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1 <br /> surveyed by Siegfried Engineering, a licensed surveying firm. <br /> The reference points were based on a notch or mark on the north <br /> ' side of each casing top, and elevations were tied to a nearby <br /> benchmark in the street. EXHIBIT- 1 is a copy of that survey. <br /> ' G O <br /> Using water levels measured by Del--Tech, and the surveyed <br /> wellhead elevations, a gradient map was constructed (PLATE XIV_,.) <br /> which shows that the groundwater gradient at the time it was <br /> measured was very flat, trending in a southeastly direction. <br /> This is close agreement with the regional gradient measured by <br /> ' County Flood Control maps. The amount of contamination measured <br /> in the three wells shows that MW #1 & MW #3 have significantly <br /> higher levels than in MW #2, although 02 is downgradient from the <br /> ' site of the removed UST' s. In fact, MW #1 has higher levels than <br /> #3, which is the closest to the removed tanks. This suggests <br /> that: (1) the gradient as measured, (to the southeast, ) is <br /> anomalous; (2) another off-site source exists to the west and/or <br /> northwest; or (3) the levels as measured are a combination of <br /> both of the above. Without additional data, it is not possible <br /> to determine the actual source. <br /> CONCLUSIONS_ <br /> ' 1 . Laboratory analysis of the soil samples from the 3 wells <br /> reveals that contamination was measured in both MW #1 and MW #3 <br /> at 16' , and at 23' only in MW #3. All soil samples from MW #2 <br /> ' were below detection levels. <br /> 2. Significant levels of BETX & TFB-G are present in groundwater <br /> ' beneath the property. <br /> 3 Although the groundwater gradient as measured agrees with <br /> regional maps, it does not agree with levels of contamination <br /> 1 found in the monitoring wells. <br /> 4. The location and amounts of contamination measured in the <br /> soil samples does not correlate well with the levels measured in <br /> ' the water samples taken from the wells; for example, MW #1, with <br /> the highest levels of contamination in the water, measured only a <br /> small amount in the soil sample taken at 16' , and none in the <br /> ' samples from 21' & 25' . MW #3, however, had measureable contam- <br /> ination in soil samples at 16' & 23' , but much lower amounts in <br /> the water than 01 . The reason for this anomaly cannot be <br /> ' explained without more data. <br /> 10 <br />