|
S E C ® R
<br /> SENSTIVE RECEPTORS
<br /> A 1996 DWR survey identified 10 wells located within the survey area These wells are located
<br /> northeast to southeast of the site and are apparently utilized as cathodic protection or irrigation
<br /> wells
<br /> MONITORING AND SAMPLING
<br /> TRC's Groundwater Monitoring Report dated June 23, 2004 is included as Attachment A,
<br /> including Tables 1- 3, Figures 1 - 5, and Graphs 1 - 8 plus field data sheets and groundwater
<br /> analytical reports, The site has been monitored and sampled since 2"d quarter, 1996 From 1996
<br /> to 2000 the Site has been monitored and sampled quarterly In 2001, the site was monitored and
<br /> sampled monthly In 2002, the site was monitored and sampled bi-monthly From 2003 to the
<br /> present, the site has been monitored and sampled quarterly Currently, 11 wells (MW-1 through
<br /> MW-4S and D, MW-6S and D, MW-8D, and MW-10S,1, and D) are monitored and sampled
<br /> quarterly and 9 wells (MW-5S and D, MW-7S and D, MW-8S and I, and MW-9S,1, and D) are
<br /> monitored and sampled semi-annually Samples are analyzed for TPHg, TPPH, BTEX, and fuel
<br /> oxygenates
<br /> Based on the second quarter 2004 monitoring and sampling event (May 27, 2004) (Attachment A)
<br /> the maximum TPHg and MtBE concentration were 100 ppb (MW-2) and 490 ppb(MW-1),
<br /> respectively
<br /> TPHg and MtBE concentrations in groundwater continue to decline particularly in source area
<br /> wells MW-1 and MW-2
<br /> 3
<br /> Offsite wells MW-8D and MW-10S, I, and D continue to report minor concentrations of TPHg and
<br /> MtBE
<br /> Based upon data collected during ongoing quarterly groundwater monitoring and sampling,
<br /> dissolved hydrocarbons are effectively delineated both laterally and vertically in the vicinity of the
<br /> site
<br /> REMEDIATION STATUS
<br /> 3
<br /> 9
<br /> SECOR's Quarterly Remedial Performance Summary is included as Attachments B (including
<br /> Tables B-1 - B-2, and Figures B-1 - B-3), Attachment C (Remediation Field Data Sheets), and
<br /> Attachment D (Remediation Certified Laboratory Analytical Reports and Chain of Custody
<br /> Documentation)
<br /> The ozone infection systems consist of panel mounted KVA C-Sparge"m Systems that produce 4
<br /> grams per hour (0 009 pounds per hour) of ozone The system infects to ten sparge points in
<br /> eight wells AS1 through AS5, AS7, AS8, and AS10, and nested wells AS6SID and AS9SID
<br /> Between March 31 and June 21, 2004, the system ran for 1,372 hours, resulting in 70 percent
<br /> runtime System data is presented in Table B-1 (Attachment B)
<br /> The performance of the ozone infection system is evaluated by groundwater sampling Monthly
<br /> groundwater samples were collected from monitoring wells MW-1, MW-2, and MW-3 on April 23,
<br /> May 25, and June 21, 2004 and analyzed for total petroleum hydrocarbons as gasoline (TPHg),
<br /> benzene, toluene, ethylbenzene, and total xylenes (BTEX compounds), and methyl tert-butyl
<br /> • ether (MtBE) Results of monthly groundwater sampling events are summarized in Table B-2
<br /> Concentration versus time graphs for dissolved TPHg, benzene, and MtBE in monitoring wells
<br /> MW-1, MW-2, and MW-3 are provided in Figures B-1, B-2, and B-3
<br />
|