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A diffusion‐based interpretation of tetrachloroethene and trichloroethene concentration profiles in a groundwater aquitard
Author(s) -
Ball William P.,
Liu Chongxuan,
Xia Guoshou,
Young Dirk F.
Publication year - 1997
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/97wr02135
Subject(s) - aquifer , groundwater , plume , environmental science , environmental remediation , contamination , diffusion , soil science , hydrology (agriculture) , groundwater pollution , vadose zone , groundwater model , geology , environmental engineering , groundwater flow , geotechnical engineering , geography , meteorology , ecology , physics , biology , thermodynamics
Analysis of subsurface soil cores from the site of a field‐scale groundwater remediation experiment at Dover Air Force Base, Delaware, has revealed that tetrachloroethene (PCE) and trichloroethene (TCE) contamination extends into an aquitard underlying a groundwater aquifer. The site location is well downgradient of the locations of contaminant release, and the aquitard contamination is believed to have begun when contaminated groundwater first arrived in the overlying aquifer. Using independent estimates of sorption and diffusion properties in the aquitard layers, mathematical modeling based on diffusion in laminate slabs has been used to make inferences regarding the historical concentration conditions in the overlying aquifer. The results suggest that plume arrival occurred within the last two decades, with some important differences in the inferred TCE and PCE plume histories. The diffusion model was also applied toward predicting future aquitard concentrations and fluxes under scenarios based on the current condition as a starting point and hypothesized conditions of future groundwater cleanup. The results demonstrate how aquitard sampling and diffusion modeling can provide essential information relevant to forensic analysis, risk assessment, and subsurface cleanup.