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being analyzed for solvents and other halogenated hy4rocarbons Since those compounds are 40 common chemicals used in paints, dry cleaning solvents, newspaper printing, and other industrial uses and are not present in gasoline, we concluded in 1997 that Valley Motors was probably not the source of these compounds Rather, the source is more likely to be the Stockton Record newspaper company or one of the paint companies or dry cleaners that are located to the west (upgradient) of the Valley Motors site In VM-6, the TPH-g concentration declined 71% between January and June, and by November it had declined to less than the detection limit This represents a minimum decline of 77% for the year The changes were somewhat different in VM-2, VNO-4, and VM-7 The TPH-g and benzene concentrations in VM-2 declined 16% and 20% (respectively) between January and June and then by another 99 8% between June and November However, a TPH-d concentration of 9,680 µg/1 (ppb) was reported (as noted above, the chromatogram was not typical of diesel fuel and probably represents degraded gasoline instead Hence, substituting the TPH-d value for the TPH- g value yields a decline between June and November of 90% and a total decline of 91% for the year) Regardless of whether the TPH-g or TPH-d value is used, the decline is so large that it is more likely due to differences in the volume of water that was purged from the well than to real declines in concentration T In VM-4 and VM-7, the January-June declines were 50% and 84%, respectively, but concentrations increased in both wells between June and November In VM-4, there was nearly a 10-fold increase in concentration, and the reported value was more than 4 times gi eater than had been detected in any previous sample ftom this well Similar results were obtained for the BTEX compounds These high concentrations seem rather anomalous, and it remains to be seen whether they will be confirmed in subsequent samples from the well In VM-7, the TPH-g concentration increased by about 33%, but the BTEX concentrations were essentially unchanged between June and November These results appear more reasonable than those for VM-4 5.0 REMEDIATION ACTIVITIES The vapor extraction unit and vapor line were installed in the first quarter of 2005 The application to install a temporary propane tank was approved in the second quarter, and the tank was mobilized to the site in November and connected to the vapor extraction unit in preparation for the start of operation The extraction unit was started in late November but attempts to reach optimum vapor destruction temperatures were unsuccessful due to a faulty solenoid Minor repairs will be performed in early December and remediation is anticipated to begin by the middle of the month Information on the start-up and initial operation of the system will be included in the Fourth Quarter Report, which will be prepared after groundwater and vapor samples are collected in late December or early January 4