Analysis of the temperature dependence of the thermal conductivity of insulating single crystal oxides

The temperature dependence of the thermal conductivity of 27 different single crystal oxides is reported from ≈20 K to 350 K. These crystals have been selected among the most common substrates for growing epitaxial thin-film oxides, spanning over a range of lattice parameters from ≈3.7 Å to ≈12.5 Å. Different contributions to the phonon relaxation time are discussed on the basis of the Debye model. This work provides a database for the selection of appropriate substrates for thin-film growth according to their desired thermal properties, for applications in which heat management is importantThis work was supported by the European Research Council (Grant No. ERC StG-259082, 2DTHERMS), and MINECO of Spain (Project No. MAT2013-44673-R) and Xunta de Galicia (Project No. EM2013/037). V.P. acknowledges support from the Ramon y Cajal Program (No. RYC-2011-09024) and E.F.V. from Xunta de Galicia through the I2C planS

Variación temporal de las concentraciones de PCBs en tejido de mejillón de dos zonas de la Bahía de Santander (España)

Se presenta la variación temporal de bifenilos policlorados (PCBs) en mejillón silvestre Mytilus galloprovincialis de dos zonas de la Bahía de Santander (norte de España) de 1991 a 2003, así como la posible influencia en sus concentraciones de los diferentes aportes externos a que están sometidas ambas zonas. Las concentraciones de SCB7 (suma de los CBs Nos. IUPAC: 28, 52, 101, 118, 138, 153 y 180) de la zona de Pantalán, oscilan entre los 21 μg kg–1 en peso húmedo (ph) y los 38 μg kg–1 ph Mientras que en la zona de Pedreña, con menor influencia antropogénica, varían entre un mínimo de 8 μg kg–1 ph y un máximo de 15 μg kg–1 ph Para conocer la evolución temporal, se usa el coeficiente de correlación Tau-b de Kendall y se comprueba la existencia de una tendencia decreciente significativa en los niveles de PCBs en ambas zonas.An analysis was made of the temporal variation of polychlorinated biphenyls (PCBs) in wild mussel, Mytilus galloprovincialis, from two areas of Santander Bay (northern Spain) during 1991–2003, as well as of the posible influence of different external contributions on their concentrations. The concentrations of the sum of seven PCBs (IUPAC numbers 28, 52, 101, 118, 138, 153 and 180) from the Pantalán area ranged from 21 to 38 μg kg–1 wet weight, whereas those from the Pedreña area, subject to less anthropogenic influence, ranged from 8 to 15 μg kg–1 wet weight. To determine the temporal evolution, the Kendall Tau-b correlation coefficient was used and a decreasing trend in PCB levels was verified for both areas.Publicado

Impact of regulated and emerging pollutants and microplastics in marine ecosystems (IMPACTA project)

Marine ecosystems are nowadays subjected to a massive input of synthetic chemicals from everywhere. Unfortunately only a small portion of them is being monitored, and it is necessary to identify which pollutants can produce adverse impacts in the marine environment. IMPACTA project (CTM2013-48194-C3) is characterizing the distribution of regulated and emerging contaminants and microplastics in marine sediments, and evaluating the biological effects that they can cause (sing sublethal embryotoxicity tests, endocrine disruption and biomarkers). Sensitive and selective analytical methods are being developed and validated for pharmaceuticals, perfluorinated compounds, organophosphorus pesticides, triazines, personal care products, nonylphenols and alkylated PAHs in sediments. Thus, relevant pollutants present in coastal and offshore areas will be identified. Furthermore potential toxic effects of the contaminants present in coastal sediments are being assessed through embryotoxicity bioassays and also the biological effects on different marine species as a consequence of their exposition to specific compounds. Another relevant contribution of this project will be the assessment of the impact of micro-plastics, first time in the Spanish coastal areas. Their potential toxic effects and their role in the transference of pollutants in the marine environment are being assessed. The concentration and composition of microplastics in sediments and demersal fish stomachs are being characterized, and their potential biological effects on marine invertebrates are also being investigated

Determinación de congéneres individuales de bifenilos policlorados en organismos marinos

Se describe la metodología empleada para el análisis de policlorobifenilos (PCBs) en organismos marinos mediante extracción con Soxhlet y purificación y separación del extracto en columnas de alúmina y gel de sílice. El análisis se realiza mediante cromatógrafo de gases con columna capilar y detector de captura de electrones.In this paper the methodology for the analysis of polychlorinated biphenyls in marine organisms is described. The samples are extracted in Soxhlet and the extracts purified and fractionated on alumina and silica gel chromatographic columns. The analysis is subsequently carried out by gas chrotatography (ECD detector), using capillary columns.Publicado

Uptake Kinetics, Bioconcentration and Debromination of BDE-47 in Juvenile Marine Fish Psetta maxima

Polybrominated diphenyl ethers (PBDEs) are a class of global flame retardants whose residues have markedly increased in fish and human tissues during the last decade. They belong to persistent and toxic contaminants which needmore attention and toxicological study as their degradation in the environment is not well understood. This study characterizes 2,2′,4,4′- tetrabromodiphenyl ether (BDE-47) bioconcentration, elimination and biotransformation in juvenile turbot Psetta maxima, in order to evaluate the risk of its bioaccumulation in the marine environment. During this study, juvenile turbot were exposed to environmentally relevant BDE-47 concentrations from 0.001 to 1 μg/L for 16 days via aqueous exposure. This study found that juvenile turbot bioconcentrated and biotransformed BDE-47. There was no difference in standard length or weight between control and exposed fish. Uptake and elimination of BDE-47 by the turbot during exposure were examined in controlled laboratory experiments. Bioconcentration of BDE-47 was similar in fish from all treatment groups. Bioconcentration was rapid and increased with exposure time, since the bioconcentration factor (BCF) was higher. However, elimination was slower in comparison and low elimination was detected after 10 days in clean water. BDE-47 concentration in water influences the BCF. Half-life ranged between 37 and 108 days and theoretical times t90 could range from 120 to 358 days. The present study demonstrates a stepwise debromination of BDE-47 to BDE-28.MAE-PCIVersión del edito

Temporal trends od Cd, Cu, Hg, Pb and Zn in mussels (Mytilus galloprovincialis) from the Spanish North-Atlantic coast 1991-1999

Temporal trends for heavy metals (Cd, Cu, Hg, Pb and Zn) in mussel ( Mytilus galloprovincialis) from the Galician and Cantabrian areas in Spain, where samples were yearly collected from 1991 to 1999, are presented. This study was carried out by the Centro Oceanográfico de Vigo of the Instituto Español de Oceanografía (I.E.O.) as part of the Spanish contribution to the Joint Assessment and Monitoring Programme (JAMP) of the OSPAR Convention. The experimental work and subsequent statistical treatment, following OSPAR procedures and guidelines, are described. In order to carry out the statistical treatment of the data, median values of the different shell length classes were used for each contaminant, year and area. The Kendall t-b correlation coefficient was used with the purpose of demonstrating the existence of a downward significant temporal trend in the pollution levels, according to the advice of ICES Working Group on Statistical Aspects of Environmental Monitoring. A decrease of copper levels was detected in Vigo, Pontevedra and Arosa, of mercury in Pontevedra and A Coruña, of lead in Vigo, Pontevedra, A Coruña and Bilbao and of zinc in Pontevedra and A Coruña. However, a cadmium positive trend was registered at Ria de Vigo. No significant trends were detected in the other cases.IEOVersión del edito