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Phase II Environmental Site Assessment Multi-Modal Station Stockton,San Joaquin County,California Page 28 • A total of twenty groundwater samples were collected from 701 and 730 E Channel Street of Block 4 TPH-G and TPH-D were detected in three groundwater samples collected from Block 4 The highest concentrations of TPH-G and TPH-D were detected at boring location DBK4-730-5 and the plumes follow the same pattern and tend to extend north to boring locations DBK4-730-10 and DBK-730-4 Soil contamination at the property was also limited to the samples collected from DBK4-730-5 and DBK4- 730-10 Low concentrations of I,I-DCE and 1,1-DCA were detected in two of the three groundwater samples collected from 701 E Channel Street Low to high concentrations of VOCs and SVOCs were detected in groundwater samples collected from 730 E Channel Street The laboratory analytical data indicate an intermingled plume consisting of VOCs typically associated with solvents is present in the northern portion of 730 E Channel Street The estimated extents of the I,1-DCB, PCE, and TCE intermingled plumes are indicated on Figures 19,20, and 22, Appendix A Moderate concentrations of 1,1-DCE were indicated at the northern portion of 730 E Channel Street Some concentrations of 1,1-DCE detected at both 701 and 730 E Channel Street were above the MCL of 6 0 µg/L The highest concentrations of 1,1-DCE were reported for samples collected from DBK4-730-9, DBK4-730-2, and DBK4-730-1 As Figure 19 indicates, it is possible that the 1,1-DCE groundwater plume extends north onto Block 1,northeast onto Block 2, and east onto Block 5 Both the TCE and PCE contaminant plumes consist of low concentrations of these constituents The TCE contaminant plume appears to be centered on boring location DBK4-730-4 and extends east to boring location DG4, south to boring location DBK4-730-2, and north to boring locations DBK4-730-9 and DBK4-730-8 The PCE plume appears to extend from boring location DBK4-730-1 in the west, boring • location DBK4-730-8 in the north, boring location DG3 in the east, and boring location DBK4-730-2 in the south PCE concentrations were not detected in samples DBK4-730-4 and DBK4-730-10, but the detection limit was raised to 50 µg/L for sample DBK4-730-10 The PCE and TCE groundwater plumes appear to be limited to the Block 4 properties To investigate the vertical extent of contaminants, a deep boring was advanced to 110 feet bgs immediately adjacent to DBK4-730-9 and a groundwater sample (HBK4-730-1-9113102) was collected from 110 feet bgs The contaminants identified at approximately 38 feet bgs were not detected at 110 feet bgs and the contaminants (cis-1,2-DCE and 1,2-DCA) detected at 110 feet bgs were not detected in the samples from 3 8 feet bgs The deep groundwater contaminants were detected below MCLS As the estimated extent of the intermingled plume appears to extend to 701 E Weber Avenue, 729 E Weber Avenue, and possibly north to Block 1, northeast to Block 2, and east to Block 5, the groundwater contamination should be further evaluated The UST that was found at 730 E Channel Street should be properly removed according to EHD requirements 6.3.6 Block 5 Laboratory analytical results for the soil and groundwater samples collected from the Block 5 properties indicate that no VOCs were detected in the soil samples Low concentrations of VOCs were detected in groundwater samples collected from four properties of Block 5 A TCE contaminant plume appears to be located in the southwestern portion of Block 5 (805 and 811 E Weber Avenue) The plume appears to be centered at boring location DBK5-805-2 (805 E Weber Avenue) and extends to bonng location DBK5-805-1 in the north, boring location DBK5-811-3 to the east, and boring location DG7 to the southwest The extent of the plume to the northeast does not appear to be clearly defined The TCE groundwater plume is indicated on Figure 22, Appendix A �t CONDOR