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Antonia K. J. Vorster 3 December 18, 1989 <br /> lateral distance from the sewer lines were measured. The soil gas survey <br /> identified areas where PCE concentrations in the soil gas were significant <br /> (i .e. , 100 µg/l or greater) . See attached map. These areas include: <br /> 1) Along the sewer line south of Village Cleaners. <br /> 2) Near the southern end of the Benjamin Holt Drive sewer line <br /> crossing. <br /> 3) Along the sewer line parallel to, and south of, Benjamin Holt <br /> Drive. The sewer line serving the former Norge Cleaning <br /> Village. <br /> 4) Near MW#4. A headspace analysis from the monitoring well <br /> indicated 1100 µg/l of PCE, and a nearby soil gas sampling <br /> point indicated 140 µg\1 . <br /> GROUND WATER MONITORING <br /> In October 1989 ground water samples were collected from monitoring wells <br /> MW#1 and MW#2. MW#1 did not have detectable levels of PCE. MW#2 had a <br /> PCE level of 1 .8 ppb. <br /> Monitoring well MW#2 is located at the northwest corner of the site and <br /> apparently has never previously tested positive for PCE. Samples were not <br /> obtained from MW#3 nor MW#4. <br /> In August 1989 San Joaquin County representatives sampled county wells LVMD <br /> #1 and #2. LVMD #2 had a PCE level of 70 ppb and as a result this well <br /> was shut down by the county. This well has a 80-foot sanitary seal with <br /> perforations beginning at 208 feet below ground surface. Purgeable <br /> halocarbons had not previously been measured in this well . <br /> LVMD #1 had a PCE level of 1 .8 ppb in August 1989. This well was <br /> retrofitted with a 80-foot pressure grouted sanitary seal in 1985 due to <br /> high levels of PCE (120 ppb) attributed to cascading water from a fracture <br /> in the well casing. This fracture was at about 42 feet below ground <br /> surface, and since LVMD #1 is located near the shallow monitoring well MW#4 <br /> (2000 ppb of PCE) , the cascading of the shallow water in the casing was <br /> believed to be the cause of the contamination in this municipal well . <br /> Apparently, the monitoring of this well since the retrofitting had not <br /> (until August 1989) measured detectable levels of PCE. <br /> No recent analytical results for LVMD #6 were submitted. <br /> These latest results indicate that ground water contamination at this site <br /> has worsened. The extent of the PCE contamination within the uppermost <br /> water bearing zone has expanded to at least the northern boundary of the <br /> site, as evidenced by the latest analytical results from monitoring well <br /> MW#2. The latest county results from LVMD #1 and #2 (and historical data <br /> for LVMD #6) indicate that the deeper water bearing zones at this site are <br /> contaminated, that the extent of this contamination is expanding (as <br />