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Sunnyside Produce UST Removal and Sampling Page 3 CONCLUSIONS AND RECOMMENDATIONS Analytical results indicate that the soil and groundwater in the vicinity of the USTs has been impacted with petroleum hydrocarbons Soil samples collected from the limits of the UST basin contained TPHd concentrations ranging from 170 to 1100 milligrams per kilogram (mg/kg), TPHg concentrations ranging from 300 to 1800 mg/kg, benzene concentrations ranging from 880 to 2400 micrograms per kilogram (ug/kg), MTBE concentrations ranging from 610 to 21000 ug/kg The UST basin soil samples also contained concentrations of other BTEX compounds ranging from 82 to 180000 ug/kg Total lead concentrations in the UST basin soil samples ranged from 1 6 to 4 5 mg/kg The groundwater sample contained a TPHd concentration of 120 milligrams per liter(mg/L), a TPHg concentration of 100 mg/L, a benzene concentration 5100 ug/L, and an MTBE concentration of 37000 ug/L The groundwater sample also contained concentrations of other BTEX compounds ranging from 1600 to 7800 ug/L, other oxygenate compounds ranging from less 200 to 7300 ug/L and a total lead concentration of 0 01 mg/L Soil samples collected from the excavation stockpile contained TPHd concentrations ranging from 200 to 540 mg/kg, TPHg concentrations ranging from 82 to 1300 mg/kg, benzene concentrations ranging from 18 to 140 ug/kg, MTBE concentrations ranging from 130 to 690 ug/kg The soil stockpile samples also contained concentrations of other BTEX compounds ranging from 180 to 79000 ug/kg, and total lead concentrations ranging from 5 to 6 6 mg/kg Given the quantity of petroleum hydrocarbons detected in soil and groundwater samples, it is recommended that a workplan be developed for a preliminary site investigation to determine the nature and extent of petroleum hydrocarbons in the local soil and groundwater environments The workplan should generally include provisions for 1) the advancement to approximately 10 feet below the water table of at least four soil borings around the former UST basin, 2) collection of soil samples, 3) conversion of the soil bonngs to monitoring wells, 4) collection of groundwater samples 5) analysis of soil and groundwater samples for concentrations of petroleum hydrocarbons, and 6) compilation of investigation, hydrogeologic and analytical data into a Preliminary Investigation and Evaluation Report Should you have questions or comments regarding the information presented, do not hesitate to contact the undersigned Respectfully Submitted, GEOTECHNICAL RESEARCH AND DEVELOPMENT Rexford Smith Registered Geologist #5307