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SUBSURFACE SOIL AND GROUNDWATER ASSESSMENT REPORT SUBSURFACE SOIL AND GROUNDWATER SAMPLING METHODOLOGY With assistance of a in direct-push soil-sampling rig,ESA obtained soil and groundwater samples P P g from the sampling locations on July 5, 2000 Prior to drilling, ESA contacted Underground ' Service Alert (USA)to clear the locations for underground utilities ESA obtained necessary drilling permits from the SJCEHD ' Sampling cores were advanced in four-foot continuous core sections using an inert acetate liner set within the stainless steel core tube Acetate liners were not reused and the core tube was ' washed with detergent and rinsed after each use Once the soil core was extracted from the coring tube,the ESA field geologist described and recorded the soil types and characteristics such as odor, staining, or signs of fill material Soil borings are provided as Attachment A of this ' report Based on the observations of physical characteristics, select sections of the core were cut from the continuous core, sealed with end caps and Teflon and placed in cooled storage prior to transportation under chain-of-custody to McCampbell Analytical Laboratories,a state-certified ' laboratory in Pacheco, California Handling and exposure of the core to air was kept to a minimum to reduce potential for volatilization of aromatic hydrocarbons Following the soil and groundwater sampling, each soil boring was back-filled to the surface with neat cement under ' supervision of the SJCEHD inspector i GROUNDWATER SAMPLING ! Groundwater samples were collected through a Hydro-punch in-situ groundwater sampling device from depths ranging from 20 to 24 feet bgs Once the Hydro-punch probe was inserted to depth,groundwater was allowed to enter the borehole through its screened, temporary sampling point Groundwater was extracted using a peristaltic pump with dedicated tubing Approximately four well-point volumes of water were purged, when possible, prior to collecting the groundwater sample After purging, groundwater was transferred into appropriate glassware, labeled and placed in cool storage prior to transportation to a state-certified analytical laboratory Prior to arrival on the site, groundwater sample glassware was laboratory-cleaned and contained appropriate preservative ' DECONTAMINATION PROCEDURES Down-hole drilling equipment arrived to the site clean and was decontaminated using a high- pressure wash and detergent after each borehole Soil samples were collected in disposable, one- use-only,acetate liners Soil cuttings were placed in a sealed storage drum, labeled, and left on- site in a secure location pending receipt of analytical results Groundwater was sampled using dedicated tubing and therefore, decontamination was not necessary Down-hole groundwater ' sampling equipment(well points) was either dedicated or thoroughly decontaminated using high- pressure wash and detergent between each use Subsurface Soil and Groundwater Assessment ESA!200252 ' 1081 W Mendocino Avenue Stockton California 13 September 1 2000