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s <br /> Installation of MW-1 <br /> Monitoring well MW-1 was installed on 5/14/2001 to a depth of 55 feet in a soil bore that was <br /> sampled on five foot intervals (See Log of Boring MW-1 attached). Groundwater analysis for the <br /> • samples produced by this monitoring well are attached. <br /> REPORT OF FINDINGS FROM THE MW#1 aka UST-1 <br /> First Half Sampling Event Sampled 06/14/04 <br /> Water Sampling and Analysis <br /> Water samples from MW#I were extracted by Del-Tech Geotechnical Support Services on 6/14/04. <br /> The samples were transported under chain of custody to Sherwood Labs.Pump purge rates were one <br /> G.P.M. Depth to the water surface was 52.56'with a+/-4' stickup on the casing. The water table at <br /> the time of sampling was about 48' below the surface. TPHd and BTEX were analyzed by EPA <br /> Methods EPA 8015(M) and EPA 8020 by BSK Laboratories. <br /> Findings from Sample Analysis <br /> Analysis by all of the above methods resulted in non-detect status for each of the analytes analyzed. <br /> Conclusions from this Groundwater Sample Analysis <br /> The laboratory results for this sample period are non-detect. The previous results of 05/24/01, <br /> 10122/01, 06/13/02, 06/09103, and 12/29/03 of water samples extracted from this monitoring well <br /> were also non-detect.The analysis of the groundwater samples from the 3/01/2002 were rejected due <br /> to the fear of contaminated samples in the laboratory(Note underlined sample data in Water Sample <br /> Analysis Recap attached).The groundwater elevation has lowered about one feet from the previous <br /> • event. <br /> Six out of a total of seven groundwater samples from monitoring well MW-1 have been analyzed <br /> as non-detect for all analytes. The only sample to indicate the presence of BTEX was sampled on <br /> 03101102. TPHd was found to be non-detect on that sample. The author concludes that this sample <br /> was contaminated in the extraction process or in analysis by the laboratory.It is safe to conclude that <br /> the spill from the UST did not reach the groundwater.An impervious strata between 35'and 45'will <br /> prevent any further downward movement of the spill plume(See soil bore lithology attached). Soil <br /> samples taken during the soil bore for MW-1 were analyzed as non-detect from a depth of 30' to <br /> termination. <br /> Estimated Diesel Mass Calculation <br /> The diesel mass of this spill is calculated at 1128 Kg. This mass was calculated using the soil <br /> analysis of samples extracted from the MW-I soil bore. The center of the radius was determined <br /> from the UST excavation wall stains. The radius of the spill had to be assumed as there is only one <br /> soil bore on this site.A 45 degree lateral dispersion angle of the plume was used in this calculation. <br /> This estimated dispersion angle may actually be more or less from the angle used in this calculation. <br /> Natural Bioremediation of the Unsaturated Zone <br /> From samples taken for the RWQCB, it was determined that the water in MW#1 contains +/- 22 <br /> ug/L of Nitrate (NO3). Nitrate is an electron acceptor for the bio-reaction of hydrocarbons. If any <br /> hydrocarbons were present in the unsaturated zone or the groundwater, they would soon be <br /> . remediated by a very active bioreaction due to the presence of a nitrate electron acceptor. <br /> 2 <br />