ARCHIVED REPORTS FIRST QUARTER GROUNDWATER MONITORING REPORT FEBRUARY 2014

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Pilkington North America,Inc. Site Backgmund ' Pages I I of 13 Laboratory analytical results of the soil samples collected from the borings indicated that TPH-D ' constituents were detected at or above the laboratory reported detection limits in all samples. All samples were collected at depths between nine and 12 feet bgs, where TPH-D concentrations were expected to be highest based on field screening and visual observations. Review of historic data indicated that there has been little change in maximum concentrations, lateral or vertical distribution since the initial investigations. The estimated total mass of diesel in soil based on calculations and assumptions as described in the Soil Investigation Report dated March 30, 2011, was approximately 37,500 pounds, or 5,300 gallons. ' Laboratory analytical results of the soil samples indicated that TPH-D was detected at higher concentrations in the samples collected from borings GP-15 through GP-20, located near the AST ' containment structure, Test Pit #1, and down gradient from these locations. The distribution of borings with elevated concentrations coincides with the distribution of recovery wells where free product has been historically present and recovery operations have taken place. The distribution of borings with elevated concentrations crossed the primary utility corridor between the main plant and the water treatment plant near the water tower. The distribution of borings with elevated concentrations also crossed the high voltage and storm drain trenches.The east-west storm drain utility and the north-south abandoned product ' piping and current water supply lines may have provided preferential distribution pathways during the initial release. A licensed inspector, Bagley Enterprises of Lodi, California, was contracted to visually inspect the diesel ' storage and piping system. No leaks were identified by the inspector. Pressure testing of the diesel delivery system was not recommended by the inspector since all piping was above ground and available to visual inspection. ' Visual inspection of the 10,000-gallon AST, piping, and distribution system indicated no active leak occurring at that location. Analytical results, field observations, and the results of the AST inspection did ' not indicate that the 1,000-gallon diesel tank and associated aboveground piping were an active source of diesel in soil or groundwater. Analytical results, field observations, and the results of the AST inspection did not indicate that the 700-gallon diesel tank was an active source of diesel in soil. The laboratory report ' indicated that the diesel chromatograph patterns from samples collected in the initial release area displayed a weakly to unmodified diesel pattern, whereas the distal samples displayed a strongly weathered diesel pattern indicating that natural attenuation is occurring at the fringes of the LNAPL ' plume. The pattern of distribution of TPH-D in soil generally correlates well to total product removed from each well. The results of the soil investigation indicated that the source of the LNAPL present in several product recovery wells is from residual diesel-saturated soils associated with a historic (1996) leak, and not from an active leak from another source. Investigation activities and results were described ' in the Soil Investigation Report dated March 30, 2011. Condor sampled the three Site monitoring wells and two facility sumps during the third quarter ' groundwater monitoring event conducted on August 3, 2011. The average groundwater elevation measured in the three Site monitoring wells was 3.53 feet, an increase of 0.32 feet since the previous monitoring event on February 7, 2011, and the calculated groundwater gradient was approximately 0.005 ' ft/ft to the northeast. Laboratory analytical results indicated that none of the constituents of concern were detected in the monitoring wells or the SE-sump. A low concentration of TPH-MO was detected in the SW-sump. ' Three diesel recovery and skimmer O/M event were conducted at the Site between April 1 and August 31, 2011. Free product was observed in recovery wells RW-2 and RW-3, and approximately 2.71 gallons of