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DGT as a Field Sampling Tool for Porewater Mercury and Methylmercury
Oral Presentation
Prepared by P. Bireta1, D. Reible2, A. Schierz2, J. Grundy3, R. Landis4
1 - University of Texas at Austin, 3605 31st St, Lubbock, TX, 79410, United States
2 - Texas Tech University, Department of Civil and Environmental Engineering, Box 41023, Lubbock, TX, 79409, United States
3 - The University of Texas at Austin, 301 E Dean Keeton, ECJ 7.102, Austin, TX, 78712, United States
4 - Dupont, 974 Centre Road, Wilmington, DE, 19805, United States
Contact Information: pbireta@gmail.com; 785-691-6267
ABSTRACT
Dissolved porewater concentrations of mercury have been shown to better correlate with mercury methylation rates than bulk mercury sediment loadings. When assessing a contaminated site, it is important to be able to measure the truly dissolved porewater concentrations of mercury and methylmercury. The diffusive gradient in thin film (DGT) technique is applied to determine porewater mercury and methyl mercury concentrations in both laboratory and field studies. DGT devices have been a useful indicator of dissolved metals in aqueous systems, although the technique is not as well developed for measuring mercury or for measuring concentrations in sediment porewater.
Issues such as background mercury in field blanks, sampler design, and analyte recovery were examined. Laboratory testing was used to evaluate mercury DGT probe uptake parameters from the sediment and to develop procedures for analysis and interpretation of the probe. DGT probes were deployed in the field at the South River (Virginia, USA). The probes were used for both site characterization and to assess the performance of an in-situ sediment amendment. For site characterization, DGT probes were used along with other samples to assess mercury mobility between a river bank and channel. Multiple disk probes and sediment depth probes were deployed in the amendment pilot study pond in-situ to determine concentrations of mercury and methyl mercury in sediment porewater and overlying water over time. This sampling showed that the DGT could be a useful tool for exploring available and mobile mercury and methyl mercury in the field.
Oral Presentation
Prepared by P. Bireta1, D. Reible2, A. Schierz2, J. Grundy3, R. Landis4
1 - University of Texas at Austin, 3605 31st St, Lubbock, TX, 79410, United States
2 - Texas Tech University, Department of Civil and Environmental Engineering, Box 41023, Lubbock, TX, 79409, United States
3 - The University of Texas at Austin, 301 E Dean Keeton, ECJ 7.102, Austin, TX, 78712, United States
4 - Dupont, 974 Centre Road, Wilmington, DE, 19805, United States
Contact Information: pbireta@gmail.com; 785-691-6267
ABSTRACT
Dissolved porewater concentrations of mercury have been shown to better correlate with mercury methylation rates than bulk mercury sediment loadings. When assessing a contaminated site, it is important to be able to measure the truly dissolved porewater concentrations of mercury and methylmercury. The diffusive gradient in thin film (DGT) technique is applied to determine porewater mercury and methyl mercury concentrations in both laboratory and field studies. DGT devices have been a useful indicator of dissolved metals in aqueous systems, although the technique is not as well developed for measuring mercury or for measuring concentrations in sediment porewater.
Issues such as background mercury in field blanks, sampler design, and analyte recovery were examined. Laboratory testing was used to evaluate mercury DGT probe uptake parameters from the sediment and to develop procedures for analysis and interpretation of the probe. DGT probes were deployed in the field at the South River (Virginia, USA). The probes were used for both site characterization and to assess the performance of an in-situ sediment amendment. For site characterization, DGT probes were used along with other samples to assess mercury mobility between a river bank and channel. Multiple disk probes and sediment depth probes were deployed in the amendment pilot study pond in-situ to determine concentrations of mercury and methyl mercury in sediment porewater and overlying water over time. This sampling showed that the DGT could be a useful tool for exploring available and mobile mercury and methyl mercury in the field.