ARCHIVED REPORTS_2011 REVISED FEASABILITY STUDY

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amec�9 part of the quarterly groundwater monitoring program. A subset of these samples were submitted for additional chemical analyses to support this intrinsic remediation assessment. Sample collection methods and wells sampled for the Q2 and Q3 events are provided in ECM, 2010b and ECM, 2010c, respectively, and summarized in Table B.4-1 and Figure B.4-1. The Q2 event included two upper and ten intermediate aquifer zone monitoring wells located near the WWTP and more than one mile northward. After those results were reviewed by AMEC, the program was expanded to include 10 monitoring and extraction wells screened within the upper aquifer zone (four B-zone wells, two onsite operating extraction wells, and four A-zone monitoring wells), intermediate aquifer monitoring well M-8C1, and five lower aquifer monitoring wells (i.e. 28 samples were analyzed for dissolved metals in Q3). Test America Laboratory of San Francisco, California, conducted the chemical analyses except where otherwise indicated below. The analyte list for Q2 and Q3 included (ECM, 2010b and 2010c): • Field parameters measured with a multi-parameter meter: dissolved oxygen (DO), oxidation-reduction potential (ORP), temperature, specific electrical conductance (SC), and turbidity. • Ferrous iron was analyzed in three groundwater samples of the Q2 event using Standard Method 3500. • Dissolved metals: major cations (sodium, calcium, magnesium and potassium) and trace metals (iron and boron) were analyzed using EPA Method 6010B. • Anions: chloride, sulfate and nitrate were analyzed using EPA Method 300.0. • Alkalinity: carbonate, bicarbonate and hydroxide alkalinity were analyzed in groundwater samples collected during the Q2 event only using EPA Method 316. • Ammonia was analyzed in groundwater samples collected during the Q3 event only using Standard Method 4500. • Total organic carbon was analyzed in groundwater samples collected during the Q2 evenly only using EPA Method 415.2. • Dissolved gases: ethene, ethane and methane were analyzed in groundwater samples collected during the Q2 event only using RSK-175 • VOCs: TCE, cDCE and vinyl chloride concentrations were analyzed using EPA Method 8260B by ZymaX Environmental Forensics Laboratories, of Escondido, California (Zymax) in addition to the routine analysis performed by Test America. AMEC Geomatrix, Inc. \\oad-fs1\doc_safe\9000s\9837.006\4000 REGULATORYTS Assessment_Apx B_012711\Attachment B.4\Attach B-4.docx 134-3