TY - JOUR
T1 - Release of arsenic from volcanic rocks through interactions with inorganic anions and organic ligands
AU - Casentini, Barbara
AU - Pettine, Maurizio
AU - Millero, Frank J.
PY - 2010/6
Y1 - 2010/6
N2 - The effects of a number of inorganic anions (F-, HCO3-, B(OH)4-, Cl-, I-) and of the siderophore DFO-B on the release of As from volcanic rocks were investigated in batch experiments. While previously reported field and laboratory data support a role of inorganic anions on As mobilization into aquifers, the role of siderophores on As-induced mobilization was less investigated. Fluoride, bicarbonate and DFO-B have shown a significant influence on the release of As from the rocks. Lava was mostly affected among the investigated rocks at pH 6 and 20°C by releasing 4% of its initial As content in the presence of 0. 01 M F-and 10% in the presence of 500 μM DFO-B. The effect of fluoride was larger at pH 6 than at pH 8. 5 for all the rocks. In the case of DFO-B, there was also a larger effect at pH 6 compared to pH 8 for the various rocks except tuff. Bicarbonate played a role under alkaline conditions while its effect was negligible at pH 6. Anion exchange processes in the presence of fluoride and bicarbonate and complexation processes in the presence of the siderophore DFO-B appear to be the major processes responsible for the release of arsenic from the rocks. The siderophore DFO-B plays mainly an indirect role on the As release by complexing Al, Fe and Mn, thus favoring the dissolution of the rocks and the consequent release of As bound to surface Al, Fe and Mn oxy-hydroxides. These findings suggest that ionic interactions with fluoride, bicarbonate and siderophore may be a further triggering factor in the mobilization of As from aquifer rocks.
AB - The effects of a number of inorganic anions (F-, HCO3-, B(OH)4-, Cl-, I-) and of the siderophore DFO-B on the release of As from volcanic rocks were investigated in batch experiments. While previously reported field and laboratory data support a role of inorganic anions on As mobilization into aquifers, the role of siderophores on As-induced mobilization was less investigated. Fluoride, bicarbonate and DFO-B have shown a significant influence on the release of As from the rocks. Lava was mostly affected among the investigated rocks at pH 6 and 20°C by releasing 4% of its initial As content in the presence of 0. 01 M F-and 10% in the presence of 500 μM DFO-B. The effect of fluoride was larger at pH 6 than at pH 8. 5 for all the rocks. In the case of DFO-B, there was also a larger effect at pH 6 compared to pH 8 for the various rocks except tuff. Bicarbonate played a role under alkaline conditions while its effect was negligible at pH 6. Anion exchange processes in the presence of fluoride and bicarbonate and complexation processes in the presence of the siderophore DFO-B appear to be the major processes responsible for the release of arsenic from the rocks. The siderophore DFO-B plays mainly an indirect role on the As release by complexing Al, Fe and Mn, thus favoring the dissolution of the rocks and the consequent release of As bound to surface Al, Fe and Mn oxy-hydroxides. These findings suggest that ionic interactions with fluoride, bicarbonate and siderophore may be a further triggering factor in the mobilization of As from aquifer rocks.
KW - Arsenic mobilization
KW - Groundwater
KW - Inorganic anions
KW - Siderophores
UR - http://www.scopus.com/inward/record.url?scp=77951978672&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77951978672&partnerID=8YFLogxK
U2 - 10.1007/s10498-010-9090-3
DO - 10.1007/s10498-010-9090-3
M3 - Article
AN - SCOPUS:77951978672
VL - 16
SP - 373
EP - 393
JO - Aquatic Geochemistry
JF - Aquatic Geochemistry
SN - 1380-6165
IS - 3
ER -