Laboratory measurements and modeling of metal-humic interactions under estuarine conditions

Hamilton−Taylor, John; Postill, A.; Tipping, Edward; Harper, Michael P.

doi:10.1016/s0016-7037(01)00777-3

Cited by 44 publications

(24 citation statements)

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“…Examples include 71 the acidification of soils [7][8][9][10][11][12][13][14] and surface waters [15] , trace metal behaviour in soils [16][17][18][19][20][21][22] , surface 72 waters [23][24][25][26][27][28][29][30][31] and groundwaters [32] , lake sediment diagenesis [33,34] , rare earth geochemistry [35-73 37] , iron and manganese geochemistry [38][39][40][41] , radionclide geochemistry [42][43][44][45] , organic matter 74 solubility in soils [46,47] , catchment modelling [48,49] , interactions of metals with biota [50,51] , 75 ecotoxicology [52][53][54][55][56][57][58][59] and Critical Loads …”

Section: Tipping Et Al Humic Ion-binding Model Vii_revisionmentioning

confidence: 99%

Humic Ion-Binding Model VII: a revised parameterisation of cation-binding by humic substances

2011

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Article (refereed) -postprintTipping, E.; Lofts, S.; Sonke, J.E.. 2011. Humic Ion-Binding Model VII: a revised parameterisation of cation-binding by humic substances. Environmental Chemistry, 8 (3). 225-235. 10.1071/EN11016Contact CEH NORA team at noraceh@ceh.ac.ukThe NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. [1,2] incorporating Humic Ion-Binding Model 55 V [3] or VI [4] permits the calculation of equilibrium chemical speciation for waters and soils in 56 which natural organic matter plays a significant role. The ion-binding models are based on 57 conventional chemical reactions involving O-containing weak acids, with empirical estimation 58 of the influence of soft ligand atoms (N, S) and electrostatic corrections, and are 59 parameterised from laboratory studies with isolated humic and fulvic acids. The NICA 60 model [5] is similarly parameterised and provides an alternative picture based on continuous 61 binding-site distributions. Tipping [2] identified both the Humic Ion-Binding Models and NICA 62 as comprehensive models, meaning that they deal with competitive interactions involving all 63 cations (including H + ), and take account of ionic strength effects and metal-proton exchange 64 ratios. They seek to represent cation-binding by the complex mixtures that comprise natural 65 organic matter as efficiently as possible, with the minimum number of parameters, in order to 66 be useful in addressing chemical processes in the environment. A different approach to 67 these parameterised models, but also potentially comprehensive, is the "forward modelling" 68 developed by Cabaniss [6] in which binding is calculated a priori from the known or assumed 69 distributed chemistry of humic substances. 70 Tipping et al. Humic Ion-Binding Model VII_REVISIONWHAM has been applied in a variety of research and regulatory areas. Examples include 71 the acidification of soils [7][8][9][10][11][12][13][14] and surface waters [15] , trace metal behaviour in soils [16][17][18][19][20][21][22] , surface 72 waters [23][24][25][26][27][28][29][30][31] and groundwaters [32] , lake sediment diagenesis [33,34] , rare earth geochemistry [35-73 37] , iron and manganese geochemistry [38][39][40][41] , radionclide geochemistry [42][43][44][45] , organic matter 74 solubility in soils [46,47] , catchment modelling [48,49] , interactions of metals with biota [50,51] , 75 ecotoxicology [52][53][54][55][56][57][58][59] and Critical Loads [60][61][62] . Given this evident utility, it is worthwhile to 76 continue to improve the humic ion-binding model and incorporate new data into its 77 parameterisation. Here we report on activities undertaken towards these goals, namely 78 modification of assumptions about multidentate binding, the fitting of new data, and the 79 introduction of a procedure to obtain more internally-consistent parameters. 80Changes in binding site formulation were prompte...

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Section: Tipping Et Al Humic Ion-binding Model Vii_revisionmentioning

confidence: 99%

Humic Ion-Binding Model VII: a revised parameterisation of cation-binding by humic substances

2011

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“…For these studies, we used a dialysis technique that allows for the in situ sampling of dissolved, low-molecular weight (LMW) organic matter (OM), and TEs over the entire water column. Dialysis probes have occasionally been used before, notably for porewater sampling (e.g., Kepkay 1985;Burdige and Kepkay 1983;Carignan et al 1985), under estuarine conditions (Hamilton-Taylor et al 2002), in the anoxic zone of a meromictic lake (Albéric et al 2000), and in an acid bog lake (Koenings 1976). Dialysis was also used in comparison with other techniques for trace metal speciation in organicpoor lakes (Gimpel et al 2003) and for thermodynamic modeling (Lead et al 1998;Lofts et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Size Fractionation of Trace Elements in a Seasonally Stratified Boreal Lake: Control of Organic Matter and Iron Colloids

et al. 2012

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The colloidal distribution and size fractionation of organic carbon and trace elements were studied in a seasonally stratified, organic-rich boreal lake, Lake Maselga, located in the European subarctic zone (NW Russia, Arkhangelsk region). This study took place over the course of 5 years in winter (glacial) and summer periods and during the spring and autumn overturn. A newly developed in situ dialysis technique (1, 10, and 50 kDa) and traditional frontal filtration and ultrafiltration (20, 10, 5, 0.22, and 0.025 lm) were used to assess element concentrations at different depths. No significant changes in element concentrations occurred during filtration through sub-colloidal pore-size membranes (20-0.22 lm), suggesting a negligible amount of particulate Fe, OC, and associated trace metals. Large colloids (0.025-0.22 lm) were found to be the main carriers of poorly soluble elements (Fe, Al, Ti, Zr, REEs, Th, and U) during the summer and winter stratification. There was also a clear change in the vertical pattern of the percentage of colloidal Al, Ti, V, Cr, Fe, and Ni during different seasons, and the greatest proportion of colloidal forms was observed during the spring and autumn overturn. This pattern is most likely linked to the dominance of soil (allochthonous) organic carbon, which complexes with trace metals during these periods. During the summer seasons, autochthonous production of small exometabolites or photodegradation increases the concentration of the lowmolecular weight fractions (\1 kDa) that dominate the speciation of divalent heavy metals Electronic supplementary material The online version of this article (in surface horizons. The colloidal status of As (30-60%), which was documented in different seasons along the full depth of the water column, is most likely linked to the presence of organic complexes. The overall results of this study suggest that changes in the colloidal speciation of trace elements with depth in different seasons depend on changes in the redox conditions, the input of soil OM, the biodegradation of plankton biomass releasing dissolved organic matter in the bottom horizons, and in upward diffusion from the sediments.

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“…Thus, macromolecular complexes were produced as a result of cross-linking of separate macromolecules by metal complexation. Pb, Cd, and Cu were found to attach primarily to the carboxylic groups of humic acid; phenolic groups were also encountered (Hamilton-Taylor et al, 2002;Porasso et al, 2002). The scarcity of these elements in the water extract is fully consistent with the fact that interaction between humic substances and metals may involve chemical binding, exceeding the weaker counterion association.…”

Section: Resultsmentioning

confidence: 62%

Chemistry of metal–humic complexes contained in Megalopolis lignite and potential application in modern organomineral fertilization

Chassapis

Roulia

Tsirigoti

2009

International Journal of Coal Geology

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Laboratory measurements and modeling of metal-humic interactions under estuarine conditions

Abstract: Laboratory measurements and modelling of metal-humic interactions under estuarine conditions 5

Cited by 44 publications

References 24 publications

Humic Ion-Binding Model VII: a revised parameterisation of cation-binding by humic substances

Humic Ion-Binding Model VII: a revised parameterisation of cation-binding by humic substances

Size Fractionation of Trace Elements in a Seasonally Stratified Boreal Lake: Control of Organic Matter and Iron Colloids

Chemistry of metal–humic complexes contained in Megalopolis lignite and potential application in modern organomineral fertilization

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