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In June 2005,Barber oversaw the installation of 10 Hydropunch®well points (HP-20 through HP- 29)located further to the east and north of the site. One groundwater sample was collected from each well point. TPHD was detected in groundwater samples collected from all well points (Barber,2008). Monitoring well MW-7 was installed in July 2006 to define the downgradient edge of groundwater containing petroleum hydrocarbons. The well was developed and was included in the quarterly monitoring program in September 2006. SHN began groundwater monitoring at the site in December 2008,and first began incorporating silica gel cleanup in the analytical program. The properties located directly to the east and north of the site are vacant land. The San Joaquin County Environmental Health Department(SJCEHD)is the current lead agency for the site. LHistoric soil and groundwater analytical data are included in Appendix B. 4.2 Sensitive Receptor Survey A limited sensitive receptor survey was performed for the site by Barber in 2003. Barber performed a survey of all water supply wells within Y2 mile radius of the site. The survey identified 63 domestic and agricultural water supply wells within the search radius. However,the water wells in the vicinity of the site are cased below 300 feet,due to concerns of brine infiltration from the Victor Fine Foods Facility. No samples have been collected from the agriculture production wells to date. A water production well is located approximately 150 feet southwest of monitoring well MW4,and is primarily used to augment some asphalt mixing on site. The on-site production well was sampled by Barber in 2003 and no petroleum hydrocarbons were detected. Monitoring well MW-7 is located between the domestic wells and the site. Historic analytical results of groundwater samples collected from MW-7 indicate that groundwater in the vicinity is not impacted with TPHD above the Water Quality Objective(WQO)of 100 micrograms per Liter (ug/L)for TPHD(RWQCB,2004). LThe majority of the site is paved with asphalt chip seal. The surrounding parcels to the north,east, west,and south are located at a slightly lower topographic relief than the site,and the entire site is surrounded by a containment berm composed of soil. Additionally,a soil containment berm is located around all the ASTs. Surface water at the site generally drains toward the southwest corner and into a storm drain drop inlet. Several straw waddles are located around the drop inlet to prevent a potential spill from entering the storm drain. Based on the data collected to date,this site is unlikely to affect any potential sensitive receptors. L 4.3 Site Geology The site is located in the Central Valley of California at an approximate elevation of 60 feet above Mean Sea Level(MSL)and is located within the San Joaquin Basin Hydrologic Study Area,which covers approximately 13,500 square miles. The site is located in an area of slightly higher topographic relief than the surrounding properties. L \\Eureka\Projects\2007\004152-WOS\PUBS\rpt\20100324-1 stHa]=OG WMR&RFC.doc i 6 L