EPrints IMDEA Water Institute
Not a member yet
1133 research outputs found
Sort by
Ecological relationships and stoichiometry within a Maritime Antarctic watershed
No full textDuring summer, ice-free areas are common in Maritime Antarctica, and vegetation and microbial communities frequently occur in the moist parts of catchments. In this paper, we present new data and evaluate the biomass, C, N, and P content of various types of vegetation, and the water catchment of an oligotrophic lake sited at Byers Peninsula, Livingston Island, South Shetland Islands. As the main results show, the total amount of C, N, and P contained in the organisms of the watershed is 144, 0.71 and 0.018 g m(-2), respectively. According to element contents, 98% of the biological C from the watershed is within mosses and microbial mats structures (79.1 and 19.0% respectively). Also, 98.7% of the N is partially distributed between moss carpets, microbial mats and lichens, 55.2, 43.5, and 3.37 x 10(-7)% respectively. On the other hand, 90.2% of P is within moss carpets structures. Nutrient pools in the communities of Limnopolar Lake itself are a minor component of the whole catchment
Automated dynamic headspace followed by a comprehensive two-dimensional gas chromatography full scan time-of-flight mass spectrometry method for screening of volatile organic compounds (VOCs) in water
No full textThis article describes an effective full scan new analytical approach for target and non-target screening of volatile organic compounds (VOCs) in water based on an automatic dynamic headspace (DHS) sampler followed by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOF-MS). The operational parameters of DHS having influence on the extraction efficiency of water samples were optimized. The performance of a developed method by DHS-GCxGC-TOFMS was assessed with special attention to the capability of an enhanced separation and reliable identification at a trace concentration level in water. For this purpose, 31 target compounds including non-halogenated, mono-, di-, tri- and tetra-halogenated VOCs were selected. DHS-GCxGC-TOFMS allowed fast and automated analysis of VOCs at a level of parts per trillion, with no matrix interference in the different types of water analyzed (drinking water-tap, and bottled, river water and sea water) and with a minimum sample preparation. Excellent method detection and quantification limits were achieved, ranging from 0.01 to 10 ng L−1 and from 0.02 to 34 ng L−1, respectively. Good linearity (r2 > 0.99), intra and inter-day repeatability (<30%) were obtained for most of the target analytes denoting the suitability of the method for quantifying VOCs and its potential use in a routine setting. This method was successfully applied to real samples. Full mass range TOFMS acquisition allowed for positive identification of both targets, through mass spectral matching to database standards, and non-targeted compounds (dichloroiodomethane and dichloroacetonitrile). Trihalomethanes, tetrachloroethene, benzene, toluene ethylbenzene and xylenes (BTEXs) were the most frequently detected contaminants in the water samples analyzed. Mean concentrations of VOCs ranged from 65–439 ng L−1 in sea water, 29–1626 ng L−1 in bottled water, 17–16 312 ng L−1 in river water and 51–54 460 ng L−1 in tap water. The feasibility of using effective software data was very useful to rapidly sort information about the presence of VOCs in water and pattern recognition
Toxicity of ibuprofen and perfluorooctanoic acid for risk assessment of mixtures in aquatic and terrestrial environments
No full textThe toxicity of ibuprofen and perfluorooctanoic acid (PFOA) was evaluated individually and in binary combination on two photosynthetic organisms, the green alga Pseudokirchneriella subcapitata, representative of aquatic environments, and the monocotyledonous Sorghum bicolor, for terrestrial ecosystems. Both non-target organisms showed different sensitivities to pollutants. The alga was more affected than the plant to each compound assayed, whether separately or mixed in EC50 proportion, and PFOA was more toxic to both bioindicators. An analysis of toxic chemical interactions covering the whole range of effect levels was conducted using the Combination Index method and indicated that synergism could be expected at low effect levels in higher plants, while for algae this type of interaction predominated at higher effect levels. Ecological risk assessment was performed by calculating the Hazard Quotient as the ratio between the measured environmental concentration and the predicted no-effect concentration, using our EC50 data derived from the mixture of pollutants. Acute hazard was found in the terrestrial compartment (soil or sediments). In the light of the data reported, we conclude that risk evaluation should include toxicological information on compound interactions that exert a toxic effect on non-target organisms
¿Cuánto vale el agua? Modelo Input-Output para el cálculo de la productividad sectorial del agua. El caso de Castilla y León
No full textQuantitative determination of poly(amidoamine) dendrimers in urine by liquid chromatography/electrospray ionization hybrid quadrupole linear ion trap mass spectrometry
No full textRATIONALE: Dendrimer nanocarriers have become of increasing interest in the field of biomedicine for their drug delivery potential. Surface modifications and optimized nanosize control are the strategies being followed to enhance drug delivery efficacy and renal clearance, especially for dendrimers of a lower generation number. The aim of this study was the development and performance evaluation of an analytical method for the quantitative determination of polyamidoamine (PAMAM) dendrimers in urine.
METHODS: PAMAM dendrimers (generations G0 to G3) were analyzed using liquid chromatography/electrospray ionization hybrid quadrupole linear ion trap mass spectrometry (LC/ESI-QqLIT-MS). Quantitative analysis was performed in selected reaction monitoring (SRM) mode. To confer a higher degree of confidence on the identification of PAMAM dendrimers, an SRM scan and collision-induced dissociation (CID), as a dependent scan, were performed in one single run using the information-dependent acquisition (IDA) mode.
RESULTS: The LC/ESI-QqLIT-MS method, in SRM mode, allowed quantitative determination in urine matrix with good repeatability and reproducibility (relative standard deviation (R.S.D.) from 2 to 15%), linearity (R >0.99) over the concentration range (6∙10(-4) to 5∙10(-2) mmol.L(-1) ), and sensitivity within the micromolar range. The detection limit values were above 1∙10(-4) mmol.L(-1) in both solvent and urine, for the generations studied.
CONCLUSIONS: The developed method has demonstrated a capability for the identification and quantification of PAMAM dendrimer nanoparticles in a complex liquid matrix. The use of an LC/ESI-QqLIT-MS system, of modest m/z range and unit resolution, offers an alternative in the analysis of lower generation PAMAM dendrimers between mass analyzers of higher resolution and the conventional LC-UV method that is commonly applied for dendrimer quantification, but which lacks sufficient identification capacity. Copyright © 2013 John Wiley & Sons, Ltd
Short-term effects of reclaimed water irrigation: Jatropha curcas L. cultivation
No full textIn a growing concern of water and energy availability decrease, the sustainable growth of Jatropha curcas L. may be a feasible and complementary alternative within the local non-conventional energies field. This study emphasizes the idea of using reclaimed water agriculture implemented as a complementary local energy option. The main goal of this work focuses on monitoring the environmental affections and feasibility of treated water reuse for J. curcas L. irrigation. Two parcels were irrigated with two different water qualities: well groundwater (WG) and reclaimed water (RW). Differences were found in terms of nitrate, ammonia, sulphate, chloride, dissolved organic carbon (DOC), chemical oxygen demand (COD) and metals concentrations between the two irrigation water qualities. However, after one year of study, no significant differences in the leaves composition were measured with the exception of Fe (WG = 85.17 and RW = 102.63 mg/kg) and Mn (WG = 83.98 and RW = 43.51 mg/kg). The statistical analysis shows no significant differences in height, collar diameter and crown diameter (WG = 142.4, 5.7 and 157.1 cm; RW = 143.5, 5.4 and 154.7 cm, respectively). So far the aquifer water quality was only slightly affected in terms of total nitrogen (NT) after irrigation when rainfall took place. DOC and COD in groundwater were always below 5 and 15 mg/L, respectively. As a conclusion, wastewater reuse for irrigation does not provide a negative effect in J. curcas L. feasibility, becoming an alternative option in the renewable energy field. An environmental monitoring is necessary to guarantee a sustainable management
Water and Development in Latina America: Rights, Markets, Economic Context and Institutional Requirements. Part 3: Reforms to overcome legal and institutional barriers to trading
No full textSalinity Levels of Soil and Water in a Mediterranean Coastal Wetland: the Pego-Oliva Marsh (Spain)
No full textIn the last decades, the increases of the anthropogenic pressure and the related socio-economic development have provoked important changes in Mediterranean coastal wetlands, which lead to the degradation of these high status ecological habitats (destruction of flooding prairies, riparian habitats and breeding areas), with also important impacts on soil and water quality.
This study is focused on the evaluation of soil and water quality parameters related to salinization in the Pego-Oliva marsh, a Natural Park in the Valencia Community (East of Spain), included in the Ramsar Convention. In this area, soil samples from several land uses (rice farming, natural marsh area, citrus crops and shrubland soils), and water samples from different sources (ditches and irrigation channels, lake, rivers, and pumps) were analysed. The main soil and water quality parameters studied were electrical conductivity (EC), sodium and chloride ion concentrations, and sodium from the soil exchangeable complex (ESP).
Main results show that 24% of soil samples have an EC>4 dSm-1, all of them coming from the rice farming and marsh areas. These soils showed mean ESP of 26.5%, with values up to 78%. However, the other land uses did not exceed an ESP of 5%. Regarding water, 82% of the samples presented an EC>2dSm-1, and sodium and chloride concentrations higher than 200 mg L-1 were found in 85% of the samples. Attending their sources, the highest values were obtained from the water samples from lake and ditches. Soil samples with the highest Na+ levels, exceeding significantly the average values, were from marsh soils, located at the southern part of the park. This zone is close to the area where the control points for marine intrusion gives the highest values of EC. These results enhance the necessity to perform a more detailed study in order to follow the sources and trends of salinization in this coastal wetland
