Laserfiche WebLink
f <br /> Findings From Water Sample Analysis <br /> All wells are non-detect for MTBE. Extraction well EW-1 shows TPHg(1.6ppm), Ethyl- <br /> Benzene(169ppb),and Xylene(215ppb). Monitoring well GMX-1 shows TPHg(6.5ppm), Benzene(ND), <br /> Toluene(90ppb), Ethyl-Benzene(521ppb), and Xylene(1030ppb). MW-2 shows TPHg(.89ppm), <br /> Benzene(.5ppb),Toluene(.6ppb),Ethyl-Benzene(27ppb),and Xylene(26ppb). The values for MW-2 are <br /> a significant decrease from the previous monitoring event because water has risen above the screen. In <br /> the previous sampling event a grab sample was taken from the cup of the casing which is confined and <br /> separate from the groundwater. MW-3,and MW-4 continue to have a clean history. For the three wells <br /> with a contaminant history (EW-1, GMX-1, and MW-2), the average of each contaminant is below <br /> drinking water health limits. <br /> The proposed clean up levels from the approved "Final Remedial Plan" and the average remaining <br /> concentrations are as follows: <br /> Compound Concentration Goals Average Remaining Concentrations <br /> Benzene 0.005mg/L 0.00017mg/L <br /> MTBE 0A01mg/L O.Omg/L <br /> TPHg 2.Omg/L 3.00mg/L <br /> The direction of flow is South East with a gradient of s=0.0013. <br /> Mass Remaining in Water <br /> From the Second Quarter,2005 sampling a TPHg concentration contour map was made and is attached. <br /> The mass of TPHg remaining was calculated to be 1.38Kg(0.35ga1). <br /> Mass Remaining in Soil <br /> The mass remaining in the soil is calculated for the soil samples of MW-2, MW-3, and MW-4. Only <br /> MW-2 showed results for contaminated soil. The estimated mass of TPHg is 4.7Kg or approximately <br /> 1.7gal. <br /> Conclusions <br /> Pumping has brought the plume to the surface for treatment and disposal. All regulated constituents have <br /> been brought within the EPA's drinking water standards. <br /> Recommendations <br /> Foothill Engineering continues to recommend that the San Joaquin County Public Health Services, <br /> Environmental Health Department issue a letter stating no further action is required for this site. <br /> Please contact Mike Vlach a -5184 if any questions arise concerning this report. <br /> EESSt <br /> Respectfully submitte 4``Q��jkOBERTGI�L� <br /> Foothill E inee in C 57707 <br /> E <br /> 40 <br /> sj. c1\0- <br /> ichael Vlach, P.E. <br /> Attachments:Site Map,Coneentrati ontours,Mass in Soil Calculation,Groundwater sample Analysis <br /> Recap, Del-Tech Field Report, Laboratory Reports <br /> cc: Diana Maragos, Attorney for Sun West Liquors, W. T. Mitchell Group <br /> 3 <br />