Mercury speciation in the environment using X-ray absorption spectroscopy

Mercury speciation and transformation in the environment can be determined using X-ray absorption spectroscopy (XAS), a method that is element-specific, and therefore can be used to study elements in their complex original matrices. This method is ideal for the study of elements in soil, water, and biological tissue, without any prior chemical modification. Because speciation of mercury is quite dependent on the chemical environment, which includes factors such as pH, temperature, oxygen content, and presence of various species, including sulfate, sulfide, dissolved organic matter, and dissolved oxygen, this method to study the chemistry of mercury can shed important light on the structure and bonding of mercury in various environments. In this chapter XAS techniques such as Hg L3- and L2-edges, Hg L3 extended X-ray absorption fine structure, and sulfur and selenium K-edges are used to study mercury speciation and binding in minerals, coal flue gas emissions, chelation with organic matter, sulfide precipitation, and in physiological forms.