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I Table 1 Groundwater Monitoring Data and Analytical Results Fornier Tosco(Unocal)Service Station#6981 4707 Pacific Avenue Stockton,California I EXPLANATIONS Groundwater monitoring data and laboratory analytical results prior to March 5, 1998,were compiled from reports prepared by MPDS Services,Inc II leum Hydrocarbons as Gasoline (ppb)=Parts per billion TOC=Top of Casing ND=Not Dete TPH- G=Total Petrocted,; (ft)=Feet B=Benzene - T=Toluene -=Not Measured/Not Analyzed 11 DTW=Depth to Water NA = Not Available S 1 =Screen interval E=Ethylbenzene ,I ;i X=Xylenes QA=Quality AssurancelTnp Blank (ft bgs)=Feet Below Ground Surface y I GWE=Groundwater Elevation MTBE=Methyl tertiary butyl ether * TOC elevations have been surveyed relative to the City of Stockton Datum On September 9, 1999 and on September 30,2000,TOC elevations were re-surveyed based on City of Stockton Benchmark,a brass cap in monument well on the east side of Pacific Avenue approximately fifty feet south I of March Lane,(Elevation= 11 56)City of Stockton datum I Laboratory report indicates the hydrocarbons detected did not appear to be gasoline 2 The analytical results of the groundwater samples collected from monitoring wells MW-8 throug3i MW-13 on January]7 and 1$, 1994,were I 1 inconsistent with the previous analytical results for these wells Therefore,MPDS Services,Inc resampled these wells on February 28, 1994 I Laboratory has identified the presence of MTBE at a level above or equal to the taste and odor threshold of 40 ppb in the sample collected from this well I� a Covered by a new sidewalk 6 I it 5 The positive result for gasoline does not appear to have a typical gasoline pattern 6M MTBE by EPA Method 8260 Field Blank 9 Well was obstructed 9 Laboratory report indicates gasoline and unidentified hydrocarbons>C8 10 Laboratory report indicates gasoline and unidentified hydrocarbons C6-C8 I II ` I Laboratory report indicates gasoline and unidentified hydrocarbons DC7 I II 12 Laboratory report indicates unidentified hydrocarbon-,>C7 'I ii Laboratory report indicates gasoline C6-C12 i4 Laboratory report indicates weathered gasoline C6-C 12 I li 15 indicates discrete peaks Laboratory report 16 Laboratory report indicates unidentified hydrocarbons C6-C12 17 TPN-G and BTEX by EPA Method 8260 is TPH-G,BTEX and MTBE by EPA Method 8260 14 Laboratory report indicates a hydrocarbon pattern is present in the requested fuel quantitation range but does not resemble the pattern of the requested fuel 20 Laboratory report indicates that sample vials for MW-9 were not received,although documentation of the sample arriving at the laboratory is presented on the Chain of Custody I f 6981 xlA638 I As*26103