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1-4 Analylical Results - Groundwater Samples Petroleum hydrocarbons in groundwater were detected in grab samples collected from borings `� SBI, SB2, SB3, SB4A, and SB6, and in wells MW-2 and MW-3. TPHg was detected in groundwater from borings SB2, SB4A, and SB6 and in wells MW2 and MW3. Concentrations ranged from 80 parts per billion (ppb) (MW3) to 67,000 ppb (SB2). Benzene was detected in these same borings and wells at concentrations of 38 ppb (MW3) to 2,200 ppb (SB2). Only toluene was detected in the groundwater from borings SBI and SB3 at concentrations slightly greater than the method detection limits. MTBE was detected in the groundwater from boring SB3 (3.5 ppb) and in monitoring. wells MW2 and MW3 (7.6 ppb and 1.2 ppb, respectively). These results were confirmed by `' additional analysis of the samples by EPA method 8260. MTBE was also detected in the groundwater from borings SB2 and SB6 by EPA Method 8020 but not by analyzing by EPA L. method 8260 indicating the results may be false positive results. ` The following describes the analytical results for geochemical analysis of the groundwater samples from the borings and monitoring wells. In the soil borings, dissolved oxygen was only detected in boring SB6 at a concentration of 2.1 ppm. In the monitoring wells, dissolved oxygen was detected at concentrations ranging from 1..2 ppm (MW3) to 1.7 ppm (MW I). Carbon dioxide was detected in all borings and wells except boring SB6. Dissolved iron was '-' not detected in groundwater from any borings or wells. Nitrate was detected in all borings and wells at concentrations ranging from 6 ppm (SB2) to 80 ppm (SB7). Sulfate was detected in �. all borings and wells at concentrations ranging from 80 ppm (SB2) to 280 ppm (SB7). Total alkalinity concentrations ranged from 310 ppm (SB6) to 620 ppm (SB2). Redox potential (Eh) ` readings from the borings were negative and ranged from -56.1 millivolts (mV) (SBI) to -214 F mV (SB5). Eh readings in the groundwater from the monitoring wells were positive and ranged from 10 mV (MW2) to 170 mV (MW1). These results are discussed further in Section 6.2. Table 2 .summarizes groundwater analytical results. Laboratory reports and chain of custody documentation for groundwater samples are included as Appendix IV. 4.5 Analytical Results - Soil Vaoor Samples Oxygen, nitrogen, carbon dioxide and methane were detected in the soil vapor samples analyzed. Oxygen was detected at concentrations ranging from 3.1 percent (SBI) to 7.5 wA95122% lumerpt 8 Shun