El pantà de Flix : anàlisi i resolució d'un problema de contaminació forta

En aquest article es realitza una perspectiva sobre el problema actual de contaminació greu de l'embassament de Flix (Ribera d'Ebre), generat pels abocaments massius dels residus de l'activitat d'una planta clor-àlcali al riu Ebre. La contaminació de l'embassament és a dos nivells: contaminació química (principalment metalls pesants i compostos orga-noclorats) i contaminació radioactiva (radionúclids derivats de de l'238U). A l'article es de-tallen les causes i es presenten les mesures de descontaminació dutes a terme, les seves conseqüències i l'estat actual dels nivells de contaminació. Aquesta situació sense prece-dents tant en el context català i espanyol, com en el context europeu, afecta a un dels rius amb major importància per al territori. L'article finalitza amb algunes propostes de treball per a la solució definitiva del problema.This paper presents a perspective of the current problem of severe contamination of the reservoir of Flix (Ribera d'Ebre), generated by massive discharges of waste from the ac-tivity of a Chloralkali plant on the river Ebro. The contamination of the reservoir is at two levels: chemical (mainly heavy metals and organochlorinated) and radioactive (derived ra-dionuclides in the 238U). The article details the causes and the decontamination measures carried out, exposes its consequences and describes the current levels of contamination. This problem of contamination is of unprecedent gravity for the Catalan, the Spanish and the European context, and affects one of the most important rivers of the territory. The ar-ticle ends with some future prospects as possible ways of solving the problem

Indicadores químicos de combustión en un hogar del Paleolítico Medio del yacimiento de Mediona I (Alt Penedès, Barcelona)

La aplicación del análisis químico orgánico a muestras arqueológicas es una técnica de desarrollo reciente. El estudio de la fracción lipídica (eso es, la fracción de materia extraíble mediante disolventes orgánicos) de restos sedimentarios en yacimientos permite recuperar una información inaccesible a otras técnicas de identificación aplicadas a la Arqueología. Este artículo describe de forma comparativa la fracción aromática del sedimento en el interior y en el exterior de un área de combustión en un yacimiento paleolítico previamente excavado.Asimismo, presenta el análisis de indicadores químicos pirogénicos con una técnica de gran potencial para la identificación de áreas de combustión en yacimientos donde éstos no están claramente definidos (simples manchas sin carbones, agrupación de piedras sin evidencias externas de termoalteración, etc.), siempre comparándolas con muestras de sedimento no termoalterado del mismo nivel arqueológico

Pollutant dehalogenation capability may depend on the trophic evolutionary history of the organism: PBDEs in freshwater food webs

Organohalogen compounds are some of the most notorious persistent pollutants disturbing the Earth biosphere. Although human-made, these chemicals are not completely alien to living systems. A large number of natural organohalogens, part of the secondary metabolism, are involved in chemical trophic interactions. Surprisingly, the relationship between organisms' trophic position and synthetic organohalogen biotransformation capability has not been investigated. We studied the case for polybromodiphenyl ethers (PBDE), a group of flame-retardants of widespread use in the recent years, in aquatic food webs from remote mountain lakes. These relatively simple ecosystems only receive pollution by atmospheric transport. A large predominance of the PBDE congener currently in use in Europe, BDE-209, largely dominated the PBDE composition of the basal resources of the food web. In contrast, primary consumers (herbivores and detritivores) showed a low proportion of BDE-209, and dominance of several less brominated congeners (e.g. BDE-100, BDE47). Secondary consumers (predators) showed large biomagnification of BDE-209 compare to other congeners. Finally, top predator fish characterized by low total PBDE concentrations. Examination of the bromine stable isotopic composition indicates that primary consumers showed higher PBDE biotransformation capability than secondary consumers. We suggest that the evolutionary response of primary consumers to feeding deterrents would have pre-adapted them for PBDE biotransformation. The observed few exceptions, some insect taxa, can be interpreted in the light of the trophic history of the evolutionary lineage of the organisms. Bromine isotopic composition in fish indicates that low PBDE values are due to not only biotransformation but also to some other process likely related to transport. Our finding illustrates that organohalogen compounds may strongly disturb ecosystems even at low concentrations, since the species lacking or having scarce biotransformation capability may be selectively more exposed to these halogenated hydrophobic semi-volatile organic pollutants due to their high bioaccumulation potential

Background fish feminization effects in European remote sites

Human activity has spread trace amounts of chemically stable endocrine-disrupting pollutants throughout the biosphere. These compounds have generated a background level of estrogenic activity that needs to be assessed. Fish are adequate sentinels for feminization effects as male specimens are more sensitive than humans to exogenous estrogenic compounds. High mountain lakes, the most distant environments of continental areas, only receive semi-volatile compounds from atmospheric deposition. We analyzed the expression levels of estrogen-regulated genes in male fish from these mountain lakes in Europe. Incipient feminization involving expression of estrogen receptor and zona radiata genes revealed a widespread diffuse estrogenic impact. This effect was correlated with the concentrations of some organochlorine compounds in fish and was consistent with the persistent occurrence of these tropospheric pollutants in the most remote planet regions. These results should be of general concern given the increasing endocrine disruption effects in human populationsPostprint (published version

Food web bioaccumulation of organohalogenated compounds in high mountain lakes

Persistent organic pollutants (POPs) are toxic substances that are usually produced for use in agricultural, industrial, and domestic applications. Because of their long-range atmospheric transport capacity, POPs are distributed worldwide. The global distillation theory predicts that there will be a temperature-dependent partitioning of these low volatility compounds in the environment. Concentration patterns of POPs in agreement with the theory have been observed for different environmental compartments, such as lake sediments and mosses, and along altitudinal and latitudinal gradients. However, concentration patterns in lake fish do not exactly match the expected results, indicating that further investigation into the bioaccumulation processes in food webs is required. Here, we briefly review the state of the question of POPs bioaccumulation in high mountain lake food webs and present some hypotheses concerning processes worthy of investigation.Los contaminantes orgánicos persistentes (POPs) son sustancias producidas para usos agrícolas, urbanos o industriales que presentan un carácter tóxico. Debido a la capacidad de transporte atmosférico a largo alcance, los POPs son distribucidos por todo el mundo. La teoría de la Destilación Global propone una distribución de estos compuestos de baja volatilidad en el medio ambiente dependiente de la temperatura del aire. Se ha observado este fenómeno en distintos compartimentos ambientales situados a lo largo de gradientes de altitud o latitud, como por ejemplo en sedimentos de lagos o en musgos. Sin embargo, algunas de las pautas observadas en peces no responden a lo esperado y ponen de relieve la falta de un conocimiento suficiente sobre la transferencia de estos contaminantes en las redes tróficas. Aquí se hace una breve revisión del estado de la cuestión sobre la bioacumalación de compuestos orgánicos persistentes en lagos de montaña y se sugieren algunas hipótesis sobre posibles procesos a investigar

Late Pleistocene palaeoproductivity patterns during the last climatic cycle in the Guyana Basin as revealed by calcareous nannoplankton

Variations in the assemblage and abundance of coccoliths reveal changes in oceanic and atmospheric dynamics in the Guyana Basin over the last climatic cycle, mainly linked to latitudinal variations in the ITCZ (Intertropical Convergence Zone). Records of the N ratio (a palaeoproductivity index of coccolithophores) allowed us to monitor nutri-thermocline fluctuations. Nannofossil accumulation rates (NAR) vary closely with the N ratio, indicating a strong correlation between these two palaeoproductivity proxies. Decreases in the N ratio and NAR values suggest lower palaeoproductivity during glacial substages, indicating a deep nutri-thermocline (deep stratification of the mixed layer) as a consequence of the piling up of warm water dragged by the NEC. This setting was favoured by the southern shift of the ITCZ and Trade winds which blew perpendicular to the Guyana coast. By contrast, increases in the N ratio and NAR values revealed higher palaeoproductivity during interglacial substages, suggesting a shoaling of the nutri-thermocline. This scenario is favoured by a northward displacement of the ITCZ with the southeast Trade winds blowing alongshore. Additionally, palaeoproductivity changes during substages of Marine Isotope Stage (MIS) 6-5 are of much higher amplitude than those recorded in substages of MIS 4-2 and the early Holocene. Similarities between the palaeoproductivity and the 65° N summer insolation records, suggest a link between the depth of nutri-thermocline, the latitudinal migration of the ITCZ and ice-sheet changes in the Northern Hemisphere

La huella de las oscilaciones globales del nivel del mar durante los últimos 530000 años en el Golfo de León y su variabilidad durante el estadio isotópico marino 3

El sondeo PRGL1-4, recuperado en el talud superior, ha proporcionado un registro único, continuo y de larga duración para la investigación del impacto de las oscilaciones del nivel del mar de escala glacial/interglacial durante el Pleistoceno Superior en la construcción del margen continental del Golfo de León, dominado por aportaciones sedimentarias de origen fluvial. El estudio en detalle de los cambios del tamaño de grano y la composición elemental del sedimento, junto con una robusta cronoestratigrafía basada en el registro de isótopos de oxígeno en foraminíferos planctónicos, ha permitido reinterpretar la sismoestratigrafia del margen para los últimos 530 ka. El sondeo PRGL1-4 comprende el apilamiento formado por cinco unidades depositadas durante las bajadas del nivel del mar de los últimos cinco ciclos glacial/interglacial de 100 ka. La extensa plataforma del Golfo de León ha jugado un papel determinante en el desarrollo del margen profundo puesto que las oscilaciones del nivel del mar, además de modificar el espacio de acomodación, influyeron directamente en cambios cíclicos del modelo deposicional a través de la activación y desactivación de procesos con gran capacidad erosiva y de transporte de sedimento más allá de la plataforma. El registro del sondeo PRGL1-4 también muestra el impacto de las oscilaciones del nivel del mar a escala milenaria durante el MIS 3, con evidencias claras de la ocurrencia de niveles del mar altos durante la fase inicial de todos y cada uno de los interestadios cálidos de los ciclos de Dansgaard-Oeschger. El registro PRGL1-4 supone, por tanto, la primera evidencia de un acoplamiento consistente entre las oscilaciones del nivel del mar y la variabilidad climática rápida de escala milenaria asociada a los ciclos de Dansgaard-Oeschger

Holocene changes in deep-water circulation of the Western Mediterranean Basin, links to North Atlantic climate variability

preliminary results from multicores recovered in the Minorca sediment drift, south of the Western Mediterranean Deep Water formation area, reveal changes in deep-water circulation during the last 2500 yr. Records of grain-size and SST Mg/Ca derived from G. bulloides show oscillations in deep-water current intensities that could be related to cool periods on land, i.e. the Little Ice Age, but also denote some relationship with changes in sea surface salinity likely associated with changes in continental humid conditions

Brown and brook trout populations in the Tatra Mountain lakes (Slovakia, Poland) and contamination by long-range transported pollutants

Fish living in the extreme conditions of the Tatra Mountain lakes were evaluated from a biological point of view as well as an important biomarker of long-range transported pollutants. In Velke Hincovo pleso and in Morskie Oko, specimens of brown trout (Salmo trutta) of extraordinarily advanced age were found (ages of 18+ and 17+ years, respectively). The capture of a 17+ year-old brown trout in Morskie Oko (2400 g, 540 mm) indicated the presence of the so-called ferox life strategy. The growth of brook trout (Salvelinus fontinalis) was faster than the growth of brown trout in the younger year classes, and while the growth of brook trout stopped after the age of 5+, the growth of brown trout continued. Concentrations of long-range transported pollutants (HCHs, HCB, DDTs, PCBs, PBDEs, and trace metals) in the Tatra Mountain fish were mostly associated with fish age, body weight and length, type of fish tissue, and lake altitude. Persistent organic pollutants (POPs) in fish muscle were dominated by PCBs 138, 153, 180, and p,p’-DDE. Conversely, PBDEs concentrations ranged at substantially lower levels compared to other POPs. Altitude correlated significantly with concentrations of a-HCH, HCB, p,p’-DDT, p,p’-DDE, and with PCBs 28 and 52. The highest contents of trace metals were found in kidney and liver samples, with higher concentrations in Velke Hincovo pleso than in Morskie Oko. The overall highest trace metal concentration levels were found for Fe, Cu, and Zn. In comparison with other European mountain lakes, the Tatra Mountain lakes are among the more contaminated.Postprint (author’s final draft