2007-11-20_REVISION - M1982015 (13)

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E-21 Engineering Inc. ?0 engineering for the 21st Century t/ ?41-t6f%a. ors Phone 303-991-6000 Fax 303-991-6001 ' 2695 South Raritan Street Phone 888-628-1083 Englewood, Colorado 80110 Fax 888-628-1084 1 September 26, 2007 ECFINID ' 2 O 2007 Ms. Teresa Bennett NOV Hazardous Waste Corrective Action Unit, Compliance Program Division of Reclamation, ' Colorado Department of Public Health and Environment Mining and Safety 4300 Cherry Creek Drive South Denver, Colorado 80246-1530 Subject: August 2007 Groundwater Monitoring Results and Remediation Progress Report ' Bayshore Pipeline Release Firestone, Colorado Spill Incident No. 2006-1029 ' E-21 Project No. 863 Dear Ms. Bennett: ' On behalf of GeoCon, E-21 Engineering, Inc. (E-21) is submitting this report summarizing the recent assessment and remediation activities associated with the gasoline release at the subject site. Pursuant to your letter dated July 16, 2007, you requested that brief quarterly reports be submitted to you within ' 30 days of receipt of laboratory data. The site map and spill area are shown on Figures 1 and 1A. New Monitoring Well Installations and Soil Laboratory Results (MW-23 to MW-29) ' On August 10 and 15, 2007, E-21 personnel supervised the installation of seven new 2" diameter monitoring wells designated MW-23 through MW-29. The wells were placed at locations generally to the north and east of the dissolved phase petroleum hydrocarbon plume to better delineate the extent ' of contamination. Well MW-2R was destroyed during construction in the area and was replaced on August 15, 2007. The location of the new wells is shown on Figure 1A. ' During drilling, soil samples were collected in 5-foot intervals and screened for indications of residual petroleum impacts using a calibrated photo ionization detector (PID). One soil sample from each boring was submitted to Origins Laboratory in Denver, Colorado for analysis, generally based on its depth and relation to the vadose zone. The soil samples were analyzed for benzene, toluene, ethyl ' benzene and xylenes (BTEX), total volatile petroleum hydrocarbons (TVPH), and methyl tert butyl ether (MTBE) using EPA Method 8260B. ' Petroleum hydrocarbons were not detected in any of the samples submitted for analysis. Additionally, there were no indications of residual petroleum hydrocarbon impacts detected during drilling. The soil laboratory results are summarized on Table 1. Boring logs and well completion details are included in ' Appendix 1. The laboratory report for the soil samples is included in Appendix 2.