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Second Semi-Annual Groundwater Monitoring Report - Third Quarter 2017 <br />Former Chevron Service Station No. 94054 <br />December 12, 2017 <br />4.0 MONITORING AND SAMPLING DATA AND RESULTS <br />4.1 GROUNDWATER MONITORING DATA ANALYSIS <br />CURRENT QUARTER MONITORING DATA <br />Wells monitored and sampled: <br />MW-1A, MW-1B, MW-1C, MW-2, MW-2B, MW-2C, <br />MW-3, MW-4, MW-4B, MW-4C, MW-4D, MW-5 through <br />MW-9, MW-9B, MW-9C, MW-9D, MW-10 through <br />MW-12, MW-12B, MW-13B, and MW-14B <br />Monitoring and sampling date: September 25 and 26, 2017 <br />Was SPH observed this quarter? No <br />DTW range (ft below TOC): 9.83 (MW-2) - 11.41 (MW-4C) <br />Average change in groundwater <br />elevation since last event (ft): <br />A Zone: 4.63 decrease [-2.22 (1Q17) to -6.85 (3Q17)] <br />B Zone: 5.24 decrease [-1.89 (1Q17) to -7.13 (3Q17)] <br />C Zone: 3.09 decrease [-4.02 (1Q17) to -7.11 (3Q17)] <br />D Zone: 3.07 decrease [-4.10 (1Q17) to -7.17 (3Q17)] <br />Groundwater flow direction and <br />gradient (ft per ft): <br />A Zone: west-northwest at 0.002 <br />B Zone: northwest at 0.002 <br />C Zone: northwest at 0.002 <br />D Zone: west-northwest at 0.003 <br /> <br />4.2 GROUNDWATER SAMPLE ANALYSIS <br />Groundwater samples collected from each well were submitted to Eurofins Lancaster <br />Laboratories of Lancaster, Pennsylvania (Eurofins). The samples were analyzed for total <br />petroleum hydrocarbons as gasoline range organics (TPH-GRO) by United States Environmental <br />Protection Agency (US EPA) Method 8015B; and benzene, ethylbenzene, toluene, and total <br />xylenes (BTEX compounds), 1,2-Dichloroethane (1,2-DCA), methyl tertiary-butyl ether (MtBE) and <br />Tert-Amyl Methyl Ether (TAME) by EPA Method 8260B. In addition, samples collected from wells <br />MW-4D, MW-9D, MW-12B, MW-12C, MW-12D, MW-13B, and MW-14B were analyzed for <br />1-2-Dibromoethane by US EPA Method 8260B. <br /> <br />4.3 QUALITY ASSURANCE / QUALITY CONTROL <br />Analytical data was quality assured and quality controlled using the Stantec lab validation form. <br />No issues were noted by the laboratories during sample analysis that would have an adverse <br />effect on the quality of the data. <br />Based on Stantec's QA/QC of the reported lab data, the data collected during the reporting <br />period is considered valid. <br />CO Stantec <br />3