SITE INFORMATION AND CORRESPONDENCE_FILE 2

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r ` , Upon review of the relevant data and updating the SCM with the October 2005 CPT investigation, GTI recommended that a pilot test be performed for evaluating a combination of bioventing with low flow biosparging at the site. This would involve injecting air into the subsurface to stimulate aerobic biodegradation of the petroleum hydrocarbons. The test would involve the installation of injection wells with associated infrastructure to sparge air into the subsurface and monitor air flow rates, pressure, vacuum and other parameters. The objective of the pilot tests would be to obtain enough data to design a treatment system to address the entire soil and groundwater plumes. On June 9, 2006 we submitted a plan for `Bioventing with Biosparging Pilot Test" to meet this objective. The work plan also included provisions for performing a soil vapor extraction pilot test utilizing higher vacuum pressures (up to 26" Hg vacuum) than used with standard SVE. This is similar to dual phase extraction technology but without the intent of extracting and treating groundwater. The SJC PHS/EHD previously denied our proposal to test this technology based on its inapplicability to diesel fuel. However, the CPT investigation indicated that some lithologic units of greater permeability are present that might benefit from this technology. The soil micro-fractures structures also may facilitate extraction through silty and clayey soils. Per San Joaquin County Environmental Health Department directive dated September 18, 2008 groundwater monitoring wells MW-2, MW-3, MW-8, MW-104, MW-105, and MW-106 were moved from quarterly to annual sampling schedule. These wells will be sampled every 4`h quarter. Status of Investigation during 1St Quarter 2009: GTI submitted the Revised Pilot Test Work Plan for dual phase extraction on January 23, 2009. The work plan was approved by SJCEHD in their correspondence dated March 23, 2009. No sampling and analysis of groundwater monitoring wells took place during the first quarter of 2009. The next monitoring event would occur during the second quarter of 2009. Limitations This report was prepared in accordance with the generally accepted standard of care and practice in effect at the time Services were rendered. It should be recognized that definition and evaluation of environmental conditions is an inexact science and that the state or practice of environmental geology/hydrology is changing and evolving and that standards existing at the present time may change as knowledge increases and the state of the practice continues to improve. Further, that differing subsurface soil characteristics can be experienced within a small distance and therefore cannot be known in an absolute sense. All conclusions and recommendations are based on the available data and information. Cleo logical7"hairs Inc. April 16,2009