Buffer capacity and lead retention in some clay materials

Yong, Raymond N.; Warkentin, B. P.; Phadungchewit, Yuwaree; Galvez‐Cloutier, Rosa

doi:10.1007/bf00154991

Cited by 105 publications

(62 citation statements)

References 15 publications

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“…Reactive sorbent minerals such as Fe / Mn / Al-(hydr)oxides are present in large amounts in LDDS and these metals have high affinity for Fe / Mn / Al -(hydr)oxides (Kinniburgh et al, 1976). In addition, the neutral to slightly alkaline pH of the sediments favored strong adsorption of these metals on oxides and hydroxides of iron and manganese as well as on the clay mineral surfaces (Brümmer, 1986;Yong et al, 1990). Sorption of these minerals is qualitatively consistent with observed leaching patterns, the affinity of metals for these minerals increasing with increasing pH.…”

Section: Actual Leachabilitymentioning

confidence: 99%

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: Actual Leachabilitymentioning

confidence: 99%

Trace Metal Leachability of Land‐Disposed Dredged Sediments

et al. 2000

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“…The latter elements are usually found to be less mobile. This is because at pH 4, Pb and Cu are still strongly retained by iron-oxides (Kinniburgh et al, 1976), organic matter (Brümmer, 1986;Livens, 1991) or clay minerals (Yong et al, 1990;Cavallaro & McBride, 1984), this in contrast to Cd or Zn. On the contaminated soil MG, sequential extraction was performed according to the BCR sequential extraction scheme (Queveauviller et al, 1994).…”

Section: Potential Leachabilitymentioning

confidence: 99%

Leaching behaviour of Cd, Cu, Pb and Zn in surface soils derived from dredged sediments

Singh

Verloo

1999

Environmental Pollution

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Leaching of heavy metals from land disposed dredged sediment spoils is a potential environmental hazard. The leaching behavior of Cd, Cu, Pb and Zn in surface soils sampled from abandoned dredged sediment disposal sites was assessed. Using simple mass-balance calculations, the significance of the leaching test results with respect to metal migration into underlying clean soil was appraised. The potential leachability, defined as the amounts released at constant pH 4, decreased in the order (% of total contents): Zn (58 %) ≈ Cd (49 %) > Cu (5 %) ≈ Pb (2 %). The kinetics of metal release were determined in a cascade shaking test using demineralized water acidified to pH 4 (HNO 3 ). Metal concentrations in the leachates were low and metal migration was, assuming uniform convective flow, predicted to be of no environmental concern. It is emphasized that any long term prediction of metal migration is uncertain.

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“…In sorption experiments with various clay minerals, Yong et al, ( 1990) found that substantial amounts of Pb were retained even at pH2.…”

Section: Discussionmentioning

confidence: 99%

Solid-phase distribution of heavy metals as affected by single reagent extraction in dredged sediment derived surface soils

Singh

Verloo

1996

Chemical Speciation & Bioavailability

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EDTA is useful to assess mobile metal pools in polluted soils and sediments. There is a need to enhance our understanding of the significance of metal fractions released. The impact of single reagent extraction with 0.05 mol L-1 EDTA on the solid phase distribution of trace metals in surface soils sampled from confined dredged sediment disposal sites was investigated. Not extracted and EDTA extracted soils were subjected to sequential extraction to fractionate the total contents into: (1) easily exchangeable and carbonate bound fraction; (2) reducible fraction; (3) oxidisable fraction; and (4) residual fraction. With EDTA, significant portions of metals associated with the acid extractable and reducible fractions were released. The oxidisable and residual fractions remained unaffected for most of the investigated metals except for the organic matter associated metals (Cu and Pb). A decrease in the residual fraction after EDTA-extraction for Cu and Pb was attributed to artifacts of the sequential extraction procedure.

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Buffer capacity and lead retention in some clay materials

Cited by 105 publications

References 15 publications

Trace Metal Leachability of Land‐Disposed Dredged Sediments

Trace Metal Leachability of Land‐Disposed Dredged Sediments

Leaching behaviour of Cd, Cu, Pb and Zn in surface soils derived from dredged sediments

Solid-phase distribution of heavy metals as affected by single reagent extraction in dredged sediment derived surface soils

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