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k1% KLEINFELDER constituents to.luenc, ethylbenzene, xylenes, aid methyl tert-butyl ether (MTBE:) were detected In the soil from the excavation. '`TPl=1-1), ethylbenzeiie, and xylenes were detected in a sample apparently collected in the northern portion of the excavation at a depth of I1 feet at concentrations of 5000 mg/kg, 600 pg/kg and 3200 pg/kg, respectively. Only MTBE was detected in a soil sample collected from the southern part of the excavation at a depth of 10 feet at 21 pg/kg. '1'1'1-1=D,. ethylbenzene, xylene; toluene, and MTBE were reported from the stockpile soil sample at 360 ing/kg, 26 pcy/kg, 8.6 pg/kg, 8.6 mg/leg and 140 pg/kg, respectively. The San ,Joaquin COLlnty I)ublic .ldcaltll Services Department, Environmental Health Division (PHS/EHD), sent a letter dated 1,'ebruary 5, 1998, as official notice of responsibility and requested a workplan to "investigate the vertical and :lateral extent of' contamination" at the site. This proposal (less the cost estimate and contract) addresses those concerns and may be submitted to PHS/EHD as said workplan. PROPOSED SERVICES Task E01 - Permitting and Pre-Field Aetivities It has been Kleinfelder's experience that this:proposal contains sufficient detail and information to be submitted to the P:1=1S/E1-ID as a workplan to review and approve a boring/well permit. Kleinfelde;r can prepare a boring/well permit application, a proposed boring/well location map, and a health and safety plan for submittal along with this proposal to PHS/EHD . Additionally, the permits must be approved prior to drilling the borings. Following obtaining approval from the PHS/EIID and :Delta Sign & Crane Service, Kleinfelder will commence with the actual assessn-lent. Task E02 - M-illing of Four Soil Borings lour (4) soil borings will be advanced to a maximum depth of approximately 50 feet below surface grade (bsg). Three of the four borings will be advanced along the perimeter of the former excavation. one boring will be advanced through the approximate center of former UST area. During the advancement of the borings, soil samples will be collected at five foot intervals for lithologic classification and qualitative field screening, with an organic vapor analyzer (OVA). The OVA measures ionizable compounds,in air in parts per million by volume (ppmv). Lithologic classification will be based on the Unified Soil Classification System (USCS). Soil samples will also be obtained hi the vadose zone for potential quantitative chemical analysis. Currently, based on our experience, we anticipate groundwater in the vicinity of the project site to be present at a depth of approximately 55 feet bsg. In the event that two consecutive samples in any boring below a depth of 20 feet have no field evidence of gas or diesel, advancement of said boring would cease. Therefore, we propose to analyze a maximum of 16 soil samples (2 samples from the vadose zone in the bottom of each boring, and 1 sample every 15 feet above the bottom two samples). 20-Y I'8-I24/2018P Irl I Page 2 or 7 © 1998,Kleinfclder. Inc. .lune IG. 1998