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amec transformation pathways of CVOCs are shown on Figure 7. As shown, PCE is reduced or degraded to TCE,which is then degraded to 11 DCE, c12DCE, and/or t12DCE, followed by degradation to vinyl chloride and finally ethene. All of these constituents, except ethene, are present in groundwater and soil vapor beneath the site and/or off-site indicating a high level of reductive dechlorination activity (AMEC, 2010a). 6.3 WATER SUPPLY WELLS The transport of CVOCs in groundwater potentially could be influenced by groundwater pumping in the area. To identify supply wells in the area, AMEC searched the California Department of Water Resources Water Data Library (http://www.water.ca.gov/watefdatalibrary). No supply or monitoring wells were identified within 0.5 miles of the site (AMEC, 2008). However, four supply wells were identified within 1-mile of the site (Appendix A). The supply wells were identified in the database as: i 01 N06E02C001 M, an irrigation well located about 0.75 mile northeast of the site (downgradient). 02N06E36N002M, an irrigation well located about 1 mile east of the site (cross gradient). • 01 N06E03K001 M, a domestic well located about 0.75 mile northwest of the site (cross gradient). • 01 N061111 E002M, a well that has been destroyed located about 1 mile south (cross gradient). The California Department of Water Resources database indicated groundwater elevation data for wells 01 N06E02C001 M and 01 N06E03K001 M were available through 2010. Recent groundwater elevation data were not available for the other wells. Water quality data and pumping information were not available in the database for any of the wells. In summary, no supply wells were identified in the immediate area of the site. Four existing supply wells were identified at locations hydraulically cross gradient and downgradient to the site within about 0.75 to 1 mile of the site. Based the locations of the wells and the distance from the site, it is considered unlikely that groundwater transport at the site would be significantly affected by pumping from the wells. 7.0 GROUNDWATER INTERIM REMEDIAL ACTION PLAN In an August 2010 letter to UniFirst, the RWQCB requested that UniFirst provide a remediation proposal to reduce the concentration of CVOCs in groundwater more quickly than by natural attenuation alone (RWQCB, 2010). The RWQCB indicated that if in situ methods were AMEC Geomatrix, Inc. 1:113000s1132901Archive113290-49.DOC 9