but the TCE discharge was almost an order of magnitude lower. The magnitude of observed

TCE in the downgradient transect compared to the source zone transect was due likely due to

reductive dechlorination in the 10 m of aquifer before arriving at the downgradient control plane.

VC was observed to be increasing in the final two years. In Figure 3-5, the mass discharge is

presented.


 Time (years)


Figures 3-5. Sages downgradient transect mass discharge in mmol/day for the six- year period
 following the 1998 ethanol flushing event.


 Very similar patterns to the source zone mass discharge was observed at the

downgradient transect. However, there was an amplification of the fluctuation of mass discharge

recorded in the source zone transect in years two and three in the plume response at the

downgradient transect. Conversely, in the source zone DCE discharge appeared to be unaffected


 -0- Molar Sum
 -4-- CE
-*---TCE


(~(X