TY - JOUR
T1 - Partitioning of metals in a degraded acid sulfate soil landscape
T2 - Influence of tidal re-inundation
AU - Claff, Salirian R.
AU - Sullivan, Leigh A.
AU - Burton, Edward D.
AU - Bush, Richard T.
AU - Johnston, Scott G.
PY - 2011
Y1 - 2011
N2 - The oxidation and acidification of sulfidic soil materials results in the re-partitioning of metals, generally to more mobile forms. In this study, we examine the partitioning of Fe, Cr, Cu, Mn, Ni and Zn in the acidified surface soil (0-0.1. m) and the unoxidised sub-soil materials (1.3-1.5. m) of an acid sulfate soil landscape. Metal partitioning at this acidic site was then compared to an adjacent site that was previously acidified, but has since been remediated by tidal re-inundation. Differences in metal partitioning were determined using an optimised six-step sequential extraction procedure which targets the " labile" , " acid-soluble" , " organic" , " crystalline oxide" , " pyritic" and " residual" fractions. The surficial soil materials of the acidic site had experienced considerable losses of Cr, Cu, Mn and Ni compared to the underlying parent material due to oxidation and acidification, yet only minor losses of Fe and Zn. In general, the metals most depleted from the acidified surface soil materials exhibited the greatest sequestration in the surface soil materials of the tidally remediated site. An exception to this was iron, which accumulated to highly elevated concentrations in the surficial soil materials of the tidally remediated site. The " acid-soluble" , " organic" and " pyritic" fractions displayed the greatest increase in metals following tidal remediation. This study demonstrates that prolonged tidal re-inundation of severely acidified acid sulfate soil landscapes leads to the immobilisation of trace metals through the surficial accumulation of iron oxides, organic material and pyrite.
AB - The oxidation and acidification of sulfidic soil materials results in the re-partitioning of metals, generally to more mobile forms. In this study, we examine the partitioning of Fe, Cr, Cu, Mn, Ni and Zn in the acidified surface soil (0-0.1. m) and the unoxidised sub-soil materials (1.3-1.5. m) of an acid sulfate soil landscape. Metal partitioning at this acidic site was then compared to an adjacent site that was previously acidified, but has since been remediated by tidal re-inundation. Differences in metal partitioning were determined using an optimised six-step sequential extraction procedure which targets the " labile" , " acid-soluble" , " organic" , " crystalline oxide" , " pyritic" and " residual" fractions. The surficial soil materials of the acidic site had experienced considerable losses of Cr, Cu, Mn and Ni compared to the underlying parent material due to oxidation and acidification, yet only minor losses of Fe and Zn. In general, the metals most depleted from the acidified surface soil materials exhibited the greatest sequestration in the surface soil materials of the tidally remediated site. An exception to this was iron, which accumulated to highly elevated concentrations in the surficial soil materials of the tidally remediated site. The " acid-soluble" , " organic" and " pyritic" fractions displayed the greatest increase in metals following tidal remediation. This study demonstrates that prolonged tidal re-inundation of severely acidified acid sulfate soil landscapes leads to the immobilisation of trace metals through the surficial accumulation of iron oxides, organic material and pyrite.
KW - Acidic soil
KW - Metal partitioning
KW - Sulfidic soil
KW - Tidal inundation
UR - http://www.scopus.com/inward/record.url?scp=82455199253&partnerID=8YFLogxK
U2 - 10.1016/j.chemosphere.2011.07.013
DO - 10.1016/j.chemosphere.2011.07.013
M3 - Article
C2 - 21821272
AN - SCOPUS:82455199253
SN - 0045-6535
VL - 85
SP - 1220
EP - 1226
JO - Chemosphere
JF - Chemosphere
IS - 8
ER -