Mass Independent Fractionation of Mercury Isotopes as Source Tracers in Sediments

Since the discovery of isotopic fractionation of mercury in nature, mass dependentfractionation (MDF) and mass independent fractionation (MIF) of mercury isotopes are used as a tracer to understand the mercury cycle. MIF is a powerful tool in understanding the Hg transformations and reaction mechanisms. Here we look into the MIF of the two odd isotopes of mercury (199Hg and 201Hg) in sediment samples collected from lakes and springs of Florida, Lake Erie, and Yucatan Peninsula. The Δ199Hg and Δ201Hg of the sediments range from + 0.52‰ to -0.48‰. From the isotopic signature we interpret the possible source of Hg in the Yucatan Peninsula carbonate to be Hg(II) from the water column. Hg in the Florida lakes and spring sedimentsprimarily comes from litterfall. Lake Erie appears to have an anthropogenic source. This study suggests that the MIF signature of Hg isotopes can be used to qualitatively determine the primary source(s) of Hg in sediments.