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' Geolog"I Teck&a Ina
<br /> Page 7
<br /> 1S1 Quarter 2004 Groundwater Momtonng Report
<br /> Project No 507 2
<br /> May 19,2004
<br /> ' Inc staff's infection of a dilute hydrogen peroxide solution into well MW-9 This process
<br /> occurred on a biweekly basis thereafter and will continue for eight events The following
<br /> ' table shows the pre-injection analytical data for March 19, 2004 and the resulting test data
<br /> from injection wells MW-9 and discrete monitoring points GP-1 through GP-3 Micio-
<br /> wells (314" PVC) GP-1 through GP-3 are located down gradient from MW-9 at distances of
<br /> ' approximately 12, 24 and 36 inches, respectively
<br /> ' Well Date Benzene Toluene Ethyl Total TPH
<br /> ug/L ug/L Benzene Xylenes Gasoline
<br /> ' ug/L ug/L ug/L
<br /> MW-9 03/19/04 25,400 9,210 3,640 14,000 137,000
<br /> 04/02/04 24,500 8,270 2,020 14,500::[ 117,000
<br /> ' 04/16/04 13,200 2,220 5,260 7,770 64,000
<br /> GF-1 _T3/1-9/04 27,200 12,600 4,180 18,700 139,000
<br /> 04/02/04 24,300 10,100 2,030 18,900E27, 0
<br /> ' 04/16/04 21,400 6,690 1,450 12,1000GP-2 03/19/04 22,500 9,490 5,010 24,500 004/02/04 22,800 9,900 5,200 25,000 0
<br /> 04/16/04 22,400 10,900 4,350 20,800 140,000
<br /> GP-3 03/19/04 13,900 393 258 8,110 85,400
<br /> 04/02/04 13,900 600 3,930 13,800 128,000
<br /> t04/16/04 1 14,000 1 575 3,490 8,860 76,900
<br /> The data indicate that MW-9 has experienced a significant reduction in contaminant
<br /> ' concentrations since the injection process started This is expected since it is the injection
<br /> point The reduction in the three micro-wells is less but measurable and the initial results
<br /> ' show promise for this remedial technology The significant rise in TPH concentrations in
<br /> GP-3 for the April 2, 2004 monitoring event suggests that the injected oxidant initially
<br /> caused a release of sorbed gasoline from the soil
<br /> 5.0 LINHTATIONS
<br /> This report was prepared in accordance with the generally accepted standard of care and
<br /> practice in effect at the time Services weie rendered It should be recognized that definition
<br /> and evaluation of environmental conditions is an inexact science and that the state or
<br /> practice of environmental geology/hydrology is changing and evolving and that standards
<br /> existing at the present time may change as knowledge increases and the state of the practice
<br />' continues to improve Further, that differing subsurface soil characteristics can be
<br /> experienced within a small distance and therefore cannot be known in an absolute sense
<br /> All conclusions and recommendations are based on the available data and information.
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