Effectiveness of a commonly used sequential extraction technique in determining the speciation of cadmium in soils

Kim, N.D.; Fergusson, J. E.

doi:10.1016/0048-9697(91)90341-b

Cited by 122 publications

(39 citation statements)

References 21 publications

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“…1). This suggests that they were either sorbed on various solid phases or associated with carbonates and Fe-Mn oxides (Tessier et al, 1979;Kim and Fergusson, 1991). Metals such as Co and Ni were more evenly distributed between the first two and the last two fractions.…”

Section: Metal Distributions In Sedimentsmentioning

confidence: 98%

Trace Metal Leachability of Land‐Disposed Dredged Sediments

et al. 2000

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The potential risk of surface and ground water contamination by trace metals leached from contaminated land disposed dredged sediment is a major environmental concern. The objective of this study was to evaluate trace metal leachability, leachate quality and environmental impacts of land-disposed dredged sediments. In addition to chemical characterization and determination of potential and actual leachability, dredged sediments were also subjected to solid phase fractionation using a sequential extraction procedure.Potential leachability, defined as the maximum metal pool that may become available for leaching at a constant pH 4, decreased in the following order: Zn ~ Cd > Mn > Ni > Co > Cu ~ As > Pb > Cr. Potential metal leachability was controlled mainly by solid phase distribution of metals in sediments. The acid extractable fraction of most metals correlated well with the potentially leachable metals extracted with a solution of pH 4 (r 2 > 0.67) except for Pb. The kinetics of metal release were determined using the cascade leaching test with water at pH 4. Except for Ni and Zn in the first fraction, metal concentrations in all consecutive leaching fractions remained below the maximum permissible level in water for human consumption. Actual metal leachability expressed as a percentage of potential leachability varied widely among trace metals and decreased in the order: As > Cu > Cr> Ni > Zn > Cd > Co > Pb. Our results indicate low risk of surface and ground water contamination resulting from land disposal of dredged sediments. 4Large quantities of sediments are dredged each year to clean and maintain the depth of navigational waterways, harbors and estuaries worldwide. In the Flemish region of Belgium alone, an average of 3,940,000 m 3 is disposed on land annually (Demoen, 1989). Land disposal of these dredged sediments may affect the surrounding environment due to the presence of harmful organic compounds and trace metals. Among other disposal alternatives such as sea dumping, landfilling and incineration, confined land disposal (upland disposal) is frequently adopted because of the increasing pressure to ban all sludge dumping at sea. Moreover, it is easy and cost effective. However, upland disposals may cause changes in their redox potential, pH and organic matter content of the land-disposed dredged sediments (LDDS). These physico-chemical changes may enhance the leachability and bioavailability of trace metals in sediment (Moore et al., 1988;Förstner, 1993;Gambrell, 1994), which may restrict the beneficial utilization of LDDS, particularly in landscape restoration, agriculture and construction.The leachability and bioavailability of trace metals in soils and sediments depend on their chemical and physical associations (Bubb and Lester, 1991; Tack and Verloo, 1993;Ma and Rao, 1997). Metals in soils and sediments may form specific mineral phases, be loosely bound on exchangeable sites, co-precipitate, be adsorbed onto mineral phases, be fixed by organic matter and sulfides or be structurally boun...

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Section: Metal Distributions In Sedimentsmentioning

confidence: 98%

Trace Metal Leachability of Land‐Disposed Dredged Sediments

et al. 2000

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“…Sequential chemical extraction is a well-established approach for the fractionation of trace metals in soils by using a series of progressively harsher reagents to dissolve increasingly refractory forms (Ure and Davidson, 2002). Although some inherent limitations caused by the non-selectivity of reagents and possible re-adsorption of metals during extraction have been reported (Nirel and Morel, 1990;Kim and Fergusson, 1991), it has been found that plant uptake and toxicity can be related to specific fractions of sequential extraction procedure (Woolson et al, 1971;Chlopecka and Adriano, 1996;Guo and Yost, 1998;Krishnamurti and Naidu, 2000). Sequential extraction techniques have been widely used to examine the physicochemical forms of metals, and thus provide better understanding of the processes affecting the phytoavailability of metals in soils (Ahnstrom and Parker, 1999).…”

Section: Introductionmentioning

confidence: 99%

The effect of ageing on the bioaccessibility and fractionation of cadmium in some typical soils of China

Tang

Zhu

Cui

et al. 2006

Environment International

149

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Ingestion of contaminated soil has been recognized as an important exposure pathway of cadmium (Cd) for humans, especially for children through outdoor hand-to-mouth activities. The effect of ageing process following the input of Cd into soil on the bioaccessibility of Cd in five typical soils of China was investigated using physiologically based in vitro test in this study. A sequential extraction procedure was employed with attempt to identify the bioaccessible fraction(s) of Cd in soils. The bioaccessibility of Cd in strongly acidic (≈ pH 4.5) soils reached nearly steady levels (76.5-76.9% and 52.0-52.6% in the gastric and small intestinal phases, respectively) after a sharp decline in the first week of ageing. In contrast, the bioaccessibility of Cd in higher pH (N 6.0) soils was found to be much lower (53.3-72.7% and 29.9-43.4% in gastric and small intestinal phases, respectively) and took 2 weeks of ageing to reach steady levels. The freshly spiked Cd was more labile than native Cd. The main proportion of spiked Cd was found in exchangeable Cd which was higher in strongly acidic soils (68.6-71.8%) than in higher pH soils (53.4-61.4%) at day 120 after a sharp decline to the nearly steady state in the first 1 and 2 weeks, respectively. Significant correlations between Cd bioaccessibility and either water soluble and exchangeable Cd individually, or the sum of water soluble and exchangeable Cd throughout the incubation period for all soils, indicate that these forms of Cd are likely to constitute the main proportion of bioaccessible Cd in soils.

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“…Several extraction schemes have been used by a number of authors, some of the widely used schemes being those of McLaren and Crawford, 1973;Tessier, et al, 1979;Xian, 1989;Kim and Fergusson, 1991;Davidson et al, 1994;Li et al, 1995. The operation of such schemes is based on the premise that the mobility and bioavailability decreases approximately in the order of the extraction procedure from readily available to unavailable (Chon et al, 1998).…”

Section: Chemical Partitioning Of CD and Cumentioning

confidence: 99%