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Union Ice Company
<br />' 1320 West Weber Avenue,Stockton, California July 12, 1994
<br /> Phase IVRemedianon Report of Findings Page 2
<br /> a
<br />' in March of 1991, a 12 hour aquifer pumping test was performed on well MW-8 This well
<br /> was pumped at a constant discharge rate of 4 16 gpm for 12 hours Drawdown was
<br /> monitored for this well and all other wells on the property during the test The recovery of
<br />' these wells was then monitored for 12 hours
<br /> The latest phase of work was designed primarily to explore the extent of the contamination
<br /> which extended to the southeast of the previous excavations This soil was not removed
<br /> because of the presence of a sewer line, which runs north to south in the area In addition, the
<br /> latest phase of work was intended to test the effectiveness of the excavations in removing the
<br /> contamination in other areas of the site
<br /> Between March 25 and 28, 1992, a total of 8 soil borings were drilled to a depth just above
<br /> the groundwater level by Osterberg & Stewart, licensed drilling contractors, from Modesto,
<br /> California The borings were drilled using a 7 25 inch diainetei hollow stem flight auger and
<br /> the soil was cored continuously, using a wireline coring deice Samples were collected in 2
<br /> 1/2 foot intervals A detailed lithologic log, listing sediment type and description, was kept
<br /> for each boring
<br /> 3.0 Scope of Work
<br /> On March 14, 15, 16, 18 and 19, 1993, re-excavation removed the remaining contaminated
<br /> soil This excavation removed approximately another 2,000 cubic yards of soil (Figure 3)
<br /> The size and shape vaned according to actual contatrunant distribution The walls and bottom
<br /> of the excavation were sampled to insure that all of the contaminated soil was removed
<br /> (Figure 3, Table 1, & Appendix A) The soil was excavated until an "ND" level was reached
<br /> in the sidewalls and bottom of the excavation Samples were analyzed by an on-site State-
<br /> certified mobile lab, Mobile Chem Labs, Inc , Martinez, California
<br /> The excavated soil was stockpiled on asphalt to the west of the excavation and sampled
<br /> (Table 3, Appendix C) Clean soils from the west end of the property were used to backfill
<br /> the excavation (Figure 4) Analytical data on the backfill material samples BF-1 through BF-
<br /> I I
<br /> F-11 are shown in Table 4 & Appendix D
<br /> Since the water table was slightly artesian, groundwater entered the excavation, along with a
<br /> considerable volume of rainwater runoff In order to move the excavator to another location
<br /> to continue sampling, the water had to be removed Samples were taken on March 22, April
<br /> 1 & 5, 1993 The analyses were conducted by Mobile Chem Labs, Inc , Martinez, California,
<br /> and GeoAnalytical Laboratories, Inc , Modesto, California The groundwater tested "ND" for
<br /> BUM and 81 pg/L Gasoline on March 22, 1993, "ND" for BTE & Gasoline and 13 µg/L
<br /> Xylene on April 1, 1993, and "ND" for BTXE, Gasoline and Diesel on April 5, 1993 (Figure
<br /> 3, Table 2, & Appendix B) The excavating contractor, Warren E Gomes Excavating, Inc ,
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