Estimating Nonlinear Volatile Organic Compounds (VOCs) Sorption to Low Carbon Content Aquifers Using Surrogate Compounds
Abstract
The CT (carbon tetrachloride) plume in Hanford site is not large and retardation of the plume is uncertain given that there is no nonreactive tracer applied synchronously with the CT. Unfortunately, direct measurement of sorption distribution coefficients (Kd) for those low Kow (octanol/water partition coefficient) compounds (e.g., CT) on low foc (organic carbon content) sediments is quite challenging using normal batch setup due to the solid/water ratio limitation. One way to solve this problem is to use more hydrophobic compounds (high Kow) as surrogates, where Kd on the target low foc aquifer sediments can be easily measured. With the help of the foc - normalized partition coefficients (Koc = Kd/foc) at different aqueous concentrations (Cw), the Kd values of the target low Kow compounds on the same materials could be estimated. In this study, the nonlinear sorption isotherms of CT and a surrogate compound 1,1,1,3- tetrachlorotetrafluoropropane on selected samples with a wide spectrum of characteristics (from "soft" to "hard" carbon) were simultaneously determined. A relationship of Koc between CT and 1,1,1,3- tetrachlorotetrafluoropropane sorption on the same materials was investigated. Thus, the distribution coefficients (Kd) of the target compound, CT, in Hanford site (Ringold formation) sediments were estimated based on the batch sorption experiments of 1,1,1,3-tetrachlorotetrafluoropropane on the same samples.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.H31D0902W
- Keywords:
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- 1831 Groundwater quality