Metallurgic calcines with very high mercury and methylmercury content from the Almad&
eacute;n mining district wereanalyzed by synchrotron-based microprobe techniques.Information about mercury speciation was obtainedby
-EXAFS (microscopic extended X-ray absorption finestructure) spectroscopy, whereas elemental associationswere evaluated by
-XRF (microscopic X-ray fluorescenceanalysis) mapping. Complementary characterizationmethodologies, including X-ray diffraction (XRD), inductivelycoupled plasma-optical spectroscopy (ICP-OES), as wellas a sequential extraction scheme (SES), were used to predictthe potential availability of mercury. Analysis of totalmetal content revealed extremely high concentrations ofmercury and iron (between 7 and 35 and 65-70 gkg
-1, respectively) and high zinc concentrations (2.2-2.5g kg
-1), whereas other metals such as copper, nickel, andlead were found at low concentration levels (30-300 mgkg
-1).
-EXAFS results indicate that cinnabar (HgS
red) is oneof the main species within the studied mercury-richparticles (5-89% of total mercury content), together withmore soluble mercury compounds such as Hg
3(SO
4)O
2(schuetteite) and HgO (5-55% of total mercury content).Additionally, element-specific
-XRF maps of selectedmercury-rich particles in the studied samples revealed anevident correlation among Hg-Pb-Ni (and S), indicatinga possible geochemical linkage of these elements. Correlationswere also found among Fe-Mn and Hg, which havebeen attributed to sorption of mercury onto oxyhydroxidesof Fe and Mn. This finding was supported by resultsfrom a sequential extraction scheme, where a significantamount of Hg was extracted with the fraction soluble in 6M HCl.