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0 0 Section 2.0 UST Removal and Soil Sampling Activities • using a portable Mini Rae photo-ionization detector(PID), and the resulting concentration was recorded. The majority of the samples tested had headspace concentrations of 0.0 part per million (ppm) with the highest concentration detected of 13.4 ppm for sample T89-N-18'. Soil samples from beneath the fuel lines were all clay with the exception of P-5-2' which was a medium sand. The majority of the soil samples collected beneath the USTs consisted of silt, with sample T91- W-18' consisting of sandy silt and samplesT87-M-18' and T87-E-18' consisting of silty sand. Stockpile soil samples were all pea gravel with silt sized fines. Soil samples results for the samples collected from beneath the USTs, fuel piping, and stockpiled overburden are summarized in Table 1 and a copy of the laboratory reports and chain-of-custody documents are included in Appendix G. After receiving the soil sample results, Tafoya backfilled the UST pit and dispenser trenches with the stockpiled overburden pea gravel (approximately 70%)and clean imported fill material for the balance of the soil to the surface (approximately 30%). All five soil samples collected from beneath the fuel lines did not contain detectable concentrations of any of the chemicals of concern. Stockpiled soil samples were also non-detect for all analytes of concern with the exception of sample SP-1 which contained total xylenes at a concentration of 0.0015 J milligrams per kilogram (mg/kg). The "J" denotes that the concentration detected was above the laboratory method detection limit but below the laboratory reporting limit. Four of the nine soil samples collected from beneath the USTs had very low detectable • concentrations of some of the analytes of concern (T89-S-18', T89-N-18', T89-M-18', and T87- W-18'). Sample T89-S-18' contained benzene (0.0061 mg/kg),toluene (0.040 mg/kg), ethylbenzene (0.0023 J mg/kg), and xylenes (0.018 mg/kg). Sample T89-N-18' contained benzene (0.0011 J mg/kg),toluene (0.013 mg/kg), ethylbenzene (0.0025 J mg/kg), and xylenes (0.018 mg/kg). Sample T89-M-18' contained benzene (0.0010 J mg/kg),toluene (0.0039 J mg/kg), and xylenes (0.00113 J mg/kg). Sample T87-W-18' only contained total xylenes at a concentration of 0.0031 J mg/kg. TPHg was not detected above the laboratory method detection limit in any of the samples collected and analyzed from the Site. It should be noted that these concentrations are extremely low and well below the State Low- Threat UST Closure Policy criteria. This Site has been previously remediated for soil and groundwater contamination for TPHg and associated VOCs including benzene, toluene, ethylbenzene, and xylenes (BTEX), and received a no further action letter for these activities in February 22, 2012. Detectable concentrations of BTEX were still present in soil and groundwater when this no further action letter was issued. The low BTEX concentrations detected were primarily beneath the southernmost UST(T89)and western most sample from T87 that were closest to the former release areas that were formerly successfully remediated. These samples did not contain any detectable concentrations of oxygenates including MTBE, DIPE, ETBE, TAME, and TBA, indicating that these low concentrations of BTEX pre-date the use of oxygenates in gasoline and are most likely the result of residual concentrations remaining in Site soil from the documented historic release at the Site b��i � �p r$medial activities, • and do not constitute a recent release from the USTs IEC190GG V 11��VV Thrifty Station No. 171 4 rro2 g 2(11Waterstone Environmental,Inc. February 2014 AL Project 13-140 E HEALTH DEPARTMENT