Metal ion binding by natural organic matter: From the model to the field

Benedetti, Marc F.; Riemsdijk, W.H. van; Koopal, L.K.; Kinniburgh, D.G.; Gooddy, Daren C.; Milne, Chris

doi:10.1016/0016-7037(96)00113-5

Cited by 231 publications

(116 citation statements)

References 25 publications

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“…Geochemists have tended to ignore them in the past because they are complex and difficult to analyse, but it is now recognised that they play a significant role in weathering processes (Heyes and Moore, 1992;Shand et al, 2005), in diagenesis (Bottrell, 1996) and in the transport of trace metals (Benedetti et al, 1996). Organic carbon concentrations can vary considerably, both spatially and temporally, so a large number of analyses are frequently required to produce a representative estimate of concentrations.…”

Section: Introductionmentioning

confidence: 99%

Organic Quality of Groundwaters

Gooddy

Hinsby

2008

Natural Groundwater Quality

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Organic carbon is present in all natural waters and plays an important role in many geochemical processes. Total organic carbon (TOC), measured on unfiltered samples, has been analysed on more than 400 groundwater samples from 8 European Union countries, and the operationally defined dissolved organic carbon (DOC), measured on filtered samples, was analysed on approximately 250 groundwater samples from 4 of these countries. TOC was found at a median concentration of 2.7 mg C/L with a range from 0.1 -59.4 mg C/L and DOC had a median concentration of 2.2 mg C/L with a range from 0.2 -58.9 mg C/L, demonstrating that very high natural organic carbon values can occasionally be found locally in some pristine aquifers. A relationship between the assimilable organic carbon (AOC) utilised by bacteria and TOC is observed although the correlation is not clear. Generally, there is a linear correlation between the TOC, DOC and the chemical oxygen demand (COD) values. Organic contaminants derived from anthropogenic activities are generally not identified in the TOC/DOC analysis as these contaminant concentrations are typically several orders of magnitude lower than the bulk aqueous carbon measurement. TOC/DOC analysis can, however be an important indicator of pollution at landfills, effluent ponds and similar pollution settings with high loads of organic carbon, but in many other situations the total or dissolved organic carbon concentration is not a good tracer or indicator of contamination. However, the total or dissolved organic carbon is a very important component in the biogeochemical cycling of elements and consequently it is recommended as a component to be measured on all groundwater samples. The measurement of a filtered organic carbon fraction is recommended where groundwaters contain significant amounts of particulate material. Measurements of TOC and DOC on the same samples in this study show comparable concentrations, however, the TOC/DOC ratio varied and TOC was not always found to be significantly greater than DOC, as may have been expected. Further investigations are needed to find the reasons for this. Further research is also needed to evaluate what part of the TOC is readily available for biogeochemical processes. Increased knowledge on this issue would help to understand better the development of the different redox environments and associated bacterial regrowth which occurs in water supply systems.

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Section: Introductionmentioning

confidence: 99%

Organic Quality of Groundwaters

Gooddy

Hinsby

2008

Natural Groundwater Quality

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“…Speciation, bio-availability and mobility of major and trace elements and organic compounds can be strongly influenced by colloidal material (Wells and Goldberg, 1991;Tipping and Hurley, 1992;Benedetti et al, 1996). Colloids in natural waters are theoretically defined as particles not affected by sedimentation.…”

Section: Introductionmentioning

confidence: 99%

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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“…Many studies have examined the concentration and retention of metals in soils and the effect of various parameters on their adsorption and solubility, including pH (McBride and Blasiak, 1979;Cavallaro and McBride, 1980;Harter, 1983;Robb and Young, 1999;Green et al, 2003), redox conditions (Davranche and Bollinger, 2001;Davranche et al, 2003;Qafoku et al, 2003), amount of metals (Garcia-Miragaya, 1984;Basta and Tabatabai, 1992;Sauvé et al, 2000), cation exchange capacity (Ziper et al, 1988), organic matter content (Gerritse and Vandriel, 1984;Elliot et al, 1986;Benedetti et al, 1996aBenedetti et al, , 1996bKinniburgh et al, 1999;Kashem and Singh, 2001), soil mineralogy (Tiller et al, 1963;Jenne, 1968;Kinniburgh et al, 1976;Cavallaro and McBride, 1984;Kuo, 1986;Lindroos et al, 2003), biological and microbial conditions (Gerritse et al, 1992;Dumestre et al, 1999;Warren and Haack, 2001) as well as developing assemblage models to mechanistically predict these processes (Dzombak and Morel, 1987;Haworth, 1990;McBride et al, 1997;Celardin, 1999;Weng et al, 2002;Impellitteri et al, 2003, Tye et al, 2003. From these studies it has emerged that total soil metal content alone is not a good measure of short-term bioavailability and not a very useful tool to determine potential risks from soil contamination (Tack et al, 1995;…”

Section: Soil Pore Water and The Concept Of (Bio)availabilitymentioning

confidence: 99%

Overview of Selected Soil Pore Water Extraction Methods for the Determination of Potentially Toxic Elements in Contaminated Soils: Operational and Technical Aspects

Bonito¹,

Breward²,

Crout³

et al. 2008

Environmental Geochemistry

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Chemical elements that are either present naturally in the soil or introduced by pollution are more usefully estimated in terms of 'availability' of the element, since it is this property that can be related to mobility and uptake by plants. A good estimation of 'availability' can be achieved by measuring the concentration of the element in soil pore water. Recent achievements in analytical techniques allowed to expand the range of interest to trace elements, which play a crucial role both in contaminated and uncontaminated soils and include those defined as potentially toxic elements (PTE) in environmental studies. A complete chemical analysis of soil pore water represents a powerful diagnostic tool for the interpretation of many soil chemical phenomena relating to soil fertility, mineralogy, and environmental fate. This chapter describes some of the current methodologies used to extract soil pore water. In particular, four laboratory-based methods, i) high speed centrifugation-filtration, (ii) low (negative-) pressure Rhizon™ samplers, (iii) high pressure soil squeezing and (iv) equilibration of dilute soil suspensions, are described and discussed in detail. A number of operational factors are presented: pressure applicable (i.e., pore size involved), moisture pre-requisites of the soil, pore water yielding, efficiency, duration of extraction, materials and possible contaminations for PTE studies. Some consideration is then taken to assess advantages and disadvantages of the methods, including costs and materials availability.

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Metal ion binding by natural organic matter: From the model to the field

Cited by 231 publications

References 25 publications

Organic Quality of Groundwaters

Organic Quality of Groundwaters

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

Overview of Selected Soil Pore Water Extraction Methods for the Determination of Potentially Toxic Elements in Contaminated Soils: Operational and Technical Aspects

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