The influence of a surfactant, linear alkylbenzene sulfonate, on the estrogenic response to a mixture of (xeno)estrogens in vitro and in vivo

This is the post-print version of the final paper published in Aquatic Toxicology. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright © 2008 Elsevier B.V. All rights reserved.The effect of the presence of a surfactant on the activity of a mixture of environmental estrogens was assessed. In their natural habitat, fish are subject not only to exposure to mixtures of estrogenic compounds, as has been addressed in previous publications, but also to other confounding factors (chemical, physical and biological), which may, in theory, affect their responses to such compounds. To assess the potential for such interference, the commonly occurring surfactant, linear alkylbenzene sulfonate (LAS), was applied to the yeast estrogen screen at various concentrations, independently and together with a mixture of estrogens at constant concentrations. LAS enhanced the estrogenic activity of the mixture, an effect which became less pronounced over the course of time. This information was used to design an in vivo study to assess induction of vitellogenin in fathead minnows exposed to the same mixture of estrogens plus LAS. A similar trend was observed, that is, the response was enhanced, but the effect became less pronounced as the study progressed. However, the enhanced response in vivo occurred only at the highest concentration of LAS tested (362 μg/L), and was transient because it was no longer apparent by the end of the study. Although LAS is a significant contaminant in terms of both concentration and frequency of detection in the aquatic environment, these data do not suggest that it will have a significant impact on the response of fish to environmental estrogens

Evidence of estrogenic mixture effects on the reproductive performance of fish

The official published version can be obtained from the link below - Copyright @ 2007 American Chemical SocietyRecent research into the effects of mixtures of estrogenic chemicals has revealed the capacity for similarly acting chemicals to act in combination, according to the principles of concentration addition. This means that, collectively, they may pose a significant environmental risk, even when each component is present at a low and individually ineffective concentration. The aim of this study was to investigate the ecological significance of mixture effects at low-effect concentrations by assessing the combined effect of estrogenic chemicals on the reproductive performance of fish. Pairs of fathead minnows were exposed to five estrogenic chemicals. Endpoints analyzed included fecundity, the expression of male secondary sexual characteristics, somatic indices, and vitellogenin induction. In the first phase of the study, a concentration-response analysis was performed to investigate the relative sensitivity of these endpoints. In the second phase, mixture effects at low-effect concentrations were explored by exposing fish to each of the mixture components, individually and in combination. Data from these experiments provide evidence of mixture effects on fitness and fecundity, demonstrating the capacity for chemicals to act together to affect reproductive performance, even when each component is present belowthe threshold of detectable effects. This has important implications for hazard assessment and contributes to our understanding of mixture effects at increasing levels of biological complexity.This work was funded by the European Commission, under contract EVK1-2001-00091

Water-Assisted Concerted Proton-Electron Transfer at Co(II)-Aquo Sites in Polyoxotungstates With Photogenerated RuIII(bpy)33+ Oxidant

The cobalt substituted polyoxotungstate [Co6(H2O)2(α-B-PW9O34)2(PW6O26)]17− (Co6) displays fast electron transfer (ET) kinetics to photogenerated RuIII(bpy)33+, 4 to 5 orders of magnitude faster than the corresponding ET observed for cobalt oxide nanoparticles. Mechanistic evidence has been acquired indicating that: (i) the one-electron oxidation of Co6 involves Co(II) aquo or Co(II) hydroxo groups (abbreviated as Co6(II)−OH2 and Co6(II)−OH, respectively, whose speciation in aqueous solution is associated to a pKa of 7.6), and generates a Co(III)−OH moiety (Co6(III)−OH), as proven by transient absorption spectroscopy; (ii) at pH>pKa, the Co6(II)−OH→RuIII(bpy)33+ ET occurs via bimolecular kinetics, with a rate constant k close to the diffusion limit and dependent on the ionic strength of the medium, consistent with reaction between charged species; (iii) at p

ChemicalDrift 1.0: an open-source Lagrangian chemical-fate and transport model for organic aquatic pollutants

A new model for transport and fate of chemicals in the aquatic environment is presented. The tool, named ChemicalDrift, is integrated into the open-source Lagrangian framework OpenDrift and is hereby presented for organic compounds. The supported chemical processes include the degradation, the volatilization, and the partitioning between the different phases that a target chemical can be associated with in the aquatic environment, e.g. dissolved, bound to suspended particles, or deposited to the seabed sediments. The dependencies of the chemical processes on changes in temperature, salinity, and particle concentration are formulated and implemented. The chemical-fate modelling is combined with wide support for hydrodynamics by the integration within the Lagrangian framework which provides e.g. advection by ocean currents, diffusion, wind-induced turbulent mixing, and Stokes drift generated by waves. A flexible interface compatible with a wide range of available metocean data is made accessible by the integration, making the tool easily adaptable to different spatio-temporal scales and fit for modelling of complex coastal regions. Further inherent capabilities of the Lagrangian approach include the seamless tracking and separation of multiple sources, e.g. pollutants emitted from ships or from rivers or water treatment plants. Specific interfaces to a dataset produced by a model of emissions from shipping and to an unstructured-grid oceanographic model of the Adriatic Sea are provided. The model includes a database of chemical parameters for a set of poly-aromatic hydrocarbons and a database of emission factors for different chemicals found in discharged waters from sulfur emission abatement systems in marine vessels. A post-processing tool for generating mean concentrations of a target chemical, over customizable spatio-temporal grids, is provided. Model development and simulation results demonstrating the functionalities of the model are presented, while tuning of parameters, validation, and reporting of numerical results are planned as future activities. The ChemicalDrift model flexibility, functionalities, and potential are demonstrated through a selection of examples, introducing the model as a freely available and open-source tool for chemical fate and transport that can be applied to assess the risks of contamination by organic pollutants in the aquatic environment

Challenges and opportunities of water quality monitoring and multi-stakeholder management in small islands: the case of Santa Cruz, Galápagos (Ecuador)

Sustainable water resources management roots in monitoring data reliability and a full engagement of all institutions involved in the water sector. When competences and interests are overlapping, however, coordination may be difficult, thus hampering cooperative actions. This is the case of Santa Cruz Island (Galápagos, Ecuador). A comprehensive assessment on water quality data (physico-chemical parameters, major elements, trace elements and coliforms) collected since 1985 revealed the need of optimizing monitoring efforts to fill knowledge gaps and to better target decision-making processes. A Water Committee (Comité de la gestión del Agua) was established to foster the coordinated action among stakeholders and to pave the way for joint monitoring in the island that can optimize the efforts for water quality assessment and protection. Shared procedures for data collection, sample analysis, evaluation and data assessment by an open-access geodatabase were proposed and implemented for the first time as a prototype in order to improve accountability and outreach towards civil society and water users. The overall results reveal the high potential of a well-structured and effective joint monitoring approach within a complex, multi-stakeholder framework.publishedVersio

Sea bass (Dicentrarchus labrax) as a potential bioindicator of estrogenic contamination in marine surface waters

Resumo apresentado sob poster apresentado ao 5th International Symposium on Fish Endocrinology, September, 2004, Castellon, Spain.Exposure of aquatic wildlife in surface waters to (xeno-)estrogens is known to cause reproductive dysfunction. Estrogenic responses in fish are the net result of complex chains of events that will depend on a number of factors, such as bioavailability, bioconcentration/bioaccumulation, and biotransformation. Most of known estrogenic chemicals are lipophilic and hydrophobic and therefore have a strong potential to accumulate in aquatic biota. Therefore, determining environmental exposures may be very difficult and not be particularly meaningful. As test organism the sea bass (Dicentrarchus labrax) was selected, a common species in European marine systems. This work is part of a study focusing on the combination effects of mixtures of estrogenic chemicals in marine and freshwater organisms. Juvenile sea bass were used in order to analyse the bioconcentration and distribution among different tissues of the chemical residues of a set of reference estrogenic chemicals such as 17ß-estradiol (E2), ethynylestradiol (EE2), nonylphenol (NP), octylphenol (OP), bisphenol-A (BPA). Fish were exposed for a period of two weeks to environmentally relevant levels of these compounds, after which liver, bile, muscle, gill and kidney were collected and analyzed. Actual concentrations of E2, EE2 and BPA seawater in the tanks were determined by either gas chromatography with ion trap detection or HPLC coupled to diode array detection. In bile, levels of BPA were determined according to a method presented earlier by Houtman et al. (13th Annual Meeting SETAC Europe, 2003). Actual NP and OP concentrations in both water and tissues were determined by HPLC-ESI-MS according to recently developed methods by Pojana et al. (J. Anal. Chem., in press). Bioconcentration and distribution of residual compounds in tissues were correlated to the levels of plasma vitellogenin (results are presented also at this conference) and to actual exposure concentrations. The general suitability of the sea bass as a bioindicator of estrogenic contamination in the marine environment is discussed.Comissão Europeia (CE) - ACE, EVK1-CT-2001-100

Are better communicators better readers? : an exploration of the connections between narrative language and reading comprehension

The association between receptive language skills and reading comprehension has been established in the research literature. Even when the importance of receptive skills for reading comprehension has been strongly supported, in practice lower levels of skills tend to go unnoticed in typically developing children. A potentially more visible modality of language, expressive skills using speech samples, has been rarely examined despite the longitudinal links between speech and later reading development, and the connections between language and reading impairments. Even fewer reading studies have examined expressive skills using a subgroup of speech samples – narrative samples – which are closer to the kind of language practitioners can observe in their classrooms, and are also a rich source of linguistic and discourse-level data in school-aged children. This thesis presents a study examining the relationship between expressive language skills in narrative samples and reading comprehension after the first two years of formal reading instruction, with considerable attention given to methodological and developmental issues. In order to address the main methodological issues surrounding the identification of the optimal linguistic indices in terms of reliability and the existence of developmental patterns, two studies of language development in oral narratives were carried out. The first of the narrative language studies drew data from an existing corpus, while the other analysed primary data, collected specifically for this purpose. Having identified the optimal narrative indices in two different samples, the main study examined the relationships between these expressive narrative measures along with receptive standardised measures, and reading comprehension in a monolingual sample of eighty 7- and 8-year-old children attending Year 3 in the UK. Both receptive and expressive oral language skills were assessed at three different levels: vocabulary, grammar and discourse. Regression analyses indicated that, when considering expressive narrative variables on their own, expressive grammar and vocabulary, in that order, contributed to explain over a fifth of reading comprehension variance in typically developing children. When controlling for receptive language however, expressive skills were not able to account for significant unique variance in the outcome measure. Nonetheless, mediation analyses revealed that receptive vocabulary and grammar played a mediating role in the relationship between expressive skills from narratives and reading comprehension. Results and further research directions are discussed in the context of this study’s methodological considerations.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Relación agua dulce-agua salada en zonas de diferente grado de erosión costera en el Partido de la Costa

La posición de la interfase agua dulce-agua salada en un ambiente costero es relativamente estable mientras no sea perturbada por extracción de agua dulce, cambios en la morfología de las unidades que la contienen o el incremento del nivel del mar. Se exponen los primeros resultados del comportamiento de los niveles freáticos y la conductividad eléctrica del agua (CE) en sectores de la costanera del Partido de La Costa. El objetivo es establecer la relación entre el agua dulce del acuífero y el agua marina de acuerdo al grado de afectación de la erosión costera. Se realizan mediciones de nivel mensuales y de conductividad eléctrica del agua en freatímetros de la costanera. La CE se mantiene estable salvo en un pozo donde se manifiesta un incremento durante el evento de marea alta. Las precipitaciones acumuladas en el periodo no parecen ser suficientes para generar un incremento de la capa freática. Los registros de mediciones continuas demuestran que las oscilaciones de los niveles freáticos se corresponden a las ondas de marea. La reducción de las curvas isofreáticas en la costanera muestra un desplazamiento de la cuña salina hacia el continente (1987-2021). Hasta el momento no se observa un comportamiento diferencial entre los datos de las zonas afectadas por distintos grados de erosión y las conservadas. Este estudio se encuentra en sus etapas iniciales por lo que se continúa con la recopilación de información.Freshwater-saltwater interface location in a coastal environment in relatively stable while it is not disturbed by freshwater pumping, changes in the geomorphological units or sea-level rise. The first results of groundwater level and electrical conductivity (EC) behavior in the shoreline of Partido de La Costa are shown in this work. The aim was to establish the relationship between the aquifer freshwater and the marine saltwater according to the level of coastal erosion. Groundwater level and EC monthly measurements are carried out in wells located in the shoreline. The EC remains stable except in a well where an increased was shown during a high-tide event. The amount of accumulated rainfall during the studied period seems not to be enough to produce an increase in groundwater level. Level logger data shown that groundwater oscillation agreed with tide waves. The increase in the isophreatic curves in the shoreline shows a movement towards the continent (1987-2021). A different behavior between data from the areas affected by different level of erosion and the preserved ones is not observed, for the time being. This study is in its initial stages therefore the data collection is a working process.Centro de Estudios Integrales de la Dinámica Exógen

Cuando la ciencia va a la escuela

A partir de las problemáticas detectadas durante las instancias regional y provincial de La Feria de Ciencias y Tecnología 2006, el Club de Ciencias del Partido de La Costa elaboró una propuesta de alfabetización científica para docentes: las Asesorías "Cuando la ciencia va a la escuela". Ella implica la articulación de la educación formal, no formal (Club de ciencias), la comunidad científica local y el ámbito municipal. Docentes y asesores de ciencia comparten las distintas etapas de una investigación escolar, aprendiendo acerca de la ciencia, su método y su didáctica; y desarrollando una serie de actitudes y valores que hacen al trabajo en equipo. Partiendo de la observación del entorno cercano como elemento motivador de problemáticas enmarcadas en los contenidos curriculares vigentes, y estableciendo una serie de pasos para verificarlas de manera observacional o experimental. Hasta el momento, se han desarrollado asesorías en 14 establecimientos educativos de los Partidos de La Costa y Pinamar, con la participación de alrededor de 80 docentes. En la presente comunicación, se comparten los fundamentos de esta propuesta de alfabetización científica y los resultados obtenidos en una situación de aprendizaje generada en la Escuela Primaria nº 6 de Mar del Tuyú, en los ciclos lectivos 2007 y 2008.Trabajos del área Ciencias NaturalesDepartamento de Ciencias Exactas y Naturale

The ACE Project: a synopsis of in vivo studies to predict estrogenic mixture effects in freshwater and marine fish

Society of Environmental Toxicology and Chemistry - SETAC Europe 15th Annual Meeting, Lille, France, May 2005.This work is part of the ACE project (ACE, EVK1-CT-2001-100) which aim is to investigate multi-component mixtures of estrogenic compounds in aquatic ecosystems. Here we present a synopsis of in vivo data related with the joint estrogenic action of five estrogenic compounds (17ß-estradiol, ethynylestradiol, nonylphenol, octylphenol and bisphenol-A) on vitellogenesis in fathead minnow (Pimephales promelas) and sea bass (Dicentrarchus labrax). The studies were conducted with freshwater adult males and marine juveniles under flow through exposure conditions for two weeks. In the first step, fish were exposed to the five compounds individually in order to generate concentration- response curves. Therefore mixture effects were predicted on the basis of the potency of each compound by using the model of concentration addition (CA). Finally, the compounds were tested as a mixture at equipotent concentrations, and the observed mixture effects were compared to the predictions. The mixture studies showed an good agreement between observed and predicted effects and provided evidence that CA can be used as a predictive tool for the effect assessment of mixtures of (xeno)estrogens in freshwater or marine ecosystems. The differences/limitations of running in vivo mixture studies with freshwater and marine species will be discussed.Comissão Europeia (CE) - ACE project - ACE, EVK1-CT-2001-100