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collected for possible future analysis. Detailed field notes , logs , obser- <br /> vations of the concrete's physical properties, and photographic documentation <br /> S <br /> will be made by the Dames & Moore geologist during each excavation. <br /> Material excavated from the pit will be placed on visqueen sheets laid out <br /> .� <br /> immediately adjacent to the trench. This material will be visually inspected <br /> for the presence of hydrocarbons. An organic vapor analyzer (OVA) will be used <br /> 7 <br /> to determine if organic vapors are •being released from the soils. Barricades <br /> will be set up around each pit during the 2-3 hours they are left open. No pit <br /> will be left open overnight. Upon completion of the documentation process , each <br /> test pit will be backfilled using the material previously excavated. The loca- <br /> tion of the edge of the concrete slab will be carefully marked by a permanent <br /> survey reference point. <br /> iWe expect that the three test pits can be excavated and filled in during a <br /> single day. As noted above, the pits will be enclosed in carefully marked <br /> °. barricades. The three pits will all be within sight of each other across the <br /> Alden Park, so that one trench may be excavated while another is being left open <br /> to inspect for possible accumulation of free oil. <br /> t Between excavations , if visible signs of oil are noted in the .soils, the <br /> backhoe bucket will be removed and cleaned prior to excavation of the next pit. <br /> LOCATE AND SAMPLE FORMER SUMPS <br /> _Purpose <br /> Theur s <br /> p po a of this task is to identify and sample any suspected locations <br /> of former sumps. To accomplish this, we will inspect existing aerial photo- <br /> graphs from the 1930's, 1940's, and 1950's which are available at Pacific Aerial <br /> Surveys of Oakland, California. We will also meet with technical represen- <br /> tatives from Renown Enterprises whom we understand may have identified the loca- <br /> tion of the one sump known to have existed. At this time, we understand that <br /> there is probably only this one sump to be located and sampled, although an <br /> attempt will be made to confirm that no others exist. <br /> !�F Probe transects , similar to those used to locate the concrete perimeter, <br /> will be performed in the area where the sump is believed to have been located in <br /> JE D 2/H -4- <br />