The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Charlotte B Braungardt - One of the best experts on this subject based on the ideXlab platform.
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stripping voltammetry for the determination of Trace Metal speciation and in situ measurements of Trace Metal distributions in marine waters
Analytica Chimica Acta, 1999Co-Authors: Eric P Achterberg, Charlotte B BraungardtAbstract:Progress in marine chemistry has been driven by improved sampling and sample handling techniques, and developments in analytical chemistry. Consequently, during the last 20 years our understanding of marine Trace Metal biogeochemistry has improved a great deal. Stripping voltammetric techniques (anodic stripping voltammetry and adsorptive cathodic stripping voltammetry) have made an important contribution to this understanding. The selectivity and extremely low detection limits have made stripping voltammetry a widely used technique for Trace Metal speciation and Trace Metal distribution measurements in seawater. Stripping voltammetry is very suitable for ship-board and in-situ applications because of the portability, low cost and capability for automation of the voltammetric instrumentation. Future developments in stripping voltammetry can be expected in the field of stand-alone submersible voltammetric analysers, capable of continuous Trace Metal measurements. Future applications of stripping voltammetry can be found in the interactions between Trace Metal speciation and growth and the functioning of organisms in pristine and Metal polluted marine waters.
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Stripping voltammetry for the determination of Trace Metal speciation and in-situ measurements of Trace Metal distributions in marine waters
Analytica Chimica Acta, 1999Co-Authors: Eric P Achterberg, Charlotte B BraungardtAbstract:Progress in marine chemistry has been driven by improved sampling and sample handling techniques, and developments in analytical chemistry. Consequently, during the last 20 years our understanding of marine Trace Metal biogeochemistry has improved a great deal. Stripping voltammetric techniques (anodic stripping voltammetry and adsorptive cathodic stripping voltammetry) have made an important contribution to this understanding. The selectivity and extremely low detection limits have made stripping voltammetry a widely used technique for Trace Metal speciation and Trace Metal distribution measurements in seawater. Stripping voltammetry is very suitable for ship-board and in-situ applications because of the portability, low cost and capability for automation of the voltammetric instrumentation. Future developments in stripping voltammetry can be expected in the field of stand-alone submersible voltammetric analysers, capable of continuous Trace Metal measurements. Future applications of stripping voltammetry can be found in the interactions between Trace Metal speciation and growth and the functioning of organisms in pristine and Metal polluted marine waters. Copyright (C) 1999 Elsevier Science B.V
Eric P Achterberg - One of the best experts on this subject based on the ideXlab platform.
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stripping voltammetry for the determination of Trace Metal speciation and in situ measurements of Trace Metal distributions in marine waters
Analytica Chimica Acta, 1999Co-Authors: Eric P Achterberg, Charlotte B BraungardtAbstract:Progress in marine chemistry has been driven by improved sampling and sample handling techniques, and developments in analytical chemistry. Consequently, during the last 20 years our understanding of marine Trace Metal biogeochemistry has improved a great deal. Stripping voltammetric techniques (anodic stripping voltammetry and adsorptive cathodic stripping voltammetry) have made an important contribution to this understanding. The selectivity and extremely low detection limits have made stripping voltammetry a widely used technique for Trace Metal speciation and Trace Metal distribution measurements in seawater. Stripping voltammetry is very suitable for ship-board and in-situ applications because of the portability, low cost and capability for automation of the voltammetric instrumentation. Future developments in stripping voltammetry can be expected in the field of stand-alone submersible voltammetric analysers, capable of continuous Trace Metal measurements. Future applications of stripping voltammetry can be found in the interactions between Trace Metal speciation and growth and the functioning of organisms in pristine and Metal polluted marine waters.
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Stripping voltammetry for the determination of Trace Metal speciation and in-situ measurements of Trace Metal distributions in marine waters
Analytica Chimica Acta, 1999Co-Authors: Eric P Achterberg, Charlotte B BraungardtAbstract:Progress in marine chemistry has been driven by improved sampling and sample handling techniques, and developments in analytical chemistry. Consequently, during the last 20 years our understanding of marine Trace Metal biogeochemistry has improved a great deal. Stripping voltammetric techniques (anodic stripping voltammetry and adsorptive cathodic stripping voltammetry) have made an important contribution to this understanding. The selectivity and extremely low detection limits have made stripping voltammetry a widely used technique for Trace Metal speciation and Trace Metal distribution measurements in seawater. Stripping voltammetry is very suitable for ship-board and in-situ applications because of the portability, low cost and capability for automation of the voltammetric instrumentation. Future developments in stripping voltammetry can be expected in the field of stand-alone submersible voltammetric analysers, capable of continuous Trace Metal measurements. Future applications of stripping voltammetry can be found in the interactions between Trace Metal speciation and growth and the functioning of organisms in pristine and Metal polluted marine waters. Copyright (C) 1999 Elsevier Science B.V
P S Rainbow - One of the best experts on this subject based on the ideXlab platform.
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Trace Metal bioaccumulation models metabolic availability and toxicity
Environment International, 2007Co-Authors: P S RainbowAbstract:Aquatic invertebrates take up and accumulate Trace Metals whether essential or non-essential, all of which have the potential to cause toxic effects. Subsequent tissue and body concentrations of accumulated Trace Metals show enormous variability across Metals and invertebrate taxa. Accumulated Metal concentrations are interpreted in terms of different Trace Metal accumulation patterns, dividing accumulated Metals into two components - metabolically available Metal and stored detoxified Metal. Examples of different accumulation patterns are described from crustaceans but have a general applicability to all aquatic invertebrates. Toxicity does not depend on total accumulated Metal concentration but is related to a threshold concentration of internal metabolically available Metal. Toxicity ensues when the rate of Metal uptake from all sources exceeds the combined rates of detoxification and excretion (if present) of the Metal concerned. The biodynamic model of Trace Metal bioaccumulation allows the prediction and explanation of widely differing accumulated Trace Metal concentrations in organisms, combining geochemical analyses of environmental Metal concentrations with the measurement of key physiological parameters for a species from the site under consideration. The combination of the biodynamic model as a unified explanation of Metal bioaccumulation with an understanding of the relationship between accumulation and toxicity sets the stage for a realistic understanding of the significance of Trace Metal concentrations in aquatic invertebrates.
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ecophysiology of Trace Metal uptake in crustaceans
Estuarine Coastal and Shelf Science, 1997Co-Authors: P S RainbowAbstract:The uptake of Trace Metals from solution by crustaceans is often described as typically following one of two routes; one passive, the other depending on active transport. In the case of passive facilitated diffusion, the Trace Metal binds initially to a Metal-binding protein in the membrane of the epithelial surface, and then passes down a thermodynamic gradient of Metal-binding ligands of increasing Metal affinities. Some Trace Metals may also follow routes for the uptake of major Metal ions, as in the case of cadmium and calcium. This uptake is ultimately driven by an energy-requiring pump in the epithelial cell membrane. This may be apical and directly transfer the Metal ion into the cell, or as in the case of sodium, a basal ATPase setting up a concentration gradient from the medium to the interior of the cell allowing entry down a Metal-transporting channel. Carrier proteins and channels may indeed be variations of the same theme. The relative importance of different routes varies between Trace Metals and between crustaceans, often according to their ecology. The physicochemistry of Trace Metal speciation in solution is important in releasing the free Metal ion, typically the bioavailable form of a Trace Metal, but the physiological responses of particular crustaceans may interact to affect uptake rates. Such physiological responses include changes in activities of major ion pumps and integumental permeability, and appear to be a feature of common, but physiologically special, euryhaline crustaceans.
Keith A. Hunter - One of the best experts on this subject based on the ideXlab platform.
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A Trace‐Metal clean, pH‐controlled incubator system for ocean acidification incubation studies
Limnology and Oceanography: Methods, 2013Co-Authors: Linn J. Hoffmann, Eike Breitbarth, Christina M. Mcgraw, Cliff S. Law, Kim I. Currie, Keith A. HunterAbstract:The emerging research field of ocean acidification studies has gained international attention during the past years and recently defined international standards in the Guide to best practices for ocean acidification research and data reporting. However, a combination of ocean acidification studies with Trace Metal research is very rare and possible Trace Metal side effects on marine phytoplankton in ocean acidification incubation studies are often not assessed. Here we describe a Trace Metal clean, pH-controlled incubator system for laboratory and seagoing ocean acidification research. Seawater pH adjustment is achieved via passing CO2 gas through diffusive silicone tubing to minimize the risk of contamination and to avoid the negative mechanical effects of gas bubbles on phytoplankton. The system measures pH automatically with an accuracy of 0.004 and a precision of 0.001 and includes a feedback regulation to adjust pH during the incubation if required. Mn, Fe, Co, Ni, Cd, and Pb measurements show that our system and the pH adjustment method do not contaminate the samples with any of these Metals. We tested this system in laboratory studies as well as during the PINTS voyage in the Tasman Sea.
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Influence of ocean warming and acidification on Trace Metal biogeochemistry
Marine Ecology Progress Series, 2012Co-Authors: Linn J. Hoffmann, Eike Breitbarth, Philip W. Boyd, Keith A. HunterAbstract:Rising atmospheric CO2 concentrations will have profound effects on atmospheric and hydrographic processes, which will ultimately modify the supply and chemistry of Trace Metals in the ocean. In addition to an increase in sea surface temperatures, higher CO2 also results in a decrease of seawater pH, known as ocean acidification, with implications for inorganic Trace Metal chemistry. Furthermore, direct or indirect effects of ocean acidification and ocean warming on marine biota will also affect Trace Metal biogeochemistry via alteration of biological Trace Metal uptake rates and Metal binding to organic ligands. Currently, we still lack a holistic understanding of the impacts of decreasing seawater pH and rinsing temperatures on different Trace Metals and marine biota, which complicates projections into the future. Here, we outline how ocean acidification and ocean warming will influence the inputs and cycling of Fe and other biologically relevant Trace Metals globally, and regionally in high and low latitudes of the future ocean, discuss uncertainties, and highlight essential future research fields.
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Trace Metal and major ion concentrations in Lakes Hayes and Manapouri
Journal of the Royal Society of New Zealand, 1999Co-Authors: Malcolm R. Reid, Jonathan P. Kim, Keith A. HunterAbstract:The major ion (Na+, K+, Mg2+, Ca2+, Sr∗, Cl, SO4 2, alkalinity, reactive Si) and Trace Metal (Cu, Zn, Fe, Mn, Cd and Pb) compositions of Lakes Hayes and Manapoun have been studied on five occasions throughout the seasonal cycle and depth range of each lake In L Manapoun, seasonal changes in both major element and Trace Metal concentrations were negligible and almost within the precision of analytical methods, indicating a highly uniform water composition Major element concentrations were extremely low by global standards, in most cases below the 1% percentile level for global fresh waters By contrast, the much shallower L Hayes exhibited much higher major element concentrations, close to the global mean In addition, this lake showed a clear anoxic sub‐surface layer during summer, in which concentrations of the redox‐active Metals Fe and Mn became very high Evidence of surface water utilisation of reactive Si, and deeper water scavenging of Cu, were both found in this lake
P S Rainbow - One of the best experts on this subject based on the ideXlab platform.
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Caddisflies Hydropsyche spp. as biomonitors of Trace Metal bioavailability thresholds causing disturbance in freshwater stream benthic communities.
Environmental Pollution, 2016Co-Authors: Zmnako A. Awrahman, P S Rainbow, Brian D. Smith, Farhan R. Khan, Wojciech FialkowskiAbstract:Demonstration of an ecotoxicological effect of raised toxic Metal bioavailabilities on benthic macroinvertebrate communities in contaminated freshwater streams typically requires the labour-intensive identification and quantification of such communities before the application of multivariate statistical analysis. A simpler approach is the use of accumulated Trace Metal concentrations in a Metal-resistant biomonitor to define thresholds that indicate the presence of raised Trace Metal bioavailabilities causing ecotoxicological responses in populations of more Metal-sensitive members of the community. We explore further the hypothesis that concentrations of toxic Metals in larvae of species of the caddisfly genus Hydropsyche can be used to predict Metal-driven ecotoxicological responses in more Metal-sensitive mayflies, especially ephemerellid and heptageniid mayflies, in Metal-contaminated rivers. Comparative investigation of two caddisflies, Hydropsyche siltalai and Hydropsyche angustipennis, from Metal-contaminated rivers in Cornwall and Upper Silesia, Poland respectively, has provided preliminary evidence that this hypothesis is applicable across caddisfly species and contaminated river systems. Use of a combined toxic unit approach, relying on independent data sets, suggested that copper and probably also arsenic are the drivers of mayfly ecotoxicity in the River Hayle and the Red River in Cornwall, while cadmium, lead and zinc are the toxic agents in the Biala Przemsza River in Poland. This approach has great potential as a simple tool to detect the more subtle effects of mixed Trace Metal contamination in freshwater systems. An informed choice of suitable biomonitor extends the principle to different freshwater habitats over different ranges of severity of Trace Metal contamination.
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Trace Metal concentrations in aquatic invertebrates why and so what
Environmental Pollution, 2002Co-Authors: P S RainbowAbstract:Abstract All aquatic invertebrates take up and accumulate Trace Metals whether essential or not, and subsequent body concentrations of Trace Metals show enormous variability across Metals and invertebrate taxa. Accumulated Metal concentrations are interpreted in terms of different Trace Metal accumulation patterns, dividing accumulated Metals into two components — metabolically available Metal and stored detoxified Metal. Crustaceans are used as examples of different accumulation patterns that will have a general applicability to all aquatic invertebrates. Toxicity is related to a threshold concentration of metabolically available Metal and not to total accumulated Metal concentration. The significance of accumulated Metal concentrations is discussed in terms of the biological significance, including the attempted recognition of a high or low concentration, and of the applied use of aquatic invertebrates in biomonitoring programmes assessing geographical and temporal variation in Trace Metal bioavailabilities in aquatic systems.
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Trace Metal accumulation in marine invertebrates marine biology or marine chemistry
Journal of the Marine Biological Association of the United Kingdom, 1997Co-Authors: P S RainbowAbstract:Trace Metals are accumulated by marine invertebrates to body concentrations higher, in many cases orders of magnitude higher, than the concentrations in an equivalent weight of the surrounding sea-water (Eisler, 1981; Rainbow, 1990; Phillips & Rainbow, 1993). Specific details of Trace Metal accumulation processes vary within the same invertebrate species between Metals, and for the same Trace Metal between invertebrates, often between closely related species (Rainbow, 1990, 1993). This short review attempts to highlight some of the comparative aspects of the processes involved that are expected and explicable in terms of the chemistry of the respective elements, and those where the physiology of the species involved intervenes to offset predictions from purely chemical principles. Although an appreciation of Trace Metal chemistry is crucial to an understanding of Trace Metal accumulation, idiosyncrasies in the biology of the invertebrate (at any taxon level) may intervene to bring about significant and unexpected comparative differences in Metal accumulation patterns.
