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  • Bundschuh, Mirco  (8)
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  • 1
    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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  • 2
    Language: English
    In: Science of the Total Environment, 15 December 2015, Vol.538, pp.246-261
    Description: Terrestrial inputs into freshwater ecosystems are a classical field of environmental science. Resource fluxes (subsidy) from aquatic to terrestrial systems have been less studied, although they are of high ecological relevance particularly for the receiving ecosystem. These fluxes may, however, be impacted by anthropogenically driven alterations modifying structure and functioning of aquatic ecosystems. In this context, we reviewed the peer-reviewed literature for studies addressing the subsidy of terrestrial by aquatic ecosystems with special emphasis on the role that anthropogenic alterations play in this water–land coupling. Our analysis revealed a continuously increasing interest in the coupling of aquatic to terrestrial ecosystems between 1990 and 2014 (total: 661 studies), while the research domains focusing on abiotic (502 studies) and biotic (159 studies) processes are strongly separated. Approximately 35% (abiotic) and 25% (biotic) of the studies focused on the propagation of anthropogenic alterations from the aquatic to the terrestrial system. Among these studies, hydromorphological and hydrological alterations were predominantly assessed, whereas water pollution and invasive species were less frequently investigated. Less than 5% of these studies considered indirect effects in the terrestrial system e.g. via food web responses, as a result of anthropogenic alterations in aquatic ecosystems. Nonetheless, these very few publications indicate far-reaching consequences in the receiving terrestrial ecosystem. For example, bottom-up mediated responses via soil quality can cascade over plant communities up to the level of herbivorous arthropods, while top-down mediated responses via predatory spiders can cascade down to herbivorous arthropods and even plants. Overall, the current state of knowledge calls for an integrated assessment on how these interactions within terrestrial ecosystems are affected by propagation of aquatic ecosystem alterations. To fill these gaps, we propose a scientific framework, which considers abiotic and biotic aspects based on an interdisciplinary approach.
    Keywords: Aquatic–Terrestrial Subsidies ; Flood Events ; Hot Moments ; Hot Spots ; Biogeochemical Processes ; Environmental Chemicals ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 3
    Language: English
    In: Ecotoxicology and Environmental Safety, January 2015, Vol.111, pp.263-270
    Description: Studies assessing the acute and chronic toxicity of silver nanoparticle (nAg) materials rarely consider potential implications of environmental variables. In order to increase our understanding in this respect, we investigated the acute and chronic effects of various nAg materials on . Thereby, different nanoparticle size classes with a citrate coating (20-, ~30-, 60- as well as 100-nm nAg) and one size class without any coating (140 nm) were tested, considering at the same time two pH levels (6.5 and 8.0) as well as the absence or presence of dissolved organic matter (DOM; 〈0.1 or 8.0 mg total organic carbon/L). Results display a reduced toxicity of nAg in media with higher pH and the presence of DOM as well as increasing initial particle size, if similarly coated. This suggests that the associated fraction of Ag species 〈2 nm (including Ag ) is driving the nAg toxicity. This hypothesis is supported by normalizing the 48-h EC -values to Ag species 〈2 nm, which displays comparable toxicity estimates for the majority of the nAg materials assessed. It may therefore be concluded that a combination of both the particle characteristics, i.e. its initial size and surface coating, and environmental factors trigger the toxicity of ion-releasing nanoparticles.
    Keywords: Nanomaterial ; Silver ; Acute Toxicity ; Crustacean ; Environmental Conditions ; Ecology ; Public Health
    ISSN: 0147-6513
    E-ISSN: 1090-2414
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  • 4
    Language: English
    In: Environmental Toxicology and Chemistry, March 2012, Vol.31(3), pp.518-523
    Description: Titanium dioxide nanoparticles (nTiO) form reactive oxygen species (ROS) under irradiation by ultraviolet light (UV). This known photocatalytic activity may finally affect the presence and toxicity of organic environmental chemicals, which have not yet been studied at ambient UV intensity. The authors used a three‐factorial design to evaluate the interaction of the carbamate insecticide pirimicarb (initial nominal concentration, 20 µg/L), ambient UV irradiation (40 W/m for 15 min), and nTiO (∼100 nm; 2.0 mg/L). Pirimicarb, pirimicarb × UV, and pirimicarb × nTiO treatments revealed a median immobilization of after 72 h ranging between 70 and 80%. This effect seemed to be caused by the initial nominal pirimicarb concentration. However, UV irradiation before an exposure of daphnids in the presence of 2.0 mg nTiO/L reduced pirimicarb concentrations to values below the limit of quantification, likely because of the formation of ROS. This reduction was associated with an almost complete removal of toxicity for . Furthermore, during a second experiment, 0.2 mg nTiO/L in combination with 15 min UV irradiation reduced pirimicarb concentrations by approximately 30%. These results indicate a detoxification and therefore remediation potential of the combined application of nTiO and UV irradiation at ambient levels. This potential has not been documented to date in surface waters, where nTiO concentrations in the low to medium µg/L range may occur. Environ. Toxicol. Chem. 2012;31:518–523. © 2011 SETAC
    Keywords: Ultraviolet Light ; Detoxification ; Photocatalysis ; Micropollutants ; Crustacea
    ISSN: 0730-7268
    E-ISSN: 1552-8618
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  • 5
    Language: English
    In: Ecotoxicology and Environmental Safety, Jan, 2015, Vol.111, p.263(8)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ecoenv.2014.09.031 Byline: Frank Seitz, Ricki R. Rosenfeldt, Katharina Storm, George Metreveli, Gabriele E. Schaumann, Ralf Schulz, Mirco Bundschuh Abstract: Studies assessing the acute and chronic toxicity of silver nanoparticle (nAg) materials rarely consider potential implications of environmental variables. In order to increase our understanding in this respect, we investigated the acute and chronic effects of various nAg materials on Daphnia magna. Thereby, different nanoparticle size classes with a citrate coating (20-, ~30-, 60- as well as 100-nm nAg) and one size class without any coating (140nm) were tested, considering at the same time two pH levels (6.5 and 8.0) as well as the absence or presence of dissolved organic matter (DOM; 〈0.1 or 8.0mg total organic carbon/L). Results display a reduced toxicity of nAg in media with higher pH and the presence of DOM as well as increasing initial particle size, if similarly coated. This suggests that the associated fraction of Ag species 〈2nm (including Ag.sup.+) is driving the nAg toxicity. This hypothesis is supported by normalizing the 48-h EC.sub.50-values to Ag species 〈2nm, which displays comparable toxicity estimates for the majority of the nAg materials assessed. It may therefore be concluded that a combination of both the particle characteristics, i.e. its initial size and surface coating, and environmental factors trigger the toxicity of ion-releasing nanoparticles. Author Affiliation: (a) Institute for Environmental Sciences, Group of Ecotoxicology & Environment, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany (b) Institute for Environmental Sciences, Group of Environmental and Soil Chemistry, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany (c) Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Lennart Hjelms Vag 9, 75007 Uppsala, Sweden Article History: Received 10 July 2014; Revised 26 September 2014; Accepted 30 September 2014
    Keywords: Ph -- Analysis ; Toxicity -- Analysis ; Soil Chemistry -- Analysis
    ISSN: 0147-6513
    Source: Cengage Learning, Inc.
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  • 6
    Language: English
    In: Environmental Sciences Europe, 2018, Vol.30(1), pp.1-17
    Description: Nanoparticles serve various industrial and domestic purposes which is reflected in their steadily increasing production volume. This economic success comes along with their presence in the environment and the risk of potentially adverse effects in natural systems. Over the last decade, substantial progress regarding the understanding of sources, fate, and effects of nanoparticles has been made. Predictions of environmental concentrations based on modelling approaches could recently be confirmed by measured concentrations in the field. Nonetheless, analytical techniques are, as covered elsewhere, still under development to more efficiently and reliably characterize and quantify nanoparticles, as well as to detect them in complex environmental matrixes. Simultaneously, the effects of nanoparticles on aquatic and terrestrial systems have received increasing attention. While the debate on the relevance of nanoparticle-released metal ions for their toxicity is still ongoing, it is a re-occurring phenomenon that inert nanoparticles are able to interact with biota through physical pathways such as biological surface coating. This among others interferes with the growth and behaviour of exposed organisms. Moreover, co-occurring contaminants interact with nanoparticles. There is multiple evidence suggesting nanoparticles as a sink for organic and inorganic co-contaminants. On the other hand, in the presence of nanoparticles, repeatedly an elevated effect on the test species induced by the co-contaminants has been reported. In this paper, we highlight recent achievements in the field of nano-ecotoxicology in both aquatic and terrestrial systems but also refer to substantial gaps that require further attention in the future.
    Keywords: Nanomaterials ; Co-contaminants ; Environmental parameters ; Review ; Fate
    ISSN: 2190-4707
    E-ISSN: 2190-4715
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  • 7
    In: Environmental Science: Nano, 2016, Vol.3(2), pp.418-433
    Description: Understanding of the interplay of generally known colloidal transformations under conditions of test media (TM) used during cultivation of organisms and biological effect (=ecotoxicological) studies is still limited, although this knowledge is required for an adequate interpretation of test outcomes and for a comparison among different studies. In this context, we investigated the aggregation and dissolution dynamics of citrate-stabilized silver nanoparticles (Ag NPs) by varying the composition of three TM (ASTM, SAM-5S, and R2A, used during bioassays with Daphnia magna , Gammarus fossarum , and bacterial biofilms, respectively) in the presence and absence of two types of natural organic matter (NOM), namely, Suwanee River humic acid (SRHA) and seaweed extract (SW). Each original test medium induced reaction-limited aggregation of Ag NPs, and aggregation increased from R2A to SAM-5S and ASTM. In addition to the differences in aggregation dynamics, the concentration and speciation of Ag( i ) differed between the three TM, whereby SAM-5S and ASTM are comparable with respect to the nature of the aggregation process but clearly differ from the R2A medium. Furthermore, Cl , mainly present in SAM-5S, induced NP stabilization. The release of silver ions from Ag NPs was controlled by the presence of NOM and organic constituents of TM and by interactions with Cl and Br . The degree of aggregation, formation of interparticle cationNOM bridges or stabilization was larger for Ca 2+ than for Mg 2+ due to the stronger ability of Ca 2+ to interact with citrate or NOM compared to Mg 2+ . These observations and the dependence of aggregation rates on the particle concentration renders the interpretation of doseresponse relationships challenging, but they may open perspectives for targeted ecotoxicological testing by modifications of TM composition.
    Keywords: Bacteria ; Media ; Stabilization ; Concentration (Composition) ; Silver ; Nanoparticles ; Dynamics ; Agglomeration ; Chemical and Electrochemical Properties (MD) ; Chemical and Electrochemical Properties (Ep) ; Chemical and Electrochemical Properties (Ed) ; Chemical and Electrochemical Properties (EC);
    ISSN: 2051-8153
    E-ISSN: 2051-8161
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  • 8
    Language: English
    In: Journal of Nanoparticle Research, 2016, Vol.18(10), pp.1-10
    Description: CeO 2 nanoparticles with various characteristics find an increasing number of applications in the electronic, medical, and other industries and are therefore likely released in the environment. This calls for investigations linking the physicochemical properties of these particles with their potential environmental impacts. In this study, CeO 2 nanoparticle powders were prepared using three different precursors [Ce(NO 3 ) 3 , CeCl 3 , and Ce(CH 3 COO) 3 ] and annealing temperatures (300, 500, and 700 °C). This procedure resulted in nine different types of nanoparticles with differing size (5–90 nm), morphology, surface Ce 3+ /Ce 4+ ratio, and slightly different crystal structures as characterized using transmission electron microscopy, dynamic light scattering, X-ray photoelectron spectroscopy, and X-ray diffraction measurements with Rietveld refinement. These CeO 2 nanoparticles underwent toxicity testing at concentrations up to 64 mg L −1 using Daphnia magna . Toxic effects were observed for three particle types with EC50 values between 5 and 64 mg L −1 . No clear correlation was observed between the physicochemical properties (size, shape, oxygen occupancy, Ce 3+ /Ce 4+ ratio) of the nanoparticles and their toxicity. However, toxicity was correlated with the amount of Ce remaining suspended in the test medium after 24 h. This indicated that toxic effects may depend on the colloidal stability of CeO 2 nanoparticles during the first day of exposure. Therefore, being readily suspended and remaining stable for several days in the aquatic media increases the likelihood that CeO 2 nanoparticles will cause unwanted adverse effects.
    Keywords: CeO ; Ecotoxicity ; Daphnia magna ; XPS ; XRD ; Health and environmental effects
    ISSN: 1388-0764
    E-ISSN: 1572-896X
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