خيارات البحث
النتائج 1971 - 1980 من 62,084
Perfluorinated substances and telomeres in an Arctic seabird: Cross-sectional and longitudinal approaches
2017
Blévin, Pierre | Angelier, Frédéric | Tartu, Sabrina | Bustamante, Paco | Herzke, Dorte | Moe, Børge | Bech, Claus | Gabrielsen, Geir Wing | Bustnes, Jan Ove | Chastel, Olivier
Telomeres are non-coding DNA repeats located at the termini of eukaryotic chromosomes, regulated by dynamic processes balancing shortening and maintenance. Despite a mechanism to slow-down telomere shortening, cell division leads to progressive attrition of chromosomes, leading to the onset of cellular senescence or apoptosis. However, telomere restoration based on telomerase activity is the primary mechanism for telomere maintenance. Telomere length is associated to health and survival and can be impacted by a broad panel of environmental factors. However, the effect of contaminants on telomeres is poorly known for living organisms. The aim of this study was to investigate relationships between some poly- and perfluoroalkyl substances (PFASs), body condition and telomere length by using both a crosssectional and longitudinal approach in adult breeding Black-legged kittiwakes (Rissa tridactyla) from Svalbard. First, we examined the associations between absolute telomere length and PFASs contamination in a given year (cross-sectional approach). Second, we investigated the relationships between telomere dynamics and PFASs contamination within a two years’ time frame (longitudinal approach). Our results did not show any significant relationships of PFASs and body condition with absolute telomere length in a given year. Surprisingly, we found a positive and significant relationship between PFASs and telomere dynamics in both sexes with elongated telomere in birds bearing the highest concentrations of PFASs. Our study underlines (i) the need to investigate PFAS effects on telomere dynamics with a longitudinal approach and (ii) a potential positive effect of these contaminants on telomere length, with the most contaminated birds showing the slowest rate of telomere shortening or even displaying elongated ones. Our study is the first to report a relationship between PFASs and telomere length in freeliving vertebrates. A possible underlying mechanism and other potential confounding factors are discussed. Organic contaminants PFASs Black-legged kittiwake Svalbard DNA | acceptedVersion
اظهر المزيد [+] اقل [-]Survival rate and breeding outputs in a high Arctic seabird exposed to legacy persistent organic pollutants and mercury
2015
Goutte, Aurélie | Barbraud, Christophe | Herzke, Dorte | Bustamante, Paco | Angelier, Frédéric | Tartu, Sabrina | Clement-Chastel, Celine | Moe, Børge | Bech, Claus | Gabrielsen, Geir W. | Bustnes, Jan Ove | Chastel, Olivier
acceptedVersion
اظهر المزيد [+] اقل [-]Polychlorinated biphenyl exposure and corticosterone levels in seven polar seabird species
2015
Tartu, S. | Angelier, F. | Bustnes, Jan Ove | Moe, Børge | Hanssen, Sveinn Are | Herzke, Dorte | Gabrielsen, Geir W. | Verboven, N. | Verreault, J. | Labadie, P. | Budzinski, H. | Wingfield, J.C. | Chastel, O.
The role of polychlorinated biphenyls (PCBs) on exposure-related endocrine effects has been poorly investigated in wild birds. This is the case for stress hormones including corticosterone (CORT). Some studies have suggested that environmental exposure to PCBs and altered CORT secretion might be associated. Here we investigated the relationships between blood PCB concentrations and circulating CORT levels in seven free-ranging polar seabird species occupying different trophic positions, and hence covering a wide range of PCB exposure. Blood P7PCB concentrations (range: 61e115,632 ng/g lw) were positively associated to baseline or stress-induced CORT levels in three species and negatively associated to stress-induced CORT levels in one species. Global analysis suggests that in males, baseline CORT levels generally increase with increasing blood P7PCB concentrations, whereas stress-induced CORT levels decrease when reaching high blood P7PCB concentrations. This study suggests that the nature of the PCB-CORT relationships may depend on the level of PCB exposure. Arctic Antarctic Birds PCBs Glucocorticoids Stress | acceptedVersion
اظهر المزيد [+] اقل [-]Microplastic concentrations in beach sediments along the German Baltic coast
2015
Stolte, Andrea | Forster, Stefan | Gerdts, Gunnar | Schubert, Hendrik
Model-based evaluation of the use of polycyclic aromatic hydrocarbons molecular diagnostic ratios as a source identification tool
2014
Katsoyiannis, Athanasios | Breivik, Knut
Polycyclic Aromatic Hydrocarbons (PAHs) molecular diagnostic ratios (MDRs) are unitless concentration ratios of pair-PAHs with the same molecular weight (MW); MDRs have long been used as a tool for PAHs source identification purposes. In the present paper, the efficiency of the MDR methodology is evaluated through the use of a multimedia fate model, the calculation of characteristic travel distances (CTD) and the estimation of air concentrations for individual PAHs as a function of distance from an initial point source. The results show that PAHs with the same MW are sometimes characterized by substantially different CTDs and therefore their air concentrations and hence MDRs are predicted to change as the distance from the original source increases. From the assessed pair-PAHs, the biggest CTD difference is seen for Fluoranthene (107 km) vs. Pyrene (26 km). This study provides a strong indication that MDRs are of limited use as a source identification tool. | acceptedVersion
اظهر المزيد [+] اقل [-]Atmospheric polychlorinated biphenyls in Indian cities: Levels, emission sources and toxicity equivalents
2013
Chakraborty, Paromita | Zhang, Gan | Eckhardt, Sabine | Li, Jun | Breivik, Knut | Lam, Paul KS | Tanabe, Shinsuke | Jones, Kevin C
Atmospheric concentration of Polychlorinated biphenyls (PCBs) were measured on diurnal basis by active air sampling during Dec 2006 to Feb 2007 in seven major cities from the northern (New Delhi and Agra), eastern (Kolkata), western (Mumbai and Goa) and southern (Chennai and Bangalore) parts of India. Average concentration of Sum25PCBs in the Indian atmosphere was 4460 (+/-2200) pg m-3 with a dominance of congeners with 4-7 chlorine atoms. Model results (HYSPLIT, FLEXPART) indicate that the source areas are likely confined to local or regional proximity. Results from the FLEXPART model show that existing emission inventories cannot explain the high concentrations observed for PCB-28. Electronic waste, ship breaking activities and dumped solid waste are attributed as the possible sources of PCBs in India. Sum25PCB concentrations for each city showed significant linear correlation with Toxicity equivalence (TEQ) and Neurotoxic equivalence (NEQ) values. | acceptedVersion
اظهر المزيد [+] اقل [-]Anthropogenic lead distribution in soils under arable land and permanent grassland estimated by Pb isotopic compositions
2008
Fernandez , Christelle (INRA , Versailles (France). UR 0251 Physico-chimie et Ecotoxicologie des Sols d'agrosystèmes contaminés) | Monna , Fabrice (Centre National de la Recherche Scientifique, Dijon(France). Centre des Sciences de la Terre) | Labanowski , Jérome (INRA , Versailles (France). UR 0251 Physico-chimie et Ecotoxicologie des Sols d'agrosystèmes contaminés) | Loubet , Michel (Université Toulouse 3, Toulouse(France). Laboratoire de Géochimie) | Van Oort , Folkert (INRA , Versailles (France). UR 0251 Physico-chimie et Ecotoxicologie des Sols d'agrosystèmes contaminés)
The role of land use on fate of metals in soils is poorly understood. In this work, we studied the incorporation of lead in two neighboring soils with comparable pedogenesis but under long-term different agricultural management. Distributions of anthropogenic Pb were assessed from concentrations and isotopic compositions determined on bulk horizon samples, systematical 5–10 cm increment samples, and on 24-h EDTA extracts. Minor amounts of anthropogenic lead were detected until 1-m depth under permanent grassland, linked to high earthworm activity. In arable land, exogenous Pb predominantly accumulated at depths <60 cm. Although the proximity between the two sites ensured comparable exposition regarding atmospheric Pb deposition, the isotopic compositions clearly showed the influence of an unidentified component for the cultivated soil. This work highlights the need for exhaustive information on historical human activities in such anthropized agrosystems when fate of metal pollution is considered.
اظهر المزيد [+] اقل [-]Comment réduire les risques d'érosion par les pratiques agricoles ? S'adapter aux systèmes érosifs et au contexte économique
1996
Papy, François | Martin, P. | Bruno, J.F.
Spatiotemporal dynamics of spring and stream water chemistry in a high-mountain area
Żelazny Mirosław | Aleksander Astel | Anna Wolanin | Stanisław Małek
The present study deals with the application of the self-organizing map (SOM) technique in the exploration of spatiotemporal dynamics of spring and stream water samples collected in the Chochołowski Stream Basin located in the Tatra Mountains (Poland). The SOM-based classification helped to uncover relationships between physical and chemical parameters of water samples and factors determining the quality of water in the studied high-mountain area. In the upper part of the Chochołowski Stream Basin, located on the top of the crystalline core of the Tatras, concentrations of the majority of ionic substances were the lowest due to limited leaching. Significantly higher concentration of ionic substances was detected in spring and stream samples draining sedimentary rocks. The influence of karst-type springs on the quality of stream water was also demonstrated. | Tatra Mountains Basin Water chemical profile Unsupervised classification Self-organizing maps Rock Spruce stands | 40 | 1048-1057 | 159
اظهر المزيد [+] اقل [-]Nanotechnology in Agriculture, the Food Sector, and Remediation: Prospects, Relations, and Constraints
Anna Gorczyca | Ewa Pociecha | Ewelina Matras
The applications and benefits of nanotechnology in the agricultural and food sector are now established as a matter of fact, but scientists still have a problem to properly acknowledge the influence of nanocompounds on the environment. We are starting to use nanopesticides and nanofertilizers, but the effects they have on organisms in the environment can be diverse in nature – ranging from the beneficial to the harmful. Environmental microbiome can be strongly modified by nanoparticles. Soil microbiomes are the basis for healthy plants and crops. At the same time, the unique properties of nanomaterials make them particularly suitable for environmental remediation due to their high surface area-to-volume ratio, which often results in higher reactivity. Nanomaterials are starting to be used for the remediation of problematic contaminants (organic and organophosphorus compounds, volatile organic compounds, some heavy metals, or herbicides), and such use offers some very promising prospects. This chapter provides an overview of nanotechnology in general, including a description of the main categories of nanomaterials, the utilization of nanotechnology in the agricultural and food sector, as well as the use of nanomaterials in environmental remediation. Lastly, some toxicological aspects of nanomaterials present in the environment are presented on the basis of the scientific literature in the field. | Nanotechnology, Nanoremediation, Ecotoxicity, Agriculture, The food industry | 20 | 1-34
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