Particulate and colloidal silver in sewage effluent and sludge discharged from British wastewater treatment plants

Johnson, Andrew C.; Jürgens, Monika D.; Lawlor, Alan; Cisowska, Iwona; Williams, Richard J.

doi:10.1016/j.chemosphere.2014.03.039

Cited by 55 publications

(31 citation statements)

References 31 publications

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“…As of March 2015, silver nanoparticles were reported to be the most frequently used nanomaterials, as they have been found in at least 435 of a total of 1814 listed nano-enabled products, according to the Nanotechnology Consumer Products Inventory (CPI) [10]. Increasing penetration of ENMsincluding Ag NPs-into the global marketplace will inevitably lead to their increased emission into the environment, during the manufacture, use and disposal phases of an ENM-enabledproduct's life-cycle [11].…”

Section: List Of Figuresmentioning

confidence: 99%

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Transformations of silver nanoparticles in wastewater effluents: links to Ag bioavailability

Azimzada

Tufenkji

Wilkinson

2017

Environ. Sci.: Nano

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As a result of the burgeoning nanotechnology industry, the number of uses of engineered silver nanoparticles (Ag NPs) in consumer products has risen significantly in recent years.Despite their utility as anti-bacterial agents, the 'nano-scale' properties of these materials may lead to eco-toxicological problems when they end up in the environment. Wastewater effluents represent one of the main routes through which Ag NPs can reach an aquatic environment, where they may potentially interact with aquatic life. However, in wastewaters, Ag NPs may undergo different chemical and physical transformations, which may alter the potential toxicity of these NPs towards aquatic organisms. The main objectives of this study are to characterize the Ag NPs in wastewater effluents and then to assess their interactions with a model organism, the green alga Chlamydomonas reinhardtii.Experiments were conducted to distinguish the effect(s) of the wastewater matrix on the dissolution of Ag NPs and to determine whether the transformed NPs or the dissolved Ag species would be most bioavailable to C. reinhardtii. It was shown that in environmental matrices such as wastewater, the bioavailability of Ag + could be significantly or completely reduced-a Nous avons étudié l'effet de la matrice des eaux usées sur la dissolution des Ag NPs et la biodisponibilité des différentes formes (particulaire et dissoute) des Ag NPs pour C. reinhardtii.Dans les matrices environnementales telles que les eaux usées la biodisponibilité de Ag + serait réduite de façon significative, si ce n'est complète; une conclusion qui va à l'encontre les résultats des études similaires faites dans des matrices biologiques simples. Cette réduction

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Section: List Of Figuresmentioning

confidence: 99%

“…A major fraction of consumer products containing Ag NPs eventually find their way through waste disposal streams and into wastewater treatment plants [5][6][7][8][9][10]. Therefore, wastewater effluents represent a major route through which NPs can reach surface waters [5,11], where aquatic organisms can be impacted.…”

Section: Introductionmentioning

confidence: 99%

Transformations of silver nanoparticles in wastewater effluents: links to Ag bioavailability

Azimzada

Tufenkji

Wilkinson

2017

Environ. Sci.: Nano

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“…sulfidation, adsorption of natural organic matter) was not studied here, these transformations will also clearly play a role in modulating their interactions with the colloidal particles and will need to be studied further. [42] Although the analytical techniques used here had some limitations, mainly due to the high heterogeneity of the complex systems, their ability to follow the nanoparticle label is an advantage over non-specific techniques such as DLS. Although it would be extremely desirable to determine heteroagglomeration sticking coefficients using FCS, these measurements are noisier than those obtained in DLS, owing to the single-particle nature of the measurements.…”

Section: Discussionmentioning

confidence: 99%

Heteroagglomeration of nanosilver with colloidal SiO2 and clay

et al. 2017

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Environmental context. The 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.Abstract. The 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, ,3 nm; polyacrylic acid-and citrate-stabilised) were covalently labelled with a fluorescent dye and then mixed with colloidal silicon oxides (SiO 2 , ,18.5 nm) or clays (,550 nm SWy-2 montmorillonite). Homo-and heteroagglomeration of the nAg were first studied in controlled synthetic waters that were representative of natural fresh waters (50 mg Ag L À1 ; pH 7.0; ionic strength 10 À7 to 10 À1 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 SiO 2 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 SiO 2 or natural (river) water.

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“…According to the literature, these elements were considered to be the most relevant. [31][32][33][34][35][36][37]. The common range of Ag for soils is 0.01-5 mg/kg, with a representative average of 0.05 mg/kg [38], 200 times less than the mean concentration observed in the sludge.…”

Section: Declared Enp Enm/product/preparationmentioning

confidence: 99%

“…The main sources of silver in wastewater are food, dental amalgams, cosmetics and textiles (plastics should be investigated); according to a Swedish study [42]. Silver in wastewater is immobilized in the sewage sludge to 98% [33]. An essential mechanism is the reaction of the Ag + ion with sulfides, producing the precipitation of Ag 2 S insoluble particles [43].…”

Section: Declared Enp Enm/product/preparationmentioning

confidence: 99%

Mineral Nanoparticles in Waste: Potential Sources, Occurrence in Some Engineered Nanomaterials Leachates, Municipal Sewage Sludges and Municipal Landfill Sludges

Hennebert¹,

Anderson²,

Merdy³

2017

J Biotechnol Biomater

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Environmental assessment of engineered nanoparticles (ENPs) currently suffers from lack of data on production, emission, behaviour and fate in natural compartments. This paper aims to bring factual data on production amounts of ENPs and emission of mineral elements in a colloidal or nanoparticulate forms stemming from products, (e.g. cosmetics, paints, concretes) and from two potential waste sinks, namely municipal sewage sludge and nonhazardous waste landfill sludge. Based on the declaration of production and importation of ENPs in France in 2014, we set out a classification of ENPs substances comprising carbon black, organic pigments, miscellaneous organic substances and mineral ENPs. These mineral ENPs were sub-classified on the basis of production and CLP ecotoxicological and hazard classifications. Major elements (Group #1) encompass ENPs substances ubiquitous in total contents, and also as a colloid fraction in waste leachates (Si, Ca, Ti, Al, Mg, Fe, Mn, P). Minor elements were divided as ENPs with soluble substances and dissolved metal ions non-classified as ecotoxic (Group #2: Ba, Bi, Cr (III), Sr, Zr, La, Pd, Mo, W, Y, Au) or with soluble substances classified as ecotoxic and hazard statement code in the CLP regulation (Group #3: Ce, Cu, Zn, Ni, Sb, Ag, Co). Paints, concrete and particularly cosmetics proved to be sources of ENPs. Colloidal forms of elements or ENPs were found in leachate obtained from paint (Si), in cosmetics leachates (Al, Si, Ti and Zn), and in one demolition concrete (Ti). No nanoparticulate forms or fraction of Ag, Ce, Ti and Zn were identified by TEM/EDS in municipal sewage sludge. However, sewage sludge could be a sink for Group #3 elements such as Ag and Ce, since their total concentrations were significant. Based on landfill leachates from municipal solid wastes, the colloidal fraction frequently contained elements of Group #3 (Ni, Zn, Cu, Co and Sb) but with low mean concentration and more rarely Ag and Ce, indicating that the fluxes of these elements from the landfill cells should be low, except for Ce. Landfills seem to not emit ENPs in their leachates. From a regulative aspect, monitoring of Ag in sewage sludge for agricultural use could be of concern.

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Particulate and colloidal silver in sewage effluent and sludge discharged from British wastewater treatment plants

Cited by 55 publications

References 31 publications

Transformations of silver nanoparticles in wastewater effluents: links to Ag bioavailability

Transformations of silver nanoparticles in wastewater effluents: links to Ag bioavailability

Heteroagglomeration of nanosilver with colloidal SiO2 and clay

Mineral Nanoparticles in Waste: Potential Sources, Occurrence in Some Engineered Nanomaterials Leachates, Municipal Sewage Sludges and Municipal Landfill Sludges

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