Solving mercury (Hg) speciation in soil samples by synchrotron X-ray microspectroscopic techniques.
Direct mercury (Hg) speciation was assessed for soil samples with a Hg concentration ranging from 7 up to 240 mg kg(-1). Hg chemical forms were identified and quantified by sequential extractions and bulk- and micro-analytical techniques exploiting synchrotron generated X-rays. In particular, microspectroscopic techniques such as mu-XRF, mu-XRD and mu-XANES were necessary to solve bulk Hg speciation, in both soil fractions <2 mm and <2 microm. The main Hg-species found in the soil samples were metacinnabar (beta-HgS), cinnabar (alpha-HgS), corderoite (Hg(3)S(2)Cl(2)), and an amorphous phase containing Hg bound to chlorine and sulfur. The amount of metacinnabar and amorphous phases increased in the fraction <2 microm. No interaction among Hg-species and soil components was observed. All the observed Hg-species originated from the slow weathering of an inert Hg-containing waste material (K106, U.S. EPA) dumped in the area several years ago, which is changing into a relatively more dangerous source of pollution.
Terzano
Roberto
R
Dipartimento di Biologia e Chimica Agroforestale ed Ambientale, University of Bari, Via Amendola 165/A, 70126 Bari, Italy. r.terzano@agr.uniba.it
Santoro
Anna
A
Spagnuolo
Matteo
M
Vekemans
Bart
B
Medici
Luca
L
Janssens
Koen
K
Göttlicher
Jörg
J
Denecke
Melissa A
MA
Mangold
Stefan
S
Ruggiero
Pacifico
P
D008628:Mercury / Q000032:analysis / Q000737:chemistry*; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission / Q000295:instrumentation; D017356:Synchrotrons; D056928:X-Ray Absorption Spectroscopy / Q000295:instrumentation; D014961:X-Ray Diffraction / Q000295:instrumentation
D012987:Soil; D012989:Soil Pollutants; D008628:Mercury