DNA adducts in fish following an oil spill exposure

On 12 December 1999, one third of the load of the Erika tanker, amounting to about 10,000 t crude oil flowed into sea waters close to the French Atlantic Coast. This oil contained polycyclic aromatic compounds (PAC) that are known to be genotoxic. Genotoxic effects induce DNA adducts formation, which can thus be used as pollution biomarkers. Here, we assessed the genotoxic impact of the “Erika” oil spill by DNA adducts detection in the liver of immature fishes (Solea solea) from four locations of the French Brittany coasts. Two months after the spill, a high amount of DNA adducts was found in samples from all locations, amounting to 92–290 DNA adduct per 109 nucleotides. Then total DNA adduct levels decreased to reach about 50 adducts per 109 nucleotides nine months after the spill. In vitro experiments using human cell cultures and fish liver microsomes evidence the genotoxicity of the Erika fuel. They also prove the formation of reactive species able to create DNA adducts. Furthermore, in vitro and in vivo DNA adducts fingerprints are similar, thus confirming that DNA adducts are a result of the oil spill

Background Light in Potential Sites for the ANTARES Undersea Neutrino Telescope

The ANTARES collaboration has performed a series of {\em in situ} measurements to study the background light for a planned undersea neutrino telescope. Such background can be caused by $^{40}$K decays or by biological activity. We report on measurements at two sites in the Mediterranean Sea at depths of 2400~m and 2700~m, respectively. Three photomultiplier tubes were used to measure single counting rates and coincidence rates for pairs of tubes at various distances. The background rate is seen to consist of three components: a constant rate due to $^{40}$K decays, a continuum rate that varies on a time scale of several hours simultaneously over distances up to at least 40~m, and random bursts a few seconds long that are only correlated in time over distances of the order of a meter. A trigger requiring coincidences between nearby photomultiplier tubes should reduce the trigger rate for a neutrino telescope to a manageable level with only a small loss in efficiency.Comment: 18 pages, 8 figures, accepted for publication in Astroparticle Physic

Direct application of compound-specific radiocarbon analysis of leaf waxes to establish lacustrine sediment chronology

Author Posting. © Springer, 2007. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Journal of Paleolimnology 39 (2008): 43-60, doi:10.1007/s10933-007-9094-1.This study demonstrates use of compound-specific radiocarbon analysis (CSRA) for dating Holocene lacustrine sediments from carbonate-hosted Ordy Pond, Oahu, Hawaii. Long-chain odd-numbered normal alkanes (n-alkanes), biomarkers characteristic of terrestrial higher plants, were ubiquitous in Ordy Pond sediments. The δ13C of individual n-alkanes ranged from −29.9 to −25.5‰, within the expected range for n-alkanes synthesized by land plants using the C3 or C4 carbon fixation pathway. The 14C ages of n-alkanes determined by CSRA showed remarkably good agreement with 14C dates of rare plant macrofossils obtained from nearby sedimentary horizons. In general, CSRA of n-alkanes successfully refined the age-control of the sediments. The sum of n-alkanes in each sample produced 70–170 μg of carbon (C), however, greater age errors were confirmed for samples containing less than 80 μg of C. The 14C age of n-alkanes from one particular sedimentary horizon was 4,155 years older than the value expected from the refined age-control, resulting in an apparent and arguable age discrepancy. Several lines of evidence suggest that this particular sample was contaminated by introduction of 14C-free C during preparative capillary gas chromatography. This study simultaneously highlighted the promising potential of CSRA for paleo-applications and the risks of contamination associated with micro-scale 14C measurement of individual organic compounds.This project was funded by Petroleum Research Fund (PRF #40088-ACS) and in part by Sigma Xi, The Scientific Research Society (Grants in aid of research, 2003)

Dark Matter Searches with the ANTARES Neutrino Telescope

[EN] The MOSCAB experiment (Materia OSCura A Bolle) uses the Geyser technique for dark matter search. The results of the first 0.5 kg mass prototype detector using superheated C3F8 liquid were very encouraging, achieving a 5 keV nuclear recoil threshold with high insensitivity to gamma radiation. Additionally, the technique seems to be easily scalable to higher masses for both in terms of complexity and costs, resulting in a very competitive technique for direct dark matter search, especially for the spin dependent case. Here, we report as well in the construction and commissioning of the big detector of 40 kg at the Milano-Bicocca University. The detector, the calibration tests and the evaluation of the background will be presented. Once demonstrated the functionality of the detector, it will be operated at the Gran Sasso National Laboratory in 2015.We acknowledge the financial support of the Spanish Ministerio de Ciencia e Innovación (MICINN) and Ministerio de Economía y Competitividad (MINECO), Grants FPA2012-37528-C02-02, and Consolider MultiDark CSD2009-00064, and of the Generalitat Valenciana, Grants ACOMP/2014/153 and PrometeoII/2014/079.Ardid Ramírez, M. (2016). Dark Matter Searches with the ANTARES Neutrino Telescope. Nuclear and Particle Physics Proceedings. 273:378-382. https://doi.org/10.1016/j.nuclphysbps.2015.09.054S37838227

Protection par voie électrochimique de hublots immergés en milieu marin vis-à-vis des biosalissures

La prévention du biofilm est un problème majeur dans la mise en oeuvre d’équipements sous-marins impliquant des mesures optiques ou simplement l’obtention d'images. Le présent article a pour but de décrire brièvement les travaux qui ont permis de valider une technique de protection par voie électrochimique. Le principe repose sur une électrolyse contrôlée de l’eau de mer pour produire des espèces chlorées à la surface même de la fenêtre a protéger. Ceci est réalisé en déposant par la technique de pyrolyse de spray un film de dioxyde d’étain, transparent et conducteur. Sur la base de nombreuses études en laboratoire et sur des sites naturels, la validité du procédé a été démontrée. En particulier, il a été établi que le dopage à l'antimoine offrait la meilleure stabilité et permettait de minimiser la consommation en énergie électrique. Dans l’état de l’art actuel, on a pu maintenir la transparence de fenêtres immergées en milieu marin pendant 5 mois au moin

Impact potentiel des additifs des géomembranes sur les écosystèmes - IMAGES

International audienceA variety of geomembranes is widely used in hydraulic applications. Some of the additives included in the manufacturing process will be extracted from the geomembrane after contact with water or a soil. Depending on their chemical nature, additives or their degradation products represent a possible source of impact on natural ecosystems. The paper present the objectives of the research program IMAGES (IMpact of ADditives in GEomembraneS) aiming at quantifying the potential impact of additives extracted from geomembranes installed in hydraulic applications. The methodology consists in identifying the additives contained in HDPE and PP Geomembranes, the additives that can be extracted following various environmental conditions, the additives degradation products, developing a model for additives extraction/diffusion from/through geomembranes and evaluating the potential toxicity of the additives extracted through ecotoxicity tests. Details on the selected protocol are given. The UV spectrometry analyses of the immersion solutions at 82°C evidence an acceleration of hindered phenol AO type degradation products extraction with the acidity of the medium. The small decrease in the OIT value after 96 days at 82°C of the HDPE GM shows that, depending on the ecotoxicity threshold determined, the alert value of AO nocivity will have to be determined with an accurate technique like UV spectrometry

Occurrence and of removal organic micropollutants in landfill leachates treated by electrochemical advanced oxidation processes.

International audienc

Impact des molécules extraites de géomembranes sur l'activité des micro-organismes en milieux aqueux

National audienceSome additives contained in GMs used for hydraulic applications are extracted to water or soil. To evaluate the ecotoxicological impacts of these chemical compounds on the environment, polypropylene ( PP ) and high density polyethylene (H P D E ) GMs are immersed in aqueous solutions (pH 4 and 7) at 80, 55 and 25°C. At various times intervals, effects of the extracted solutions on microorganisms are evaluated. Ecotoxicological tests highlight negative effects of the first 11 days extracted molecules on micro algae growth and microcrustacean behavior. However, after prolonged exposure, microalgae growth is stimulated. These results may be related to the change of the chemical nature of the molecules detected by UV spectroscopy.Certains additifs ajoutés aux GMB (Géomembranes) utilisées pour l'étanchéité des ouvrages hydrauliques sont extraits vers le milieu environnant (eau et sol). Afin d'évaluer l'impact écotoxicologique de ces composés chimiques sur le milieu, des GMB en polypropylène (PP) et polyéthylène haute densité (PEHD) sont immergées dans des solutions aqueuses à pH 4,3 et 6,7, et à 80, 55 et 25°C. À différentes échéances, les effets des solutions d'extraction sur le comportement des micro-organismes sont évalués. Les tests d'écotoxicité montrent que les molécules extraites les 11 premiers jours nuisent à la croissance des micro-algues et au comportement des micro-crustacés, alors qu'une exposition prolongée stimule la croissance des micro-algues. Ces résultats sont reliés à un changement de la nature chimique des molécules extraites observé par spectrométrie UV

New insights into the key microbial phylotypes of anaerobic sludge digesters under different operational conditions

Analyses on bacterial, archaeal communities at family level and methane-production metabolism were conducted in thirteen full-scale and pilot-scale anaerobic sludge digesters. These digesters were operated at different conditions regarding solids concentration, sludge retention time, organic loading rate and feedstock composition, seeking to optimize digester capacity. Correlations between process parameters and identified microbial phylotypes were evaluated based on relative abundance of these phylotypes determined by Quantitative PCR and 16S rDNA amplicon sequencing. Results showed that, Total Solids concentration (TS), among the evaluated operational parameters, demonstrated the most positive correlation with chemical parameters (including NH3 and VFAs) and significant impact on the abundance of key microbial phylotypes regardless of other factors. Digesters were grouped into 'Higher-TS' with higher stress (TS > 44 g/L, NH3 > 90 mg/L, VFAs > 300 mg/L) and 'Lower-TS' under easier status (TS <= 44 g/L, NH3 < 120 mg/L, VFAs < 525 mg/L) in this study. We identified the key microbial phylotypes, i.e. the most abundant and discriminating populations, in 'Higher-TS' digesters with high biogas production rate, which were the class Clostridia, the family Methanosarcinaceae and the order Methanobacteriales. Thermoanaerobacteraceae and Syntrophomonadaceae were identified as key families of Clostridia. Methane was produced both from acetoclastic and hydrogenotrophic methanogenesis. By contrast, in 'Higher-TS' digesters with low biogas production rate, the classes Alpha-, Beta- and Gamma-proteobacteria were detected in higher percentages, of which Rhodobacteraceae, Comamonadaceae and Xanthomonadaceae were the most abundant families respectively, and Methanomicrobiales was the prevailing methanogen order. Consistently, hydrogenotrophic pathway was predominant for methanogenesis, indicating existence of syntrophic acetate oxidation in such 'high-stress', low biogas production rate digesters. These microbial phylotypes were therefore considered to be associated to 'Higher-TS' operation. In 'Lower-TS' digesters, the abundance of the class Delta-proteobacteria, the families Anaerolineaceae, Rikenellaceae, Candidatus Cloacamonas and Methanosaetaceae was obviously higher compared with those in 'Higher-TS' digesters, which were thus considered to be marker phylotypes of easy status. The influence of TS and NH3 on the microbiome should be considered when a 'TS-increasing' strategy is applied to increase digester capacity