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UPDATE 28 8-02-94 conservative using the highest permeability calculated from soil samples and an organic carbon of 0 1% The models were run on three areas of approximately 100 square feet each. Area 1 (polygon 1) is the area around soil boring SB13 , Area 2 (polygon 2) is the area around soil boring SB14 and Area 3 (polygon 3) is the area around soil boring SB15 . Under the above conditions VLEACH ran on the February 2, 1994 data, predicted that over a 140 year timeframe 430 pounds of gasoline range hydrocarbons would be delivered to ground water and BIOPLUME calculated that the majority of the hydrocarbons would be oxidized, with only one area of impact (SB14) , where dissolved oxygen would be reduced to zero in an area of approximately 300 square feet Maximum impact would occur during year 55 with 17 5 grams/square foot The impact would then decline as dissolved oxygen levels start to increase back to background of 8 mg/L These models showed that the contamination in soil as of February 2, 1994 , using a worst case senario, would only impact the ground water near SB14 , be of limited lateral extent, never leave the site and would eventually degrade with time The VES was restarted on February 16 , 1994, see Table 3 Since the above mentioned fate modeling was performed (February 2 , 1994) another 124 pounds of gasoline range hydrocarbons have been removed from the site The above models were updated (thru July 12 , 1994) with this new removal amount and can be found as Appendix A of this report Basically the Models VLEACH and BIOPLUME were adjusted by the subtracting the removed 124 pounds from the amount that remained on February 2 , 1994 of 531 pounds and then determining the percentage of contaminant that remained for each sample point used in the original modeling Approximately 76 6% of the February 2 , 1994 calculated contaminant remains in the soil as of July 12 , 1994 Also BIOPLUME was adjusted to respond to ug/L of ground water concentrations instead of the mg/L as was previously modeled, February 2 , 1994 Results of this current modeling (July 12 , 1994) indicate that during the 100 years biodegradation is faster than contaminant delivery, therefore the TPHg would never reach 1 ug/L During the decade ending in year 60 maximium impact would occur with a dissolved oxygen of 1 38 mg/L near SB14 As long as there is oxygen available the petroleum hydrocarbons will be degraded as they come in contact with ground water The following table shows the modeled predictions for dissolved oxygen in ground water, the amount of gasoline range hydrocarbons that will come in contact with the ground water, and the net results of TPHg in the ground water, where oxidation will occur, beneath SB14 pages