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 12 of 19 ' • Various dissolved metals (Ba, B, Al, Ca, Fe, K, Mg, Mn, Na, and Zn) were detected in groundwater samples collected in October 2014. Concentrations of Ba detected in samples collected from wells MW-1, MW-2A, and MW-5A were ' above the State of California Primary MCL for Ba in drinking water; concentrations of Ba detected in the remaining samples were below the MCL; and concentrations of Fe and Mn detected were significantly above the State of California Secondary MCLs for drinking water. Concentrations of Ca, B, Mg, Na, K, and Zn all appear to be within normal background levels. Analytical results of metals are summarized in Table 4. ' • Hexavalent chromium was not detected above the laboratory reporting limit (0.2 pg/1) in groundwater samples collected in October 2014 (Table 4). ' 0 Bromide was detected at concentrations ranging between 1.77 mg/l (MW-3A) and 8.42 mg/I (MW-1). ' • Bromate was detected at concentrations ranging between 1.06 mg/l (MW-3A) and 6.63 mg/I (MW-1); Bromate concentrations were significantly above the State of California Primary MCL of 0.01 mg/l for drinking water. Additionally, the ' laboratory detection limit for bromate (1.0 mg/1) was above the Primary MCL of 0.01 mg/I (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 1.10 mg/I in MW-3A and 8.61 mg/I in MW-2A (Nitrite as N) and between 0.884 mg/I in ' MW-3A and 9.9 mg/l 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 October 2014 (Table 5). Analytical results of groundwater samples collected in October 2014 are summarized in Tables 2, 4, and 5. The laboratory reports (CTEL Lab Project. No. CT214-1410017), ' quality assurance/quality control reports, and chain-of-custody forms are included in Appendix E. EDF files and depth to water data were uploaded to the State GeoTracker database system. Graphs illustrating depth to groundwater, groundwater elevation and ' TPH-g concentrations versus time (trend graphs) for each hydrogeologic unit are presented in Appendix F. Additionally, graphs illustrating TPH-g, benzene, and 1,2-DCA concentrations versus time for wells MW-1, MW-3/B, and MW-5A are presented in ' Appendix F. Advanced GeoEnvironmental Inc. 1