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  • 1
    Language: English
    In: Accounts of chemical research, 19 March 2013, Vol.46(3), pp.854-62
    Description: Over the last decade, nanoparticles have been used more frequently in industrial applications and in consumer and medical products, and these applications of nanoparticles will likely continue to increase. Concerns about the environmental fate and effects of these materials have stimulated studies to predict environmental concentrations in air, water, and soils and to determine threshold concentrations for their ecotoxicological effects on aquatic or terrestrial biota. Nanoparticles can be added to soils directly in fertilizers orplant protection products or indirectly through application to land or wastewater treatment products such as sludges or biosolids. Nanoparticles may enter aquatic systems directly through industrial discharges or from disposal of wastewater treatment effluents or indirectly through surface runoff from soils. Researchers have used laboratory experiments to begin to understand the effects of nanoparticles on waters and soils, and this Account reviews that research and the translation of those results to natural conditions. In the environment, nanoparticles can undergo a number of potential transformations that depend on the properties both of the nanoparticle and of the receiving medium. These transformations largely involve chemical and physical processes, but they can involve biodegradation of surface coatings used to stabilize many nanomaterial formulations. The toxicity of nanomaterials to algae involves adsorption to cell surfaces and disruption to membrane transport. Higher organisms can directly ingest nanoparticles, and within the food web, both aquatic and terrestrial organisms can accumulate nanoparticles. The dissolution of nanoparticles may release potentially toxic components into the environment. Aggregation with other nanoparticles (homoaggregation) or with natural mineral and organic colloids (heteroaggregation) will dramatically change their fate and potential toxicity in the environment. Soluble natural organic matter may interact with nanoparticles to change surface charge and mobility and affect the interactions of those nanoparticles with biota. Ultimately, aquatic nanomaterials accumulate in bottom sediments, facilitated in natural systems by heteroaggregation. Homoaggregates of nanoparticles sediment more slowly. Nanomaterials from urban, medical, and industrial sources may undergo significant transformations during wastewater treatment processes. For example, sulfidation of silver nanoparticles in wastewater treatment systems converts most of the nanoparticles to silver sulfides (Ag₂S). Aggregation of the nanomaterials with other mineral and organic components of the wastewater often results in most of the nanomaterial being associated with other solids rather than remaining as dispersed nanosized suspensions. Risk assessments for nanomaterial releases to the environment are still in their infancy, and reliable measurements of nanomaterials at environmental concentrations remain challenging. Predicted environmental concentrations based on current usage are low but are expected to increase as use increases. At this early stage, comparisons of estimated exposure data with known toxicity data indicate that the predicted environmental concentrations are orders of magnitude below those known to have environmental effects on biota. As more toxicity data are generated under environmentally-relevant conditions, risk assessments for nanomaterials will improve to produce accurate assessments that assure environmental safety.
    Keywords: Nanostructures -- Chemistry ; Soil Pollutants -- Chemistry ; Water Pollutants, Chemical -- Chemistry
    ISSN: 00014842
    E-ISSN: 1520-4898
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  • 2
    Language: English
    In: Chemosphere, October 2012, Vol.89(7), pp.876-883
    Description: ► The labile pool of in amended soils was observed to decrease with age in soils. ► A strong linear relationship was observed between and value results. ► Labile in Mo contaminated soils was 〈10% of the total Mo in soils. Aging reactions in soils can influence the lability and hence bioavailability of added metals in soils through their removal from labile pools into pools from which desorption is slow (non-labile pools). The aims of this study were to examine the effect of aging reactions on the lability of soluble molybdate added into soils with varying physical and chemical properties and develop models to predict changes in the labile pool of in soils with incubation time. Soils were spiked with soluble at quantities sufficient to inhibit barley root growth by 10% (EC ) or 90% (EC ) and incubated for up to 18 months. The labile pool of ( value) was observed to decrease in soils with incubation time, particularly in soils with high clay content. A strong relationship was observed between measures of lability in soils determined using and value techniques ( = 0.98) suggesting values provided a good measure of the potential plant available pool of in soils. A regression model was developed that indicates clay content and incubation time were the most important factors affecting the labile pool of in soils with time after addition ( = 0.70–0.75). The aging model developed suggests soluble will be removed into non-labile pools more rapidly with time in neutral to alkaline clay soils than in acidic sandy soils. Labile concentrations in molybdenum (Mo) contaminated soils was found to be 〈10% of the total Mo concentrations in soils.
    Keywords: Molybdenum ; Aging ; Lability ; E Value ; L Value ; Regression ; Chemistry ; Ecology
    ISSN: 0045-6535
    E-ISSN: 1879-1298
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  • 3
    Language: English
    In: The Science of the Total Environment, Oct 1, 2013, Vol.463-464, p.120(11)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.scitotenv.2013.05.089 Byline: Geert Cornelis, Liping Pang, Casey Doolette, Jason K. Kirby, Mike J. McLaughlin Abstract: With industrialization and urbanization soils are increasingly exposed to engineered nanoparticles (ENP), yet knowledge regarding the transport of ENP in natural soils is lacking, a process that was examined further in the current study. Saturated columns of 11 natural soils with varying physical and chemical properties were spiked with two pore volumes of a solution containing 1.7mgAgL.sup.-1 as polyvinylpyrrolidone (PVP)-coated silver nanoparticles (AgNP) (40nm actual diameter) and eluted at a constant flow rate of 1mlmin.sup.-1. Breakthrough of Ag was analyzed using filtration theory and a HYDRUS-1D transport model that incorporated two-site kinetic attachment-detachment. Separate kinetic batch studies suggested fast heteroaggregation between negatively charged AgNP and positively charged sites on the common soil colloids maghemite or montmorillonite. The concentration of such sites in the soil correlates positively with the oxalate-extractable aluminum concentration of the soils, a measure that correlated positively with collision efficiency. This correlation thus suggested favorable deposition of AgNP and/or enhanced straining following heteroaggregation of AgNP with mobile soils colloids. Occurrence of heteroaggregation was supported by the batch studies, enhanced size-exclusion in the soil with the highest porosity, and reversible attachment-detachment predicted from HYDRUS modeling, whereas straining and favorable deposition were suggested by irreversible attachment. Our study suggests that under similar experimental conditions, PVP-coated AgNP would rapidly interact with natural colloids in soils significantly reducing their mobility and hence potential risk from off-site transport. Article History: Received 12 April 2013; Revised 27 May 2013; Accepted 29 May 2013 Article Note: (miscellaneous) Editor: Damia Barcelo
    Keywords: Montmorillonite -- Chemical Properties ; Montmorillonite -- Analysis ; Oxalic Acid -- Chemical Properties ; Oxalic Acid -- Analysis ; Nanoparticles -- Chemical Properties ; Nanoparticles -- Analysis ; Iron Oxides -- Chemical Properties ; Iron Oxides -- Analysis ; Soils -- Chemical Properties ; Soils -- Analysis ; Urbanization -- Chemical Properties ; Urbanization -- Analysis ; Oxalates -- Chemical Properties ; Oxalates -- Analysis
    ISSN: 0048-9697
    Source: Cengage Learning, Inc.
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  • 4
    Language: English
    In: Geology, Jan, 2013, Vol.41(1), p.27(4)
    Description: The Ediacaran period began with the deglaciation of the ca. 635 Ma Marinoan snowball Earth and the deposition of cap dolostones on continental shelves worldwide during post-glacial sea-level rise. These carbonates sharply overlie glacial sediments deposited at low pale-olatitudes and preserve negative carbon isotope excursions. The snowball Earth hypothesis invokes an almost complete cessation of primary productivity in the surface ocean. Because assimilatory uptake of Zn appears to fractionate its isotopes, Zn isotope ratios measured in carbonate precipitated in the surface ocean should track fluctuations in primary productivity. Here we report the first Zn isotopic data, together with carbon and oxygen isotopic profiles from a Neoproterozoic cap dolostone, the Nuccaleena Formation in the Flinders Ranges, South Australia. We interpret the Zn isotopic data in terms of a two-stage evolution of the deglacial ocean. Slightly [sup.66]Zn-enriched values at the base of the cap dolostone indicate immediate resumption of the biological pump upon melting of the surface ocean, but this signal was diluted by intense surface runoff that drove [delta][sup.66]Zn ([sup.66]Zn/[sup.64]Zn, versus the JMC Lyon reference) values down to the composition of continentally derived Zn. A subsequent rise in [delta][sup.66]Zn records a vigorous increase in primary production and export from a nutrient-laden surface ocean. doi: 10.1130/G33422.1
    Keywords: Stratigraphy ; Isotope Geochemistry ; Australasia ; Australia ; C-13/C-12 ; Carbon ; Carbonate Rocks ; Chemostratigraphy ; Climate Change ; Deglaciation ; Dolostone ; Ediacaran ; Flinders Ranges ; Geochemistry ; Isotope Ratios ; Isotopes ; Marine Environment ; Metals ; Neoproterozoic ; Nuccaleena Formation ; Nutrients ; Paleo-Oceanography ; Paleoclimatology ; Paleoecology ; Precambrian ; Productivity ; Proterozoic ; Sedimentary Rocks ; Snowball Earth ; South Australia ; Stable Isotopes ; Upper Precambrian ; Vendian ; Zinc ; Zn-66/Zn-64;
    ISSN: 0091-7613
    E-ISSN: 19432682
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  • 5
    Language: English
    In: Journal of Hazardous Materials, 30 December 2015, Vol.300, pp.788-795
    Description: Silver nanoparticles (AgNPs) can enter terrestrial systems as sulfidised AgNPs (Ag S-NPs) through the application of biosolids to soil. However, the bioavailability of Ag S-NPs in soils is unknown. The two aims of this study were to investigate (1) the bioavailability of Ag to lettuce ( ) using a soil amended with biosolids containing Ag S-NPs and (2) the effect of commonly used agricultural fertilisers/amendments on the bioavailability of Ag, AgNPs and Ag S-NPs to lettuce. The study used realistic AgNP exposure pathways and exposure concentrations. The plant uptake of Ag from biosolids-amended soil containing Ag S-NPs was very low for all Ag treatments (0.02%). Ammonium thiosulfate and potassium chloride fertilisation significantly increased the Ag concentrations of plant roots and shoots. The extent of the effect varied depending on the type of Ag. Ag S-NPs, the realistic form of AgNPs in soil, had the lowest bioavailability. The potential risk of AgNPs in soils is low; even in the plants that had the highest Ag concentrations (Ag +thiosulfate), only 0.06% of added Ag was found in edible plant parts (shoots). Results from the study suggest that agricultural practises must be considered when carrying out risk assessments of AgNPs in terrestrial systems; such practises can affect AgNP bioavailability.
    Keywords: Silver Sulfide Nanoparticles ; Bioavailability ; Fertiliser ; Plant Uptake ; Biosolids ; Soil ; Engineering ; Law
    ISSN: 0304-3894
    E-ISSN: 1873-3336
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  • 6
    Language: English
    In: Quaternary International, 16 November 2012, Vol.279-280, pp.246-246
    Keywords: Geology
    ISSN: 1040-6182
    E-ISSN: 1873-4553
    Source: ScienceDirect Journals (Elsevier)
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  • 7
    In: New Phytologist, July 2013, Vol.199(2), pp.367-378
    Description: The fractionation of stable copper (Cu) isotopes during uptake into plant roots and translocation to shoots can provide information on Cu acquisition mechanisms. Isotope fractionation (65Cu/63Cu) and intact tissue speciation techniques (X‐ray absorption spectroscopy, XAS) were used to examine the uptake, translocation and speciation of Cu in strategy I (tomato–Solanum lycopersicum) and strategy II (oat–Avena sativa) plant species. Plants were grown in controlled solution cultures, under varied iron (Fe) conditions, to test whether the stimulation of Fe‐acquiring mechanisms can affect Cu uptake in plants. Isotopically light Cu was preferentially incorporated into tomatoes (Δ65Cuwhole plant‐solution = c. −1‰), whereas oats showed minimal isotopic fractionation, with no effect of Fe supply in either species. The heavier isotope was preferentially translocated to shoots in tomato, whereas oat plants showed no significant fractionation during translocation. The majority of Cu in the roots and leaves of both species existed as sulfur‐coordinated Cu(I) species resembling glutathione/cysteine‐rich proteins. The presence of isotopically light Cu in tomatoes is attributed to a reductive uptake mechanism, and the isotopic shifts within various tissues are attributed to redox cycling during translocation. The lack of isotopic discrimination in oat plants suggests that Cu uptake and translocation are not redox selective.
    Keywords: Copper ; Fractionation ; Isotopes ; Plant ; Speciation ; Spectroscopy ; Translocation ; Uptake
    ISSN: 0028-646X
    E-ISSN: 1469-8137
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  • 8
    Language: English
    In: Earth and Planetary Science Letters, 2011, Vol.309(1), pp.100-112
    Description: We have measured the iron isotope compositions and trace element concentrations of a suite of iron formation (IF) samples from the Neoproterozoic Rapitan Group, which was deposited during the older of two glacial episodes recorded in the Windermere Supergroup of the northern Canadian Cordillera. Like most other Neoproterozoic examples, iron in the Rapitan IF resides almost exclusively as hematite. This mineralogical simplicity compared to Archean and Paleoproterozoic banded iron formations is attributed to a limited supply of organic carbon to the Rapitan glacial ocean that inhibited diagenetic production of reduced iron phases. Sedimentological considerations indicate that the Rapitan IF was deposited during a rise in relative sea level related to a period of glacial advance and isostatic subsidence. Trace element data, including rare earth element plus yttrium (REE + Y) patterns, suggest an anoxic deep ocean dominated by low-temperature hydrothermal input and capped by a weakly oxic surface ocean. The iron isotope data show a trend of increasing δ Fe (versus IRMM-14) up-section from ~−0.7‰ to 1.2‰, corresponding to a shift from a muddy IF facies to a dominantly jaspilitic IF facies. This distinct isotopic pattern likely records a steep isotopic gradient across the iron chemocline in Rapitan seawater. ► We present trace element and iron isotope data on the Rapitan iron formation. ► The iron isotope data show a large rise in iron isotope values up-section. ► This isotopic trend is coupled to increasing water depth. ► The trend likely records a vertical iron isotope gradient in Rapitan seawater. ► We propose a new model for iron isotopic variability in ancient iron formations.
    Keywords: (Banded) Iron Formation ; Iron Isotopes ; Rapitan Group ; Neoproterozoic ; Glaciation ; Rare Earth Elements ; Geology ; Physics
    ISSN: 0012-821X
    E-ISSN: 1385-013X
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  • 9
    Language: English
    In: Journal of Hazardous Materials, Nov 15, 2013, Vol.262, p.496(8)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jhazmat.2013.08.021 Byline: Divina A. Navarro, Rai S. Kookana, Jason K. Kirby, Sheridan M. Martin, Ali Shareef, Jun Du, Mike J. McLaughlin Abstract: acents Release of C.sub.60 is influenced by soil type. acents Systems with elevated concentrations of DOC release relatively more C.sub.60. acents Different forms of C.sub.60 have similar release behaviour. acents Non-photoactivated formation of hydrophilic C.sub.60 appears to be a possibility in soil. acents Apparent release of C.sub.60 from contaminated biosolids applied to soils will be limited. Author Affiliation: (a) CSIRO Land and Water, Advanced Materials Transformational Capability Platform-Nanosafety, Contaminant Chemistry and Ecotoxicology Program, PMB 2, Glen Osmond, SA 5064, Australia (b) Soil Science, School of Agriculture, Food and Wine, University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia Article History: Received 30 April 2013; Revised 29 July 2013; Accepted 7 August 2013
    Keywords: Soils ; Fullerenes ; Terrestrial Ecosystems
    ISSN: 0304-3894
    Source: Cengage Learning, Inc.
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  • 10
    Language: English
    In: Science of the Total Environment, 01 October 2013, Vol.463-464, pp.120-130
    Description: With industrialization and urbanization soils are increasingly exposed to engineered nanoparticles (ENP), yet knowledge regarding the transport of ENP in natural soils is lacking, a process that was examined further in the current study. Saturated columns of 11 natural soils with varying physical and chemical properties were spiked with two pore volumes of a solution containing 1.7 mg Ag L as polyvinylpyrrolidone (PVP)-coated silver nanoparticles (AgNP) (40 nm actual diameter) and eluted at a constant flow rate of 1 ml min . Breakthrough of Ag was analyzed using filtration theory and a HYDRUS-1D transport model that incorporated two-site kinetic attachment–detachment. Separate kinetic batch studies suggested fast heteroaggregation between negatively charged AgNP and positively charged sites on the common soil colloids maghemite or montmorillonite. The concentration of such sites in the soil correlates positively with the oxalate-extractable aluminum concentration of the soils, a measure that correlated positively with collision efficiency. This correlation thus suggested favorable deposition of AgNP and/or enhanced straining following heteroaggregation of AgNP with mobile soils colloids. Occurrence of heteroaggregation was supported by the batch studies, enhanced size-exclusion in the soil with the highest porosity, and reversible attachment–detachment predicted from HYDRUS modeling, whereas straining and favorable deposition were suggested by irreversible attachment. Our study suggests that under similar experimental conditions, PVP-coated AgNP would rapidly interact with natural colloids in soils significantly reducing their mobility and hence potential risk from off-site transport.
    Keywords: Engineered Nanoparticle ; Colloid Chemistry ; Aggregation ; Deposition ; Modeling ; Contaminated Soils ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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