Speciation Analysis of Methyl Mercury and Inorganic Mercury in Contaminated Top Soils from Oakridge Tennessee by ICPMS

Graduate #43
Discipline: Chemistry and Chemical Sciences
Subcategory: Chemistry (not Biochemistry)

Iris Denmark - Jackson State University
Co-Author(s): Zikri Arslan, Jackson State University

During the 1950s and early 1960s, elemental mercury (Hg) was used to produce enriched 6Li isotope at the Y-12 National Security Complex (Y-12 Plant) for manufacturing components of various nuclear weapons systems. It is estimated that 350,000 kg of Hg was released to the environment contaminating facilities, soil, sediment, surface water, and groundwater within the boundaries of the Y-12 Plant and the downstream environment (i.e., East Fork Poplar Creek [EFPC]). EFPC is a 23-km stream where the headwaters start in the Y-12 Plant, flows through the city of Oakridge, TN, and empties into the Clinch River. Although various remediation efforts have reduced Hg fluxes from the Y-12 Plant over the last twenty-five years, the Hg concentration in water continue to exceed the regulatory limit (51 ng/L). Within the last six years, researchers have investigated the speciation and mobility of Hg in the EFPC floodplain soils and sediments. The objective of this work is to develop an analytical procedure that applies to the speciation of mercury in contaminated soils from EFPC. Total mercury levels were measured by ICP-MS in EFPC top soils after acid digestion. Results show extensive content from contamination. Here, we specifically focus on levels of methyl mercury (MeHg), which is very toxic. Because MeHg is water soluble, there could still be trace amounts constantly leaching into the freshwaters. For speciation, cold vapor generation approach will be utilized for ICP-MS detection. Various extraction approaches will be utilized to separate traces of MeHg, if any, from the soil matrix. Determinations will be performed by CV-ICP-MS as it is one of the most sensitive analytical instrumentation methods for detection of trace elemental composition in a sample.

Funder Acknowledgement(s): I acknowledge Jackson State University and LSMAMP for funding my research project.

Faculty Advisor: Zikri Arslan, zikri.arslan@jsums.edu

Role: As per the following research project, I have taken a major part in all of it. I do receive some assistance from my research adviser for data analysis and compilation.