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<br /> CSUS-Multi Campus Regional Center—Quarterly Groundwater Monitoring
<br /> January 23,2003
<br /> Page 2
<br /> Summary of December 2002 Quarterly Groundwater Monitoring Results(continued)
<br /> Groundwater Contamination continued
<br /> Maximum Concentration:
<br /> Benzene Benzene(µg/1..) 2.9
<br /> Toluene Toluene(µg/L) 2.5
<br /> Ethyl benzene Ethyl benzene(µg/L) 1.3.
<br /> Nature of contamination: Xylenes Xylenes(µg/L) 11
<br /> MTBE MTBE(µg/L) 75 ,-
<br /> 1,2-DCA
<br /> 5 ,-
<br /> 1,2-DCA 1,2-DCA(gg/L) 40".,,
<br /> TPH-G TPH-G(µg/L) 610✓
<br /> TPH-K TPH-K(µg/L) 540
<br /> A
<br /> FIELD OBSERVATIONS
<br /> No separate phase petroleum or sheen was noted in the groundwater recovered from the wells. A
<br /> moderate petroleum odor was noted in the groundwater recovered from both MW-2 and MW-3.
<br /> Groundwater monitoring field forms are attached.
<br /> I
<br /> i. GROUNDWATER ELEVATIONS AND GRADIENT
<br /> On December 27, 2002, the depth to groundwater was measured in monitor wells MW-1, MW-2; and
<br /> MW-3. Groundwater elevation data is presented in Table 1, below. The average depth to groundwater in
<br /> the monitor wells was approximately 39.83 feet below the surveyed well collar measuring points'(the
<br /> measuring points are slightly below the ground surface). The average groundwater elevation measured in
<br /> the monitoring wells decreased approximately 0.74 feet between September 11, 2002, and December 27,
<br /> f 2002. The estimated groundwater gradient for the site on December 27, 2002,was 0A010 ft/ft to the
<br /> northeast and is shown in Figure 2, attached.
<br /> I Table 1 Groundwater Elevation Data(December.27, 2002)
<br /> Well Number TOC Elevation feet Depth to Groundwater feet Groundwater Elevation(feet)
<br /> MW-1 17.42 39.87 -22.45 i
<br /> MW-2 17.59 39.98 -22.39
<br /> { MW-3 17.16 39.63 -22.47 i
<br /> I
<br /> All measurements are in feet.
<br /> TOC—Top of Casing
<br /> TOC Elevation:Referenced to NAVD88 datum from NGS Benchmark HS3999. u
<br /> LABORATORY ANALYTICAL RESULTS
<br /> �.
<br /> All groundwater samples were analyzed for total petroleum hydrocarbons quantified as gasoline,
<br /> kerosene, diesel, and motor oil (TPH-G, -K, -D, AND -MO) by EPA Method 8015m, for benzene,
<br /> { toluene, ethyl benzene, and total xylenes (BTEX) by EPA Method 8020, and for gasoline
<br /> }
<br /> oxygenates/additives by EPA Method 8260B. The gasoline oxygenates/additives include methyl tertiary-
<br /> butyl ether (MTBE), ethanol, tertiary-butanol (TBA), di-isopropyl ether (DIPE), ethyl tertiary-butyl :ether i
<br /> (ETBE), tertiary-amyl methyl ether (TAME), 1,2-dibromoethane (EDB or 1,2-DBA), and . 1,2-
<br /> dichloroethane (1,2-DCA). Excelchem Environmental Labs of Roseville, California analyzed the
<br /> groundwater samples. The laboratory analytical results for the groundwater samples collected from the
<br /> a monitor wells on December 27, 2002, are presented in Table 2, on the next page, and in Figure 3,
<br /> attached. Historical groundwater monitoring data ate included in Table A, attached. The laboratory
<br /> certificates of analyses and chain-of-custody record are also attached.
<br /> os
<br /> f.a CONDOR
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