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Work Plan for Additional Phase II Subsurface Investigation <br /> 434 Dr.Martin Luther King Jr.Boulevard <br /> Stockton,California 95206 <br /> Partner Project Number 17-191672.4 <br /> September 25,2017 <br /> Page 1 2 <br /> geophysical survey and the advancement of five borings(B1 through B5)for the collection of representative <br /> soil and/or groundwater samples. The geophysical survey did not identify the presence of existing USTs, <br /> excavations, and/or anomalies. The Phase II identified concentrations of total petroleum hydrocarbons as <br /> gasoline (TPH-g) and as diesel (TPH-d), and benzene, toluene, ethylbenzene, and xylenes (BTEX) in <br /> groundwater exceeding certain San Francisco Bay Regional Water Quality Control Board (RWQCB) <br /> Environmental Screening Levels(ESLs) at one or more boring locations. Based on the results of the Phase II, <br /> Partner recommended additional investigation to further evaluate the extent of impacts at the subject <br /> property and the potential human health risks. <br /> Based on borings advanced during Partner's Phase II,the underlying subsurface consists of predominantly <br /> silt and silty clay from the ground surface to approximately 10 feet below ground surface (bgs), underlain <br /> by silty sand and sand to approximately 28 feet bgs. Groundwater was first encountered between <br /> approximately 23 and 26 feet bgs with an inferred flow direction to the north-northwest. <br /> PARTNER <br />