ARCHIVED REPORTS_XR0007387 CASE 1

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Ik'q KLEINEELDER TPH-D was detected in the groundwater samples collected from MW-1 during the October 2000 and January 2001 sampling events at concentrations ranging from 14 4 to 18 6 mgll BTEX were not detected from groundwater samples collected during these two sampling events TPH-G, which was analyzed for the first time in January 2001, was detected In the groundwater sample collected from MW-1 at 3 3 mgll Based upon analytical data obtained during these sampling events, the CVRWQCB and EHD requested continued quarterly groundwater sampling and preparation of a workplan to address the extent of the contamination in the vicinity of the subject site, Including a sensitive receptor survey and estimates as to the amount of contamination In soil and groundwater At the request of General Mills, Kieinfelder installed three additional monitoring wells in the vicinity of the UST in January 2002 (MW2, MW-3 and MW4) During the Installation, soil samples were collected from the borings and submitted for laboratory analysis None of these samples contained detectable concentrations of TPH-G, TPH-D, nor BTEX, at or above laboratory reporting limits Four quarterly sampling events were conducted in 2002 with groundwater samples collected from all four monitoring wells MW-1 through MW-4 Monitoring wells MW-2, MW-3 and MW-4 were installed as perimeter monitoring wells MW-2 and MW-3 were installed downgradient of the UST area and MW-1 was installed upgradient of the UST area Based on findings of the four quarterly sampling events conducted during 2002, fuel constituents continued to be present in MW-1, including TPH-D, TPH-G, ethylbenzene and total xylenes at relatively lower concentrations (See Table 2) Floating product was noted in September 2002 in monitoring well MW-1 Product thickness since this time has been noted in MW-1 at thicknesses ranging from a film (<0 01 feet) to approximately 0 33 feet (4 1 riches) A trace concentration of TPH-D (0 076 m gll) was detected in the June 2002 sampling event in downgradient well MW-2 No petroleum constituents were otherwise detected in perimeter monitoring wells MWs 2, 3 or 4 in 2002 During the quarterly sampling events in 2003 petroleum constituents were detected only in MW-1, with the exception of the 3rd quarter, 2003 in which TPH-D was detected in MW- 2 at 0 14 mgll Product was measured in MW-1 in consecutive quarterly events in 2003, beginning with the 1st quarter 2003 at 4, 112, 314 and 114 Inches, respectively TPH-D ranged from 13 to 32 mgll in MW-1 during 2003 Product thickness measured in MW-1 during 2004 ranged from 112 inch (1St quarter) to 115 inch (3rd quarter) In 2004, TPH-D concentrations ranged from 550 mgll (1St quarter) to 24 mgll (3rd quarter) No requested petroleum constituents were detected in MWs 2, 3 or 4 during the 2004 quarterly sampling events The following Sections document Kleinfelder's findings from the second quarter 2005 Asampling event 28209 T09/5T05R1323/DH Iv Page 5 of 12 0 2005, Kleinfelder, Inc October 21, 2005