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i <br /> ATTACHMENT A <br /> PROPOSED WORKPLAN <br /> PHASE II FIELD INVESTIGATION <br /> WESTERN OIL AND SPREADING <br /> 19256 N. HIGHWAY 99 <br /> ACAMPO, CALIFORNIA <br /> File No 40-YP9-179 <br /> February 16, 2000 <br /> 1.0 INTRODUCTION <br /> This workplan was developed after discussions with Mr Jeff Hopkins and review of written <br /> comments presented by the PHSIEHD A preliminary soil and groundwater investigation of the <br /> L <br /> contamination of the former underground storage tank (UST) at the site was conducted on March <br /> 23 and March 24, 1999 by Gallardo & Associates Five soil borings were advanced to depths of <br /> approximately 40 feet bgs Analytical results of the soil sample collected from B-1 at 40 feet bgs <br /> were 730 ppm of TPH-diesel, 530 ppb of TPH-kerosene, and 17 ppm of TPH-gasoline <br /> Analytical results of the soil sample collected from B-2 at 30 feet bgs were 13,000 ppm of TPH- <br /> diesel, 11,000 ppm of TPH-kerosene, and 230 ppm of TPH-gasoline <br /> Analytical results of the groundwater encountered in boring B-1 indicated concentrations of <br /> 5,900 ppb TPH-diesel, 4,300 ppb TPH-kerosene, and 71 ppb TPH-gasoline It is unknown if this <br /> is perched water Groundwater in the area was approximately 50 to 60 feet bgs in Fall 1993 <br /> according to PHSIEHD The groundwater sample was collected from a depth of approximately <br /> 26 feet bgs <br /> According to information supplied by Mr Ross Atkinson of the Regional Water Quality Control <br /> Board, site specific data from the Victor Fine Food project indicate there are at least three aquifer <br /> zones beneath the VFF site The shallow aquifer, Zone A occurs between 50 and 75 feet below <br /> ground surface (bgs), Zone B is between 110 and 140 feet bgs, and Zone C is between 170 and <br /> 200 feet bgs Depth to groundwater in these zones were measured in early 1999 at between <br /> approximately 45 and 50 feet below ground surface The groundwater now direction in each <br /> zone was calculated in a northerly direction The groundwater gradient in the shallow A zone <br /> was calculated at 0 0015 ft./ft <br /> The PHS/EHD has requested a workplan to define the lateral and vertical extent of soil and <br /> groundwater contamination at the site <br /> 40-Y P9179/40 l OP019 2 <br /> Copyright 2000 Kleinfelder Inc. <br /> KLEINFELDER 780 Chadbourne Road Suite D, Fairfield CA 94585 9643 (707) 429-4070 (707)429-4162 fax <br />