The speciation of manganese in freshwaters

Chiswell, B.; Mokhtar, Mazlin

doi:10.1016/0039-9140(86)80156-4

Cited by 61 publications

(29 citation statements)

References 29 publications

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“…This seems to realistically explain the observations since (marine) phytoplankton have also been shown to bind Mn (Stauber and Florence, 1985;Davidson and Marchant, 1987;Lubbers et al, 1990). There is no direct evidence that the Mn precipitation occurs on the phytoplankton cells, but the high correlations with photosynthetic rate suggest that (extraceilular) precipitation in the oxidative micro-environment of photosynthetic active cells with a high pH, may initiate the process (Chiswell and Mokhtar, 1986;Richardson et al, 1988).…”

Section: Manganese Oxidation In Riversmentioning

confidence: 69%

Effects of phytoplankton on metal partitioning in the lower River Rhine

1995

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Effects of phytoplankton on metal partitioning in the lower River RhineAdmiraal, W.; Tubbing, G.M.J.; Breebart, L. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Download date: 10 May 2018 Pergamon 0043-1354(94)00204-5Wat. Res. Vol. 29, No. 3, pp. 941-946, 1995 Copyright © 1995 Abstract--Since algal growth has been shown to play a key role in determining the fate of metals in lakes and marine waters, we wondered if the Rhine phytoplankton, so much stimulated by nutrient input, would affect the partitioning of metals between the dissolved and particulate phases, thereby altering the retention of metals in the Rhine delta. In a seasonal study in which variations in the partitioning of Mn, Cu, Zn, Cd and Pb (expressed as log Kp values) were correlated with phytoplankton parameters, it appeared that manganese occurred mainly in the particulate form during algal blooms, whereas dissolved manganese predominated during periods low in phytoplankton. Photosynthetic activity (up to 700/~g C l-~ h -~) correlated slightly better with the [log Kp]-Mn than the chlorophyll a concentration (up to 140/~g 1 -~) and the pH (up to 8.35), suggesting that phytoplankton photosynthesis promotes Mn precipitation in the river. The variability in the partitioning of Cu, Zn, Cd and Pb in 1990 did not seem to be determined by the seasonal differences in phytoplankton and manganese partitioning, although increased values of [log Kp]-Zn had been indicated for the summer of 1983, when metal concentrations had generally been higher than in 1990. The lack of effect of riverine phytoplankton blooms on partitioning of metals other than Mn contrasts with observations in stagnant waters. However, the low levels of cellular metal observed in cultures, along with the single growth pulse that phytoplankton shows during its short residence in the river, are consistent with the observations.

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Section: Manganese Oxidation In Riversmentioning

confidence: 69%

Effects of phytoplankton on metal partitioning in the lower River Rhine

1995

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“…Dissolved Ni has a negative correlation with temperature (0.90) and SO4 2 -(0.80), and a positive correlation with ammonia (0.80), Eh (0.76), and conductivity (0.74). Mn was determined preferably in samples of nonfiltered water, because the more probable inorganic specie in oxydizing environments with pH between 7 and 10 is MnO2 [14,15]. Under similar pH and Eh conditions, Fe appears as Fe(OH)3, which is highly insoluble.…”

Section: Resultsmentioning

confidence: 99%

Analysis of Physical and Chemical Parameters for Discrimination of Water Origin in a Hydroelectric Reservoir

Barreto¹,

Scarmínio

Solci

et al. 2007

CLEAN Soil Air Water

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Seventeen physical and chemical parameters were obtained from a hydroelectric reservoir located in a tropical region in the south of Brazil. Multivariate Principal Component Analysis (PCA) and Hierarchical Group Analysis (HGA) were used to identify the parameters discriminating the origin of water from the Tibagi and the Primeiro de Maio River, after it has passed the mixing region. The study was conducted during the dry and rainy seasons in July 2002 and February 2003 at three depths and three sampling sites located 0, 5, and 10 km away from the mixing region. The statistical methods showed to be appropriate for identifying the contribution of each tributary in the water mixing site of a complex water system. The most important discriminating parameter was the absorbance relation A(253 nm)/A(203 nm), followed by the concentrations of Fe(III), Mn(III), and Ni(II). An anthropogenic interference was found in the reservoir due to high Ni(II) and orthophosphate concentrations caused by a nearby town sewage discharge. The interference was more important during the dry periods due to the lower dispersion of the pollutants. Urgent initiatives should be taken from the state government to build treatment stations for the wastewater of the small cities around the Capivara hydroelectric reservoir to prevent the drinking water quality from deteriorating.

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“…This under-prediction may be related to Mn's wide range of possible oxidation states (Chriswell and Mokhtar 1986), the range of permitted minerals for precipitation, the lack of accurate surface complexation constants or a combination of these factors. Tonkin et al (2004) also reported difficulties related to obtaining good speciation predictions of Mn compared to observed data.…”

Section: Metals Exhibiting No Correlation Between Predictions and Meamentioning

confidence: 99%

Speciation and hydrological transport of metals in non-acidic river systems of the Lake Baikal basin: Field data and model predictions

et al. 2016

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The speciation of metals in aqueous systems is central to understanding their mobility, bioavailability, toxicity and fate. Although several geochemical speciation models exist for metals, the equilibrium conditions assumed by many of them may not prevail in field-scale hydrological systems with flowing water. Furthermore, the dominant processes and/or process rates in non-acidic systems might differ from well-studied acidic systems. We here aim to increase knowledge on geochemical processes controlling speciation and transport of metals under nonacidic river conditions. Specifically, we evaluate the predictive capacity of a speciation model to novel measurements of multiple metals and their partitioning, under highpH conditions in mining zones within the Lake Baikal basin. The mining zones are potential hotspots for increasing metal loads to downstream river systems. Metals released from such upstream regions may be transported all the way to Lake Baikal, where increasing metal contamination of sediments and biota has been reported. Our results show clear agreement between speciation predictions and field measurements of Fe, V, Pb and Zn, suggesting that the partitioning of these metals mainly was governed by equilibrium geochemistry under the studied conditions. Systematic over-predictions of dissolved Cr, Cu and Mo by the model were observed, which might be corrected by improving the adsorption database for hydroxyapatite because that mineral likely controls the solubility of these metals. Additionally, metal complexation by dissolved organic matter is a key parameter that needs continued monitoring in the Lake Baikal basin because dependable predictions could not be made without considering its variability. Finally, our investigation indicates that further model development is needed for accurate As speciation predictions under non-acidic conditions, which is crucial for improved health risk assessments on this contaminant.

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The speciation of manganese in freshwaters

Cited by 61 publications

References 29 publications

Effects of phytoplankton on metal partitioning in the lower River Rhine

Effects of phytoplankton on metal partitioning in the lower River Rhine

Analysis of Physical and Chemical Parameters for Discrimination of Water Origin in a Hydroelectric Reservoir

Speciation and hydrological transport of metals in non-acidic river systems of the Lake Baikal basin: Field data and model predictions

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