Mercury Isotope Fractionation During Transport and Transformation ProcessesEPA Grant Number: F6A20648
Title: Mercury Isotope Fractionation During Transport and Transformation Processes
Investigators: KostervanGroos, Paul G.
Institution: University of California - Berkeley
EPA Project Officer: Lee, Sonja
Project Period: August 22, 2006 through August 21, 2009
Project Amount: $111,000
RFA: STAR Graduate Fellowships (2006) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Engineering and Environmental Chemistry , Fellowship - Environmental Engineering , Mercury
Mercury transport and transformation processes, including methylation, have proven difficult to quantify. Analysis of the seven stable mercury isotopes could help provide significant insight. Natural abundance stable isotope analysis has greatly aided quantification of transport and transformation processes in water, carbon, and nitrogen cycles, and it is finding increased application for evaluating pollutants in the natural environment.
The objective of this work is to experimentally determine how transport and transformation processes influence mercury isotope compositions, and subsequently, to evaluate these processes by examining mercury isotope compositions of environmental samples.
Newly developed multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) methods will be utilized to determine mercury isotope compositions. These compositions will be examined during experiments designed to isolate equilibrium, sorption, diffusion, and kinetic effects such that mechanistic fractionation factors can be determined. Accurate fractionation factors of common physical-chemical processes are necessary for interpreting environmental samples and quantifying relevant processes. Mercury containing materials from historic mining operations in California will be among the first environmental samples characterized.
Accurate analysis of isotope compositions, coupled with measured fractionation factors, will be a powerful tool for quantifying mercury transport and transformation processes. This research will aid the development of these tools. We expect to observe variations in mercury isotope compositions among different environmental samples that result from the fractionating processes listed above. Historic mining activities, which often included repeated processing of mercury materials, are anticipated to have led to significant differences in isotopic composition, which could be used as tracers of these activities.