ARCHIVED REPORTS XR0009934 - Laserfiche WebLink

Home Browse Search

t J Extended Investigation of Groundwater Quality - 152 East 11th Street, Tracy Page 5 The drilling equipment was used to advance a spht-spoon sampling tool loaded with four clean, 2 in diameter by 6 m long brass tubes so as to recover soil samples from depths of 5, 10 and 15 ft in the boretngs for all four wells (i e NAV 5, NAV 6, NAV 7 and NAV 8) To provide as much information as possible about the distribution of hydrocarbons, if any, to the subsurface at the well locations, it was initially planned to also take samples from 20 and 25 ft in each boring even though it was anticipated that some problems may be encountered to recovering samples from beneath the water table However, fine to medium course, flowing sand was countered in each of the four holes at depths of between 15 and 19 ft This sand rose in the augers and to some cases trapped the sampling tool in the augers and prevented sampling. Consequently, samples could not be recovered from greater depth sin all of the wells Despite these difficulties, samples were obtained from a depth of 20 ft in Wells NAV 6 and NAV 7 and in the case of NAV 7 an additional sample was recovered from a depth of 24 ft The incidents of flowing sand rising in the augers is noted on the monitoring well logs (See Appendix A) The blow counts recorded as the sampling tool was advanced tato the bottom of the boring at each sampling depth are also noted on the logs Following sample recovery and examination of the core, the brass tube from the selected sampling depth was removed from the sampling tool, cleaned externally, its ends covered with alummum foil and closed with tightly fitting plastic caps The caps were secured with adhesiveless tape Each selected sample tube was then labeled for identification, entered into chain-of-custody control and packed on chemical ice for transport, within 24 hours, to Chromalab Inc 's laboratory m San Ramon, California for analysis The soil samples were analyzed for the following suite of analytes Analyte Method of Analysis Total Petroleum Hydrocarbons EPA Method 5030/8015 (as Gasoline) Benzene EPA Method 8020 Toluene EPA Method 8020 Ethylbenzene EPA Method 8020 Total Xylenes EPA Method 8020 None of the samples contained any detectable concentrations of gasoline or its components The analytical results are included in summary form in Table 1 and copies of the laboratory certificates of analysis are presented in Appendix B (Note For convenience of reference, the results of the analyses of all soil samples recovered from all well boremp that have been for sunk for both the 152 and 153 East 11th, Street properties are compiled m Table 6)