791 research outputs found
Changing metal lability, fractionation and toxicity in an oxidising sediment
No full textExtended abstract.Anna Royle, Annette L. Nolan, Mike J. McLaughli
Long-term natural attenuation of Cu added to soils predicted by soil pH and time
No full textExtended abstract.Yibing Ma, Enzo Lombi, Annette L. Nolan, Mike J. McLaughli
Metal bioaccumulation and toxicity in soils - why bother with speciation?
No full textCopyright © 2003 CSIROThis review assesses metal speciation in soils, including analytical techniques used for measurement and the advantages and disadvantages of using chemical speciation information, in both the solid and aqueous phase, to predict adverse effects of metal contamination in soils and for use in soil protection policies. Other techniques used to assess metal lability and bioavailability in soil are also discussed.Annette L. Nolan, Enzo Lombi and Mike J. McLaughli
Short-term natural attenuation of copper in soils: Effects of time, temperature, and soil characteristics
No full textCopyright © 2006 Society of Environmental Toxicology and ChemistryNatural attenuation of metals added to soils refers to the processes by which the mobility and bioavailability/toxicity of the added metals decline with time. In this paper, we used isotopic dilution techniques to investigate the short-term (30 d) natural attenuation of Cu added to 19 European soils at two effective concentrations shown to inhibit plant (tomato) growth by 10 and 90%. The results showed that the lability of Cu added to soils rapidly decreased after addition, especially in the soils with pH > 6.0, followed by a slow decrease in Cu lability. The lability of Cu added to soils also decreased with increasing incubation temperature. The activation energies and the apparent diffusion rate coefficients for the attenuation processes were 33 to 36 kJ/mol and 0.66 to 20.9 × 10−10/s at 20°C, respectively, and were consistent with Cu diffusion in meso- and micropores. The attenuation of Cu lability was modeled on the basis of three processes: precipitation/nucleation of Cu on soil surfaces, Cu occlusion within organic matter, and diffusion of Cu into micropores. The soil and environmental factors governing attenuation rates were soil pH, organic matter content, incubation time, and temperature. Soil pH is the key factor for natural attenuation of Cu added to soils. The model can be used to scale ecotoxicological data generated from different soils and under different incubation times and temperatures.Yibing Ma, Enzo Lombi, Annette L. Nolan and Mike J. McLaughli
Grain quality and contamination around Port Pirie
No full textGRDC Code CSO245; Report prepared by CSIRO Land and WaterBA Zarcinas, MJ McLaughlin, S Mason, A Nolan, L Spouncer, G Ohmsen, J Hannay, M Wursthttp://www.grdc.com.au/Resources/Publications/2004/07/Grain-quality-and-contamination-around-Port-Piri
Stable isotope techniques for assessing labile Cu in soils: Development of an L-value procedure, its application, and reconciliation with E values
No full textPublication Date (Web): April 6, 2006Isotopic techniques have become a valuable tool for assessing the lability or potential availability of elements in soil. Until now, work on soil Cu has been limited to E-value methods where soil solution extracts are obtained by physical means due to the very short (12.4 h) half-life of the radio isotope 64Cu. However, a stable isotope method has recently been developed for determining soil Cu E values that utilizes enhancement of the 65Cu isotope in soil and measurement of the subsequent ratio with 63Cu. We have developed an L-value technique for soil Cu, where plants are used to sample the soil solution and therefore give a direct measure of the plant available Cu. The L-value technique developed was then compared, and found to be equivalent, with E values using equilibration periods up to and including the growth period of plants in the L-value method.Ian W. Oliver, Yibing Ma, Enzo Lombi, Annette L. Nolan, and Mike J. McLaughli
Nolan, Lee Considered - General Robert E. Lee And Civil War History
No full textRobert E. Lee holds almost as much fascination among today's population as he did among the generation that fought the Civil War. Except for Thomas L Connelly's 1977 critical book, The Marble Man, Lee has virtually escaped scholarly analysis and has remained on a pedestal of public worship that borders on the dogmatic. To reconsider these gilded assumptions, Alan T. Nolan, author of several combat histories on the Civil War, examines the wide variety of existing sources on six particular themes: Lee as opponent of slavery; devoted Virginian forced into the war; brilliant military strategist; magnanimous adversary; nobleman who maintained a sense of honor even in defeat; and promoter of post-war reconciliation
Aging of nickel added to soils as predicted by soil pH and time
No full textAlthough aging processes are important in risk assessment for metals in soils, the aging of Ni added to soils has not been studied in detail. In this study, after addition of water soluble Ni to soils, the changes over time in isotopic exchangeability, total concentrations and free Ni2+ activity in soil pore water, were investigated in 16 European soils incubated outdoors for 18 months. The results showed that after Ni addition, concentrations of Ni in soil pore water and isotopic exchangeability of Ni in soils initially decreased rapidly. This phase was followed by further decreases in the parameters measured but these occurred at slower rates. Increasing soil pH increased the rate and extent of aging reactions. Semi-mechanistic models, based on Ni precipitation/nucleation on soil surfaces and micropore diffusion, were developed and calibrated. The initial fast processes, which were attributed to precipitation/nucleation, occurred over a short time (e.g. 1 h), afterwards the slow processes were most likely controlled by micropore diffusion processes. The models were validated by comparing predicted and measured Ni aging in three additional, widely differing soils aged outdoors for periods up to 15 months in different conditions. These models could be used to scale ecotoxicological data generated in short-term studies to longer aging times.Yibing Ma, Enzo Lombi, Mike J. McLaughlin, Ian W. Oliver, Annette L. Nolan, Koen Oorts, Erik Smolder
The post-transcriptional gene silencing machinery functions independently of DNA methylation to repress a LINE1-like retrotransposon in Neurospora crassa
No full textPost-transcriptional gene silencing (PTGS) involving small interfering RNA (siRNA)-directed degradation of RNA transcripts and transcriptional silencing via DNA methylation have each been proposed as mechanisms of genome defence against invading nucleic acids, such as transposons and viruses. Furthermore, recent data from plants indicates that many transposons are silenced via a combination of the two mechanisms, and siRNAs can direct methylation of transposon sequences. We investigated the contribution of DNA methylation and the PTGS pathway to transposon control in the filamentous fungus Neurospora crassa. We found that repression of the LINE1-like transposon, Tad, requires the Argonaute protein QDE2 and Dicer, each of which are required for transgene-induced PTGS (quelling) in N.crassa. Interestingly, unlike quelling, the RNA-dependent RNA polymerase QDE1 and the RecQ DNA helicase QDE3 were not required for Tad control, suggesting the existence of specialized silencing pathways for diverse kinds of repetitive elements. In contrast, Tad elements were not significantly methylated and the DIM2 DNA methyltransferase, responsible for all known DNA methylation in Neurospora, had no effect on Tad control. Thus, an RNAi-related transposon silencing mechanism operates during the vegetative phase of N.crassa that is independent of DNA methylation, highlighting a major difference between this organism and other methylation-proficient species. © The Author 2005. Published by Oxford University Press. All rights reserved
Avena fatua (Wild Oats) : Wild Oats
No full textClass: Monocotyledoneae
Family: Poaceae
Genus: Avena
Species: fatu
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