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containing three 12 , 000-gallon USTs (one diesel and two <br /> gasoline) which are "permitted, and currently in use. " It <br /> is further stated that these USTs are not included in the <br /> evaluation of onsite USTs. According to Table 3 . 1-1 and <br /> Plate 4 , Site 59 is the location of UST Nos. 27a (a 4 , 000- <br /> gallon diesel tank) and 27b (a 250-gallon lube oil tank) , <br /> both of which were removed in 1988. (Table 3 . 1-2 reverses <br /> the description for these two tanks. ) It is unclear if <br /> Site No. 59 also includes the three currently in-use tanks. <br /> Provide the correct description for these tanks and this <br /> SWMU. <br /> 24 . A discrepancy exists in the text and tables as to the total <br /> volume of waste oil and lubrication oil historically stored <br /> in USTs at DDRW-Tracy. This discrepancy could be <br /> significant to this investigation, based on the possible <br /> solvent constituents in waste oil. Clarify this <br /> discrepancy. <br /> 25. In the Category 3 USTs, it is proposed that the groundwater <br /> monitoring well for each UST site be placed 1110 to 20 feet <br /> downgradient of the UST excavation. " According to the Tri- <br /> Regional Board guidelines (1990, III. l.a & b) , the <br /> monitoring wells must be placed within 10 feet of the <br /> excavation in the verified downgradient direction. <br /> SURFACE FLOW <br /> 26. Based on the results of previous investigations by various <br /> consultants and on the EPA aerial photograph review, onsite <br /> surface flow and storm drainage was historically routed, <br /> generally, across Contaminant Area 1 into a drainage ditch <br /> at the northwestern corner of the site. This outlet was <br /> later closed and the storm-drainage was rerouted into the <br /> Storm Drain Holding Pond. Very few samples of any of the <br /> media involved (soil, sludge, and liquid) have been <br /> retrieved for analysis by any of the consultants involved in <br /> the investigation of DDRW-Tracy. Apparently no samples have <br /> been retrieved from the drainage ditch which was <br /> historically the outlet for all surface flow from the site. <br /> Provide for the appropriate sampling. <br /> 27. The results of the analysis of a soil sample from outside <br /> the boundaries of the northwestern corner of the Storm Drain <br /> Holding Pond showed high levels of metals. A sludge sample <br /> retrieved for analysis from a storm drain line just east of <br /> Building 236, Area 1, showed a concentration of 1 ppm of <br /> PCE. <br /> A more thorough survey and sampling of the historic and <br /> current surface flow/storm drain system onsite should be <br /> included in this Work Plan to better define the role of <br /> I-7 <br />