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Morita Brothers Well Abandonment Plan Project No. 912.2 January 29, 2010 NNo • March, 2002 -- In GTI's March 18, 2002 "Risk Evaluation & Appendix B Closure Checklist" work plan, GTI proposed performing contaminant mass estimate calculations and limited fate and transport calculations. The work plan was submitted to the SJC EHD and is necessary to receive site closure concurrence from the Regional Water Quality Control Board. In their letter correspondence dated April 24, 2002, the SJC EHD denied GTI's work plan and directed that a work plan for additional plume definition be submitted. • December, 2003 — nine additional groundwater monitoring wells (MW -11, MW -108, MW -109, MW -110, MW -111, MW -202, MW -208, MW -209 and MW -210) were installed under the supervision of GTI. • 1992 to 1999 — intermittent monitoring/sampling (18 events) of wells MW -1 through MW -3. • 2000 to April, 2009 — quarterly groundwater monitoring & sampling of all site monitoring wells. • November, 2004 — SJC EHD directed submittal of a work plan to update the site conceptual model using CPT borings, as part of the consideration of this site for closure. • January, 2006 — Four Cone Penetrometer Test (CPT) boreholes advanced with depth discrete soil and groundwater sampling, under the supervision of GTI. • May, 2006 — GTI prepared and submitted Site Conceptual Model (SCM) which included recommendation of closure for the site. • September, 2006 — SJC EHD directed further soil and soil gas investigation to compare contamination levels with by San Francisco Bay Regional Water Quality Control Board (SFBRWQCB) Environmental Screening Levels (ESLs) and the California Human Health Screening Levels (CHHSLs). • November, 2006 — GTI prepared and submitted a work plan for additional investigation, which was tentatively approved by SJC EHD in June, 2007. • August, 2007 — GTI prepared and submitted work plan addendum, which was approved by SJC EHD October, 2007. • February & March, 2008 — GTI conducted soil and gas investigation per the approved work plan and addendum, which included advancement of SB -1 and GP -I and collection of soil and groundwater samples. Two borings were not able to be advanced due to drill rig accessibility issues. • April, 2008 — GTI prepared and submitted a Risk Evaluation report based on the soil and soil gas investigation. • June, 2008 — GTI advanced two GeoProbe boreholes and collected groundwater grab samples to complete the work plan. • July, 2008 — GTI prepared and submitted an addendum to the risk evaluation report of the soil and soil gas investigation. • February, 2009 — SJC EHD indicated they cannot concur with the site closure request at this time, as further data is needed to verify the model of a migrating low mass plume posing minimal risk to sensitive receptors, human health and additional groundwater supply. • April, 2009 — SJC EHD directed GTI not to perform groundwater monitoring on site until further notice. Cleological rechAics /a. 2 7242 Well Aband WP 1-29-10