Laserfiche WebLink
' 03 March 2004 <br /> • AGE-NC Project No 01-0827 <br />' Page 5 of 6 <br /> current distribution of contaminates is presumed limited,however,the"drowned"nature of <br />' the wells may lead to unrepresentative analytical data <br /> • 1,2-DCA was not detected in the ground water samples this quarter <br /> t • The concentrations of benzene in samples MW-6 and VW-2d and MTBE in sample VW-2d <br /> were above the DHS's Primary Maximum Contaminant Levels (MCL) for drinking water <br /> However,the use of the shallow and deeper ground water in the region does not immediately <br /> appear to be for domestic use <br />' Oxidation is a process to which a molecule or ion loses electrons Reduction is a process by <br /> which electrons are gained A measurement of the potential for these processes to occur is <br /> called ORP (Oxidation Reduction Potential) Low ORP values, detected in the source area, <br />' demonstrate the presence of generally reduced environment in the saturated zone near the <br /> source area This reduced environment is likely due to the high saline and sulfur enriched <br /> shallow water at the site Ideally, the introduction of oxygen rich air(ozone air sparging)in <br /> to the source area will produce an oxidizing environment which will lead to a reduction in <br /> contaminant levels Dissolved oxygen concentrations collected from wells at the site, since <br /> operation of the ozone air sparge system commenced, indicate an adequate migration of <br /> ozone-rich sparged air into the subsurface In addition,since the initiation of operation of the <br /> ozone-sparging system dissolved concentrations of TPH and BTEX compounds have <br /> reduced <br />' 5.0 RECOMMENDATIONS <br /> Based on the findings of the remediation activities recounted in this report, AGE recommends <br />' • Continued quarterly ground water monitoring, the next monitoring event is scheduled for <br /> early second quarter 2004 <br />' • Removal of the analysis for TPH-d from the quarterly monitoring schedule based on very low <br /> to non-dectable historical concentrations Additionally, limit sampling to impacted ground <br /> waterwells,mostly due to the excessive distance ofthe other non-impacted wells,to the UST <br />' area <br /> • Continue operation of the ozone air sparging system,which was approved by the San Joaquin <br /> tEnvironmental Health Department <br /> 1 <br />