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903806-SS4 CON-34 <br /> 4.3.5 Woodward-Clyde Groundwater Investigation <br /> 4.3.5.1 Introduction <br /> 4.3.5.1.1 The WCC groundwater investigation is described in Section <br /> 2.0. The details associated with well construction and sampling, the <br /> results of the chemical analyses, and the areas of contamination are <br /> discussed in the following sections. <br /> 4.3.5.2 Objective <br /> 4.3.5.2.1 The objective for the installation and sampling of the WCC <br /> monitoring wells was to better assess the lateral and vertical extent of <br /> groundwater contamination, both on- and off-Depot. A total of 46 <br /> monitoring wells were installed, LM 47-52 in May 1987, LM 53-62 in November <br /> to December 1987, LM 63-74 in October and November 1988, LM 80-84, and LM <br /> 91 in August 1989, and LM 75-79, LM 85-90 and LM-92 in June and July <br /> 1990. Offsite wells were located in areas where.. surface access was easily <br /> attained to minimize interference with ongoing farming activities, and were <br /> placed on or adjacent to farm service roads at locations acceptable to the <br /> landowners. As a result of the restraints imposed by landowners, it was <br /> not possible to obtain detailed groundwater quality information in the area <br /> f immediately downgradient of Contaminant Area 3. A list of all monitoring <br /> wells completed during this and previous investigations, along with their <br /> screened interval , is included in Table 4.3-3. <br /> 4.3.5.3 Completed Groundwater Sampling <br /> 4.3.5.3.1 Wells LM 47-52 were sampled in May 1987; Wells LM 53-62 were <br /> sampled in November and December 1987; and Wells LM 62-92 were sampled in <br /> November 1988, January 1989, or July/August 1990. Chemical analysis of <br /> groundwater in these wells included purgeable halocarbons (EPA 601) and <br /> trace metal analyses (EPA 200.7) . <br /> 4.3.5.3.2 Groundwater sampling of 58 of the 59 monitoring wells which <br /> existed as of April 25, 1988 was completed between April 25 and May 17, <br /> 1988 by WCC to provide a nearly simultaneous groundwater sampling round. <br /> With the exception of LM 10, which had insufficient water for sampling, <br /> this sampling included the collection of samples from Wells LM 1-43 and LM <br /> 47-62. <br /> 4-168 <br />