ARCHIVED REPORTS - OZONE PILOT TEST & SEMI-ANNUAL GROUNDWATER MONITORING REPORT - THIRD QUARTER 2014

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20 March 2015 AGE Project No. 00-0769 ' Page 7 of 19 of California Primary MCL of 0.01 mg/I for drinking water. Additionally, the laboratory detection limit for bromate (1.0 mg/1) was above the Primary MCL of 0.01 mg/l (Table 5). However, bromate concentrations were significantly above ' the State of California Primary MCL in baseline samples collected in June 2013, prior to ozone injection. • Nitrite as N and Nitrogen were detected at concentrations ranging between 0.98 mg/I in MW-3A and 8.8 mg/I in MW-2A (Nitrite as N) and between 1.04 mg/I in MW-3A and 10.9 mg/I in MW-2A (Nitrogen as N). ' • Chemical Oxygen Demand (COD), pH, electrical conductivity, total dissolved solids (TDS), chlorine, sulfate, and total alkalinity were all detected at low to normal background concentrations (Table 5). • Ammonia, dissolved sulfide, orto-phosphate, and fluoride were not detected above laboratory reporting limits in the groundwater samples analyzed in August ' 2014 (Table 5). Additionally, on 04 and 05 August 2014, the third quarter 2014 semi-annual ' groundwater monitoring event was performed utilizing single-completed wells MW-1 and MW-10, clustered monitoring wells MW-2A/B and MW-3A/B and multi-chambered (CMT) monitoring wells MW-4 (A-E), MW-5 (A-E), MW-6 (B-D), MW-7 (A-B), MW-8A, ' and MW-9A. During the third quarter 2014, all thirty-two monitoring points were gauged for groundwater elevation. ' Water Table Zone: HU-1 Upper Zone- 25 feet to 51 feet bsg • Depths to groundwater were measured from HU-1 wells MW-1, MW-213, MW-3B, ' MW-4A, MW-5A, MW-6A, MW-7A, MW-8A, and MW-9A and groundwater samples were collected from HU-1 wells MW-1, MW-213, MW-313, MW-4A, MW-5A, MW-7A, MW-8A, and MW-9A. • Depths to groundwater ranged between 20.15 feet (MW-8A) btoc and 22.37 feet (MW-1) btoc (Table 1). Groundwater elevations at the site ranged between 10.77 ' feet (MW-9A) below NAVD88 and 11.71 feet (MW-1) below NAVD88. • Utilizing HU-1 wells, groundwater was inferred to be flowing toward the northeast under an average hydraulic gradient of 0.0008 feet per feet (ft/ft). Figure 3 ' illustrates contoured groundwater elevations as measured on 04 August 2014; wells MW-1 and MW-5A were not used to infer groundwater flow direction or calculate hydraulic gradient because the wells are located in close proximity to ' ozone injection wells OZ-4 through OZ-8 and based on groundwater elevation data it appears the groundwater in this area is being affected by ozone injection. ' • TPH-g were detected in groundwater samples collected from wells MW-1, MW- 213, MW-3B, MW-4A, MW-5A, and MW-7A at concentrations ranging from of 420 micrograms per liter (pg/1) in MW-7A to 230,000 pg/I in MW-1. BTEX compounds Advanced GeoEnvironmental Ine.