| 1. |
- Fang, Zhao, 1986, et al.
(författare)
-
TiO2 nanoparticle interactions with supported lipid membranes – an example of removal of membrane patches
- 2016
-
Ingår i: RSC Advances. - 2046-2069. ; 6:94, s. 91102-91110
-
Tidskriftsartikel (refereegranskat)abstract
- There is a need for different levels of model systems for effect studies of engineered nanoparticles and the development of nanoparticle structure–activity relationships in biological systems. Descriptors for nanoparticles based on their interactions in molecular model systems may become useful to predict toxicological responses of the nanoparticles in cells. Towards this end, we report on nanoparticle-induced formation of holes in supported model membranes. Specifically, TiO2 nanoparticle – lipid membrane interactions were studied under low ionic strength, basic conditions (pH 8), using different membrane compositions and several surface-sensitive analytical techniques. It was found that for mixed POPC/POPG (PG fractions ≥ 35%) membranes on silica supports, under conditions where electrostatic repulsion was expected, the addition of TiO2 nanoparticles resulted in transient interaction curves, consistent with the removal of part of the lipid membrane. The formation of holes was inferred from quartz crystal microbalance with dissipation (QCM-D) monitoring, as well as from optical measurements by reflectometry, and also verified by atomic force microscopy (AFM) imaging. The interaction between the TiO2 nanoparticles and the PG-containing membranes was dependent on the presence of Ca2+ ions. A mechanism is suggested where TiO2 nanoparticles act as scavengers of Ca2+ ions associated with the supported membrane, leading to weakening of the interaction between the membrane and the support and subsequent removal of lipid mass as TiO2 nanoparticles spontaneously leave the surface. This mechanism is consistent with the observed formation of holes in the supported lipid membranes.
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| 2. |
- Hartmann, Nanna B., et al.
(författare)
-
Are We Speaking the Same Language? Recommendations for a Definition and Categorization Framework for Plastic Debris
- 2019
-
Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 53:3, s. 1039-1047
-
Tidskriftsartikel (refereegranskat)abstract
- Copyright © 2019 American Chemical Society. The accumulation of plastic litter in natural environments is a global issue. Concerns over potential negative impacts on the economy, wildlife, and human health provide strong incentives for improving the sustainable use of plastics. Despite the many voices raised on the issue, we lack a consensus on how to define and categorize plastic debris. This is evident for microplastics, where inconsistent size classes are used and where the materials to be included are under debate. While this is inherent in an emerging research field, an ambiguous terminology results in confusion and miscommunication that may compromise progress in research and mitigation measures. Therefore, we need to be explicit on what exactly we consider plastic debris. Thus, we critically discuss the advantages and disadvantages of a unified terminology, propose a definition and categorization framework, and highlight areas of uncertainty. Going beyond size classes, our framework includes physicochemical properties (polymer composition, solid state, solubility) as defining criteria and size, shape, color, and origin as classifiers for categorization. Acknowledging the rapid evolution of our knowledge on plastic pollution, our framework will promote consensus building within the scientific and regulatory community based on a solid scientific foundation.
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| 3. |
- Kukkonen, J., et al.
(författare)
-
Towards a Comprehensive Evaluation of the Environmental and Health Impacts of Shipping Emissions
- 2022
-
Ingår i: Springer Proceedings in Complexity. - Cham : Springer International Publishing. - 2213-8684 .- 2213-8692. ; , s. 329-336
-
Konferensbidrag (refereegranskat)abstract
- We present a new concept for marine research, applied in the EU-funded project EMERGE, “Evaluation, control and Mitigation of the EnviRonmental impacts of shippinG Emissions” (2020–2024; https://emerge-h2020.eu/ ). For the first time, both the various marine and atmospheric impacts of the shipping sector have been and will be comprehensively analyzed, using a concerted modelling and measurements framework. The experimental part of the project focuses on five European geographical case studies in different ecologically vulnerable regions, and a mobile onboard case study. The EMERGE consortium has also developed a harmonised and integrated modelling framework to assess the combined impacts of shipping emissions, both (i) on the marine ecosystems and (ii) the atmospheric environment. The first results include substantial refinements of a range of models to be applied, especially those for the STEAM and OpenDrift models. In particular, the STEAM (Ship Traffic Emission Assessment Model) model has been extended to allow for the effects of atmospheric and oceanographic factors on the fuel consumption and emissions of the ships. The OpenDrift model has been improved to take into account the partitioning, degradation, and volatilization of pollutants in water. The predicted emission and discharge values have been used as input for both regional scale atmospheric dispersion models, such as WRF-CMAQ (Weather Research and Forecasting—Community Multiscale Air Quality Model) and SILAM (System for Integrated modeLling of Atmospheric composition), and water quality and circulation models, such as OpenDrift (Open source model for the drifting of substances in the ocean) and Delft3D (oceanographic model). The case study regions are Eastern Mediterranean, Northern Adriatic Sea, the Lagoon of Aveiro, the Solent Strait and the Öresund Strait. We have also conducted a substantial part of the experimental campaigns scheduled in the project. The final assessment will include the benefits and costs of control and mitigation options affecting water quality, air pollution exposure, health impacts, climate forcing, and ecotoxicological effects and bioaccumulation of pollutants in marine biota.
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| 4. |
- Nylund, Amanda, 1989, et al.
(författare)
-
Hydrographical implications of ship-induced turbulence in stratified waters, studied through field observations and CFD modelling
- 2023
-
Ingår i: Frontiers in Marine Science. - 2296-7745. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Ship-related energy pollution has received increasing attention but almost exclusively regarding radiated underwater noise, while the effect of ship-induced turbulence is lacking in the literature. Here we present novel results regarding turbulent wake development, the interaction between ship-induced turbulence and stratification, and discuss the impact of turbulent ship wakes in the surface ocean, in areas with intense ship traffic. The turbulent wake development was studied in situ, using Acoustic Doppler Current Profilers (ADCP) and conductivity, temperature, depth (CTD) observations of stratification, and through computational fluid dynamics (CFD) modelling. Our results show that the turbulent wake interacts with natural hydrography by entraining water from below the pycnocline, and that stratification influences the turbulent wake development by dampening the vertical extent, resulting in the wake water spreading out along the pycnocline rather than at the surface. The depth and intensity of the turbulent wake represent an unnatural occurrence of turbulence in the surface ocean. The ship-induced turbulence can impact local hydrography, nutrient dynamics and increase plankton mortality due to physical disturbance, especially in areas with intense traffic. Therefore, sampling and modelling of e.g., contaminants in shipping lanes need to consider hydrographic conditions, as stratification may alter the depth and spread of the wake, which in turn governs dilution. Finally, the frequent ship traffic in estuarine and coastal areas, calls for consideration of ship-induced turbulence when studying hydrographic processes.
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| 5. |
- Zhao, Fang, et al.
(författare)
-
TiO2 nanoparticle interactions with supported lipid membranes – an example of removal of membrane patches
- 2016
-
Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 6:94, s. 91102-91110
-
Tidskriftsartikel (refereegranskat)abstract
- There is a need for different levels of model systems for effect studies of engineered nanoparticles and the development of nanoparticle structure–activity relationships in biological systems. Descriptors for nanoparticles based on their interactions in molecular model systems may become useful to predict toxicological responses of the nanoparticles in cells. Towards this end, we report on nanoparticle-induced formation of holes in supported model membranes. Specifically, TiO2 nanoparticle – lipid membrane interactions were studied under low ionic strength, basic conditions (pH 8), using different membrane compositions and several surface-sensitive analytical techniques. It was found that for mixed POPC/POPG (PG fractions ≥ 35%) membranes on silica supports, under conditions where electrostatic repulsion was expected, the addition of TiO2 nanoparticles resulted in transient interaction curves, consistent with the removal of part of the lipid membrane. The formation of holes was inferred from quartz crystal microbalance with dissipation (QCM-D) monitoring, as well as from optical measurements by reflectometry, and also verified by atomic force microscopy (AFM) imaging. The interaction between the TiO2 nanoparticles and the PG-containing membranes was dependent on the presence of Ca2+ ions. A mechanism is suggested where TiO2 nanoparticles act as scavengers of Ca2+ ions associated with the supported membrane, leading to weakening of the interaction between the membrane and the support and subsequent removal of lipid mass as TiO2 nanoparticles spontaneously leave the surface. This mechanism is consistent with the observed formation of holes in the supported lipid membranes.
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| 6. |
- Abbas, Zareen, 1962, et al.
(författare)
-
Synthesis, characterization and particle size distribution of TiO2 colloidal nanoparticles
- 2011
-
Ingår i: Colloids and Surfaces A: Physicochemical and Engineering Aspects. - : Elsevier BV. - 0927-7757. ; 384:1-3, s. 254-261
-
Tidskriftsartikel (refereegranskat)abstract
- Nanoparticles of controlled size, well defined shape, pure phase and of clean surfaces are ideal model systems to investigate surface/interfacial reactions. In this study we have explored the possibility of synthesizing TiO2 nanoparticles in the size range of 7–20 nm under well controlled experimental conditions. A simple method based on the hydrolysis of TiCl4 was used to obtain particles having surfaces free from organics. Stable dispersions of TiO2 nanoparticles of various sizes were obtained by optimizing the reaction/dialysis time and temperature. The synthesized TiO2 particles were found to be predominantly of anatase phase and narrow particle size distributions were obtained. The TiO2 particles were characterized with respect to their phase, size and shape by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. Particle size distribution in a colloidal dispersion was obtained by the electrospray scanning mobility particle sizer (ES-SMPS) method and compared with an average particle size determined from dynamic light scattering (DLS). The average particle sizes obtained by the DLS and ES-SMPS methods were in good agreement, while a primary particle size of 4 nm was found in X-ray diffraction irrespective of the particle size in solution. Early stages of the nucleation process were monitored by the ES-SMPS method. These results show that small particles of 4–5 nm are initially formed and it is highly likely that large particles are formed due to aggregation of primary particles.
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| 7. |
- Alasonati, E, et al.
(författare)
-
Asymmetrical flow field flow fractionation - Multidetection system as a tool for studying metal-alginate interactions
- 2006
-
Ingår i: Environmental Chemistry. ; 3:3, s. 192-198
-
Tidskriftsartikel (refereegranskat)abstract
- The present study explores the potential use of asymmetrical flow field flow fractionation (aFlFFF) with a multidetection system for the study of metal-alginate interactions. aFlFFF, coupled on-line to a differential refractive index and seven angle laser light scattering detectors was used to provide information on the alginate size distributions. In parallel, the metal distributions of metal-alginate complexes were probed by aFlFFF-high resolution inductively coupled plasma-mass spectrometry. Average values and continuous distributions of molar masses, radiuses of gyration and hydrodynamic radiuses, which are critical for understanding the role of alginates as carriers of metal pollutants, were evaluated in presence of Pb or Cd and compared with those in metal-free solutions of alginate. The values of number average and weight average molar mass, weight average radius of gyration and shape factor for alginate were 150 and 188 kg mol(-1), 53 nm and 1.7, respectively. Alginate molar mass and radius of gyration distributions were slightly shifted to higher values by the addition of micromolar concentrations of Pb or Cd. The alginate size distribution in the presence of Cd was similar to the alginate-alone control, whereas in the presence of Pb the size distribution was broader with a shift of the maximum toward higher molar masses.
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| 8. |
- Arvidsson, Rickard, 1984, et al.
(författare)
-
Challenges in Exposure Modeling of Nanoparticles in Aquatic Environments
- 2011
-
Ingår i: Human and Ecological Risk Assessment. - : Informa UK Limited. - 1080-7039 .- 1549-7860. ; 17:1, s. 245-262
-
Tidskriftsartikel (refereegranskat)abstract
- Managing the potential environmental risks of nanoparticles requires methods to link nanoparticle properties with macro-scale risks. This study outlines challenges in exposure modeling of nanoparticles in aquatic environments, such as the role of natural organic matter, natural colloids, fractal dimensions of agglomerates, coatings and doping of particles, and uncertainties regarding nanoparticle emissions to aquatic environments. The pros and cons of the exposure indicators mass concentration, particle number concentration, and surface area are discussed. By applying colloid chemistry kinetic equations describing particle agglomeration and sedimentation for the case of titanium dioxide nanoparticles, a limited exposure assessment including some of the factors mentioned is conducted with particle number concentration as the exposure indicator. The results of the modeling indicate that sedimentation, shear flows, and settling are of less importance with regard to particle number based predicted environmental concentrations. The inflow of nanoparticles to the water compartment had a significant impact in the model, and the collision efficiency (which is affected by natural organic matter) was shown to greatly affect model output. Implications for exposure modeling, regulation and science are discussed. A broad spectrum of scientific disciplines must be engaged in the development of exposure models where nano-level properties are linked to macro-scale risk.
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| 9. |
- Arvidsson, Rickard, 1984, et al.
(författare)
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Exposure assessments of nanoparticles in aquatic environments – considerations, review and recommendations
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Synthetic nanoparticles are new forms of chemical substances. They can be found in several different forms, such as free particles, surface bound and dissolved in liquid. Nanoparticles can also exist as free, individual particles or agglomerate consisting of multiple particles. This report discusses the assessment of possible risks of nanoparticles. Chemical risk is usually considered to consist of two elements: (1) Exposure to the substance, and (2) the substance's toxicity. So far, the risk-related research on nanoparticles has had a strong focus on the particles ' toxic effects. In this report, we would instead focus on how exposure to nanoparticles can be calculated and assessed, with focus on nanoparticles in water. In the report, we provide an initial background and definitions of nanomaterials and nanoparticles, and describe briefly a standard method of risk assessment of chemicals in the environment. Then we go through important considerations that should be made in the exposure assessment of nanoparticles. First we discuss three considerations related to the emissions of nanoparticles, namely the lack of data for annual production of nanoparticles, the importance of applying a substance flow perspective, and lack of data for so-called emission factors for nanoparticles of various products and materials. Furthermore, we discuss considerations for modeling of nanoparticles behavior in water, mainly by listing a number of key processes with large influence. These are agglomeration, sedimentation, and dissolution. Related to that, we discuss how natural organic materials, coatings and aging of particles can affect these processes. We note here three particle properties that are important in order to describe nanoparticles dispersion in water, in a similar way that the octanol-water partition coefficient and half-life is important to describe the fate of organic chemicals in the environment. For nanoparticles these are the particle size (a) and the density (ρ). We also identify a number of more complex parameters affecting particle behavior in the environment, but not only because of the different particle characteristics, but also depending on characteristics related to the environment. These are the collision efficiency (α), point of zero charge (pHpzc), Hamaker constant (A) and a so-called form factor (β) that affect the sedimentation. In addition to the general difficulty to measure or calculate these parameters they also co-vary. Furthermore, we make a review of 11 currently available exposure models for nanoparticles in aquatic environment. We note that the studies differ regarding modeling method, which sources of emissions that are included, the nanoparticles taken into account, estimated concentrations in the environment, and whether the results are presented as mass or particle concentration. Only two studies trying to model the nanoparticle exposure based on particle properties in a manner similar to standard methods for chemical risk assessment. The other modeling studies are instead based on data on flows of specific nanomaterials, and not on generic algorithms. Next, we describe a number of challenges that occur when measuring nanoparticles in the environment. Finally, we provide the following recommendations to ensure good exposure assessment of nanoparticles in the future: 1. Information of flows and stocks of nanoparticles in society need to be collected. 2. Emission factors would need to be developed for each product that makes use of nanoparticles. 3. Emissions should be reported both as mass and particle number until it becomes clearer which one is most relevant. 4. More research is needed in order to determine which particle properties need to be known in order to calculate the concentration of nanoparticles in the environment. 5. At least the particle size and particle size distribution, as well as the specific particle density should be reported. 6. More research is required to improve the experimental measurements of nanoparticles to be able to validate exposure models.
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| 10. |
- Arvidsson, Rickard, 1984, et al.
(författare)
-
MODELLING ENVIRONMENTAL FATE OF TiO2 NANOPARTICLES IN WATER – IMPLICATIONS FOR EMPIRICAL VALIDATION STUDIES
- 2009
-
Ingår i: 4th International Conference on the Environmental Effects of Nanoparticles and Nanomaterials, 6-9 September, Vienna, Austria.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The potential environmental effects of nanoparticles (NPs) require interdisciplinary research to assess the risks. One part of a risk assessment concerns exposure, which builds on knowledge of the environmental fate. In this particular case the fate of TiO2 NPs in the water compartment was modelled by applying a second order kinetic rate equation and the DLVO theory. Assumptions were made regarding water parameters such as pH, salt concentration and temperature, as well as regarding particle properties such as Hamaker constant, primary particle size and point of zero charge. The effect of sedimentation was taken into account, but as one would expect the influence of sedimentation on such small particles is very small. The model was implemented in MATLAB®. Results indicate the importance of agglomeration as an important fate mechanism, and that pH andpoint of zero charge are important parameters with regards to agglomeration. Other parameters such as the Hamaker constant, salt concentration and temperature were shown not to have a significant effect, which is in goodcorrelation with empirical studies. Also, we would like to see our model validated by empirical studies. Important implications then are to include a continuous inflowof NPs in the experimental setup and to work at environmentally relevant water properties. For example is the effect of natural organic matter (NOM) on theagglomeration not modelled, despite that its significance has been pointed out in many studies. This is due to a weak link between mathematical expressions andempirical data for this particular part of the model. It is of importance that this linkage is strengthened both by theoretical and empirical studies on NOM aimingat producing mathematical expressions, and empirical data, that can assist fate modelling of NPs.
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| 11. |
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| 12. |
- Brandt, Josef, et al.
(författare)
-
Deep Learning for Reconstructing Low-Quality FTIR and Raman Spectra─A Case Study in Microplastic Analyses
- 2021
-
Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 93:49, s. 16360-16368
-
Tidskriftsartikel (refereegranskat)abstract
- Herein we report on a deep-learning method for the removal of instrumental noise and unwanted spectral artifacts in Fourier transform infrared (FTIR) or Raman spectra, especially in automated applications in which a large number of spectra have to be acquired within limited time. Automated batch workflows allowing only a few seconds per measurement, without the possibility of manually optimizing measurement parameters, often result in challenging and heterogeneous datasets. A prominent example of this problem is the automated spectroscopic measurement of particles in environmental samples regarding their content of microplastic (MP) particles. Effective spectral identification is hampered by low signal-to-noise ratios and baseline artifacts as, again, spectral post-processing and analysis must be performed in automated measurements, without adjusting specific parameters for each spectrum. We demonstrate the application of a simple autoencoding neural net for reconstruction of complex spectral distortions, such as high levels of noise, baseline bending, interferences, or distorted bands. Once trained on appropriate data, the network is able to remove all unwanted artifacts in a single pass without the need for tuning spectra-specific parameters and with high computational efficiency. Thus, it offers great potential for monitoring applications with a large number of spectra and limited analysis time with availability of representative data from already completed experiments. © 2021 The Authors. Published by American Chemical Society.
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| 13. |
- Breitbarth, Eike, et al.
(författare)
-
Dissolved iron (II) in the Baltic Sea surface water and implications for cyanobacterial bloom development
- 2009
-
Ingår i: Biogeosciences. ; 6, s. 2397-2420
-
Tidskriftsartikel (refereegranskat)abstract
- Iron chemistry measurements were conducted during summer 2007 at two distinct locations in the Baltic Sea (Gotland Deep and Landsort Deep) to evaluate the role of iron for cyanobacterial bloom development in these estuarine waters. Depth profiles of Fe(II) were measured by chemiluminescent flow injection analysis (CL-FIA) and reveal several origins of Fe(II) to the water column. Photoreduction of Fe(III)-complexes and deposition by rain are main sources of Fe(II) (up to 0.9 nmol L−1) in light penetrated surface waters. Indication for organic Fe(II) complexation resulting in prolonged residence times in oxygenated water was observed. Surface dwelling heterocystous cyanobacteria where mainly responsible for Fe(II) consumption in comparison to other phytoplankton. The significant Fe(II) concentrations in surface waters apparently play a major role in cyanobacterial bloom development in the Baltic Sea and are a major contributor to the Fe requirements of diazotrophs. Second, Fe(II) concentrations up to 1.44 nmol L−1 were observed at water depths below the euphotic zone, but above the oxic anoxic interface. Finally, all Fe(III) is reduced to Fe(II) in anoxic deep water. However, only a fraction thereof is present as ferrous ions (up to 28 nmol L−1) and was detected by the CL-FIA method applied. Despite their high concentrations, it is unlikely that ferrous ions originating from sub-oxic waters could be a temporary source of bioavailable iron to the euphotic zone since mixed layer depths after strong wind events are not deep enough in summer time.
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| 14. |
- Breitbarth, Eike, et al.
(författare)
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Iron biogeochemistry across marine systems – progress from the past decade
- 2010
-
Ingår i: Biogeosciences. - 1726-4170. ; 7, s. 1075-1097
-
Forskningsöversikt (refereegranskat)abstract
- Based on an international workshop (Gothenburg, 14–16 May 2008), this review article aims to combine interdisciplinary knowledge from coastal and open ocean research on iron biogeochemistry. The major scientific findings of the past decade are structured into sections on natural and artificial iron fertilization, iron inputs into coastal and estuarine systems, colloidal iron and organic matter, and biological processes. Potential effects of global climate change, particularly ocean acidification, on iron biogeochemistry are discussed. The findings are synthesized into recommendations for future research areas.
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| 15. |
- Calisi, A., et al.
(författare)
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Ecotoxicological effects of silver nanoparticles in marine mussels
- 2022
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 851
-
Tidskriftsartikel (refereegranskat)abstract
- As the production of silver nanoparticles (AgNPs) is becoming more prevalent, it is becoming increasingly necessary to understand the toxicological effects they can have on different ecosystems. In the marine bioindicator species M. galloprovincialis Lam we predicted toxicity and bioaccumulation of 5 nm alkane-coated and 50 nm uncoated silver nanoparticles (AgNPs) along with silver nitrate as a function of the actual dose level. We generated a time persistence model of silver in seawater and used the Area Under the Curve (AUC) as independent variable in the hazard assessment. This approach allowed us to evaluate unbiased ecotoxicological endpoints for acute (survival) and chronic toxicity (byssal adhesion). Logistic regression analysis rendered an overall LC5096h values of 0.81 & PLUSMN; 0.07 mg h L-1 irrespectively of the silver form. By contrast, for byssal adhesion regression analysis revealed a much higher toxicological potential of silver nitrate vs AgNPs with EC5024h values respectively of 0.0024 & PLUSMN; 0.0009 vs 0.053 & PLUSMN; 0.016 and 0.063 (no computable error for 50 nm AgNP) mg h L-1, undoubtedly confirming a prevalence of ionic silver effects over AgNPs. Bioaccumulation was more efficient for silver nitrate > 5 nm AgNP > 50 nm AgNP reflecting a parallel with the prefer-ential uptake route / target organ. Finally, we derived Risk Quotient (RQs) for acute and chronic effects of nanosilver in shellfish and showed that the RQs are far from the Level of Concern (LoC) at current estimated environmental concentrations (EECs). This information can ultimately help researchers, policy makers, and industry professionals decide how to safely regulate and/or dis-pose of AgNPs.
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| 16. |
- Callegaro, S., et al.
(författare)
-
Effects of alginate on stability and ecotoxicity of nano-TiO2 in artificial seawater LLER CL, 1993, COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTSSYMP ON
- 2015
-
Ingår i: Ecotoxicology and Environmental Safety. - : Elsevier BV. - 0147-6513. ; 117, s. 107-114
-
Tidskriftsartikel (refereegranskat)abstract
- The large-scale use of titanium dioxide nanoparticles (nano-TiO2) in consumer and industrial applications raised environmental health and safety concerns. Potentially impacted ecosystems include estuarine and coastal organisms. Results from ecotoxicological studies with nano-TiO2 dispersed in salt exposure media are difficult to interpret due to fast flocculation and sedimentation phenomena affecting the dispersion stability. The goal of this study was to investigate the stabilisation effect of alginate on uncoated nano-TiO2 in artificial seawater dispersions used in ecotoxicity bioassays. The most effective stabilisation was obtained at alginate concentration of 0.45 g/L after sonicating dispersions for 20 min (100 W). The size distribution remained constant after re-suspension, indicating that no agglomeration occurred after deposition. Ecotoxicity tests on Anemia franciscana and Phaeodactylum tricornutum did not show any adverse effects related to the presence of alginate in the exposure media, and provided evidence on possible reduced bioavailability of nano-TiO2. The suitable concentration of alginate is recommended to occur on a case-by-case basis. (C) 2015 Elsevier Inc. All rights reserved.
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| 17. |
- Cornelis, Geert, 1978, et al.
(författare)
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A signal deconvolution method to discriminate smaller nanoparticles in single particle ICP-MS
- 2014
-
Ingår i: Journal of Analytical Atomic Spectrometry. - : Royal Society of Chemistry (RSC). - 0267-9477. ; 29:1, s. 134-144
-
Tidskriftsartikel (refereegranskat)abstract
- Single particle ICP-MS (spICP-MS) analysis of inorganic nanoparticles (NPs) cannot accurately distinguish dissolved ion signals and signals from relatively small NPs, although these particles are often more reactive than their larger counterparts. A signal deconvolution method was developed for spICP-MS analysis using gold (Au) NPs of nominally 10, 15 or 30 nm diameter. The signal distributions of dissolved Au standards were parameterised as a function of concentration using a mixed Polyagaussian probability mass function. Dissolved curves were fitted using this parameterisation to the low-intensity signals of samples containing NPs to subtract and deconvolute the dissolved signals from the particle signals. The dissolved signals were quantified in this process. The accuracy of the deconvolution method was confirmed for all NP suspensions studied when comparing the size and number concentration obtained with the deconvolution method with values based on transmission electron microscopy. This method thus allows analysis of NP suspensions with spICP-MS where it was hitherto not possible. The applicability domain lies predominantly with relatively small NPs and/or when a relatively high concentration of dissolved ions of the element of interest is present, where overlapping between dissolved and particulate signals occurs.
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| 18. |
- Corsi, I., et al.
(författare)
-
Common Strategies and Technologies for the Ecosafety Assessment and Design of Nanomaterials Entering the Marine Environment
- 2014
-
Ingår i: Acs Nano. - 1936-0851. ; 8:10, s. 9694-9709
-
Tidskriftsartikel (refereegranskat)abstract
- The widespread use of engineered nanomaterials (ENMs) in a variety of technologies and consumer products inevitably causes their release into aquatic environments and final deposition into the oceans. In addition, a growing number of ENM products are being developed specifically for marine applications, such as antifouling coatings and environmental remediation systems, thus increasing the need to address any potential risks for marine organisms and ecosystems. To safeguard the marine environment, major scientific gaps related to assessing and designing ecosafe ENMs need to be filled. In this Nano Focus, we examine key issues related to the state-of-the-art models and analytical tools being developed to understand ecological risks and to design safeguards for marine organisms.
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| 19. |
- Danielsson, Karin, et al.
(författare)
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Influence of organic molecules on the aggregation of TiO2 nanoparticles in acidic conditions
- 2017
-
Ingår i: Journal of nanoparticle research. - : Springer Science and Business Media LLC. - 1388-0764 .- 1572-896X. ; 19
-
Tidskriftsartikel (refereegranskat)abstract
- © 2017, The Author(s).Engineered nanoparticles released into the environment may interact with natural organic matter (NOM). Surface complexation affects the surface potential, which in turn may lead to aggregation of the particles. Aggregation of synthetic TiO2 (anatase) nanoparticles in aqueous suspension was investigated at pH 2.8 as a function of time in the presence of various organic molecules and Suwannee River fulvic acid (SRFA), using dynamic light scattering (DLS) and high-resolution transmission electron microscopy (TEM). Results showed that the average hydrodynamic diameter and ζ-potential were dependent on both concentration and molecular structure of the organic molecule. Results were also compared with those of quantitative batch adsorption experiments. Further, a time study of the aggregation of TiO2 nanoparticles in the presence of 2,3-dihydroxybenzoic acid (2,3-DHBA) and SRFA, respectively, was performed in order to observe changes in ζ-potential and particle size over a time period of 9months. In the 2,3-DHBA-TiO2 system, ζ-potentials decreased with time resulting in charge neutralization and/or inversion depending on ligand concentration. Aggregate sizes increased initially to the micrometer size range, followed by disaggregation after several months. No or very little interaction between SRFA and TiO2 occurred at the lowest concentrations tested. However, at the higher concentrations of SRFA, there was an increase in both aggregate size and the amount of SRFA adsorbed to the TiO2 surface. This was in correlation with the ζ-potential that decreased with increased SRFA concentration, leading to destabilization of the system. These results stress the importance of performing studies over both short and long time periods to better understand and predict the long-term effects of nanoparticles in the environment.
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| 20. |
- Dubascoux, S., et al.
(författare)
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Field-flow fractionation and inductively coupled plasma mass spectrometer coupling: History, development and applications
- 2010
-
Ingår i: Journal of Analytical Atomic Spectrometry. - : Royal Society of Chemistry (RSC). - 0267-9477 .- 1364-5544. ; 25, s. 613-623
-
Tidskriftsartikel (refereegranskat)abstract
- Field-Flow Fractionation (FFF) is now recognised as a versatile pool of techniques allowing particle size or molar mass to be obtained in a wide variety of samples covering numerous applications in the fields of environment, materials or biology. In the same time, Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) has an indisputable place in the field of elemental detectors and the coupling between FFF and ICP-MS can be considered as an emerging technique capable to reach relevant physico-chemical information at sub-micrometre scale and trace element concentration level. This paper gives some key elements of FFF-based fractionation linking theory and practical analytical aspects, from injection and preconcentration to analysis. The different components of the coupling are described. Summary tables of the main operating conditions of FFF-ICP-MS coupling are presented and operating conditions such as carrier composition, flow and nebulizers are discussed. Special attention is given to the FFF-ICP-MS interface. Qualitative and quantitative analysis is also discussed. Applications in the fields of environment, bioanalysis and nanoparticles are presented in order to illustrate the potentialities of such coupling.
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| 21. |
- Farkas, Julia, et al.
(författare)
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Characterization of the effluent from a nanosilver producing washing machine
- 2011
-
Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 37:6, s. 1057-1062
-
Tidskriftsartikel (refereegranskat)abstract
- The increasing number of nanomaterial based consumer products raises concerns about their possible impact on the environment. This study provides an assessment of the effluent from a commercially available silver nanowashing machine. The washing machine released silver in its effluent at an average concentration of 11 mu g L(-1), as determined by inductive coupled mass spectrometry (ICP-MS). The presence of silver nanoparticles (AgNPs) was confirmed by single particle ICP-MS as well as ion selective electrode measurements and filtration techniques. Size measurements showed particles to be in the defined nanosize range, with an average size of 10 nm measured with transmission electron microscopy (TEM) and 60-100 nm determined with nanoparticle tracking analysis (NTA). The effluent was shown to have negative effects on a natural bacterial community as its abundance was clearly reduced when exposed to the nanowash water. If washing machines capable of producing AgNPs become a common feature of households in the future, wastewater will contain significant loadings of AgNPs which might be released into the environment.
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| 22. |
- Farkas, Julia, et al.
(författare)
-
Effects of silver and gold nanoparticles on rainbow trout (Oncorhynchus mykiss) hepatocytes.
- 2010
-
Ingår i: Aquatic toxicology (Amsterdam, Netherlands). - : Elsevier BV. - 1879-1514 .- 0166-445X. ; 96:1, s. 44-52
-
Tidskriftsartikel (refereegranskat)abstract
- The use of nanomaterials is rapidly increasing, while little is known about their possible ecotoxicological effects. This work investigates the toxic effects of silver (Ag) and gold (Au) nanoparticles on rainbow trout hepatocytes. In addition to toxicity assessment the particles were characterized by transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). Hepatocyte primary cultures were exposed to Au and Ag nanoparticles, with and without dissolved organic carbon (DOC), as well as HAuCl(4) and AgNO(3) as ionic solutions at concentrations up to 17.4mg/L and 19mg/L, respectively. Ag and Au particles were within the small nanometer size range when dispersed in pure water. In media with higher ionic strength and DOC, particles tended to agglomerate. Cytotoxicity assessments showed that Ag nanoparticles caused a significant reduction in membrane integrity and cellular metabolic activity in a concentration-dependent manner. Au nanoparticles caused a threefold elevation of ROS levels, but no cytotoxicity occurred at concentrations tested. The addition of DOC did not alter the particles potency of cytotoxicity or ROS induction capacity. The current study shows that Ag and Au nanoparticles have adverse effects on rainbow trout hepatocytes at low mg/L concentrations.
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| 23. |
- Farkas, Julia, et al.
(författare)
-
Uptake and effects of manufactured silver nanoparticles in rainbow trout (Oncorhynchus mykiss) gill cells.
- 2011
-
Ingår i: Aquatic toxicology (Amsterdam, Netherlands). - : Elsevier BV. - 1879-1514 .- 0166-445X. ; 101:1, s. 117-25
-
Tidskriftsartikel (refereegranskat)abstract
- Nanoparticles are already widely used in technology, medicine and consumer products, but there are limited data on their effects on the aquatic environment. In this study the uptake and effect of citrate (AgNP(CIT)) and polyvinylpyrrolidone (AgNP(PVP)) coated manufactured silver nanoparticles, as well as AgNO(3) (Ag(+)) were tested using primary gill cells of rainbow trout (Oncorhynchus mykiss). Prior to use, the nanoparticles were characterized for size, surface charge and aggregation behavior. Gill cells were cultured either as monolayers on solid support, or as multilayers on a permeable support cell culturing system, enabling transport studies. The uptake of silver nanoparticles and Ag(+) after exposure to 10 mg L(-1) was determined with microscopical methods and inductively coupled plasma mass spectrometry (ICP-MS). Cytotoxicity, in terms of membrane integrity, as well as oxidative stress (depletion of reduced glutathione) was tested at silver concentrations ranging from 0.1 mg L(-1) to 10 mg L(-1). Results show that AgNP(CIT) nanoparticles are readily taken up into gill cell monolayers while uptake was less for AgNP(PVP). In contrast, it appears that the slightly smaller AgNP(PVP) were transported through cultured multilayers to a higher extent, with transport rates generally being in the ng cm(-2) range for 48 h exposures. Transport rates for all exposures were dependent on the epithelial tightness. Moderate cytotoxic effects were seen for all silver treatments. Levels of reduced glutathione were elevated in contrast to control groups, pointing on a possible overcompensation reaction. Taken together silver nanoparticles were taken up into cells and did cause silver transport over cultured epithelial layers with uptake and transport rates being different for the two nanoparticle species. All silver treatments had measurable effects on cell viability.
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| 24. |
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| 25. |
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| 26. |
- Gallego-Urrea, Julian A., 1977, et al.
(författare)
-
Coagulation and sedimentation of gold nanoparticles and illite in model natural waters: Influence of initial particle concentration
- 2016
-
Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 3-4, s. 67-74
-
Tidskriftsartikel (refereegranskat)abstract
- Gold nanoparticles (AuNP) possess unique characteristics that render them adequate for applications and also to be used as a model NP to evaluate the fate and behavior at low NP concentrations due to the ease of detection by modern analytical techniques. Moreover, AuNP may result in some negative effects in the environment and there is a necessity to predict their aquatic environmental concentrations by parameterizing the underlying transport and transformation processes. This study investigated the coagulation and sedimentation of 30 nm citrate-coated AuNP under enviro-mimicking conditions, i.e. model natural freshwaters (MNW) covering the range of European water chemistries relevant for colloids and NP (major ions, pH and dissolved organic matter) and artificial seawater (ASW). Firstly, the coagulation rates of AuNP at mg/L concentrations were evaluated using time-resolved dynamic light scattering which showed a decreased rate upon addition of Suwannee river natural organic matter (SRNOM) at low ionic strength (IS) but remained relatively high at high IS. Contrastingly, AuNP approaching environmental realistic concentrations (80 μg/L) in quiescent microcosms showed slow decline rates in all MNW and ASW regardless of the presence of SRNOM, as measured by nanoparticle tracking analysis and elemental Au spectrometry. When illite was added as model natural colloid the rates of decline of AuNP remained low as well. This is owing to limited collisions at low particle number concentrations. The results show that besides IS, pH, NOM concentration and type and the intrinsic surface charge of the particles, the particle number concentration and size distribution of both AuNP and natural colloids determine the extent of the large-scale fate of NP in aquatic environments.
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| 27. |
- Gallego-Urrea, Julian A., 1977, et al.
(författare)
-
Influence of different types of natural organic matter on titania nanoparticle stability: effects of counter ion concentration and pH
- 2014
-
Ingår i: Environmental Science-Nano. - : Royal Society of Chemistry (RSC). - 2051-8153. ; 1:2, s. 181-189
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of biopolymeric (alginate) and refractory macromolecules (humic and fulvic acids) on the aggregation kinetics of anatase titanium dioxide (titania) nanoparticles were evaluated. The particles were synthesized using a wet-chemical method based on the hydrolysis of TiCl4. Stable suspensions of positively-charged titania were obtained at pH 2.5. One batch of this product was shifted above the point of zero charge to pH 12. These dispersions were mixed with three different types of well characterized environmental macromolecules: sodium alginate, fulvic acid and humic acid, and evaluated in terms of the stability. Changes in the particle size were measured using time-resolved dynamic light scattering (TR-DLS) at different concentrations of three electrolytes: NaCl, CaCl2 and Na2SO4, and at different solution pH values. Results were in agreement with DLVO calculations. The use of TR-DLS for determining aggregation rates is critically discussed.
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| 28. |
- Gallego-Urrea, Julian A., 1977, et al.
(författare)
-
Measurements of nanoparticle number concentrations and size distributions in contrasting aquatic environments using nanoparticle tracking analysis
- 2010
-
Ingår i: Environmental Chemistry. - 1449-8979. ; 7, s. 67-81
-
Tidskriftsartikel (refereegranskat)abstract
- A feasibility study of nanoparticle tracking analysis (NTA) for aquatic environmental samples is presented here. The method has certain virtues such as minimum perturbation of the samples, high sensitivity in terms of particle concentration, and provision of number-based size distributions for aquatic samples. NTA gave linear calibration curves in terms of number concentration and accurately reproduced size measurements of certified reference material nanoparticles. However, the accuracy of the size distributions obtained with this method exhibited a high dependence on set-up parameters and the concentrations were shown to be strongly correlated with the refractive index of the material under examination. Different detection cameras and different data acquisition modeswere compared and evaluated. Also, the effect of filtration of the samples was assessed. The size distributions for the contrasting environmental samples were fairly reasonable compared with other studies but an underestimation of small sizes was observed, which can be explained by a materialdependent lower detection limit in terms of size. The number concentrations obtained for the natural nanoparticles ranged from 0.5 to 20×108 particles mL−1 and correlated well with conventional turbidity measurements.
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| 29. |
- Gallego-Urrea, Julian A., 1977, et al.
(författare)
-
Multimethod 3D characterization of natural plate-like nanoparticles: shape effects on equivalent size measurements
- 2014
-
Ingår i: Journal of nanoparticle research. - : Springer Science and Business Media LLC. - 1388-0764 .- 1572-896X. ; 16:5
-
Tidskriftsartikel (refereegranskat)abstract
- The fundamental properties and processes that govern nanoparticle behavior in colloidal dispersions are critical to predict their performance in applications and also their environmental and health implications. Illite is a platy clay mineral that is present in large amounts in aquatic environments and can be used as a model natural particle for environmental risk assessment. However, the high-aspect ratio of illite makes conventional analysis, usually assuming a spherical size, insufficient for the assessment of shape-dependent properties. In the current paper, a multimethod characterization of a suspension of illite particles was done using atomic force microscopy, scanning electron microscopy, dynamic light scattering (DLS), nanoparticle tracking analysis, differential centrifugal sedimentation, and centrifugal- field flow fractionation coupled to multiangle light scattering and DLS. The relation between the different measurands was investigated, and the effect of the shape on the equivalent particle size was reported. While some of the used techniques are capable of assessing the aspect ratio of illite, the results confirm the need for multiple techniques and analysis of different types of measurands especially for high-aspect-ratio particles.
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| 30. |
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| 31. |
- Gelting, J., et al.
(författare)
-
Fractionation of iron species and iron isotopes in the Baltic Sea euphotic zone
- 2009
-
Ingår i: Biogeosciences Discuss.. ; 6, s. 6635-6694
-
Tidskriftsartikel (refereegranskat)abstract
- Measurements of the physiochemical speciation of Fe in the euphotic zone were performed at three different locations, over a well defined salinity gradient, during spring and summer in the Baltic Sea. The average of total Fe changed from 114 nM in the Bothnian Sea, 44 nM at Landsort Deep and 15 nM at Gotland Deep. Particulate Fe (PFe) was the dominating phase at all stations and on average accounted for 75–85% of the total Fe pool. At all three locations, a decrease in total Fe of 80–90% from initial measurements compared to the summer was found. A strong positive correlation between PFe and chl-a was observed. Hence, primary production strongly regulates cycling of suspended Fe. However, this relation is not dominated by active uptake of Fe in phytoplankton; instead this reflects cycling of phosphorus, growth of diatoms, and removal of PFe during phytoplankton sedimentation. The average colloidal iron fraction, CFe, showed decreasing concentrations along the salinity gradient; Bothnian Sea 15 nM; Landsort Deep 1 nM and Gotland Deep 0.5 nM. Field Flow Fractionation data indicate that the main colloidal carrier phase for Fe in the Baltic Sea is a carbon-rich fulvic acid associated compound, likely of riverine origin. The Fe isotope composition (δ56Fe) of the PFe showed constant positive values in the Bothnian Sea surface waters (+0.08 to +0.20‰). Enrichment of heavy Fe in the Bothnian Sea PFe is most likely associated to input of aggregated land derived Fe-oxyhydroxides and a rapid overturn of Fe(II). At the Landsort deep, the fractionation of PFe changed between −0.08‰ to +0.28‰. The negative values, in early spring, probably indicate exchange over the oxic-anoxic boundary at ~80 m depth.
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| 32. |
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| 33. |
- Gonçalves, Sandra F., et al.
(författare)
-
Effects of silver nanoparticles to the freshwater snail Physa acuta: The role of test media and snails' life cycle stage
- 2017
-
Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 36:1, s. 243-253
-
Tidskriftsartikel (refereegranskat)abstract
- Silver nanoparticles (AgNP) are highly used worldwide, which will most likely lead to their release to the environment and subsequently increase environmental concentrations. Therefore studying AgNPs' deleterious effects to organisms is crucial to understand their environmental impacts. The freshwater snail Physa acuta was chosen to evaluate the potential deleterious effects of AgNP and counterpart AgNO3, through water only exposures. AgNPs' toxicity is greatly influenced by medium composition. Thus, two test media were tested: Artificial Pond Water (APW) and modified APW (modified by removing calcium chloride from medium). Acute tests (96h) were performed with juvenile and adult snails, in both media, to assess lethality, and egg mass chronic tests, with APW medium only, to assess embryo viability and mortality, carried out until reaching 90% hatching success in the control. Acute toxicity increased with decreasing shell length for both silver forms (ion and nanoparticle), i.e. juveniles where more sensitive than adults. Different test media led to dissimilar LC50 values, with chloride playing an important role in toxicity, most probably by complexation with silver ions and thus reducing silver's bioavailability, uptake and toxicity. Chronic tests showed that hatching success was more sensitive to silver in the ionic form than in the particulate form. Different forms of silver, exposure media and life cycle stages led to different patterns of toxicity, highlighting an impairment in the snails' life cycle.
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| 34. |
- Gondikas, Andreas P., 1981, et al.
(författare)
-
Nanomaterial Fate in Seawater: A Rapid Sink or Intermittent Stabilization?
- 2020
-
Ingår i: Frontiers in Environmental Science. - : Frontiers Media SA. - 2296-665X. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Coastal seas and oceans receive engineered nanoparticles that are released from nano-enabled consumer and industrial products and incidental nanoparticles that are formed as byproducts of combustion and friction. The marine environment is often perceived as a rapid sink for particles, because of the high salinity promoting the attachment between particles producing heavy agglomerates that sediment on the seafloor. In this work the effect of seasonal production of extracellular polymeric substances (EPS) on particle stability is tested using seawater collected from the Gullmarn fjord in the winter, spring, and summer. A novel approach is used that is based on light scattering of the bulk particle population for tracking agglomerates and of single particles for tracking particles smaller than approximately 300 nm. Results show that organic particles formed from EPS during algal blooms are capable of stabilizing nanoparticles in marine waters for at least 48 h. In contrast, particles agglomerate rapidly in the same seawater that has previously been filtered through 0.02 mu m pore size membranes. Furthermore, particles with fibrillar shape have been detected using atomic force microscopy, supporting the argument that organic particles from EPS are responsible for the stabilization effect. These results suggest that seasonal biological activity can act as an intermittent stabilization factor for nanoparticles in marine waters.
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| 35. |
- Gossmann, I., et al.
(författare)
-
Unraveling the Marine Microplastic Cycle: The First Simultaneous Data Set for Air, Sea Surface Microlayer, and Underlying Water
- 2023
-
Ingår i: Environmental Science & Technology. - 0013-936X. ; 57:43, s. 16541-16551
-
Tidskriftsartikel (refereegranskat)abstract
- Microplastics (MP) including tire wear particles (TWP) are ubiquitous. However, their mass loads, transport, and vertical behavior in water bodies and overlying air are never studied simultaneously before. Particularly, the sea surface microlayer (SML), a ubiquitous, predominantly organic, and gelatinous film (<1 mm), is interesting since it may favor MP enrichment. In this study, a remote-controlled research catamaran simultaneously sampled air, SML, and underlying water (ULW) in Swedish fjords of variable anthropogenic impacts (urban, industrial, and rural) to fill these knowledge gaps in the marine-atmospheric MP cycle. Polymer clusters and TWP were identified and quantified with pyrolysis-gas chromatography-mass spectrometry. Air samples contained clusters of polyethylene terephthalate, polycarbonate, and polystyrene (max 50 ng MP m(-3)). In water samples (max. 10.8 mu g MP L-1), mainly TWP and clusters of poly-(methyl methacrylate) and polyethylene terephthalate occurred. Here, TWP prevailed in the SML, while the poly-(methyl methacrylate) cluster dominated the ULW. However, no general MP enrichment was observed in the SML. Elevated anthropogenic influences in urban and industrial compared to the rural fjord areas were reflected by enhanced MP levels in these areas. Vertical MP movement behavior and distribution were not only linked to polymer characteristics but also to polymer sources and environmental conditions.
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| 36. |
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| 37. |
- Hammes, Julia, et al.
(författare)
-
Geographically distributed classification of surface water chemical parameters influencing fate and behavior of nanoparticles and colloid facilitated contaminant transport.
- 2013
-
Ingår i: Water Research. - : Elsevier BV. - 0043-1354. ; 47:14, s. 5350-5361
-
Tidskriftsartikel (refereegranskat)abstract
- The current production and use of nanomaterials in consumer products have increased the concern about the possibility that these enter the rivers during their entire life cycle. Further, many aquatic contaminants undergo partitioning to the ubiquitous aquatic colloids. Here is presented the development of a set of European water types for environmental risk assessment of chemicals transported as nanovectors as is the case of environmental fate of manufactured nanoparticles and colloid-bound contaminants. A compilation of river quality geochemical data with information about multi-element composition for near 800 rivers in Europe was used to perform a principal component analysis (PCA) and define 6 contrasting water classes. With the aid of geographical information system algorithms, it was possible to analyse how the different sampling locations were predominantly represented within each European water framework directive drainage basin. These water classes and their associated Debye–Hückel parameter are determining factors to evaluate the large scale fate and behaviour of nanomaterials and other colloid-transported pollutants in the European aquatic environment.
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| 38. |
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| 39. |
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| 40. |
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| 41. |
- Hassellöv, Martin, 1970, et al.
(författare)
-
Application of cross-flow ultrafiltration for the determination of colloidal abundances in suboxic ferrous-rich ground waters.
- 2007
-
Ingår i: The Science of the total environment. - : Elsevier BV. - 0048-9697. ; 372:2-3, s. 636-44
-
Tidskriftsartikel (refereegranskat)abstract
- A suboxic groundwater from a sandy coastal aquifer was sampled using a new air free, large volume sampling method. Subsequent processing for size fractionation was completed with a modified cross-flow ultrafiltration (CFF) system equipped with a 1 kDa CFF membrane. By purging the CFF system with nitrogen, no oxygen was able to reach the sample. With this optimization, the sample was processed with higher than 90% recovery in terms of both iron and phosphate. Only about 4% of iron and 20% of phosphate in the filtered (0.2 microm) groundwater sample was found to be in colloidal form in the groundwater. In contrast, if no care was taken to maintain the suboxic environment of the original sample, iron was rapidly and completely oxidized and subsequently adsorbed to the CFF membrane. Other elements, such as phosphorus, were also lost to the CFF membrane to a substantial degree, and the mechanism is most likely coprecipitation with iron oxides. This study thus strongly supports the importance of maintaining ambient redox conditions during sampling and fractionation, especially for the determinations of colloid abundances in groundwater.
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| 42. |
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| 43. |
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| 44. |
- Hassellöv, Martin, 1970, et al.
(författare)
-
Detection methods for FFF
- 2005
-
Ingår i: Encyclopedia of Chromatography, 2nd edition. - New York City : Marcel Dekker Inc.. ; , s. 437-442
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 45. |
- Hassellöv, Martin, 1970, et al.
(författare)
-
Iron Oxides as Geochemical Nanovectors for Metal Transport in Soil-River Systems
- 2009
-
Ingår i: Elements. - : Mineralogical Society of America. - 1811-5209 .- 1811-5217. ; 4:6, s. 401-406
-
Tidskriftsartikel (refereegranskat)abstract
- Topsoils are often contaminated by trace metals, and it is important to understand how different processes govern the transport of such metals to fresh and marine waters. This paper presents measurements of natural nanoparticles and colloidal organic matter in soil and river samples from Germany and Sweden. In our analytical approach, a nanoparticle separation technique is combined with multielement detection and applied to soil and river samples to link the macroscale field observations with detailed molecular studies in the laboratory. It was determined that lead is associated with iron oxide colloids, which are ubiquitous nanoparticles that can be efficiently transported. Eventually both iron oxides and lead are removed by flocculation under conditions of estuarine mixing. Iron-rich nanoparticles compete efficiently with natural organic matter (NOM) complexation for lead binding in both the soil and river systems studied.
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| 46. |
- Hassellöv, Martin, 1970
(författare)
-
Large volume sample injection in FFF
- 2005
-
Ingår i: Encyclopedia of Chromatography, 2nd edition. - New York City : Marcel Dekker Inc.. ; , s. 911-913
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 47. |
- Hassellöv, Martin, 1970, et al.
(författare)
-
Marint mikroskopiskt skräp längs Bohuskusten 2015 - i jämförelse med tidigare studier 2013 och 2014
- 2018
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Prover för mikroskopiskt skräp togs i november 2015 på 14 lokaler längs västkusten på uppdrag av Länsstyrelsen i Västra Götalands län och rapporteras här i detalj tillsammans med jämförelser från tidigare provtagningstillfällen (december 2013, april 2014 och december 2014) på samma lokaler. Syftet har varit att mäta halter och karaktärisera mikroskopiskt skräp samt undersöka lämpliga metodval för eventuella framtida övervakningsprogram. •Halter och karaktär av mikroskräp varierade stort beroende på vilken provtagnings- och filtreringsmetod som användes. Undersökningen 2015noterade ca 100 000 gånger högre halter av mikroskräpspartiklar frånytvattenprover på ett filter med storlek 10 μm (0,01 mm) jämfört med 300μm (0,3 mm) siktduk som användes vid trålning i havsytan. •Antalet antropogena (av mänskligt ursprung) partiklar som fastnade på 300μm filter varierade från ca. 0.1 till ca. 10 partiklar/m3 havsvatten oTill skillnad från tidigare provtagningar med 300μm som utförtsmed pump strax under havsytan så gav detta års trålprovtagning ejlika dominerande inslag av fibrer, utan plastpartiklar och fibreråterfanns i jämförbar förekomst. oHalterna 2015 var i samma storleksordning som tidigarerapporterats för svenska kustvatten. Dock hade fördelningen mellanplastpartiklar och syntetiska fibrer förskjutits mot plastpartiklarvilket kan förklaras mot systematiska skillnader i tidigareprovtagningsmetodik. •I proverna som togs med 10 μm filter återfanns i genomsnitt ca. 38mikroskräpspartiklar per liter (exkl. svarta och röda) vilket var en vissökning från tidigare provtagningar (18/l dec 2013 och april 2014 samt 9/ldec 2014). oEn högre förekomst av röda partiklar (58 partiklar/liter) uppmättes.Kemiska analyser visade dock att flertalet av de röda partiklarnabestod av järnoxider; dvs ej nödvändigtvis dominerat av partiklarfrån båtbottenfärg som tidigare antagits. Endast en mindre andelröda partiklar kan härröra från polymert ursprung. Därmed har rödapartiklar inte räknats in i samlingsbegreppet mikroskräp. oHalterna av potentiella förbränningspartiklar på 10 μm filter varmycket höga i Göteborgsområdet, Stenungsund samt Brofjorden.Genomsnittligt antal i Göteborgsområdet var ca. 3000 partiklar perliter. Medelhalten för alla stationer var cirka 1800 partiklar per liter. oSyntetfibrer och naturfibrer förekom i högst halter i Danafjord,Åstol, Galterön och Stretudden vilket troligtvis kan härledas tillutsläpp från avloppsreningsverk i närheten till provtagningspunkterna. • Resultaten pekar såväl i år som tidigare år på att stadsmiljön är en viktig källa till marint mikroskopiskt skräp. Källor kan vara från kommunala avlopp, dagvatten från vägar och stadsytor, industrier samt olika former av förbränning. • Förekomst av mikroskopiska skräppartiklar undersöktes i utgående vatten från fyra kommunala avloppsreningsverk (ARV): Uddevalla, Strömstad, Stenungsund och Skärhamn. För undersökningen kunde följande noteras; o Antalet uppmätta mikroskräppartiklar uppgick till mellan ca 10 och 80 partiklar per kubikmeter utgående vatten, med lägst antal partiklar i Skansverket (Uddevalla) och mest partiklar i Stenungsund. Dagarna innan provtagning i Stenungsund hade det regnat kraftigt vilket kan påverka resultatet. o Halterna var väsentligt lägre än de flesta tidigare mätningar avseende partiklar och syntetiska fibrer och kraftigt lägre avseende på ickesyntetiska fibrer. Största andelen (över 50% i vissa fall) av partiklarna bestod av fibrer (syntetiska och icke syntetiska), men det ska noteras att filter med storlek 300 μm förmodligen underskattar fiberhalten väsentligt
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| 48. |
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| 49. |
- Hassellöv, Martin, 1970, et al.
(författare)
-
Progress towards monitoring of microlitter in Scandinavian marine environments: State of knowledge and challenges
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Microlitter consists of minute particles of anthropogenic or processed natural material. The project brings together research groups to conduct specific case studies in gradients from near urban sources such as the traffic environment and cities to the coastal water and sediments in order to study the relative occurrence of specific sources and their environmental dispersion and distribution. The conclusion were first that in sediments from the road environment (tunnel runoff water), tire particles, asphalt and road markings could be identified, and in the urban creek sediments many black particles including elastomers, charcoal-like and oil and soot where in high abundance and decreased rapidly out in the recipient. The results emphasize the role of the cities as hotspot source functions for microlitter in the coastal environment and also where mitigating measures could be directed.
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| 50. |
- Hassellöv, Martin, 1970, et al.
(författare)
-
REACH missar nano!
- 2009
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Ingår i: Miljöforskning. ; 2009:3-4
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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