FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

GEOMATRIX 3.0 INVESTIGATIVE OBJECTIVES AND APPROACH In May 2002, Geomatrix implemented a soil and groundwater investigation and analytical program at the site. The field investigation program and Work Plan was developed based on review of previous work conducted at the site and in accordance with the revised CTA. Sam- pling locations are shown on Figure 3. Specific objectives of the sampling program are sum- marized below. ® • Assess lateral extent of petroleum hydrocarbon-affected soil. Boring GMX-9 was drilled to assess the southern lateral extent of petroleum-affected soil northwest of the building in the area of MW-2 and GMX-3. • Assess vertical extent of petroleuyn hydrocarbon-affected soil. Borings GMX-8 and GMX-1B were drilled within the area of petroleum-affected soil to assess the vertical extent of affected soil along the northern property boundary of the site. • Assess groundwater quality. Geomatrix collected groundwater samples from on- site monitoring wells MW-2, MW-3, and MW-4 and off-site monitoring well WSFMW-1 to assess groundwater quality at the site and cross-downgradient (north) of affected soil. • Assess the presence of separate phase petroleum in MW-1. Geomatrix evaluated the continued presence of a thin layer of separate-phase petroleum in MW-1. 4.0 FIELD AND ANALYTICAL METHODS Prior to conducting field activities, Geomatrix obtained a boring permit from the SJC-PHS (Appendix A), notified Underground Service Alert (USA), and contacted Cruz Brothers Sub- Surface Locators, Inc., of Milpitas, California,to perform an underground utility clearance at each boring location. Soil boring, groundwater sampling, and analytical methods are described in Sections 4.1, 4.2, and 4.3, respectively. 4.1 SOIL BORINGS Three soil borings (GMX-8, GMX-9, and GMX-1B) were advanced on May 20 and May 21, 2002 by Gregg Drilling and Testing Inc. (Gregg Drilling) under Gcomatrix supervision. Bor- ings were advanced to depths ranging from 60 to 90 feet bgs using a Mobile B-61 hollow stem auger drill rig equipped with 8-inch diameter augers. Boring depths were based on field obser- vations of petroleum hydrocarbon-impacted soil. All drilling and soil sampling equipment was steam cleaned prior to use. 1loaklldeptdatalDoc_safe1G000s15447.00RReportlUS Can Soi]GW Rpt.doc