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Lammersvdle School District March 3, 1992 02320 2124 Page 4 Samples were collected in accordance with the Leaking Underground Fuel Tank Field Manual published by the State of California Leaking Underground Fuel Tank Task Force dated October 1989 On January 29, 1992, all monitoring wells except MW-1 were monitored for depth to water, and for the presence of liquid phase hydrocarbons Monitoring wells MW-1, MW-4, MW-9, and MW-10 were sampled using the same guidelines mentioned above 5.0 SITE CONDITIONS 5 1 SOIL CONDITIONS Soils underlying the site consist of layers of clay, poorly sorted sand, and silty sand During previous drilling, presence of hydrocarbons in sods was noted by field geologists in borings for MW-1, MW-2, and MW-6 only No other soil borings have had indications of the presence of gasoline hydrocarbons Soil samples selected from sod borings for monitoring wells MW-9 and MW-10 were analyzed, and had no detectable amounts of gasoline-range hydrocarbons The analytical results of sad samples are summarized in Table 4 The corresponding laboratory reports and charn-of-custody manifests are contained in Appendix B 5 2 GROUNDWATER CONDITIONS The water table levels at the site have decreased approximately 2 feet since the August 27, 1991 monitoring event by McCain Environmental Services The groundwater flow direction has been to the north over the three consecutive monitoring events, (May 20, 1991, August 27, 1991, and January 29, 1992), and the hydraulic gradient has been approximately 0 01 In the groundwater samples collected from monitoring wells in January 1992 dissolved TPH-G was detected in only two samples, MW-2 (2,400 parts per billion Ippb1) and MW-6 114,000 ppb) Dissolved benzene was detected only in sample MW-6 (1,200 ppb) No BTEX components were detected in sample MW-2, but toluene near the method detection limit was found in MW-7 No sample was collected from MW-1 The analytical results of groundwater samples are summarized ,n Table 5 The corresponding laboratory reports are contained in Appendix B 21240SR1 RPT GROUNDWATER x TECHNOLOGY