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The Newark Group, Inc. - 2- 27 February 2013 800 W. Church St., Stockton San Joaquin County installed for the US Army Corps of Engineers Final 2006 Groundwater Sampling Report, McCormick and Baxter Superfund Site (2007). The SRS, included in the Report, states that there are no public supply wells located within 2,000' of the Site, and that five (5) unused private water supply wells exist onsite. Figure 4 shows two of the supply wells are located between three areas of investigation near the southern border of the Site: one well is approximately <500' between Area B-7 (former USTs) and Area B-14 (unknown source), and the second well is similarly spaced between Area B-14 and Area B-15 (former UST). A third supply well (a fire suppression well for the Site recycling facility) is located along the northern boundary of the Site, within the Site Case 1 (Dopaco Area) area <100' from eight (8) former USTs, a fourth supply well <500' north of Area B-15, and the fifth supply well <1,000' north of Area B-15. Although the five onsite supply wells have not been tested for petroleum hydrocarbons, the supply wells are reported as screened in the deeper aquifer at >200' below ground surface (bgs), and the Report stated the wells are not threatened by the USTs releases. Three (3) monitoring wells (not shown on Figure 3) for the McCormick and Baxter Superfund Site (a former creosote preservative facility approximately 2,000' to the north of the Site) are located onsite and screened from 65' to 95' bgs. The nearest perennial surface water body, McLead Lake (an extension of the Stockton Shipping Channel) runs east to west, and is approximately 2,000' to the north of the Site. McDougall Slough (a dry channel draining into McLead Lake) runs north to south, and is the nearest ephemeral surface water body at 115' east of the Site. Residences are located to the north across Church Street and to the west across Garfield Avenue. Interstate 5 is located to the east, and a Union Pacific railroad switching yard serving industrial properties is located to the south. A paper recycling facility operates on the western portion of the Site. Depth to groundwater has varied from 12' below ground surface (bgs) at the Dopaco (Case 1) monitoring wells in December 2012 to 20' bgs in grab groundwater samples from 2004 to 2012. Site soils/sediments consist of interbedded clays, silts, sands, and gravels to 57' bgs, the total depth of the Case 2 USTs investigation. Groundwater flow direction has varied towards the southwest (2005, McCormick Baxter wells, screened 65' to 90' bgs) and to the north-northeast (2012, Dopaco wells, screened 30' to 35' bgs) at a gradient of 0.004 ft/ft. The Report estimated 1,191 lbs. of combined mass of total petroleum hydrocarbons as gasoline (TPHg) and TPH as diesel (TPHd) remain in soil, and an estimated 0.01 Ib of TPHg and 5.23 lbs. of TPHd remain in groundwater, based on the average concentrations used in the mass calculations. The Report Table 4 maximum extent of soil contamination used to calculate mass varied from 524.5 sq.' (Area B-7) to 105.9 sq.' (Area B-14) to 717.3 sq.' (Area B-15).