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Trace metal
About: Trace metal is a research topic. Over the lifetime, 5125 publications have been published within this topic receiving 181046 citations.
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TL;DR: Half‐saturation constants for the reduction of Cu(II) complexes with carbonate, phenanthroline and bathocuproinedisulfonate are in the range 2.3–14.7 μM, which suggests that trace metal complexes are not the main electron acceptor in natural waters.
Abstract: The phytoplankton cell surface reduces external copper(II) and iron(III) complexes and redox dyes. This reductive activity appears to be mediated by one or more plasmalemma redox enzymes. Trace metal complexes are directly reduced by the redox enzyme, therefore the reduction rate is not regulated by the metal free ion activity in solution. This is in direct contrast to previous measurements of trace metal interactions with the phytoplankton cell membrane. Half-saturation constants for the reduction of Cu(II) complexes with carbonate, phenanthroline and bathocuproinedisulfonate are in the range 2.3-14.7 ..mu..M, which suggests that trace metal complexes are not the main electron acceptor in natural waters. In the diatom Thalassiosira weissflogii there is additional reductive activity associated with the cell wall.
121 citations
TL;DR: In this paper, measurements of volumetric discharge and concentrations of dissolved (0.45 μm) major ion and trace metal components of road drainage water have been made during ten storm events at a motorway site in northwest England.
121 citations
TL;DR: For example, heavy metal concentrations were determined in suspended particulates, filtered water and sediment collected in the Mississippi River and from its marine delta as discussed by the authors, showing that more than 90% of the metal load of the river is associated with particulate matter.
Abstract: Heavy metal concentrations were determined in suspended particulates, filtered water and sediment collected in the Mississippi River and from its marine delta. More than 90% of the metal load of the river is associated with particulate matter, which is relatively constant in chemical composition with time and place. The Mississippi River suspended material is similar to average crystal rocks in Fe, Al, V, Cr, Cu, Co, Mn, and Ni concentration but is generally enriched in Zn, Cd and Pb. Sediment cores dated by the Pb 210 method show that the Cd and Pb enrichments are recent phenomenon and are most likely due to the activities of man. About 6000 tonne of Pb and 300 tonne of Cd are being added to the delta sediments by man each year, more than 30 times the amount added to the Southern California Bight. River particulate matter is essentially identical to deltaic sediments in Al, Fe, Cr, V, Cd and Pb concentration, but the sediments are depleted in Co, Cu, Mn, Ni and Zn by 20 to 40%. Chemical leaching of the solids show the metal losses to be primarily from the oxide phase, suggesting diagenetic reduction and mobilization as a mechanism. Trace metal concentrations in filtered Mississippi River water were below the limits for safe drinking water and were similar to world average river values. The abundant river suspended matter and high pH combine to keep dissolved trace metal concentrations low.
121 citations
TL;DR: A review of the literature on trace metal concentrations and speciation can be found in this paper, where the dominant mechanism in control of concentration for most metals appears to be adsorption on biologically produced particulate matter.
121 citations
TL;DR: In this paper, the authors studied principle rock−water interactions that control trace metal concentrations in a complex geochemical environment containing multiple contaminants and multiple solid phases by combining kinetic and thermodynamic evaluation of the water chemistry with spectroscopic analyses of the sediments, which allowed the number of geochemical reactions needed to model and predict trace metal mobility over a range of natural settings to be greatly constrained.
Abstract: We have studied principle rock−water interactions that control trace metal concentrations in a complex geochemical environment containing multiple contaminants and multiple solid phases by combining kinetic and thermodynamic evaluation of the water chemistry with spectroscopic analyses of the sediments. This approach allows the number of geochemical reactions needed to model and predict trace metal mobility over a range of natural settings to be greatly constrained. In the U.S. Tri-State Mining District (Kansas−Missouri−Oklahoma) the most important geochemical interactions are degassing of CO2(g)-rich waters; the short-term uptake and release kinetics of zinc, cadmium, and lead; competition between iron oxyhydroxides and carbonates for zinc, cadmium, and lead; and catalysis of sulfide dissolution by iron in near-neutral waters. In our field study, degassing of CO2(g) waters is responsible for the range of pH measured at each site over the 1-year field study. Trace metal release and uptake kinetics by iron...
120 citations