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!1 ffjZAVMA Working To Restore Nature 1 accordance with the Quality Assurance/Quality Control Plan and the site specific Health and Safety Plan on file with PHS/EHD Soil Excavation and Sampling On December 2-9, 1993, approximately 1400 cubic yards of residual petroleum hydrocarbon contaminated soil was excavated from the vicinity of the former underground fuel storage tanks The extent of the excavation and former tank locations are depicted on Figure 3 Excavation was conducted by Goins Environmental Construction (Lic #674281) under the direct supervision of a RESNA geologist Excavation activities were observed and approved by Ms Linda Turkatte of PHS/EHD A Photoionization Detector (PID) calibrated to an isobutylene standard and visual and olfactory methods were utilized during excavation to assist in evaluating the lateral and vertical extent of soil impaction PID readings ranging from 0 0 to 72 1 ppm and petroleum hydrocarbon odor indicated that residual petroleum hydrocarbon impacted soils existed in the area of the former diesel tank between approximately 6 and 11 feet below grade along the eastern wall where excavation was limited due to the existing structure Excavation continued along the north, west and south sides of the pit until field evidence indicated that contamination was no longer present During the excavation process, the pit was dewatered by pumping groundwater which flowed into the pit to the building's sewage clean-out in accordance with a temporary discharge permit granted by the City of Stockton Municipal Utilities District A groundwater sample was collected by lowering a disposable bailer into the water in the pit The sample was submitted for analysis of TPHg, TPH as diesel (TPHd) and benzene, toluene, ethylbenzene and xylenes (BTEX) by EPA methods 8015/8020 Analytical results are included in Table 4 Following excavation, confirmation samples were collected under the direction of Ms Turkatte A total of 9 sidewall and 2 excavation bottom samples were collected The soil sampling locations are depicted on Figure 3 Samples were collected from the excavator's bucket three inches below the surface of the soil The samples were collected into prewashed brass liners Each liner was sealed with Teflon sheets and plastic caps, sealed in air -tight bags, and preserved on ice pending shipment to Sequoia Analytical (DHS Cert #1210) in Redwood City, California Sample descriptions are included in Attachment 1 Soil samples were transported under chain -of -custody to the laboratory for analysis of BTEX, TPHg and TPHd by the methods described above Excavated petroleum hydrocarbon impacted soil was underlain and covered with 6 -mil plastic sheeting pending laboratory analysis Stockpiled soil samples were collected and analyzed for BTEX, TPHg and TPHd by the methods described above Six 4 -sleeve composite samples were collected from the stockpiled soil (approximately one per 200 cubic yards of soil) Sample locations are shown on Figure 3 An appropriate disposal and/or remediation plan for stockpiled soils is currently being investigated �. SXR1293 DRF 3