Major and trace elements associated with colloids in organic-rich river waters: ultrafiltration of natural and spiked solutions

Dupré, Bernard; Viers, Jérôme; Dandurand, Jany; Polvé, Mireille; Bénézeth, Pascale; Vervier, Philippe; Braun, Jean‐Jacques

doi:10.1016/s0009-2541(99)00060-1

Cited by 183 publications

(96 citation statements)

References 60 publications

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“…Free calcium represents 80% to 96% of the total Ca in the bulk water and the rest corresponds to calcium diffusely bound (i.e., in the Donnan phase) to the organic matter. Calcium specific binding to carboxylic and phenolic type groups always represents Ͻ0.13% of the total calcium concentration in the fraction Ͻ0.22 m. This result is similar to the findings of Dupré et al (1999) who showed with Sr isotopic measurements that Ͻ0.22 m Sr was totally present in an exchangeable form. The calculations show that the complexed fraction is probably negligible in most cases.…”

Section: Modelling Of Ca In the Amazonian Riverssupporting

confidence: 89%

Association of calcium with colloidal particles and speciation of calcium in the Kalix and Amazon rivers

Dahlqvist

Benedetti

Andersson

et al. 2004

Geochimica et Cosmochimica Acta

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Abstract-A considerable amount of colloidally bound Ca has been detected in water samples from Amazonian rivers and the Kalix River, a sub-arctic boreal river. Fractionation experiments using several analytical techniques and processing tools were conducted in order to elucidate the matter. Results show that on average 84% of the total Ca concentration is present as free Ca. Particulate, colloidal and complexed Ca constitute the remaining 16%, of which the colloidal fraction is significant. Ultrafiltration experiments show that the colloidal fraction in the sampled Amazonian rivers and the Kalix River range between 1% and 25%.In both the Amazonian and the Kalix rivers the technique of cross-flow ultrafiltration was used to isolate particles and colloids. The difference in concentration measured with ICP-AES and a Ca ion-selective electrode in identical samples was used to define the free Ca concentration and thus indirectly the magnitude of the particulate, colloidal and complexed fractions. Results from the Kalix and Amazonian rivers are in excellent agreement. Furthermore, the results show that the colloidal concentrations of Ca can be greatly overestimated (up to 227%) when conventional analysis and calculation of ultrafiltration data is used due to retention of free Ca ions during the ultrafiltration process. Calculation methods for colloidal matter are presented in this work, using complementary data from ISE analysis.In the Kalix River temporal changes in the fractionation of Ca were studied before, during and after a spring-flood event. Changes in the size distribution of colloidally associated Ca was studied using FlFFF (Flow Field-Flow Fractionation) coupled on-line to a HR ICP-MS. The FlFFF-HR ICP-MS fractograms clearly show the colloidal component of Ca, supporting the ultrafiltration findings. During winter conditions the size distribution of colloidally associated Ca has a concentration maximum at ϳ5 to 10 nm in diameter, shifting to smaller sizes (Ͻ5 nm) during and after the spring flood. This shift in size distribution follows a change in the river during this period from ironoxyhydroxy colloids being the most important colloidal carrier phase to humic substances during and after the spring flood.WHAM and NICA-Donnan models were used to calculate the amount of colloidally bound Ca. The results similar for both models, show that on average 16% of the Ca may be associated to a colloidal phase, which is in broad agreement with the measurements.

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Section: Modelling Of Ca In the Amazonian Riverssupporting

confidence: 89%

Association of calcium with colloidal particles and speciation of calcium in the Kalix and Amazon rivers

Dahlqvist

Benedetti

Andersson

et al. 2004

Geochimica et Cosmochimica Acta

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“…Second, the fine variations measured by the RL are reproduced in the laboratory, validating the observed diurnal variations and supporting the reliability of the RL to detect changes of the order of a percent within a day. The third observation is that small yet systematic offsets between the two sets of data exist, up to 3 % for Mg. One possible explanation for this difference is that the filtration procedures differed between the RL and the manual sampling, which may have led to a discrepancy in the concentration measurements related to the potential for some elements to be hosted in the colloidal phase (Dupré et al, 1999). In addition, the most accurate measurements were obtained with the RL rather than with the laboratory equipment because the RL is continuously processing solutions with a similar matrix, thereby minimizing memory effects and cross-contamination that can compromise measurements if widely differing samples are run successively on the same instrument.…”

Section: Reproducibility: Rl Vs Laboratorymentioning

confidence: 99%

The potamochemical symphony: new progress in the high-frequency acquisition of stream chemical data

Floury¹,

Gaillardet²,

Gayer³

et al. 2017

Hydrol. Earth Syst. Sci.

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Abstract. Our understanding of hydrological and chemical processes at the catchment scale is limited by our capacity to record the full breadth of the information carried by river chemistry, both in terms of sampling frequency and precision. Here, we present a proof-of-concept study of a "lab in the field" called the "River Lab" (RL), based on the idea of permanently installing a suite of laboratory instruments in the field next to a river. Housed in a small shed, this set of instruments performs analyses at a frequency of one every 40 min for major dissolved species (Na + , K + , Mg 2+ , Ca 2+ , Cl − , SO 2− 4 , NO − 3 ) through continuous sampling and filtration of the river water using automated ion chromatographs. The RL was deployed in the Orgeval Critical Zone Observatory, France for over a year of continuous analyses. Results show that the RL is able to capture long-term fine chemical variations with no drift and a precision significantly better than conventionally achieved in the laboratory (up to ±0.5 % for all major species for over a day and up to 1.7 % over 2 months). The RL is able to capture the abrupt changes in dissolved species concentrations during a typical 6-day rain event, as well as daily oscillations during a hydrological low-flow period of summer drought. Using the measured signals as a benchmark, we numerically assess the effects of a lower sampling frequency (typical of conventional field sampling campaigns) and of a lower precision (typically reached in the laboratory) on the hydrochemical signal. The highresolution, high-precision measurements made possible by the RL open new perspectives for understanding critical zone hydro-bio-geochemical cycles. Finally, the RL also offers a solution for management agencies to monitor water quality in quasi-real time.

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“…For trace metals speciation in natural waters, numerous analytical techniques have been used ranging from complexation studies with simple ligands to utrafiltration studies of the influence of organic matter and colloidal particles [7,8]. A special importance was given into two methods -anodic stripping voltammetry and diffusive gradients in thin films (DGT) [9,10]. Differential pulse anodic stripping voltammetry (DP-ASV) techniques have been used for more than 30 years for laboratory trace metal measurements in waters, and routine instrumentations have been developed [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

The use of differential pulse anodic stripping voltammetry and diffusive gradient in thin films for heavy metals speciation in soil solution

et al. 2008

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Abstract:In the soil solutions obtained in situ with suction cups from soils (Cambisol and Fluvisol) of pot experiment with Salix smithiana Smith, Lolium perenne L. and Thlaspi caerulescens J. & C. Presl heavy metals species (Cd, Pb and Cu) were assayed by differential pulse anodic stripping voltammetry and diffusive gradient in thin films. Prediction of accumulation performed best at free metal ion concentrations in unchanged pH (in 10 -3 mol L -1 NaClO 4 base electrolyte). The speciation provided by differential pulse anodic stripping voltammetry according to pH can provide a detailed description of the soil solution matrix. The concentration of free metals in unchanged pH represents a small part of the total content and varied from 0.04 to 0.75% with two exceptions found for accumulating plants (the content of Cd 2+ in the soil solution from T. caerulescens was about 6% and the content of Cu 2+ in the soil solution from S. smithiana was about 30%). The available concentration as determined by diffusive gradient in thin films was not in correlation with the heavy metals concentration in plant biomass. Warsaw and Springer-Verlag Berlin Heidelberg. © Versita

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Major and trace elements associated with colloids in organic-rich river waters: ultrafiltration of natural and spiked solutions

Cited by 183 publications

References 60 publications

Association of calcium with colloidal particles and speciation of calcium in the Kalix and Amazon rivers

Association of calcium with colloidal particles and speciation of calcium in the Kalix and Amazon rivers

The potamochemical symphony: new progress in the high-frequency acquisition of stream chemical data

The use of differential pulse anodic stripping voltammetry and diffusive gradient in thin films for heavy metals speciation in soil solution

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