The persistence and transformation of silver nanoparticles in littoral lake mesocosms monitored using various analytical techniques

2014 ◽  
Vol 11 (4) ◽  
pp. 419 ◽  
Author(s):  
Lindsay M. Furtado ◽  
Md Ehsanul Hoque ◽  
Denise M. Mitrano ◽  
James F. Ranville ◽  
Beth Cheever ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Surface Waters ◽  
Lake Water ◽  
Natural Waters ◽  
Municipal Wastewater ◽  
Analytical Techniques ◽  
Aquatic Organisms ◽  
Silver Ions ◽  
Icp Ms ◽  
The Individual

Environmental context Silver nanoparticles discharged with municipal wastewater may contaminate surface waters and harm aquatic ecosystems. We applied several analytical techniques to investigate the persistence and transformation of silver nanoparticles in a natural lake environment, and show, through multiple lines of evidence, that they persisted in lake water for several weeks after addition. The nanoparticles were releasing silver ions through dissolution, but these toxic ions were likely binding with natural organic matter in the lake water. Abstract Silver nanoparticles (AgNPs) may be released into surface waters, where they can affect aquatic organisms. However, agglomeration, dissolution, surface modifications and chemical speciation are important processes that control the toxicity of AgNPs. The purpose of the study was to apply various methods for monitoring the persistence and transformation of AgNPs added to littoral lake mesocosms. Analysis of total Ag showed that the levels in the mesocosms declined rapidly in the first 12h after addition, followed by a slower rate of dissipation with a half-life (t1/2) of ~20 days. Analysis using single particle ICP-MS (spICP-MS) showed no evidence of extensive homo-agglomeration of AgNPs. The stability of AgNPs was likely due to the low ionic strength and high concentrations of humic-rich dissolved organic carbon (DOC) in the lake water. Analyses by spICP-MS, cloud point extraction (CPE) and asymmetric flow field flow fractionation coupled to ICP-MS (AF4-ICP-MS) all indicated that the concentrations of AgNP decreased over time, and the nanoparticles underwent dissolution. However, the concentrations of dissolved silver, which includes Ag+, were generally below detection limits when analysed by centrifugal ultrafiltration and spICP-MS. It is likely that the majority of free ions released by dissolution were complexing with natural organic material, such as DOC. An association with DOC would be expected to reduce the toxicity of Ag+ in natural waters. Overall, we were able to characterise AgNP transformations in natural waters at toxicologically relevant concentrations through the use of multiple analytical techniques that compensate for the limitations of the individual methods.

scholarly journals Uranium Speciation and Bioavailability in Aquatic Systems: An Overview

2002 ◽  
Vol 2 ◽  
pp. 707-729 ◽  
Author(s):  
Scott J. Markich
Keyword(s):  
Surface Waters ◽  
Metal Ion ◽  
Natural Waters ◽  
Analytical Techniques ◽  
Time Resolved ◽  
Analytical Technique ◽  
Major Form ◽  
Uranyl Carbonate ◽  
Inorganic Ligands ◽  
The Relationship

The speciation of uranium (U) in relation to its bioavailability is reviewed for surface waters (fresh- and seawater) and their sediments. A summary of available analytical and modeling techniques for determining U speciation is also presented. U(VI) is the major form of U in oxic surface waters, while U(IV) is the major form in anoxic waters. The bioavailability of U (i.e., its ability to bind to or traverse the cell surface of an organism) is dependent on its speciation, or physicochemical form. U occurs in surface waters in a variety of physicochemical forms, including the free metal ion (U4+or UO22+) and complexes with inorganic ligands (e.g., uranyl carbonate or uranyl phosphate), and humic substances (HS) (e.g., uranyl fulvate) in dissolved, colloidal, and/or particulate forms. Although the relationship between U speciation and bioavailability is complex, there is reasonable evidence to indicate that UO22+and UO2OH+are the major forms of U(VI) available to organisms, rather than U in strong complexes (e.g., uranyl fulvate) or adsorbed to colloidal and/or particulate matter. U(VI) complexes with inorganic ligands (e.g., carbonate or phosphate) and HS apparently reduce the bioavailability of U by reducing the activity of UO22+and UO2OH+. The majority of studies have used the results from thermodynamic speciation modeling to support these conclusions. Time-resolved laser-induced fluorescence spectroscopy is the only analytical technique able to directly determine specific U species, but is limited in use to freshwaters of low pH and ionic strength. Nearly all of the available information relating the speciation of U to its bioavailability has been derived using simple, chemically defined experimental freshwaters, rather than natural waters. No data are available for estuarine or seawater. Furthermore, there are no available data on the relationship between U speciation and bioavailability in sediments. An understanding of this relationship has been hindered due to the lack of direct quantitative U speciation techniques for particulate phases. More robust analytical techniques for determining the speciation of U in natural surface waters are needed before the relationship between U speciation and bioavailability can be clarified.

scholarly journals Heteroagglomeration of nanosilver with colloidal SiO2 and clay

2017 ◽  
Vol 14 (1) ◽  
pp. 1 ◽  
Author(s):  
Sébastien Maillette ◽  
Caroline Peyrot ◽  
Tapas Purkait ◽  
Muhammad Iqbal ◽  
Jonathan G. C. Veinot ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Polyacrylic Acid ◽  
Natural Waters ◽  
Colloidal Particles ◽  
Colloidal Stability ◽  
Analytical Techniques ◽  
Dark Field ◽  
Correlation Spectroscopy ◽  
Colloidal Clay ◽  
High Concentrations

Environmental contextThe fate of nanomaterials in the environment is related to their colloidal stability. Although numerous studies have examined their homoagglomeration, their low concentration and the presence of high concentrations of natural particles implies that heteroagglomeration rather than homoagglomeration is likely to occur under natural conditions. In this paper, two state-of-the art analytical techniques were used to identify the conditions under which nanosilver was most likely to form heteroagglomerates in natural waters. AbstractThe environmental risk of nanomaterials will depend on their persistence, mobility, toxicity and bioaccumulation. Each of these parameters is related to their fate (especially dissolution, agglomeration). The goal of this paper was to understand the heteroagglomeration of silver nanoparticles in natural waters. Two small silver nanoparticles (nAg, ~3nm; polyacrylic acid- and citrate-stabilised) were covalently labelled with a fluorescent dye and then mixed with colloidal silicon oxides (SiO2, ~18.5nm) or clays (~550nm SWy-2 montmorillonite). Homo- and heteroagglomeration of the nAg were first studied in controlled synthetic waters that were representative of natural fresh waters (50μg Ag L–1; pH 7.0; ionic strength 10–7 to 10–1 M Ca) by following the sizes of the nAg by fluorescence correlation spectroscopy. The polyacrylic acid-coated nanosilver was extremely stable under all conditions, including in the presence of other colloids and at high ionic strengths. However, the citrate-coated nanosilver formed heteroaggregates in presence of both colloidal SiO2 and clay particles. Nanoparticle surface properties appeared to play a key role in controlling the physicochemical stability of the nAg. For example, the polyacrylic acid stabilized nAg-remained extremely stable in the water column, even under conditions for which surrounding colloidal particles were agglomerating. Finally, enhanced dark-field microscopy was then used to further characterise the heteroagglomeration of a citrate-coated nAg with suspensions of colloidal clay, colloidal SiO2 or natural (river) water.

Zirconium interferences on the detection of silver nanoparticles by single particle ICP-MS: implications on natural water analysis

2020 ◽  
Author(s):  
Patrice Turcotte ◽  
Christian Gagnon
Keyword(s):  
Mass Spectrometry ◽  
Water Analysis ◽  
Surface Waters ◽  
Single Particle ◽  
False Positive ◽  
Natural Waters ◽  
Argon Plasma ◽  
Hand Detection ◽  
Zirconium Oxides ◽  
Icp Ms

Abstract Background: The analysis of silver nanoparticle (NP-Ag) by the single particle technique with argon plasma-coupled mass spectrometry (SP-ICP-MS) is an increasingly used analytical approach. The sensitive technique, distinguishing particle size distribution, allows working at concentrations similar to those found in environmental samples. The two natural Ag isotopes 107 and 109, with abundances of 52 and 48% respectively, have similar sensitivity in ICP-MS detection. However, it is common to encounter isobaric interferences in mass spectrometry, and the element silver is not an exception, as much with the 107 isotope as 109. For both isotopes, zirconium oxides present isobaric interferences, either 91Zr16O, 90Zr16O1H for the isotope 107 and the 92Zr16O1H for the 109. Results: For surface water analysis by ICP-MS in regular technique, these interferences do not generally impact the analysis of total Ag concentrations (mainly dissolved) as they can be then simply subtracted like background signal. On the other hand, detection of NPAg was impacted by the interfering colloidal Zr. The analysis of Zr by the SP-ICP-MS technique of surface waters showed the presence of colloidal Zr, a random signal that cannot be simply subtracted from NP Ag signal. Our results show that, Zr colloids are effectively interfering with the NP-Ag assays by SP-ICP-MS technique where interferences translated into a false positive. Conclusion: The analytical issue related isobaric interferences from the naturally occurring colloidal Zr was attenuated (up to 250% in this assay) by the use of the 109 isotope in the Ag detection, limiting false positive detections and improving the reliability of NP-Ag measurements in natural waters. Therefore , more specific detection of NP Ag in surface waters that naturally contain Zr colloids can be accomplished.

scholarly journals Occurrence and size distribution of silver nanoparticles in wastewater effluents from various treatment processes in Canada

2021 ◽  
Author(s):  
Christian Gagnon ◽  
Patrice Turcotte ◽  
François Gagné ◽  
Shirley Anne Smyth
Keyword(s):  
Silver Nanoparticles ◽  
Size Distribution ◽  
Particle Number ◽  
Aquatic Organisms ◽  
Consumer Products ◽  
Treatment Technology ◽  
Ag Nps ◽  
Toxicological Effects ◽  
Treatment Processes ◽  
Icp Ms

AbstractThe occurrence of silver (Ag) in urban effluents is partly associated with the increasing use of silver nanoparticles (Ag NPs) as an antiseptic agent in various consumer products. Distinction among Ag forms must be taken into account in the assessment of exposure and toxicological effects to aquatic organisms. Wastewater treatment processes effectively remove Ag particles and colloids (mostly > 95%), but this still leaves notable concentrations (in order of ng/L) escaping to effluent-receiving waters. Total suspended Ag concentrations in various studied effluents ranged from 0.1 to 6 ng/L. The purpose of this study was then to measure and characterize Ag NPs in urban effluents for their concentrations and size distribution using the single particle ICP-MS technique (SP-ICP-MS). Wastewater influents and effluents from various treatment plants—from aerated lagoons to advanced treatment technology—were collected for three sampling days. Our results showed the presence of Ag NP in all samples with concentrations reaching 0.5 ng/L on a mass basis. However, on a particle number basis, Ag NP concentrations (expressed in particle/mL) in the 20–34-nm fraction (up to 3400 particles/mL) were much more abundant (> 700%) than in the > 35-nm larger fraction. The proportion of Ag at the nanoscale (1–100 nm) represents less than 8% of the total suspended Ag for all effluent samples, regardless of their origins. A significant correlation (linear regression: r2 > 0.7) was observed between Ag NP and total suspended Ag concentrations in investigated effluents. Because Ag nanotoxicity is size dependent, the determination of size distribution and exposure concentration on a particle number basis is urgently needed for risk assessment of this class of nanoparticles.

Antimicrobial Activity of Silver Nanoparticles Synthesized by Streptomyces Species JF714876

2012 ◽  
Vol 5 (1) ◽  
pp. 1638-1642 ◽  
Author(s):  
Vidyasagar G M ◽  
Shankaravva B ◽  
R Begum ◽  
Imrose ◽  
Sagar R ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Silver Ions ◽  
Human Beings ◽  
Streptomyces Species ◽  
Force Microscopy ◽  
E Coli ◽  
Extracellular Synthesis ◽  
Atomic Force ◽  
Uv Visible

Microorganisms like fungi, actinomycetes and bacteria are considered nanofactories and are helpful in the production of nanoparticles useful in the welfare of human beings. In the present study, we investigated the production of silver nanoparticles from Streptomyces species JF714876. Extracellular synthesis of silver nanoparticles by Streptomyces species was carried out using two different media. Silver nanoparticles were examined using UV-visible, IR and atomic force microscopy. The size of silver nanoparticles was in the range of 80-100 nm. Antimicrobial activity of silver nanoparticle against bacteria such as E. coli, S. aureus, and dermatophytes like T. rubrum and T. tonsurans was determined. Thus, this study suggests that the Streptomyces sp. JF741876 can produce silver ions that can be used as an antimicrobial substance.

Testing of photocatalytic potential of silver nanoparticles produced through nonthermal plasma reduction reaction and stabilized with saccharides

2021 ◽  
pp. 1-14
Author(s):  
N.U.H. Altaf ◽  
M.Y. Naz ◽  
S. Shukrullah ◽  
H.N. Bhatti
Keyword(s):  
Silver Nanoparticles ◽  
Band Gap ◽  
Light Exposure ◽  
Argon Plasma ◽  
Silver Ions ◽  
Reduction Reaction ◽  
Diameter Distribution ◽  
Light Spectrum ◽  
Plasma Reduction ◽  
Narrow Diameter Distribution

In this study, silver nanoparticles (AgNPs) were produced through an atmospheric pressure plasma reduction reaction and tested for photodegradation of methyl blue (MB) under sunlight exposure. The argon plasma born reactive species were used to reduce silver ions to AgNPs in the solution. Glucose, fructose and sucrose were also added in the solution to stabilize the growth process. The glucose stabilized reaction produced the smallest nanoparticles of 12 nm, while sucrose stabilized reaction produced relatively larger nanoparticles (14 nm). The nanoparticles exhibited rough morphology and narrow diameter distribution regardless of stabilizer type. The narrow diameter distribution and small band gap helped activating majority of nanoparticles at a single wavelength of light spectrum. The band gap energy of AgNPs varied from 2.22 eV to 2.41 eV, depending on the saccharide type. The photoluminescence spectroscopy of AgNPs produced emission peaks at 413 nm, 415 nm, and 418 nm. The photocatalytic potential of AgNP samples was checked by degrading MB dye under sunlight. The degradation reaction reached a saturation level of 98% after 60 min of light exposure.

Green synthesised silver nanoparticles incorporated electrospun poly(methyl methacrylate) nanofibers with different architectures for ophthalmologic alternatives

2021 ◽  
Vol 36 (2) ◽  
pp. 93-110
Author(s):  
Princy Philip ◽  
Tomlal Jose ◽  
Sarath KS ◽  
Sunny Kuriakose
Keyword(s):  
Silver Nanoparticles ◽  
Methyl Methacrylate ◽  
Antibacterial Properties ◽  
Analytical Techniques ◽  
Morphological Properties ◽  
Gram Positive ◽  
Gram Negative ◽  
Poly Methyl Methacrylate ◽  
Antimicrobial Studies ◽  
Eye Problems

Silver nanoparticles with 5–10 nm diameters are synthesised using Couroupita guianensis flower extract. The synthesised silver nanoparticles found to show good antimicrobial activity against gram negative and gram positive bacteria. Poly(methyl methacrylate) nanofibers with pristine, surface roughened and coaxial hollow forms are prepared by electrospinning. The structural and morphological properties of these pure and structurally modified poly(methyl methacrylate) nanofibers are evidenced by various analytical techniques. The antimicrobial studies of poly(methyl methacrylate) nanofibers having different architectures incorporated with silver nanoparticles are carried out. It is found that, all the three forms of poly(methyl methacrylate) nanofibers incorporated with silver nanoparticles show antibacterial properties against both gram positive and gram negative bacteria. Among these, surface roughened poly(methyl methacrylate) nanofibers incorporated with silver nanoparticles show highest antibacterial activity than the other two structural forms. The present study offers an alternative to the existing optical lenses. People especially those who suffer from eye problems can protect their eyes in a better way from infectious agents by wearing optical lens made from C. guianensis stabilised silver nanoparticles incorporated poly(methyl methacrylate) nanofibers than that made from pure poly(methyl methacrylate) nanofibers or films.

An insight into the determination of size and number concentration of silver nanoparticles in blood using single particle ICP-MS (spICP-MS): Feasibility of application to samples relevant to in vivo toxicology studies

2021 ◽  
Author(s):  
Isabel Abad-Álvaro ◽  
Diego Leite ◽  
Dorota Bartczak ◽  
Susana Cuello ◽  
Beatriz Gomez-Gomez ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Single Particle ◽  
Number Concentration ◽  
Biological Matrices ◽  
Icp Ms ◽  
Toxicological Studies ◽  
Insight Into

Toxicological studies concerning nanomaterials in complex biological matrices usually require a carefully designed workflow that involves handling, transportation and preparation of a large number of samples without affecting the nanoparticle...

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