scholarly journals Unravelling Metal Speciation in the Microenvironment Surrounding Phytoplankton Cells to Improve Predictions of Metal Bioavailability

2020 ◽  
Vol 54 (13) ◽  
pp. 8177-8185
Author(s):  
Fengjie Liu ◽  
Qiao-Guo Tan ◽  
Dominik Weiss ◽  
Anne Crémazy ◽  
Claude Fortin ◽  
...  
Keyword(s):  
Metal Speciation ◽  
Metal Bioavailability ◽  
Phytoplankton Cells

Ion-exchange technique (IET) for measuring Cu2+, Ni2+ and Zn2+ activities in soils contaminated with metal mixtures

2017 ◽  
Vol 14 (1) ◽  
pp. 55 ◽  
Author(s):  
D. M. Schwertfeger ◽  
W. H. Hendershot
Keyword(s):  
Organic Matter ◽  
Ion Exchange ◽  
Metal Binding ◽  
Mean Squared Error ◽  
Metal Speciation ◽  
Ion Exchange Resin ◽  
Metal Bioavailability ◽  
Soil Extracts ◽  
Metal Mixtures ◽  
Exchange Technique

Environmental contextTerrestrial environments receiving trace metal contaminants are often impacted by more than one metal. This study demonstrates the adaptation of an ion-exchange technique to simultaneously obtain Cu2+, Ni2+ and Zn2+ activities in soil extracts. These measurements can be used to better understand and predict the behaviour and bioavailability of soil metals in metal–mixture contamination scenarios. AbstractReliable estimates of metal speciation are critical for predicting metal bioavailability and the toxicological effects of metal mixtures in the soil environment; however, simultaneous measurements of metal free ion activities in complex matrices pose a challenge. Although speciation models maybe useful, the uncertainty of metal binding to natural organic matter requires that such models be validated with empirical data. In this study, an ion-exchange resin technique (IET) was adapted for the analysis of Cu2+, Ni2+ and Zn2+ in soil extracts. The analysis was performed with three different soil types spiked with single and multiple metal additions to obtain a range of metal concentrations and combinations. Method detection limits of 0.006, 0.04 and 0.05µM for Cu2+, Ni2+ and Zn2+ were achieved. The values obtained by IET were comparable with those estimated by Visual MINTEQ, giving a root mean squared error of 0.21, 0.30 and 0.34 (n=30) for the Cu, Ni and Zn data. The Cu2+ activities obtained by IET were within an order of magnitude of those obtained by a Cu ion-selective electrode, being on average 6-fold greater, with better agreement occurring in samples having lower organic matter contents. The resulting soil metal speciation data revealed that the partitioning of soil Cu to the potentially bioavailable Cu2+ pool differed in the binary mixture with Ni compared with the single-metal Cu treatments. These data can be used to assess metal bioavailability and aid in the interpretation of ecotoxicological effects observed in soils where multiple metals are a concern.

HEAVY METAL SPECIATION IN BOTTOM SEDIMENTS OF THE VYSHNEVOLOTSKY RESERVOIR

2018 ◽  
pp. 46-54
Author(s):  
O. A. Lipatnikova
Keyword(s):  
Heavy Metal ◽  
Organic Matter ◽  
Bottom Sediments ◽  
Metal Speciation ◽  
Organic Matter Content ◽  
Water Reservoir ◽  
Matter Content ◽  
Heavy Metal Speciation ◽  
Mobile Forms ◽  
Manganese Hydroxides

The study of heavy metal speciation in bottom sediments of the Vyshnevolotsky water reservoir is presented in this paper. Sequential selective procedure was used to determine the heavy metal speciation in bottom sediments and thermodynamic calculation — to determine ones in interstitial water. It has been shown that Mn are mainly presented in exchangeable and carbonate forms; for Fe, Zn, Pb и Co the forms are related to iron and manganese hydroxides is played an important role; and Cu and Ni are mainly associated with organic matter. In interstitial waters the main forms of heavy metal speciation are free ions for Zn, Ni, Co and Cd, carbonate complexes for Pb, fulvate complexes for Cu. Effects of particle size and organic matter content in sediments on distribution of mobile and potentially mobile forms of toxic elements have been revealed.

Metal Bioavailability and Speciation in a Wetland Tailings Repository Amended with Biosolids Compost, Wood Ash, and Sulfate

2003 ◽  
Vol 32 (3) ◽  
pp. 851 ◽  
Author(s):  
Pam S. DeVolder ◽  
Sally L. Brown ◽  
Dean Hesterberg ◽  
Kumi Pandya
Keyword(s):  
Wood Ash ◽  
Metal Bioavailability ◽  
Biosolids Compost

Chemical Composition and Metal Speciation in Porewaters from the Upper Qu’Appelle River Basin, Saskatchewan

1993 ◽  
Vol 28 (1) ◽  
pp. 83-110 ◽  
Author(s):  
Richard E. Farrell ◽  
Jae E. Yang ◽  
P. Ming Huang ◽  
Wen K. Liaw
Keyword(s):  
Amino Acids ◽  
Trace Metal ◽  
River Basin ◽  
Drainage Basin ◽  
Metal Speciation ◽  
Anthropogenic Activities ◽  
High Concentration ◽  
Metal Concentrations ◽  
Carbonate Equilibria ◽  
The Impact

Abstract Porewater samples from the upper Qu’Appelle River basin in Saskatchewan, Canada, were analyzed to obtain metal, inorganic ligand and amino add profiles. These data were used to compute the aqueous speciation of the metals in each porewater using the computer program GEOCHEM-PC. The porewaters were classified as slightly to moderately saline. Metal concentrations reflected both the geology of the drainage basin and the impact of anthropogenic activities. Whereas K and Na were present almost entirely as the free aquo ions, carbonate equilibria dominated the speciation of Ca. Mg and Mn (the predominant metal ligand species were of the type MCO3 (s). MCO30. and MHCO3+). Trace metal concentrations were generally within the ranges reported for non-polluted freshwater systems. Whereas the speciation of the trace metals Cr(III) and Co(II) was dominated by carbonate equilibria, Hg(II)-, Zn(II)- and Fe(II)-speciation was dominated by hydroxy-metal complexes of the type M(OH)+ and M(OH)2°. The speciation of Fe(III) was dominated by Fe(OH)3 (s). In porewaters with high chloride concentrations (> 2 mM), however, significant amounts of Hg(II) were bound as HgCl20 and HgClOH0. The aqueous speciation of Al was dominated by Al(OH)4− and Al2Si2O4(OH)6 (s). Total concentrations of dissolved free amino acids varied from 15.21 to 25.17 umole L−1. The most important metal scavenging amino acids were histidine (due to high stability constants for the metal-histidine complexes) and tryptophan (due to its relatively high concentration in the porewaters. i.e., 5.96 to 7.73 umole L−1). Secondary concentrations of various trace metal-amino add complexes were computed for all the porewaters, but metal-amino acid complexes dominated the speciation of Cu(II) in all the porewaters and Ni(II) in two of the porewaters.

Metal and phosphate speciation during anaerobic digestion of phosphorus rich sludge

1997 ◽  
Vol 36 (6-7) ◽  
pp. 191-200 ◽  
Author(s):  
C. M. Carliell ◽  
A. D. Wheatley
Keyword(s):  
Anaerobic Digestion ◽  
Metal Speciation ◽  
Extraction Methods ◽  
Phosphate Removal ◽  
Metal Species ◽  
Chemical Extraction ◽  
Inorganic P ◽  
Similar Work ◽  
Extractable P ◽  
Phosphate Speciation

Chemical extraction methods are used to investigate metal and phosphate speciation during anaerobic digestion of phosphorus-rich sludge. Tests were performed using model compounds to evaluate the efficacy of the reagents in the extraction sequences and these results compared with similar work by other researchers. The metal speciation method was found to be suitable for identifying shifts in metal distribution but was unrepresentative of actual metal species. The phosphate speciation method did give adequate separation of the phosphate compounds tested. Full-scale digesters treating chemical and biological phosphate removal (CPR and BPR) sludge were analysed according to the methods developed. Results show that digestion of CPR sludge did not increase the soluble P concentration in the digester and that most of the precipitated phosphorus appeared to be retained in the sludge as inorganic P. The digester treating BPR sludge showed increased soluble and water-extractable P, in comparison to the control digester. Trace metal speciation profiles were found to be affected by addition of CPR sludge.

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