An interdisciplinary physical-chemical approach for characterization of arsenic in a calciner residue dump in Cornwall (UK).
During the later stages of hard-rock mining in Cornwall, UK, widespread processing and refining of arsenic in purpose-built calciners resulted in severe, localized contamination of soils with arsenic. Several physical-chemical techniques were applied to characterize arsenic in a calciner residue dump: X-ray powder diffraction (XRD), sequential extraction combined with hyphenated speciation methods, and X-ray absorption spectroscopic (XAS) methods such as XANES (X-ray absorption near-edge structure) and EXAFS (extended X-ray absorption fine structure). Arsenic was predominantly present in pentavalent form, bound to amorphous or poorly-crystalline hydrous oxides of Fe (probably alpha-hematite). A small amount of a non-classified crystalline iron arsenate phase was found, viz. Fe2(As(AsO4)3). There was also evidence for the presence of some arsenate bound to quartz (alpha-SiO2). The overall results make us believe that the normally assumed relative safety, from a mobility point of view, is questionable since only a small fraction of arsenic is found in a crystalline iron arsenate form.
van Elteren
Johannes Teun
JT
National Institute of Chemistry (KI), Hajdrihova 19, SI-1001, Ljubljana, Slovenia. elteren@ki.si
Slejkovec
Zdenka
Z
Arcon
Iztok
I
Glass
Hylke-Jan
HJ
D001151:Arsenic / Q000032:analysis* / Q000737:chemistry; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004739:England; D004784:Environmental Monitoring / Q000379:methods; D007220:Industrial Waste / Q000032:analysis*; D008906:Mining; D012989:Soil Pollutants / Q000032:analysis*; D013053:Spectrophotometry / Q000379:methods; D014961:X-Ray Diffraction / Q000379:methods
D007220:Industrial Waste; D012989:Soil Pollutants; D001151:Arsenic