Fractionation of Mercury Isotopes in an Aqueous Environment

Description

Fractionation of mercury isotopes in an aqueous environment: Chemical Oxidation
Dimitri Stathopoulos
The study of fractionation patterns for the stable isotopes of mercury is a growing field. The potential for stable isotopes to trace mercury through the environment from pollution sources to sinks make the subject interesting to geochemists and useful to a wider audience. The purpose of this study is to measure the fractionation of mercury as it is oxidized in an aqueous medium. Samples in this study are prepared by chemically oxidizing different proportions of elemental mercury using four different oxidants. The oxidized portion is then separated from the elemental portion and an analysis of the isotope ratios for both portions is performed using a multicollector inductively coupled plasma mass spectrometer MC-ICP/MS. These isotope ratios are measured against the preoxidation isotope ratio to determine what if any change has occurred. From the findings of this work, it is now known chemical oxidation causes both mass dependent and mass independent fractionation. Mass dependent fractionation causes an enrichment of the heavier isotopes in the oxidized portion while the opposite is true for the elemental portion. Mass independent fractionation occurred only in the odd isotopes and causes a depletion of odd isotopes in the oxidized portion and enrichment in the elemental portion. These trends were found to be true for all oxidants tested as the pattern of fractionation does not change with varying oxidants.
Author Keywords: Isotope, Mass Dependent, Mass Independent, Mercury, Oxidation