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• WORK PROPOSED FOR NEXT QUARTER(Second, 2002) 1 Delta will continue to remove floating product from well MW-1 on a weekly basis, monitor free product thickness in selected wells, and remove floating product when necessary 2 Delta will continue to monitor depth-to-water in selected vapor extraction and monitoring wells 3 Delta will sample select vapor extraction and monitoring wells The onsite water supply well will also be sampled The next sampling event is tentatively scheduled for June 2002 Groundwater samples will be analyzed for total petroleum hydrocarbons as gasoline (TPHG), benzene, toluene, ethylbenzene, and total xylenes (BTEX) by USEPA Method 8015/8020 DHS LUFT, and for tertiary butyl alcohol (TBA), methyl tertiary butyl ether (MTBE), di-isopropyl ether (D1PEw), ethyl tertiary butyl ether (ETRE), tertiary amyl methyl ether (TAME), and 1,2-dichloroethane (1,2-DCA) using USEPA Method 8260B The sample from the onsite water supply well will also be analyzed for nitrates using USEPA Method 300 0, and for fecal coliform using APHA standard parameters 4 Delta will prepare As-Built drawings illustrating the construction details of the remediation piping installed during the first quarter 2002 5 Delta will submit a soil sampling report documenting the results of the compliance soil sampling DISCUSSION Free product was observed in well MW-1 at a thickness of 0 42 feet, and a product sheen was observed in wells VW-1 and VW-4 TPHG was detected in the samples collected from wells VW-2 (33,000 pg/L) and VW-3 (43,000 pg/L) Benzene was detected in samples collected from VW-2 (9,700 pg/L), VW-3 (6,000 pg/L), and VW-6 (5,100 pg/L) Petroleum hydrocarbons were not detected in the samples collected from wells MW-2 or VW-5 MTBE was detected in groundwater samples collected from wells VW-2 (350 pg/L), VW-3 (490 pg/L), VW-5 (6 7 pg/L), and VW-6 (270 pg/L) Other fuel oxygenates were not detected in any of the monitoring wells Petroleum hydrocarbons or fuel oxygenates were not detected in the sample collected from the domestic well These data are similar to previous chemical analytical data In wells MW-3 through MW-9, VW-7, VW-9 through VW-13, VW-16, VW-18, and VW-20 there was less than 1 foot of water column in the well, the water in these wells does not appear to be formation water, therefore the wells were not sampled Wells VW-8, VW-17, and VW-19 were dry The groundwater in wells MW-1, MW-2, VW-1 through VW-6, and VW-14 was measured at depths of 29 13 to 106 00 feet below top of well casing (TOC) The groundwater between 29 13 and 59 51 feet TOC (wells MW-2,VW-1 through VW-6, and VW-14) appears to be perched and, based on dry wells at the site installed to similar depths, of limited lateral extent These groundwater data are similar to groundwater data from previous quarters ATTACHMENTS • Table 1 Groundwater Monitoring Summary, Monitoring Well MW-1 • Table 2 Groundwater Level Data • Table 3 Groundwater Analytical Summary • Figure 1 Site Location Map • Figure 2 Site Plan • Figure 3 Groundwater Analytical Summary • Appendix A Field Data Sheets • • Appendix B Sampling and Analysis Procedures Appendix C Certified Analytical Reports and Chain-of-Custody Records P 1ARCO161001QTRLY120021Arco_6100_1 Q02 doc Delta