Revealing forms of iron in river-borne material from major tropical rivers of the Amazon Basin (Brazil)

Allard, Thierry; Menguy, Nicolas; Salomon, J.; Calligaro, Thomas; Weber, T.; Calas, Georges; Benedetti, Marc F.

doi:10.1016/j.gca.2004.01.014

Cited by 114 publications

(83 citation statements)

References 54 publications

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“…The hydroxylated carboxylic acids, such as glycolic and tartaric acids, are less volatile, and relatively strong acids could be more effective than monocarboxylic acids to complex iron under atmospheric conditions. Humic substances are known to provide binding sites, due to the presence of phenolate or carboxylate groups, for iron in aquatic systems (Allard et al, 2004;Weber et al, 2006). Similar complexation could be observed for HULIS in the atmospheric waters.…”

Section: Introductionmentioning

confidence: 56%

“…In the case of the tartrate molecule (C4), the presence of -OH groups on the chain of carbon atoms decreases the inductive effect and could explain its impact on iron solubility. In spite of the complexity of the humic acid structure, it is known that the large variety of carboxylate groups makes humic substances good electron donors and hence they have an important role in the control of iron bioavailability in the surface waters and in soils (Allard et al, 2004). Thus, the combination of the ability as electron donor and ligand could explain the promoting effect of HULIS analogue.…”

Section: Dissolution Processmentioning

confidence: 99%

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Effect of atmospheric organic complexation on iron-bearing dust solubility

2013

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Recent studies reported that the effect of organic complexation may be a potentially important process to be considered by models estimating atmospheric iron flux to the ocean. In this study, we investigated this process effect by a series of dissolution experiments on iron-bearing dust in the presence or the absence of various organic compounds (acetate, formate, oxalate, malonate, succinate, glutarate, glycolate, lactate, tartrate and humic acid as an analogue of humic like substances, HULIS) typically found in atmospheric waters. Only 4 of tested organic ligands (oxalate, malonate, tartrate and humic acid) caused an enhancement of iron solubility which was associated with an increase of dissolved Fe(II) concentrations. For all of these organic ligands, a positive linear dependence of iron solubility to organic concentrations was observed and showed that the extent of organic complexation on iron solubility decreased in the following order: oxalate >malonate = tartrate > humic acid. This was attributed to the ability of electron donors of organic ligands and implies a reductive ligand-promoted dissolution. This study confirms that among the known atmospheric organic binding ligands of Fe, oxalate is the most effective ligand promoting dust iron solubility and showed, for the first time, the potential effect of HULIS on iron dissolution under atmospheric conditions

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Section: Introductionmentioning

confidence: 56%

Section: Dissolution Processmentioning

confidence: 99%

Effect of atmospheric organic complexation on iron-bearing dust solubility

2013

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“…The amount of dissolvable Fe in aeolian transported materials varies greatly, ranging anywhere from 2% to 20% for direct measurements (Baker and Jickells 2006;Baker et al 2006) whereas indirect estimates for the Pacfic are higher at ~40% (Boyle et al 2005). The amount of dissolved Fe (Allard et al 2004;de Baar and de Jong 2001) carried by rivers varies strongly and is influenced by pH, catchment area, and vegetation cover. Much of the river transported soluble Fe in estuaries, however, is quickly converted, at higher salinity values, into the biologically unavailable colloidal and particulate phase (Boyle et al 1977;Guieu et al 1996).…”

Section: Introductionmentioning

confidence: 99%

Application of cross‐flow filtration for determining the solubility of iron species in open ocean seawater

Schlösser

Croot

2008

Limnology & Ocean Methods

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Measurements of soluble iron species (organic and inorganic) are important for understanding the transport of iron within the ocean and its bioavailability. Recent developments in ultrafiltration equipment and analytical detection techniques for low level Fe determination has turned the spotlight on obtaining data on soluble iron species. However there have, until now, been few studies that have characterized the performance of an ultrafiltration system with respect to well described soluble iron complexes. In the present work, we describe a methodological study characterizing the behavior of soluble and colloidal iron species in seawater by combining a crossflow ultrafiltration system (Vivaflow 50 TM ) with a radioisotope ( 55 Fe). During this study, we were able to maintain excellent mass balances by including all components: not only the solution phases (retentate and permeate) but wall-adsorbed and filter-adsorbed iron, which were recovered by an acid-rinsing step. Wall and filter adsorption were unavoidable when solutions were saturated with respect to Fe'. However in undersaturated solutions, such as with an excess of desferrioxamine B, wall and filter adsorption were minimized, indicating that these effects should be slight for natural samples where iron-binding ligands are in excess. Our results have important implications for the use of ultrafiltration membranes for open ocean iron biogeochemical studies.

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“…Given the usual fast precipitation kinetics of Fe oxy-hydroxides at circumneutral pH [59], very low free Fe concentrations should be found in system, and the observed oversaturation of Fe can be explained by the 0.45 µm cutoff membrane which allows the presence of both dissolved Fe and small colloidal Fe oxy-hydroxides [60] in the filtrate. Given results from Allard et al [60] the smallest Fe oxy-hydroxides are likely to consist in amorphous material (such as ferrihydrite) whereas the crystallized ones, like goethite, would be found in the SPM fraction. Similarly, these calculations display that BA water is oversaturated with respect to Al oxyhydroxides phases, suggesting the presence of Al in colloidal form [61] in solution.…”

Section: Water Chemistrymentioning

confidence: 99%

Colloids and suspended particulate matters influence on Ni availability in surface waters of impacted ultramafic systems in Brazil

Zelano¹,

Sivry²,

Quantin³

et al. 2013

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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International audienceThe overall objective of this work was to assess the modification of Ni availability and lability consequently to anthropic activity. Surface waters were collected in two ultramafic complexes (Barro Alto and Niquelandia) from Goias State (Brazil) impacted by mining and metallurgical activities. For the nearly first time, Isotopic Exchange Kinetic technique (IEK) was performed on these natural water samples to quantify the pool of isotopically exchangeable Ni from the suspended particulate matter (SPM) in water, defined here as E-Ni(W). The SPM mineralogy was investigated by X-Ray Diffraction (XRD), Scanning and Transmission Electron Microscopy (SEM and TEM). This allowed to establish the link between Ni availability and its solid speciation. Goethite, chlorite, talc and serpentine were identified as the main Ni bearing phases in SPM far from metallurgy (Barro Alto site) while in samples located in the area influenced by metallurgy (Niquelandia) Ni was mainly associated to spherical micrometric particles, related to fly ash produced by the ore combustion. In Niquelandia samples 4,1, value was found ranging between 2.4 and 565 mu g L-1, while in Barro Alto E-Ni(W) was 62 mu g L-1, which corresponds to E-Ni values of 49,000 and 2350 mg kg(-1), in SPM from Niquelandia and Barro Alto, respectively. Moreover, IEK experiments highlighted differences in kinetic of Ni exchanges: the maximum E-Ni(W) value was reached after only 19 hours of interaction in Barro Alto sample, while in Niquelandia ones E-Ni(W) hardly reached 70 to 95% of the maximum after the same period of time. On the one hand, both the low proportion and high velocity of Ni exchanges observed in Barro Alto sample may be attributed to surface complexation on talc, serpentine, chlorite and goethite. On the other hand, both the higher proportion of exchangeable stock and slower isotopic exchanges should be mostly attributed in Niquelandia samples to Ni interaction with the anthropogenic spherical and porous particles of Fe-Mg-Si-Al composition, related to FBA released by metallurgic activity

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Revealing forms of iron in river-borne material from major tropical rivers of the Amazon Basin (Brazil)

Cited by 114 publications

References 54 publications

Effect of atmospheric organic complexation on iron-bearing dust solubility

Effect of atmospheric organic complexation on iron-bearing dust solubility

Application of cross‐flow filtration for determining the solubility of iron species in open ocean seawater

Colloids and suspended particulate matters influence on Ni availability in surface waters of impacted ultramafic systems in Brazil

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