Entity

Time filter

Source Type

Langen Brütz, Germany

Schreiber R.,Helmholtz Center for Environmental Research | Schreiber R.,University of Koblenz-Landau | Kuster A.,German Federal Environment Agency UBA | Feiler U.,German Federal Institute of Hydrology BfG | And 2 more authors.
Journal of Soils and Sediments | Year: 2011

Purpose: The objective of this study was to modify a sediment contact protocol to a multiwell plate exposure system which supplements measurement of the fresh weight change (FWC) using the non-invasive effective quantum yield of energy conversion at photosystem II (PS II) reaction centres (Y(II)) in parallel. Since Y(II) is a functional parameter and FWC represents a whole-plant structural response, the determination of a more pronounced response in one of these parameters may hint at the mode of action of contaminants. By the observation of Y(II) at different time points, extrapolation of effect development over time may be gained from modelling. Material and methods: An established sediment contact protocol was adapted to an exposure in multiwell plates. During exposure, the Y(II) of exposed Myriophyllum aquaticum was measured using an imaging-pulse amplitude-modulated chlorophyll fluorometer. At the end of the 13-day exposure, the FWC was determined and the IC50 for FWC and Y(II) was estimated using concentration-response modelling. A concentration-time-response model was used to describe the effect development on Y(II) over time. This protocol was applied to natural sediments and to artificial sediments which were spiked with different contaminants. Results and discussion: It was shown that for the PS II inhibitor atrazine, the IC50 was four times lower on the Y(II) compared to the value for the FWC. In contrast, for the acetolactate-synthase inhibitor metsulfuron methyl, no effect on the Y(II) of exposed M. aquaticum could be found, while a 100% inhibition in FWC was detected. For dinitro-o-cresol, a decoupler of oxidative phosphorylation, the IC50 for the FWC and the Y(II) were of the same order of magnitude. These results are in agreement with the current mode of action understanding and show the potential of this method to interpret differences in determined IC values as mode of action dependent. Moreover, a clear decrease in estimated IY(II),txC50 values by the end of the 13-day exposure was found for atrazine. This strengthens the hypothesis that effects of contaminants in sediment are not immediately evident but may evolve over time. Conclusions: With the miniaturised sediment contact assay, mode of action dependent differences in IC values on the FWC and the Y(II) could be determined. Based on results from the concentration-time-response modelling, it could be assumed that during the 13-day exposure all contaminants may not fully exert their effects. Since investigated natural sediments did not show inhibitions on Y(II), while pronounced effects on the FWC were found, the FWC may also be worthwhile to be studied over time. © 2011 Springer-Verlag. Source


Bobbink R.,Radboud University Nijmegen | Hicks K.,University of York | Galloway J.,University of Virginia | Spranger T.,German Federal Environment Agency UBA | And 13 more authors.
Ecological Applications | Year: 2010

Atmospheric nitrogen (N) deposition is a recognized threat to plant diversity in temperate and northern parts of Europe and North America. This paper assesses evidence from field experiments for N deposition effects and thresholds for terrestrial plant diversity protection across a latitudinal range of main categories of ecosystems, from arctic and boreal systems to tropical forests. Current thinking on the mechanisms of N deposition effects on plant diversity, the global distribution of G200 ecoregions, and current and future (2030) estimates of atmospheric N-deposition rates are then used to identify the risks to plant diversity in all major ecosystem types now and in the future. This synthesis paper clearly shows that N accumulation is the main driver of changes to species composition across the whole range of different ecosystem types by driving the competitive interactions that lead to composition change and/or making conditions unfavorable for some species. Other effects such as direct toxicity of nitrogen gases and aerosols, long-term negative effects of increased ammonium and ammonia availability, soil-mediated effects of acidification, and secondary stress and disturbance are more ecosystem- and site-specific and often play a supporting role. N deposition effects in mediterranean ecosystems have now been identified, leading to a first estimate of an effect threshold. Importantly, ecosystems thought of as not N limited, such as tropical and subtropical systems, may be more vulnerable in the regeneration phase, in situations where heterogeneity in N availability is reduced by atmospheric N deposition, on sandy soils, or in montane areas. Critical loads are effect thresholds for N deposition, and the critical load concept has helped European governments make progress toward reducing N loads on sensitive ecosystems. More needs to be done in Europe and North America, especially for the more sensitive ecosystem types, including several ecosystems of high conservation importance. The results of this assessment show that the vulnerable regions outside Europe and North America which have not received enough attention are ecoregions in eastern and southern Asia (China, India), an important part of the mediterranean ecoregion (California, southern Europe), and in the coming decades several subtropical and tropical parts of Latin America and Africa. Reductions in plant diversity by increased atmospheric N deposition may be more widespread than first thought, and more targeted studies are required in low background areas, especially in the G200 ecoregions. © 2010 by the Ecological Society of America. Source


Hartmann N.M.,German Federal Environment Agency UBA
Virology Journal | Year: 2013

Background: Human adenoviruses are promising candidates for addressing health risks associated with enteric viruses in environmental waters. Relatively harmless but common, these DNA viruses persist within the population and are generally considered extremely stable, remaining infectious in water for long periods of time. Group-specific or single species detection of human adenoviruses in environmental samples is usually based on polymerase chain reaction assays. Simultaneous identification of specific species or serotypes needs additional processing. Here we present a simple molecular approach for the monitoring of serotypic diversity in the human adenovirus populations in contaminated water sites. Methods: Diversity patterns of human adenoviruses in environmental samples, collected in an outdoor artificial stream and pond simulation system, were analyzed using a closed tube polymerase chain reaction method with subsequent melting point analysis. Results: Human adenovirus serotype 41 was the most prominent adenovirus serotype detected in environmental water samples, but melting point analyses indicated the presence of additional adenovirus serotypes. Conclusions: Based on investigations with spiked and environmental samples, a combination of qPCR and melting point analysis was shown to identify adenovirus serotypes in sewage contaminated water. © 2013 Hartmann et al. Source


Kuster A.,German Federal Environment Agency UBA | Alder A.C.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Escher B.I.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Escher B.I.,University of Queensland | And 16 more authors.
Integrated Environmental Assessment and Management | Year: 2010

β-Adrenergic receptor blockers (b-blockers) are applied to treat high blood pressure, ischemic heart disease, and heart rhythm disturbances. Due to their widespread use and limited human metabolism, b-blockers are widely detected in sewage effluents and surface waters. b-Adrenergic receptors have been characterized in fish and other aquatic animals, so it can be expected that physiological processes regulated by these receptors in wild animals may be affected by the presence of bblockers. Because ecotoxicological data on b-blockers are scarce, it was decided to choose the β -blocker atenolol as a case study pharmaceutical within the project ERAPharm. A starting point for the assessment of potential environmental risks was the European guideline on the environmental risk assessment of medicinal products forhumanuse. In Phase I of the risk assessment, the initial predicted environmental concentration (PEC) of atenolol in surface water (500 ng L -1) exceeded the action limit of 10 ng L -1. Thus, a Phase II risk assessment was conducted showing acceptable risks for surface water, for groundwater, and for aquatic microorganisms. Furthermore, atenolol showed a low potential for bioaccumulation as indicated by its low lipophilicity (log KOW0.16), a low potential for exposure of the terrestrial compartment via sludge (log KOC2.17), and a low affinity for sorption to the sediment. Thus, the risk assessment according to Phase II-Tier A did not reveal any unacceptable risk for atenolol. Beyond the requirements of the guideline, additional data on effects and fate were generated within ERAPharm. A2-generation reproduction test with the waterflea Daphnia magna resulted in the most sensitive no-observed-effect concentration (NOEC) of 1.8mg L -1. However, even with this NOEC, a risk quotient of 0.003 was calculated, which is still well below the risk threshold limit of 1. Additional studies confirm the outcome of the environmental risk assessment according to EMEA/CHMP (2006). However, atenolol should not be considered as representative for other b-blockers, such as metoprolol, oxprenolol, and propranolol, some of which show significantly different physicochemical characteristics and varying toxicological profiles in mammalian studies. Integr Environ Assess Manag 2010;6:514523. © 2009 SETAC. Source


Kuno R.,Companhia Ambiental do Estado de Sao Paulo | Roquetti M.H.,Companhia Ambiental do Estado de Sao Paulo | Becker K.,German Federal Environment Agency UBA | Seiwert M.,German Federal Environment Agency UBA | Gouveia N.,University of Sao Paulo
International Journal of Hygiene and Environmental Health | Year: 2013

Human biomonitoring is an important tool for the evaluation of environmental exposure to contaminants. The data that are obtained from these studies might be compared to appropriate reference values (RVs) in a specific population. The RVs were derived from the rounded values of the upper limit of the 95th confidence interval of the 95th percentile for lead (Pb), cadmium (Cd) and mercury (Hg) in blood from adults in the metropolitan area of Sao Paulo (MASP), Brazil to investigate the association between blood metals and sociodemographic and lifestyle factors. Blood samples from 653 nonsmoking blood donors without occupational exposure to the studied metals were collected in 2006. Our evaluations distinguished a younger group (18-39 years) and an older group (40-65 years). RVs in the younger group were 60. μg. Pb/L and 4. μg. Hg/L for men and 47. μg. Pb/L and 4. μg. Hg/L for women. RVs in the older group were 80. μg. Pb/L and 5. μg. Hg/L for men and 63. μg. Pb/L and 6. μg. Hg/L for women. The RV for Cd was 0.6. μg/L for adults aged 18-65 years. Pb and Cd levels demonstrated a significant association with sex and age. Male blood contained 50% more Pb, and the older group exhibited 23% more Pb. Fish consumption and amalgam fillings were primarily related to Hg levels. RVs for lead were similar to the Czech Republic and Germany but higher than the US population. The RV for Cd in Brazil was well below the RVs of these countries. The RVs for Hg in Brazil were similar to the US but higher than Germany and the Czech Republic. © 2012 Elsevier GmbH. Source

Discover hidden collaborations