of old reverse osmosis (RO) membranes/modules in order to envisage their reuse. A mechanistic approach using the Spiegler-Kedem-Katchalsky model helps us to observe that the old RO membrane acquired a convective mass transfer. We defined a novel Peclet number (denoted Pe′) usable to distinguish between diffusional and convective mass transfer. We observed that for the old membrane Pe′ numbers are always higher than 1. Furthermore, SEM/AFM and EDX experiments show crystals and bacteria particles as fouling agents, roughness increase for the old membrane (from 73 to 220 nm) due to foulants deposition. EDX experiments demonstrated that FexOy crystals are dominant. SP measurements help us to observe a displacement of the isoelectric point (IEP) for the virgin membrane from 2.7 ± 0.3 to 4.6 ± 0.3 in comparison to the old one showing chemical modifications of the inner active layer suspected due to biofouling residuals. In the last part and for the first time, module materials reuse occurred in the place of their incineration as geotextile in proper home garden. Crown Copyright © 2009. Source


De Los Reyes C.,University of Cadiz | Avila-Roman J.,University of Seville | Ortega M.J.,University of Cadiz | De La Jara A.,Instituto Tecnologico Of Canarias | And 3 more authors.
Phytochemistry | Year: 2014

The chemical study of the microalgae Chlamydomonas debaryana and Nannochloropsis gaditana has led to the isolation of oxylipins. The samples of C. debaryana have yielded the compounds (4Z,7Z,9E,11S,13Z)-11-hydroxyhexadeca-4, 7,9,13-tetraenoic acid (1), (4Z,7E,9E,13Z)-11-hydroxyhexadeca-4,7,9,13- tetraenoic acid (2), (4Z,6E,10Z,13Z)-8-hydroxyhexadeca-4,6,10,13-tetraenoic acid (3), (4Z,8E,10Z,13Z)-7-hydroxyhexadeca-4,8,10,13-tetraenoic acid (4), and (5E,7Z,10Z,13Z)-4-hydroxyhexadeca-5,7,10,13-tetraenoic acid (5), which are derived from the fatty acid 16:4Δ4,7,10,13 together with the compound (5Z,9Z,11E,15Z)-13-hydroxyoctadeca-5,9,11,15-tetraenoic acid (7) derived from coniferonic acid (18:4Δ5,9,12,15). In addition, the known polyunsaturated hydroxy acids 11-HHT (6), (5Z,9Z,11E)-13- hydroxyoctadeca-5,9,11-trienoic acid (8), (13S)-HOTE (9), (9E,11E,15Z)-13- hydroxyoctadeca-9,11,15-trienoic acid (10), 9-HOTE (11), 12-HOTE (12), 16-HOTE (13) and (13S)-HODE (14) have also been obtained. The chemical study of N. gaditana has led to the isolation of the hydroxy acid (15S)-HEPE (15) derived from EPA (20:5Δ5,8,11,14,17). The structures of the isolated compounds were established by spectroscopic means. The optical activity displayed by oxylipins 1, 2, 6, 7, 9, 10, 14, and 15 suggests the occurrence of LOX-mediated pathways in C. debaryana and N. gaditana. In anti-inflammatory assays, all the tested compounds inhibited the TNF-α production in LPS-stimulated THP-1 macrophages. The most active oxylipin was the C-16 hydroxy acid 1, which at 25 μM caused a 60% decrease of the TNF-α level. © 2014 Elsevier Ltd. All rights reserved. Source


Mendoza H.,Instituto Tecnologico Of Canarias | Carmona L.,Instituto Tecnologico Of Canarias | Assuncao P.,Instituto Tecnologico Of Canarias | Freijanes K.,Instituto Tecnologico Of Canarias | And 3 more authors.
Bioresource Technology | Year: 2015

The lipid extractability of 14 microalgae species and strains was assessed using organic solvents (methanol and chloroform). The high variability detected indicated the potential for applying this parameter as an additional criterion for microalgae screening in industrial processes such as biofuel production from microalgae. Species without cell walls presented higher extractability than species with cell walls. Analysis of cell integrity by flow cytometry and staining with propidium iodide showed a significant correlation between higher resistance to the physical treatments of cell rupture by sonication and the lipid extractability of the microalgae. The results highlight the cell wall as a determining factor in the inter- and intraspecific variability in lipid extraction treatments. © 2015. Source


Betancort Rodriguez J.R.,Instituto Tecnologico Of Canarias | Millan Gabet V.,Instituto Tecnologico Of Canarias | Melian Monroy G.,Instituto Tecnologico Of Canarias | Bello Puerta A.,Canaragua | Fonseca Barrio I.,Sociedad General de Aguas de Barcelona SGAB
Desalination and Water Treatment | Year: 2013

Scarcity of water for human consumption in many places such as arid and semi-arid regions is well known. This situation has become even more complicated in those areas where there are virtually no energy sources or the electrical grid is too weak or has not been provided. In these cases, the solar membrane distillation (MD) technology is an emerging and promising solution to small distributed desalination systems. Regardless of the technology used for desalination, the water produced the desalination plant has to fulfil the local requirements on water quality for human consumption. In this work, the main physico-chemical and microbiological characteristics of water produced by two types of solar MD technologies are presented. The necessity to fulfil the European requirements on disinfection and remineralization post-treatment is also considered. © 2013 Desalination Publications. Source

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