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J. H. KLEINFELDER & ASSOCIATES <br /> File: W-2001-1 <br /> January 29 , 1986 <br /> Page 22 <br /> for total chromium at 0.08 mg/l in monitoring well No. 1 exceeded <br /> the State drinking water action level of 0.05. All other <br /> analytical results for metals were within drinking water action <br /> levels as established by the DOHS. <br /> IX. FINDINGS <br /> 1 . The site was utilized for sheet metal fabrication and pain- <br /> ting to manufacture garage doors. Before painting gal- <br /> vanized doors were cleaned, phosphatized, and sealed. Waste <br /> waters from the metal cleaning and paint spray booth opera- <br /> tions were stored in an unlined pond. The waste waters may <br /> have contained acids , bases , metals such as zinc and <br /> organics such as toluene and pthalates. The pond has been <br /> in service since the early 1960's and solids have been <br /> removed periodically by dredging. The types of chemical and <br /> paints have changed over the history of the site. Metals , <br /> volatile and aromatics chemicals from past cleaning, <br /> phosphatizing and spray booth waste waters in the unlined <br /> pond have the potential to impact ground water. <br /> 2 . The site is located on alluvial and flood plain deposits of <br /> the Mokelumne River. Borings on the site encountered inter- <br /> bedded units of silty sands , sandy silts , silt , and coarse <br /> sand. A very dense sandy silt unit was encountered in all <br /> borings at an approximate depth of 40 feet below grade . <br /> 3 . Three soil borings were drilled to an approximate depth of <br /> 62 feet below grade. Soil samples were collected for <br /> ` geologic information. <br /> t 4 . Three soil borings were completed as monitoring wells. One <br /> well was located upgradient of the pond , and two <br /> downgradient. The wells were completed 20 feet into the <br /> uppermost water bearing zone. Ground was first encountered <br /> at an approximate depth of 44 feet below grade. <br /> 5 . The three monitoring wells were developed, sampled, and the <br /> water samples analyzed. The chemical analyses results were <br /> below detection limits for volatile halocarbons using EPA <br /> Method 601 , and for purgeable aromatics using EPA Method <br />