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ing <br /> Groundwater Monitoringwand Analytical ReciiritS <br /> Former Tosco(Unocal)Service Station#6991 <br /> 4707 Pacific Avenue <br /> Stockton Califomia <br /> EXPLANATIONS <br /> Groundwater monitoring data and laboratory analytical results prior to March 5 1998 were compiled from reports prepared by MPDS Services Inc <br /> TPH-G=Total Petroleum Hydrocarbons as Gasoline (ppb)=Parts per billion <br /> TOC=Top of Casmg ND=Not Detected <br /> (R)=Feet B=Benzene <br /> T=Tolu -ene -=Not Memured/Not Analyzed <br /> (BTW=Depth to Water NA = Not Available <br /> S I =Screen Interval E=Ethylbenzene <br /> (ft bgs)=Feet Below Ground Surface <br /> X=Xylenes QA=Quality AcstlrancelTnp Blank <br /> GWE=Groundwater Elevation MTBE=Methyl ternary butyl ether <br /> * TOC elevations have been surveyed relative to the City of Stockton Datum On September 9 1999 and on September 10 2000 TQC elevations were <br /> 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 <br /> of March Lane (Elevation= 11 56)City of Stockton datum <br /> 1 Laboratory report indicates the hydrocarbons detected did not appear to be gasoline <br /> 2 The analytical results of the groundwater samples collected)from monitoring wells MW-R through M W-I 1 on lanitary 17 and 19, 1994,were <br /> inconsistent with the previotis analytical results for these wells Therefore,MPDS Services Inc resampled these well,;on February 29, 1994 <br /> ` 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 <br /> 4 Covered by a new sidewalk <br /> ` The positive resull for gasoline does not appear to have a typical gasolme pattern <br /> MTBE by EPA Method 8260 <br /> 7 Field Blank <br /> s: Well was obstnicted <br /> `i Laboratory report indicates gasoline and unidentified hydrocarbons>CR <br /> in Laboratory report indicates gasoline and tinidentified hydrocarbon-,C6-CR <br /> tl Laboratory report indicates gasoline and unidentified hydrocarbons<C7 <br /> 12 Laboratory report indicates unidentified hydrocarbons>C7 <br /> 11 Laboratory report indicate-,gasoline C6-C 12 <br /> 14 Laboratory report indicates weathered gasoline C6-C 12 <br /> i4 Laboratory report indicates discrete peaks <br /> 16 Laboratory report indicates unidentified hydrocarbons C6-C 12 <br /> t7 TPI -G and BTEX by EPA Method R260 <br /> 19 TPH-G, BTEX and MTBE by EPA Method 9260 <br /> to Laboratory report indicates a hydrocarbon pattern 15 present in the requested ftiel quantitation range but does not resemble the pattern of the requested fuel <br /> 20 Laboratoty report indicates that sample vials for MW-9 were not received although documentation of the sample arriving at the laboratory is presented on the Cham of Cu-,tody <br /> 0991 XW11180178 2r MofQ;l�tlltlt <br />