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,' ~ . <br />excavation. Ms. Davis indicated that the boundaries of the abatement excavation were set <br />according to recommendations made by [he Paragon Group. RACII clean up levels for TEPH <br />are 250 ppm and for BTEX are 50 ppm. I[ is anticipated that during subsequent extraction <br />activities, all of the remaining contaminated soil will be excavated. According to Ms. Davis, <br />any contaminated soil that is subsequently excavated from the pit will be stockpiled and <br />handled as was the material that was excavated during abatement activities There is concern <br />for the remaining contaminated soils. Although the BTEX concentrations fall below the <br />RACII clean up levels, 50 ppm, the TEPH concentrations are higher than the limit set at 250 - <br />ppm. Please submit a Technical Revision indicating that if contamination of groundwater is <br />discovered, additional excavation must take place immediately. Additionally, prior [o <br />cessation of dewatering activities, the remainder of the contaminated soils must be excavated <br />in order to avoid contact with groundwater when [he groundwater rebounds. <br />4. Approximately 83,000 gallons of groundwater and free-phase product were pumped from the <br />abatement excavation site and shipped to Key Energy Services for treatment and disposal. <br />Approximately 450 gallons of free-phase product was recovered from the shipped liquid. An <br />additional 20,000 gallons of groundwater was pumped from the excavation site and was <br />stored onsite for use at the site. At the time of the Paragon Report, two groundwater samples <br />had been collected to test for contamination of groundwater, one from the excavation site <br />itself and the other from the dewatering trench located along [he northeast portion of the pi[. <br />The dewatering trench samples tested below [he laboratory detection limits for BTEX and for <br />TEPH. The abatement excavation pit sample indicated levels of 47 µg/L for xylenes and 126 <br />mg/L TEPH. The Water Quality Control Commission has set a standard of 10,000 µg/L for <br />total xylenes and has no standard for TEPH. George Morvak, an employee at the Water <br />Quality Control Commission, however, indicated [hat there really should be no detectable <br />levels of TEPH in groundwater. Ms. Davis indicated [hat at no time was [her visible <br />evidence that contaminants had migrated to the dewatering trench, and believes that this is <br />still being monitored regularly, although there are no formal monitoring parameters set for <br />the dewatering trench. Please commit to a formal monitoring program for the dewatering <br />trench. <br />i <br />5 The Cache La Poudre River is located approximately 1,300 feet east of the leak site-and <br />~~al approki~nately 3,500 f/[.n heart, downgradient oaf the site. Please samplehe river <br />do~strrtam of the site in ord to determine jcontamt4ants are leaking Ito the surface <br />water. Add`tion Il~indica[e wh her~ny-drinking water urface waterintakes are located <br />within IS miles downstream of the site. <br />6. The Paragon report recommended the installation of groundwater monitoring wells to <br />monitor groundwater quality. According to Ms. Davis, five monitoring wells were installed <br />on July 9 and July 10, 2001. These wells have been sampled once since their installation and <br />will be sampled quarterly for a total of one year. Currently, the wells are being surveyed in <br />order to determine groundwater elevation and groundwater Flow direction. Ms. Davis <br />indicated that groundwater is expected to be Flowing in a northeasterly direction. Please <br />forward the quarterly test results from the monitoring wells to the Division. Ats-o advise the <br />division of groundwater Flow direction when the accurate groundwater Flo/w~ directions is <br />determined. - ~rv (~ P-{o "7 H an.~ a ~.o.Q-e, Gp~t•-{-a.,,,. -t•y-r -1'~ i S ~g 0 ~ 1 , <br />~~ 7/There is a I rge stockpile of asphalt to be recycled which is located to the south of the <br />G' monitoring ells. Please indicate whether the pile of asphalt will affect groundwater. Also <br />h~~e~5 please indict if any li or containment few es were used to contain potential soil or <br />~5) pgr-oundwater co amina[iogn rom the stoe c~piled phalt. <br />it~7(olc7 ~ 5 ~~ Ce,-side ~"~""r `l <br />