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1.
Environ Sci Technol ; 48(12): 6612-9, 2014 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-24837817

RESUMEN

Understanding the variability of the natural abundance in nitrogen stable isotopes (expressed as δ(15)N) of primary uptake compartments (PUCs; e.g., epilithon or macrophytes) is important due to the multiple applications of stable isotopes in freshwater research and can give insights into environmental and anthropogenic factors controlling N dynamics in streams. While previous research has shown how δ(15)N of PUCs varies with δ(15)N of dissolved inorganic N (DIN) among streams, less is known about how δ(15)N of PUCs varies over time. Here, we examined monthly variation of δ(15)N of PUCs and of DIN species (nitrate and ammonium) over a year, and compared it among streams with contrasting human impacts and PUC types. Our results showed no evidence of isotopic seasonal patterns. Temporal variability in δ(15)N-PUCs increased with human impact, being the highest in the urban stream, probably influenced by the high variability of δ(15)N-DIN. Among compartments, in-stream PUCs characterized by fast turnover rates, such as filamentous algae, showed the highest temporal variability in δ(15)N values (from -3.6 to 23.2 ‰). Our study elucidates some of the environmental and biological controls of temporal variability of δ(15)N in streams, which should be taken into account when using stable isotopes as an ecological tool.


Asunto(s)
Monitoreo del Ambiente , Actividades Humanas , Nitrógeno/análisis , Ríos/química , Carbono/análisis , Humanos , Compuestos Inorgánicos/análisis , Isótopos de Nitrógeno/análisis , Solubilidad , España , Factores de Tiempo
2.
Environ Sci Technol ; 47(18): 10155-62, 2013 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-23930789

RESUMEN

High variability in the natural abundance of nitrogen stable isotopes (δ(15)N) has been reported for primary uptake compartments (PUCs; e.g., epilithon, filamentous algae, bryophytes, macrophytes) in human-impacted aquatic ecosystems, but the origin of this variability is not yet well understood. We examined how δ(15)N of different PUC types relate to δ(15)N of dissolved inorganic nitrogen (DIN) species (nitrate and ammonium) and to the stream nutrient concentrations in which they grow. We selected 25 reaches located across the fluvial network of La Tordera catchment (NE Spain, 868.5 km(2)), encompassing a gradient of human pressures from headwaters to the river valley. δ(15)N-PUC variability was mostly explained by location within the fluvial network and was strongly related to the δ(15)N of DIN species, especially of ammonium. Models were stronger for PUCs growing within the stream channel and thus using streamwater as their main source of nutrients. Regression models including nutrient concentrations improved the prediction power for δ(15)N-PUCs, suggesting that nutrient concentrations and stoichiometry cannot be ignored in explaining the natural abundance of nitrogen isotopes in PUCs. These results provide insights into what controls variability in δ(15)N of PUCs within a stream network, with implications for the application of stables isotopes as an ecological tool.


Asunto(s)
Compuestos de Amonio/análisis , Nitratos/análisis , Isótopos de Nitrógeno/análisis , Ríos/química , Contaminantes Químicos del Agua/análisis , Monitoreo del Ambiente , España
3.
Sci Total Environ ; 875: 162602, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-36878289

RESUMEN

Microbial contamination in grocery shops (GS) should be evaluated since food commodities are commonly handled by workers and customers increasing the risk of food contamination and disease transmission. The aim of this study was to evaluate the microbial contamination in Portuguese and Spanish GS with a multi-approach protocol using passive (electrostatic dust cloths and surface swabs) sampling methods. The molecular detection of Aspergillus sections, mycotoxin analysis, screening of azole resistance as well as cytotoxicity measurement were conducted to better estimate the potential health risks of exposure and to identify possible relations between the risk factors studied. Fruits/vegetables sampling location was the one identified has being the most contaminated (bacteria and fungi) area in GS from both countries. Aspergillus section Fumigati and Fusarium species were observed in samples from Portuguese groceries with reduced susceptibilities to azoles commonly used in the clinical treatment of fungal infections. Fumonisin B2 was detected in Portuguese GS possible unveiling this emergent threat concerning occupational exposure and food safety. Overall, the results obtained raise concerns regarding human health and food safety and must be surveilled applying a One Health approach.


Asunto(s)
Micotoxinas , Salud Única , Humanos , Portugal , España , Supermercados , Micotoxinas/análisis , Aspergillus , Contaminación de Alimentos/análisis , Frutas/química
4.
PLoS One ; 14(12): e0226402, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31841545

RESUMEN

Recent advances on the environmental determinants of Kawasaki Disease have pointed to the important role of the atmospheric transport of a still unknown agent potentially triggering the disease. The hypothesis arose from an innovative methodology combining expertise in climate dynamics, the analysis of ocean and atmosphere data, the use of dispersion models and the search for biological agents in air samples. The approach offered a new perspective to reveal the identity of the potential trigger, but at the same time, it increased the level of complexity, which could potentially lead to the misinterpretation of the mechanisms. Some years after it was originally formulated, we here provide a brief clarification on the approach and limits of the methodology in order to prevent an eventual misuse of our research ideas and theory, so that further research can better focus on the knowledge gaps that still remain open.


Asunto(s)
Clima , Ambiente , Síndrome Mucocutáneo Linfonodular/etiología , Atmósfera , Canadá/epidemiología , Monitoreo del Ambiente , Geografía , Humanos , Incidencia , Japón/epidemiología , Síndrome Mucocutáneo Linfonodular/epidemiología , Nueva Zelanda/epidemiología , Factores Desencadenantes , Factores de Riesgo , Estaciones del Año , Estados Unidos/epidemiología , Viento
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