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Domestic Well Sampling Program Results Forward Landfill 3.0 SAMPLING AND ANALYSIS As summarized in Table 1, six residences (three on Newcastle Road and three on Santa Ana Way) reported VOCs during the primary sampling events. In response to the detection of VOCs, confirmation samples were collected between June 30 and July 13, 2017, and VOCs were confirmed in four of the six residences. Table 2 summarizes the primary and retest results for the Newcastle Road residences, and Table 3 summarizes the primary and retest results for the Santa Ana Way residences. As shown in Table 2, quantifiable concentrations of PCE and TCE were confirmed in samples from 7255 and 7317 Newcastle Road;TCE in the samples from 7485 Newcastle Road; and estimated trace concentrations of 1,1-dichloroethane (1,1-DCA) and trichlorofluoromethane (TCFM) in the samples from 7317 Newcastle Road. Though not associated with the Forward Landfill, the nitrate/nitrite results of also exceeded the MCL of 10 mg/L at all three Newcastle Road residences. Out of an abundance of caution, Forward has provided bottled water service for these three Newcastle residences and the adjacent tenant at 7253 Newcastle (shares the well with 7255). Forward has also started the permitting to have these four Newcastle Road residences connected to municipal water from the City of Stockton. As shown in Table 3, only estimated trace concentrations of 1,2-dichloropropane (1,2-DCP) were confirmed in samples from 6555 Santa Ana Way. However, 1,2 DCP is not believed to be associated with a release from the Forward Landfill. All of the detected concentrations were below state and federal Maximum Contaminant Level for drinking water (MCL), with the exception of TCE in the confirmation sample collected from 7317 Newcastle Road. 4.0 CONCLUSIONS AND RECOMMENDATIONS A summary report was mailed to each resident that participated in the Domestic Well Sampling Program. The report included a description of the sampling activities, the geographic position of each well (latitude and longitude coordinates), a copy of the well completion report (if available), a discussion of the analytical results, a discussion of an alternative drinking water supply solution (if applicable), and recommendation if their well should be included in the semiannual Domestic Well Sampling Program. Each summary report is provided in Appendix A. Based on the plume configuration, analytical results, and number of residences (and geographic location) that participated in the sampling program, eight residences are recommended to be included in the semiannual Domestic Well Sampling Program, and Figure 4 depicts the geographic location of these eight residences. It is believed that these eight residences along with the proposed and existing groundwater monitoring network for the Forward Landfill provide sufficient coverage of the lateral extent of the VOC plume and will assist in evaluating changes in the water quality over time. In the event that VOCs are not detected in any of the eight Domestic Well Sampling Program wells over a two year period, it is recommended that the well(s) be removed from the program. Enclosure: Project 5017.1030 I Domestic Well Sampling Program Results.docx 3 November 2017