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

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

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

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

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

Identification of most relevant variables and processes to assess the environmental impacts of remediation technologies along their life cycles: Focus on the waste management scenarios

The application of Life Cycle Assessment (LCA) to remediation technologies is still not a consolidated practice and it is especially lacking in the assessment of the environmental impacts associated to the management of the waste produced during remediation. This study aims at addressing these methodological gaps by identifying the typologies of waste typically generated during the remediation of a contaminated site and classifying them according to the European Waste Catalogue (EWC) codes. Thereafter, the following steps are: (i) the identification of the waste management scenarios (WMSs) applicable to the identified waste typologies, (ii) the selection of Life Cycle Assessment processes that can be used to assess the impacts of the different WMSs and (iii) the quantification and comparison of the environmental impacts caused by the different WMSs applied considering hazardousness levels to which the same waste may belong in relation to its contamination levels and characteristics: inert, non-hazardous and hazardous waste (Waste Framework Directive 2008/98/EC). As results, a matrix reporting the classes and typologies of waste, their EWC codes, their different WMSs and the suitable LCA processes from the Ecoinvent database that can be applied to each EWC within a specific WMS, has been developed. Additionally, the comparative assessment of the impacts caused by the Ecoinvent processes applicable to the same waste typology within the same WMS has been performed to support the selection of the most appropriate WMS case by case

Assessing uncertainty of hydrological and ecological parameters originating from the application of an ensemble of ten global-regional climate model projections in a coastal ecosystem of the lagoon of Venice, Italy

With increasing evidences of climate change affecting coastal waters, there is a strong need to understand future climate conditions and assess the potential responses of delicate coastal ecosystems. Results of climate change studies based on only one GCM-RCM combination should be interpreted with caution as results are highly dependent on the assumptions of the selected combination. In this study we examined the uncertainty in the hydrological and ecological parameters of the Zero river basin (ZRB) – Palude di Cona (PDC) coastal aquatic ecosystem generated by the adoption of an ensemble of climate projections from ten different combinations of General Circulation Model (GCM) – Regional Climate Model (RCM) under two emission scenarios (RCP4.5 and RCP8.5) implemented in the hydrological model (SWAT) and the ecological model (AQUATOX). The baseline period of 1983–2012 was used to identify climate change variations in two future periods: mid-century (2041–2070) and late-century (2071–2100) periods. SWAT outputs from the ensemble indicate a summer reduction in inorganic nitrogen loadings of 1–22% and a winter increase of 1–19%. Inorganic phosphorus loadings indicate a yearly increase of 32–61%. AQUATOX outputs from the ensemble show major changes in the summer period, with an increase in Chl-a concentration of 9–56%, a decrease in diatoms of 74–98% and an increase in cyanobacteria of 421–3590%. Obtained results confirm that the use of multiple GCM-RCM projections can provide a more robust assessment of climate change impacts on the hydrology and ecology of coastal waters, but at the same time highlight the large uncertainty of climate change-related impact studies, which can affect the decision-making processes regarding the management and preservation of sensitive aquatic ecosystems such as those in coastal areas. © 2019 Elsevier B.V