We present a new field measurement and numerical interpretation method (combined termed ‘test’) to parameterize the diffusion of trichloroethene (TCE) and its biodegradation products (DPs) from the matrix of sedimentary rock. The method uses a dual-packer system to interrogate a low-permeability section of the rock matrix adjacent to a previously contaminated borehole and uses the borehole monitoring history to establish the pre-test condition. TCE and its DPs are removed from the groundwater between the packers at the onset of the testing. The parameters estimated by fitting a radial diffusion model to the concentration history and borehole concentration data, also termed back-diffusion, are the tortuosity factor and sorption coefficients of TCE and DPs in the rock matrix and the TCE and DP biodegradation rate coefficients in the borehole. We demonstrate the equipment design and the interpretive method using a borehole accessing the grey mudstone at a TCE contaminated site in the Newark Basin. In this test, both nonreactive (bromide) and reactive (trichlorofluoroethene) tracers are used to constrain the estimated parameters; however, the bromide tracer was not needed to estimate the parameters in this test. The parameters estimated from the field test are consistent with values measured independently in laboratory experiments using field samples of similar lithology. From the interpretation, we compute the TCE and DP concentration distributions in the rock matrix prior to the test to illustrate how the results can be used to enhance understanding of contaminant distribution in the rock matrix.
|Title||A borehole test for chlorinated solvent diffusion and degradation rates in sedimentary rock|
|Authors||Richelle M. Allen-King, Rebecca L. Kiekhaefer, Daniel J. Goode, Paul A. Hsieh, Michelle Lorah, Thomas E. Imbrigiotta|
|Publication Subtype||Journal Article|
|Series Title||Groundwater Monitoring and Remediation|
|Record Source||USGS Publications Warehouse|
|USGS Organization||Maryland Water Science Center; New Jersey Water Science Center; Pennsylvania Water Science Center|
Contaminant Fate and Transport Studies in Fractured Sedimentary Rock Aquifers at the former Naval Air Warfare Center (NAWC), West Trenton, N.J.
A finite-difference algorithm used to simulate radial diffusion, adsorption, and reactions of chlorinated ethenes in porous media
Daniel J Goode
Contaminant Fate and Transport Studies in Fractured Sedimentary Rock Aquifers at the former Naval Air Warfare Center (NAWC), West Trenton, N.J.Contaminants associated with industrial, airport, and other activities are present in groundwater in fractured-rock aquifers, posing long-term hazards to drinking-water supplies and ecosystems. The heterogeneous character of fractured rock challenges our understanding, monitoring, and remediation of such sites.
A finite-difference algorithm used to simulate radial diffusion, adsorption, and reactions of chlorinated ethenes in porous mediaSimulations of radial diffusion, adsorption, and reactions of volatile organic compounds (VOCs) - trichloroethene (TCE), cis-1,2-dichloroethene (cDCE), vinyl chloride (VC), trichlorofluoroethene (TCFE) - and bromide (Br) in a porous media are conducted using rock properties identified from a mudstone aquifer in the Newark Basin, near West Trenton, New Jersey. The simulations are conducted using a
Daniel J Goode