Enhanced soil toxic metal fixation in iron (hydr)oxides by redox cycles

Contin, Marco; Mondini, Claudio; Leita, L.; Nobili, Maria De

doi:10.1016/j.geoderma.2007.03.017

Cited by 81 publications

(40 citation statements)

References 39 publications

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“…13 Coprecipitation of Zn with newly formed oxides under oxic conditions could also have limited the subsequent release of this ME during anoxic conditions. Similar results were obtained by Contin et al 16 who observed the stabilization of Zn and other ME in soils amended with Fe-rich waste subjected to similar redox alternations. The aging of Zn-containing coprecipitates could have further contributed to Zn stabilization as suggested by the findings of Davranche and Bollinger.…”

Section: Column Experimentssupporting

confidence: 90%

“…15 Soil redox oscillations may also increase the crystallinity of Fe oxides enhancing the fixation of some ME into their structure. 16 Contrasting results were also obtained for the partitioning of ME between phases with variable lability, in flooded soils. While Kashem and Singh 17 reported that the addition of organic matter (OM) favoured the partitioning of ME in more labile pools, Huang et al 18 showed that OM amendment of submerged soils caused a decrease in oxidizable, and Fe and Mn oxide-bound Cu leading to a relative increase in more stable forms.…”

Section: Introductionmentioning

confidence: 92%

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Leaching potential of metallic elements from contaminated soils under anoxia

Balint

Nechifor

Ajmone-Marsan

2014

Environ. Sci.: Processes Impacts

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Environmental ImpactThe higher frequency and intensity of extreme rainfall events, as well as the variations in precipitation patterns and intensities as a result of climate change may cause important shifts in soil hydrological regime. This could expose contaminated soils to significant variations in redox potentials possibly influencing metallic element behaviour and their potential transfer to other environmental compartments. This study shows that alternating soil redox conditions may enhance the release and redistribution of metals in more labile fractions. In particular, the presence of redox-sensitive minerals, such as chalcopyrite, in soils affected by mine tailings, could release significant amounts of Cu due to the alternating redox conditions and therefore have important environmental implications. Graphical abstractThe alternation of redox cycles may play a higher role in the release, leaching and redistribution of metallic elements from contaminated soils with respect to oxidizing and reducing conditions alone. AbstractUnderstanding metallic element (ME) behaviour in soils subjected to alternating redox conditions is of significant environmental importance, particularly for contaminated soils. Although variations in the hydrological status of soils may lead to the release of ME, redox-driven changes in ME dynamics are still not sufficiently understood. We studied the effects of alternating redox cycles 2 on the release, leaching and redistribution of Zn, Cu and Pb in metal mine-contaminated and noncontaminated soils by means of a column experiment. Although the release of Zn was promoted by the onset of reductive conditions, successive redox cycles favoured metal partitioning in less labile fractions limiting its further mobilization. The release of Cu in soil porewaters and redistribution in the solid phase towards more labile pools were strongly dependent on the alternation between oxidizing and reducing conditions. In contaminated soils, the presence of chalcopyrite could have determined the release of Cu under oxic conditions and its relative immobilization under subsequent anoxic conditions. The behaviour of Pb did not seem to be influence by redox status, although higher concentrations in the column leachates with respect to soil porewaters suggested that alternating redox conditions could nonetheless result in substantial mobilization. This study provides evidence that the alternation of soil redox conditions may play a more important role in determining the release and leaching of metallic elements from soils with respect to reducing or oxidizing conditions considered separately.

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Section: Column Experimentssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 92%

Leaching potential of metallic elements from contaminated soils under anoxia

Balint

Nechifor

Ajmone-Marsan

2014

Environ. Sci.: Processes Impacts

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“…In this study, we focused on the prediction of the directly available metal pool under drained, oxidizing conditions since it has been suggested that uptake of metals by rice is controlled largely during the period following the shift from flooded to drained conditions (Simmons et al 2008). It is known, however, that both solubility and availability of metals decrease under reducing conditions when the soil is water-logged (Kashem and Singh 2004;Contin et al 2007). The return to oxidizing conditions can lead to an increase in the availability and Fig.…”

Section: Discussionmentioning

confidence: 99%

Characterization of soil heavy metal pools in paddy fields in Taiwan: chemical extraction and solid-solution partitioning

et al. 2009

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Background, aim, and scope Ongoing industrialization has resulted in an accumulation of metals like Cd, Cu, Cr, Ni, Zn, and Pb in paddy fields across Southeast Asia. Risks of metals in soils depend on soil properties and the availability of metals in soil. At present, however, limited information is available on how to measure or predict the directly available fraction of metals in paddy soils. Here, the distribution of Cd, Cu, Cr, Ni, Zn, and Pb in 19 paddy fields among the total, reactive, and directly available pools was measured using recently developed concepts for aerated soils. Solid-solution partitioning models have been derived to predict the directly available metal pool. Such models are proven to be useful for risk assessment and to derive soil quality standards for aerated soils. , and directly available metal pools (0.01 M CaCl 2 ) were determined. Solid-solution partitioning models were derived by multiple linear regressions using an extended Freundlich equation using the reactive metal pool, pH, and the cation exchange capacity (CEC). The influence of Zn on metal partitioning and differences between both sampling events (May/November) were evaluated. Results Total metals contents range from background levels to levels in excess of current soil quality standards for arable land. Between 3% (Cr) and 30% (Cd) of all samples exceed present soil quality standards based on extraction with AR. Total metal levels decreased with an increasing distance from the irrigation water inlet. The reactive metal pool relative to the total metal content is increased in the order Cr << Ni = Zn < Pb < Cu < Cd and ranged from less than 10% for Cr to more than 70% for Cd. Despite frequent redox cycles, Cd, Pb, and Cu appear to remain rather reactive. The methods to determine the reactive metal pool in soils yield comparable results, although the 0.43 M HNO 3 extraction is slightly stronger than HCl and EDTA. The close correlation between these methods suggests that they release similar fractions from soils, probably those reversibly sorbed to soil organic matter (SOM) and clay. The average directly available pool ranged from less than 1% for Cu, Pb, and Cr to 10% for Ni, Zn, and Cd when compared to the reactive metal pool. For Cd, Ni, Zn, and to a lesser extent for Cu and Pb, solid-solution partitioning models were able to explain up to 93% (Cd) of the observed variation in the directly available metal pool. CaCl 2 extractable Zn increased the directly available pool for Ni, Cd, and Cu but not that of Pb and Cr. In the polluted soils, the directly available pool was higher in November compared to that in May. Differences in temperature, rainfall, and changes in soil properties such as pH are likely to contribute to the differences observed within the year. The solid-solution partitioning model failed to explain the variation in the directly available Cr pool, probably because Cr is present in precipitates rather than being adsorbed onto SOM and clay. Despite obvious differences in parent material, source of pollu...

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“…3). This was in contrast with the enhanced fixation of Cu into Fe oxides with redox cycling reported by Contin et al (2007), further confirming that the source of Cu may play an important role in determining Cu dynamics. Other mechanisms that could be responsible for the contrasting decrease in Cu concentrations (Fig.…”

Section: Influence Of Redox Alternation On Fe Mn Dom and Cu Dynamicmentioning

confidence: 50%

Copper dynamics under alternating redox conditions is influenced by soil properties and contamination source

Balint

Said-Pullicino

Ajmone-Marsan

2015

Journal of Contaminant Hydrology

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Understanding the effect of soil redox conditions on contaminant dynamics is of significant importance for evaluating their lability, mobility and potential transfer to other environmental compartments. Under changing redox conditions, soil properties and constituents such as Fe and Mn (hydr)oxides and organic matter (OM) may influence the behaviour of associated metallic elements (ME). In this work, the redox-driven release and redistribution of Cu between different soil pools was studied in three soils having different contamination sources. This was achieved by subjecting soil columns to a series of alternating reducing and oxidizing cycles under non-limiting C conditions, and assessing their influence on soil pore water, leachate and solid phase composition. Results showed that, in all soils, alternating redox conditions led to an increase in the distribution of Cu in the more labile fractions, consequently enhancing is susceptibility to loss. This was generally linked to the redox-driven cycling of Fe, Mn and dissolved organic matter (DOM). In fact, results suggested that the reductive dissolution of Fe and Mn (hydr)oxides and subsequent reprecipitation as poorly-ordered phases under oxic conditions, contributed to the release and mobilization of Cu and/or Cu-containing organometallic complexes. However, the behaviour of Cu, as well as the mechanisms controlling Cu release and loss with redox cycling, were influenced by both soil properties (e.g. pH, contents of easily reducible Fe and Mn (hydr)oxides) and source of Cu contamination.

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Enhanced soil toxic metal fixation in iron (hydr)oxides by redox cycles

Cited by 81 publications

References 39 publications

Leaching potential of metallic elements from contaminated soils under anoxia

Leaching potential of metallic elements from contaminated soils under anoxia

Characterization of soil heavy metal pools in paddy fields in Taiwan: chemical extraction and solid-solution partitioning

Copper dynamics under alternating redox conditions is influenced by soil properties and contamination source

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