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Organically complexed iron enhances bioavailability of antimony to maize ( Zea mays ) seedlings in organic soils
Author(s) -
Ptak Corey,
McBride Murray
Publication year - 2015
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.3113
Subject(s) - bioavailability , antimony , chemistry , organic matter , environmental chemistry , soil water , arsenic , metalloid , rhizosphere , extraction (chemistry) , dissolution , inorganic chemistry , organic chemistry , metal , biology , ecology , bioinformatics , genetics , bacteria
Antimony (Sb) is a metalloid belonging to group 15 of the periodic table. Chemical similarities between arsenic (As) and Sb produce concerns about potential health effects of Sb and enrichment in the environment. Antimony is found in oxic environments predominately as an oxyanionic species, antimonite (Sb[OH] 6– ). As a result of its net negative charge, Sb[OH] 6– was not initially predicted to have strong interactions with natural organic matter. Oxyanionic species could bind the negatively charged organic matter via a ternary complexation mechanism, in which cationic metals mediate the strong association between organic matter functional groups and oxyanions. However, these interactions are poorly understood in how they influence the bioavailability of oxyanionic contaminants to plants. Iron (Fe) additions to organic soils have been found to increase the number of organically complexed Fe sites suitable for Sb exchange, resulting in a reduced bioavailable fraction of Sb. The bioavailability of Sb to maize seedlings as a function of organically complexed Fe was examined using a greenhouse study. A significant increase in plant tissue Sb was observed as organically complexed Fe increased, which was not predicted by methods commonly used to assess bioavailable Sb. Extraction of soils with organic acids common to the maize rhizosphere suggested that organic acid exudation can readily mobilize Sb bound by organic Fe complexes. Environ Toxicol Chem 2015;34:2732–2738. © 2015 SETAC