GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 324-26
Presentation Time: 9:00 AM-6:30 PM

TRICHLOROETHYLENE SORPTION TO SEDIMENTARY ROCKS OF THE NEW JERSEY BASIN INDICATE MATURE ORGANIC MATTER


BROTSCH, Jonathan, Geology, SUNY University at Buffalo, 411 Cooke Hall, The State University of New York, University at Buffalo, Buffalo, NY 14260, jbrotsch@buffalo.edu

The former Naval Air Warfare Center (NAWC) in Trenton, New Jersey, has legacy trichloroethylene (TCE) contamination that persists at high dissolved concentrations in spite of decades of pump-and-treat control. The geology at NAWC consists of fractured, low permeability mudstones of the New Jersey basin. The four primarily lithologies exhibit more than an order of magnitude in fraction organic carbon (foc) content. Representative samples of each of the lithologies, reflecting the foc range, were chosen for this study. Batch sorption experiments were used to generate sorption isotherms spanning approximately four orders of magnitude in aqueous concentration. The isotherms for all of the samples were very nonlinear, as characterized by Freundlich slopes less than 0.75. The isotherms showed mostly similar slopes (similar Freundlich exponents). Overall the samples with the highest foc were able to sorb a greater amount of TCE. However, at moderate to low aqueous concentrations, the sorbed to solution concentration ratios for all samples (i.e. Kd) were at least an order of magnitude greater than predicted from the empirical approach using a literature average for the carbon-normalized TCE Kd (Koc). Our results are consistent with literature reports of TCE sorption to mature organic matter or to organic matter containing black carbon. Ongoing work will compare the isotherms to the properties of the organic matter. The sorption data gathered will be used to model retarded pore diffusion from the low permeability matrix rock to high permeability zones.