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  • 1
    Language: English
    In: Water Research, 15 November 2015, Vol.85, pp.148-157
    Description: Since rivers are typically subject to rapid changes in microbiological water quality, tools are needed to allow timely water quality assessment. A promising approach is the application of predictive models. In our study, we developed multiple linear regression (MLR) models in order to predict the abundance of the fecal indicator organisms (EC), intestinal enterococci (IE) and somatic coliphages (SC) in the Lahn River, Germany. The models were developed on the basis of an extensive set of environmental parameters collected during a 12-months monitoring period. Two models were developed for each type of indicator: 1) an extended model including the maximum number of variables significantly explaining variations in indicator abundance and 2) a simplified model reduced to the three most influential explanatory variables, thus obtaining a model which is less resource-intensive with regard to required data. Both approaches have the ability to model multiple sites within one river stretch. The three most important predictive variables in the optimized models for the bacterial indicators were NH –N, turbidity and global solar irradiance, whereas chlorophyll content, discharge and NH –N were reliable model variables for somatic coliphages. Depending on indicator type, the extended mode models also included the additional variables rainfall, O content, pH and chlorophyll . The extended mode models could explain 69% (EC), 74% (IE) and 72% (SC) of the observed variance in fecal indicator concentrations. The optimized models explained the observed variance in fecal indicator concentrations to 65% (EC), 70% (IE) and 68% (SC). Site-specific efficiencies ranged up to 82% (EC) and 81% (IE, SC). Our results suggest that MLR models are a promising tool for a timely water quality assessment in the Lahn area.
    Keywords: Escherichia Coli ; Intestinal Enterococci ; Somatic Coliphages ; Bathing Water Quality ; Monitoring ; Management Tool ; Engineering
    ISSN: 0043-1354
    E-ISSN: 1879-2448
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  • 2
    Language: English
    In: PLoS ONE, 02 November 2010, Vol.5(11), pp.1-12
    Description: It is recognized that microorganisms inhabiting natural sediments significantly mediate the erosive response of the bed (‘‘ecosystem engineers'') through the secretion of naturally adhesive organic material (EPS: extracellular polymeric substances). However, little is known about the individual...
    Keywords: Life Sciences ; Ecology, Environment ; Life Sciences ; Microbiology and Parasitology ; Sciences (General)
    ISSN: 1932-6203
    E-ISSN: 1932-6203
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  • 3
    Language: English
    In: PLoS ONE, 01 January 2018, Vol.13(6), p.e0199132
    Description: The application of engineered silver nanoparticles (AgNPs) in a considerable amount of registered commercial products inevitably will result in the continuous release of AgNPs into the natural aquatic environment. Therefore, native biofilms, as the prominent life form of microorganisms in almost all known ecosystems, will be subjected to AgNP exposure. Despite the exponentially growing research activities worldwide, it is still difficult to assess nanoparticle-mediated toxicity in natural environments. In order to obtain an ecotoxicologically relevant exposure scenario, we performed experiments with artificial stream mesocosm systems approaching low dose AgNP concentrations close to predicted environmental concentrations. Pregrown freshwater biofilms were exposed for 14 days to citrate-stabilized AgNPs at a concentration of 600 μg l-1 in two commonly used sizes (30 and 70 nm). Sublethal effects of AgNP treatment were assessed with regard to biofilm structure by gravimetric measurements (biofilm thickness and density) and by two biomass parameters, chlorophyll a and protein content. The composition of bacterial biofilm communities was characterized by t-RFLP fingerprinting combined with phylogenetic studies based on the 16S gene. After 14 days of treatment, the structural parameters of the biofilm such as thickness, density, and chlorophyll a and protein content were not statistically significantly changed by AgNP exposure. Furthermore, t-RFLP fingerprint analysis showed that the bacterial diversity was not diminished by AgNPs, as calculated by Shannon Wiener and evenness indices. Nevertheless, t-RFLP analysis also indicated that AgNPs led to an altered biofilm community composition as was shown by cluster analysis and multidimensional scaling (MDS) based on the Bray Curtis index. Sequence analysis of cloned 16S rRNA genes further revealed that changes in community composition were related with the displacement of putatively AgNP-sensitive bacterial taxa Actinobacteria, Chloroflexi, and Cyanobacteria by taxa known for their enhanced adaptability towards metal stress, such as Acidobacteria, Sphingomonadales, and Comamonadaceae. This measurable community shift, even after low dose AgNP treatment, causes serious concerns with respect to the broad application of AgNPs and their potentially adverse impact on the ecological function of lotic biofilms, such as biodegradation or biostabilization.
    Keywords: Sciences (General)
    E-ISSN: 1932-6203
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  • 4
    Language: English
    In: PLoS ONE, 2013, Vol. 8(10)
    Description: The estuary of the River Elbe between Hamburg and the North Sea (Germany) is a sink for contaminated sediment and suspended particulate matter (SPM). One major concern is the effect of human activities on the hydrodynamics, particularlythe intensive dredging activities in this area that may result in remobilization of sediment-bound pollutants. The aim of this study was to identify pollutants contributing to the toxicological risk associated with re-suspension of sediments in the Elbe Estuary by use of an effect-directed analysis that combines chemical and biological analyses in with specific fractionation techniques. Sediments were collected from sites along the Elbe Estuary and a site from a small harbor basin of the Elbe Estuary that is known to be polluted. The sixteen priority EPA-PAHs were quantified in organic extracts of sediments. In addition, dioxin equivalents of sediments were investigated by use of the 7-ethoxyresorufin O-deethylase assay with RTL-W1 cells and the Ah receptor-mediated luciferase transactivation assay with H4IIE-luc cells. Quantification of the 16 priorityPAHs revealed that sediments were moderately contaminated at all of the sites in the Elbe River Estuary (,0.02–0.906 mg/gdw). Sediments contained relatively small concentrations of dioxin equivalents (Bio-TEQ) with concentrations ranging from15.5 to 322 pg/g dw, which were significantly correlated with dioxin equivalents calculated based on toxicity referencevalues and concentrations of PAH. The concentration of Bio-TEQ at the reference site exceeded 200,000 pg/g dw. In apotency balance the 16 PAHs explained between 47 and 118% of the Bio-TEQ in the luciferase assay, which can be explained by the constant input of PAHs bound to SPM from the upper course of the Elbe River into its estuary. Successful identification of a significant portion of dioxin-like activity to priority PAHs in complex environmental samples such assediments has rarely been reported.
    Keywords: Natural Sciences ; Earth And Related Environmental Sciences ; Environmental Sciences ; Naturvetenskap ; Geovetenskap Och Miljövetenskap ; Miljövetenskap ; Enviromental Science ; Miljövetenskap
    ISSN: 1932-6203
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  • 5
    Language: English
    In: Journal of Soils and Sediments, 2011, Vol.11(6), pp.1099-1114
    Description: Byline: Sabine Ulrike Gerbersdorf (1), Henner Hollert (2), Markus Brinkmann (2), Silke Wieprecht (1), Holger Schuttrumpf (3), Werner Manz (4) Keywords: Biofilm; Freshwater; Interdisciplinary approach; Management of sediments; Pollutants; Risk assessment Abstract: Purpose Freshwater sediments and their attached microbial communities (biofilms) are essential features of rivers and lakes, providing valuable ecosystem services such as nutrient recycling or self-purification which extend beyond the aquatic environment. Anthropogenic pollutants, whether from the industrial era or as a result of our contemporary lifestyles, can negatively affect these functions with hitherto unknown consequences on ecology, the economy and human health. Thus far, the singular view of the involved disciplines such as ecotoxicology, environmental microbiology, hydrology and geomorphology has prevented a deeper understanding of this emerging issue. Main features This paper discusses briefly the progressions and the state-of-the-art methods within the disciplines of concern related to contaminated sediments, ranging from ecotoxicological test systems, microbiological/molecular approaches to unravel changes of microbial ecosystems, up to the modelling of sediment transport and sorption/desorption of associated pollutants. The first bilateral research efforts on contaminated sediments include efforts to assess ecotoxicological sediment risk including sediment mobility (i.e. ecotoxicology and engineering), enhance bioremediation potential (i.e. microbiology and ecotoxicology) or to understand biostabilisation processes of sediments by microbial assemblages (i.e. microbiology and engineering). Conclusions and perspectives In freshwater habitats, acute, chronic and mechanism-specific toxic effects on organisms, shifts in composition, structure and functionality of benthic microbial communities, as well as the obstruction of important ecosystem services by continuously discharged and long-deposited pollutants, should be related to the in situ sediment dynamics. To achieve an improved understanding of the ecology of freshwater sediments and the impairment of their important ecosystem functions by human-derived pollutants, we suggest a "triad plus x" approach combining advanced methods of ecotoxicology, environmental microbiology and engineering science. Author Affiliation: (1) Department of Hydraulic Engineering and Water Resources Management, Institute of Hydraulic Engineering, University Stuttgart, Pfaffenwaldring 61, 70569, Stuttgart, Germany (2) Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Worringer Weg 1, 52074, Aachen, Germany (3) Institute of Hydraulic Engineering and Water Resources Management, RWTH Aachen University, Mies-van-der-Rohe-Strasse 1, 52056, Aachen, Germany (4) Institute for Integrated Natural Sciences, University Koblenz--Landau, Universitatsstrasse 1, 56070, Koblenz, Germany Article History: Registration Date: 25/04/2011 Received Date: 20/11/2010 Accepted Date: 24/04/2011 Online Date: 11/05/2011 Article note: Responsible editor: Ian G. Droppo
    Keywords: Biofilm ; Freshwater ; Interdisciplinary approach ; Management of sediments ; Pollutants ; Risk assessment
    ISSN: 1439-0108
    E-ISSN: 1614-7480
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  • 6
    Language: English
    In: Science of the Total Environment, 01 December 2015, Vol.535, pp.3-19
    Description: Engineered inorganic nanoparticles (EINP) from consumers' products and industrial applications, especially silver and titanium dioxide nanoparticles (NP), are emitted into the aquatic and terrestrial environments in increasing amounts. However, the current knowledge on their environmental fate and biological effects is diverse and renders reliable predictions complicated. This review critically evaluates existing knowledge on colloidal aging mechanisms, biological functioning and transport of Ag NP and TiO NP in water and soil and it discusses challenges for concepts, experimental approaches and analytical methods in order to obtain a comprehensive understanding of the processes linking NP fate and effects. Ag NP undergo dissolution and oxidation with Ag S as a thermodynamically determined endpoint. Nonetheless, Ag NP also undergo colloidal transformations in the nanoparticulate state and may act as carriers for other substances. Ag NP and TiO NP can have adverse biological effects on organisms. Whereas Ag NP reveal higher colloidal stability and mobility, the efficiency of NOM as a stabilizing agent is greater towards TiO NP than towards Ag NP, and multivalent cations can dominate the colloidal behavior over NOM. Many of the past analytical obstacles have been overcome just recently. Single particle ICP-MS based methods in combination with field flow fractionation techniques and hydrodynamic chromatography have the potential to fill the gaps currently hampering a comprehensive understanding of fate and effects also at a low field relevant concentrations. These analytical developments will allow for mechanistically orientated research and transfer to a larger set of EINP. This includes separating processes driven by NP specific properties and bulk chemical properties, categorization of effect-triggering pathways directing the EINP effects towards specific recipients, and identification of dominant environmental parameters triggering fate and effect of EINP in specific ecosystems (e.g. soil, lake, or riverine systems).
    Keywords: Transport ; Aggregation ; Analytics ; Environment ; Aging ; Ecotoxicology ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 7
  • 8
    Language: English
    In: Applied and Environmental Microbiology, Oct, 2008, Vol.74(19-20), p.6427-6436
    Description: A whole-fungus hybridization based on computer-assisted comparative sequence analysis is performed to detect actively growing freshwater fungi with new taxon-specific rRNA-targeting fluorescence in situ hybridization (FISH) probes. The newly developed FISH probes have helped to visualize the growing hyphae and germinating conidia on leaves and in membrane cages.
    Keywords: Fluorescence -- Evaluation ; In Situ Hybridization -- Usage ; Ribosomal Rna -- Research ; Water Molds -- Genetic Aspects ; Water Molds -- Environmental Aspects
    ISSN: 0099-2240
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  • 9
    Language: English
    In: Ecological Indicators, August, 2012, Vol.19, p.118(12)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ecolind.2011.08.007 Byline: Markus A. Wetzel (a)(b), Peter C. von der Ohe (c), Werner Manz (b), Jochen H.E. Koop (a)(b), Dierk-Steffen Wahrendorf (a) Keywords: Sediment contamination; Water framework directive; Benthic indicators; W-statistic; BOPA; BO2A; AMBI; M-AMBI Abstract: Indices to assess the ecological status of water bodies according to the European Water Framework Directive (WFD) frequently produce widely differing results when applied to estuarine systems. Although several ecological indices have been employed to coastal environments and in estuaries in particular, there is still a lack of knowledge about their suitability for assessing the ecological status of heavily modified water bodies. Thus, we evaluated the performances of indices and fauna parameters (AMBI, M-AMBI, BOPA, BO2A, W-value, Shannon diversity, species richness, abundance) that have been discussed in the WFD context using data on invertebrates dwelling in two typical morphological units: the navigation channel and the river bank habitats of Elbe estuary (Germany). In addition, we tested their ability to identify several environmental factors (grain size distribution and chemical sediment contamination). All indices were able to detect major changes in macrofauna composition along the estuarine salinity gradient and were able to differentiate between navigation channel and shallow bank habitats. A strong significant correlation was found with most indices with the exceptions of the W-value and the BOPA with mean grain size. Almost all indices signaled poor ecological quality in the coarser fairway sediments against the finer sublitoral bank sediments. However, AMBI and BOPA showed the opposite: both indicators classified the invertebrate assemblages from the navigation channel better compare than the shallower habitats. The correlation of ecological indices and parameters with sediment contaminants and the toxicity of the sediment calculated as toxic units showed a diverse picture: all indices, except species richness and the BOPA, had a certain significant correlation with several individual sediment pollutants, however, only one index, the W-value, was correlated significant with the majority of chemical pollutants (Pb, Cd, Cu, Ni, Hg, Zn, [beta]-HCH, pp'-DDD, and TBT) and the toxic units. Our results show clearly that ecological quality classification of heavily modified estuaries depends strongly on both the index and the habitat. Thus, we conclude that no index should be used on its own to estimate the ecological quality of estuaries. Further investigations and the improvement or development of such indices should place emphasis on their independence from the grain size spectrum of the sediments and on their good correlation with its pollution status. Author Affiliation: (a) Department of Animal Ecology, German Federal Institute of Hydrology - BfG, Am Mainzer Tor 1, 56068 Koblenz, Germany (b) Institute for Integrated Natural Sciences, University Koblenz - Landau, Universitatsstrasse 1, 56070 Koblenz, Germany (c) Department of Effect-Directed Analysis, UFZ Helmholtz Centre for Environmental Research, Permoserstra[sz]e 15, 04318 Leipzig, Germany
    Keywords: Estuaries -- Comparative Analysis ; Chemical Wastes -- Comparative Analysis ; Salinity -- Comparative Analysis ; Sediments (Geology) -- Comparative Analysis ; Hydrology -- Comparative Analysis ; Water Resource Management -- Comparative Analysis ; Pollution -- Comparative Analysis
    ISSN: 1470-160X
    Source: Cengage Learning, Inc.
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  • 10
    Language: English
    In: Vakuum in Forschung und Praxis, April 2014, Vol.26(2), pp.42-47
    Description: Polymers made of renewable resources increasingly replace conventional plastic materials made of petroleum. Socalled bioplastics can be found e. g. in food industry, for agricultural usage or in the medical field. The range of applications can be further expanded with specialized coating of their surface. Especially in case of food packaging and the usage within medical devices as well as the storage of these composite materials, sterilization or at least the partial reduction of microbial growth is an important issue which needs to be addressed early in the production process. In this work, a commercially available polyhydroxyalkanoate (PHA) pure bioplastic foil of 50 μm thickness was coated with 100 nm of diamond‐like carbon (DLC) and afterwards treated by four different standard methods of sterilization and / or disinfection, namely deep‐freezing, ultraviolet irradiation, autoclaving and immersion in ethanol. The surface morphology of treated DLC‐coated and uncoated samples was investigated and compared to the untreated DLC‐coated and uncoated samples using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Measurements exhibited damage of the composite for autoclaved and in ethanol immersed samples, whereas deep‐frozen and ultraviolet irradiated samples showed no structural changes. These findings clearly demonstrate deep‐freezing and ultraviolet irradiation to be appropriate methods for the disinfection and sterilization, respectively, of the DLC‐coated pure bioplastic foil. DLC‐beschichtete Biokunststoff‐Folie — Auswirkungen verschiedener Sterilisationsmethoden auf die Oberflächenmorphologie Aus erneuerbaren Ressourcen hergestellte Polymere ersetzen zunehmend Erdöl‐basierte konventionelle Kunststoffe. Die sogenannten Biokunststoffe sind z. B. in der Nahrungsmittelindustrie, der Landwirtschaft oder der Medizin zu finden. Ihr Anwendungsspektrum kann durch spezielle Oberflächenbeschichtungen aber noch erweitert werden. Insbesondere in der Nahrungsmittelverpackungsindustrie, bei der Verwendung in medizinischen Apparaturen und Implantaten sowie deren Lagerung ist die Sterilisierung oder zumindest die teilweise Reduzierung der mikrobiellen Aktivität ein wichtiger Aspekt, der bereits frühzeitig im Produktionsprozess berücksichtigt werden muss. In der vorliegenden Arbeit wurde kommerziell erhältliche 50 μm dicke Polyhydroxyalkanoat (PHA)‐Biokunststoff‐Folie mit 100 nm diamant‐ähnlichem Kohlenstoff (DLC) beschichtet und danach mit vier verschiedenen Standardmethoden der Sterilisation und/oder Desinfektion, nämlich UV‐Bestrahlung, Autoklavieren, Tiefkühlung, und Eintauchen in Ethanol, behandelt. Die Oberflächenstruktur der so behandelten Proben (DLC‐beschichtet und unbeschichtet) wurde mittels REM (Rasterelektronenmikroskopie) und AFM (Rasterkraftmikroskopie) untersucht und mit den entsprechenden unbehandelten Proben verglichen. Die Messungen ergaben Beschädigungen des Materialverbundes bei der Behandlung durch Autoklavieren und Ethanol, wohingegen die tiefgekühlten und UV‐bestrahlten Proben keinerlei strukturelle Veränderungen zeigten. Diese Ergebnisse zeigen klar, dass Tiefkühlung und UV‐Bestrahlung geeignete Methoden für die Desinfizierung bzw. Sterilisation dieser DLC‐beschichteten Biokunststoff‐Folien darstellen.
    Keywords: Nahrungsmittelindustrie ; Oberflächenbeschichtung ; Sterilisierung ; Produktionsprozess ; Desinfektion ; Tiefkühlen ; Biokunststoff ; Oberflächenmorphologie ; Polymer ; Kunststoff ; Landwirtschaft ; Polyhydroxyalkanoat ; Diamantähnlicher Kohlenstoff ; Ethanol ; Autoklavierung ; Desinfizieren ; Mikrobenwachstum ; Autoklav ; Immersion ; Strukturumwandlung ; Medizinische Anwendung ; Engineering ; Physics;
    ISSN: 0947-076X
    E-ISSN: 1522-2454
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