ARCHIVED REPORTS_ANNUAL 2010 GROUNDWATER MONITORING AND SAMPLING REPORT

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r 7� ¢ TABLE 3 GROUNDWATER ANALYTICAL RESULTS (PAHs)t,2,3 ALDEN PARD Tracy, California Concentrations reported inµg/L Abbreviations: Cal/EPA=California Environmental Protection Agency D=Duplicate sample E=Indicates the reported value is estimated due to associated quality control results EPA=United States Environmental Protection Agency ESL=Environmental Screening Level (F)=Results for analysis of filtered sample GC/MS=Gas chromatography/mass spectrometry ID=Identification J=Indicates the reported value is an estimated concentration detected between the method detection limit and limit of quantitation LVI=Large-volume injection MCL=Maximum Contaminant Level NA=Not analzyed ND=Not detected at or above laboratory detection limit IRIS=Integrated Risk Information System NS=Not sampled PAHs=Polynuclear aromatic hydrocarbons RWQCB=Regional Water Quality Control Board SPO=Separate-phase oil U=Indicates the analyte was analyzed for,but not detected above the level of the associated value WQO=Water Quality Objective <=Denotes analyte not detected at or above the laboratory reporting limit µg/L=Micrograms per liter ---=Not Available Notes: x Starting with the second quarter 2006,laboratory analytical data are being qualified and flagged as appropriate.See the respective Data Usability Summary section of the reports for detailed information on the qualifiers used. 1. PAHs were analyzed by Lancaster Laboratories,Inc.,using EPA Method 8270C SIM or LVI.The QC limits for PAHs and surrogate standard recoveries by LVI GC/MS are advisory only until sufficient data points can be obtained to calculate statistical limits. 2. Results in bold exceed WQOs and/or ESLs. 3. See Attachment-C for data usability summary. 4. WQO-Taste and Odor(EPA National Recommended Ambient Water Quality Criteria). 5. WQO-Toxicity(EPA IRIS Reference Dose as a Drinking Water Level). 6. WQO-Toxicity(Cal/EPA Cancer Potency as a Drinking Water Level). 7. WQO -Toxicity(EPA National Recommended Ambient Water Quality Criteria,one in a million cancer risk,source of drinking water). 8. WQO -Toxicity(EPA National Recommended Ambient Water Quality Criteria,Non-cancer health effects,source of drinking water). 9. WQO- California State Notification Level(formerly Action Level). 10.ESL-Taste and Odor(Ceiling Value). 11.ESL-Aquatic Habitat Goal. 12.ESL-Toxicity(Drinking Water). 13.Naphthalene was detected at approximately 0.07µg/L(below normal reporting limit)in the laboratory method blank sample. 14.Naphthalene(0.02µg/L)and phenanthrene(0.011 pg/L)were detected in the field equipment blank. Wells MW-1/KJC,MW-2,and MW-13 were destroyed in April 2006.Trace concentrations of PAHs(naphthalene and phenanthrene) were detected in samples collected in February 2006 from these wells. PAHs have not been historically detected in these wells. As such,confirmation samples were collected on March 30,2006 from MW-1/KJC,MW-2,and MW-13 prior to well destruction activities. The March 30,2006,results are reported. 15.Phenanthrene and flouranthene were detected in the method blank associated with this sample.The sample was re-extracted and comparable sample results were observed.The results reported are from the initial extraction of the sample. 16.2-methylnaphthalene was detected MW-9 at a concentration of 12µg/L on 4/03/97;in MW-19 at 2µg/L and 4µg/L(duplicate)on April 3, 1997;and in MW-21 at a concentration of 4 pg/L on April 3, 1997. 17. 1-methylnaphthalene was detected in a sample from MW-9(2.34 pg/L;July 9, 1997)and in MW-19 at a concentration of 2.34µg/L on July 9, 1997. 18.Fluoranthene and benzo(b)fluoranthene were detected in the method blank associated with this sample. The sample was re-extracted outside of the method required holding time. Comparable sample results were observed between the two extractions. The results reported are from the initial extraction of the sample. The blank values were not subtracted from the analytical results. 19,Concentration estimated by the laboratory. Sources: WQOs defined in the Central Valley RWQCB Water Quality Control Plena(Basica Plan)for the Sacramento River Basin and Sawn Joaquin River Basin.(Fourth Edition),October 2007. WQOs may be stated in either numerical or narrative form. Narrative water quality objectives are interpreted by values from SWRCB A Compilation of Water Quality Goals-July 2008. ESLs from the San Francisco Bay RWQCB Screening for Environmental Concerns at Sites with Contaminated Soil and Groundwater (Interim Final),May 2008. _ a The Benham Companies,LLC R Wh.Uy Owned Subsid y Page 13 of 13 From Science laSotutiers