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Phase II Environmental Site Assessment Investigation Report 206 Sutter Street, Stockton, California Page 4 4.2 GROUNDWATER TPH-D was detected at concentrations of 17,000 milligrams per liter (µg/L) in DP-1, 260 µg/L in DP-4, and 170 µg/L in DP-6. TPH-MO was detected at concentrations of 40,000 µg/L in DP-1 and 510 µg/L in DP-7. TPH-G was detected at concentrations of 5,100 µg/L in DP-1 with lighter than water immiscible sheen or product present and 110 µg/L in DP-4. Detected VOCs by EPA Method 8021B includes benzene at 25 µg/L, toluene at 36 µg/L, ethylbenzene at 38 µg/L, m, p-xylene at 20 µg/L, 0-xylene at 1.9 µg/L, and xylenes at 22 µg/L in DP-1. VOCs were not detected at or above their respective reporting limits in DP-7. Detected VOCs by EPA Method 8062B includes benzene at 9.5 µg/L, ethylbenzene at 29 µg/L, xylenes at 17 µg/L, naphthalene at 24 µg/L, n-butyl benzene at 5.7 µg/L, 1,2,4-trimethylbenzene at 6.6 µg/L, 1,3,5- trimethylbenzene at 10 µg/L, isopropyl benzene at 15 µg/L, 4-isopropyl toluene at 6.7 µg/L, n-propyl benzene at 31 µg/L, and sec-butylbenzene at 3.1 µg/L in DP-1. DP-4 had concentrations of VOCs including benzene at 1.3 µg/L, tert-butyl benzene at 0.58 µg/L, 1,2-dichroethane at 0.20 µg/L, and isopropyl benzene at 0.51 µg/L. VOCs were not detected at or above their respective reporting limits in any of the other collected groundwater samples. VOC results were compared to the Maximum contaminant levels (MCLs) adopted by the California State Water Resources Control Board (SWRCB), and naphthalene was compared to the California Division of Water’s California Notification Level (CNL) of 17 µg/L. Benzene by both EPA methods was detected above the MCL of 1.0 µg/L with the highest benzene concentration at 25 µg/L and Naphthalene was detected above the CNL of 17 µg/L in the groundwater sample collected at DP-1. Benzene was detected slightly above the MCL of 1.0 µg/L in the groundwater sample collected at DP-4. Detected laboratory analytical results for the groundwater samples are included on Table B, Appendix D. All soil and groundwater laboratory analytical reports and chain of custody forms are included in Appendix E. 5.0 CONCLUSIONS Condor conducted a Phase II ESA for the property located at 206 Sutter Street, Stockton, San Joaquin County, California. The purpose of the work was to evaluate whether past use of the property had adversely affected soil and/or groundwater beneath the Site. The evaluated property included one parcel designated as Assessor Parcel Number (APN) 139-250-030. Based on review of historical documents the Site appears to have had been occupied by a commercial fueling station in the southwestern portion of the Site from approximately the 1930’s to the 1960’s which was replaced by The Ambassador Hotel in the late 1960s or early 1970s. In 2016 the hotel was demolished. In February 2017, Condor conducted a project-wide geotechnical engineering study for the Ten Space Development Project in downtown Stockton and advanced two geotechnical borings on the Site. Boring B-3 was terminated at approximately 10 feet bgs due to a concrete obstruction and B-4 observations included stained soil and a smell of gasoline starting at approximately 30 feet down to the boring terminus at 50 feet bgs. Groundwater depths within the Stockton area historically ranged from 80 to 100 feet bgs during the time when shallow groundwater was utilized for public water supply until the early 1980s. Shallow groundwater subsequently was not used for public supply and rebounded to shallower depths of approximately 20-30 feet bgs beneath Stockton. Currently, the regional groundwater gradient is easterly due to the critically over- drafted groundwater basin from agricultural irrigation to the east, which has created a large regional cone of depression centered approximately 10 miles east of Stockton. This regional easterly gradient beneath Stockton has been present since the 1980s. As a result, many Stockton releases that occurred prior to the