Carbon Tetrachloride Partition Coefficients Measured by Aqueous Sorption to Hanford Sediments from Operable Units 200-UP-1 and 200-ZP-1

Wellman, Dawn M. ; Riley, Robert G. ; Cordova, Elsa A. ; Parker, Kent E. ; Mitroshkov, Alexandre V.

Pacific Northwest National Laboratory (U.S.)

关键词: Desorption;    Diffusion;    Adsorption Isotherms;    Sediments;    Ground Water;   

DOI  :  10.2172/936768
RP-ID  :  PNNL-16100 Rev. 1
RP-ID  :  AC05-76RL01830
RP-ID  :  936768

美国|英语

来源: UNT Digital Library

【 摘 要 】

Kd values obtained on sediment samples from 200-UP-1 and 10-ZP-1 contribute to a larger Kd database that exists for other Hanford sediments, and contains significant desorption data for CCl4. Adsorption results presented here validate the use of a linear adsorption isotherm (Kd) to predict short contact time CCl4 adsorption to sediments in 200-UP-1 groundwater plume for a distinct ranges in CCl4 concentration. However, this does not imply that values of Kd will be constant if the groundwater chemical composition at 200-UP-1 changes with space or time. Additionally, results presented here suggest the potential significance of slower intraparticle diffusion on the long-term fate of CCl4 within the subsurface Hanford environment. Such behavior could afford prolonged desorption of CCl4 and serve as a long-term source of contaminant CCl4 to the aquifer. Further evaluation of possible bimodal sorption behavior for CCl4 and the mechanism of CCl¬4 sequestration should be the subject of future investigations to provide a thorough, mechanistic understanding of the retention and long-term fate of CCl4. Comparison of previous data with new results (e.g., from this study) will allow inferences to be made on how the 200-UP-1 Kd values for CCl4 may compare with sediments from other Hanford locations. This site-specific sorption data, when complemented by the chemical, geologic, mineralogic, hydrologic, and physical characterization data that are also being collected (see Sampling and Analysis Plan for the 200-UP-1 Groundwater Monitoring Well Network, DOE 2002) can be used to develop a robust, scientifically defensible data base to allow risk predictions to be generated and to aid in future remediation decisions for the 200-UP-1 and 200-ZP-1 operable units.