ARCHIVED REPORTS XR0006998 - Laserfiche WebLink

Home Browse Search

Merman&Hcicn s Manna-First Quarter 1998 Groundwater Monitoring April 16 1998 ' Pagc 2 collected by Condor from the US T excavation at depths of 9 to 12 feet below the ground surface Laboratory analyses indicated elevated concentrations of I PII-G, B I EX, and total extractable petroleum hydrocarbons quantified as diesel (TEPH) in the soil samples On August 22, 1995 three hydropunch bonngs were drilled at the site Gasoline odors were noted in each ' borehole Laboratory analyses indicated concentrations of IPH-G and B F X in the soil and groundwater samples analyzed from each borehole Based on the results of the August, 1995, investigation, Condor recommended additional investigation be conducted to evaluate the extent of the hydrocarbon plume On August 29, 1996, five Geoprobe boreholes were installed at the site rhe results of the laboratory analyses indicated that elevated ' concentrations of IPH-G, BTEX, and methyl tertiary butyl ether (MTBh) were detected in soil and groundwater samples at the north portion of the site and that further investigation was necessary to evaluate the extent of soil and groundwater contamination Based on the results of the Geoprobe investigation, Condor recommended that monitor wells be installed at the site to investigate and monitor the lateral extent of the gasoline and diesel contamination plume On September 111, 1991, Condor installed four monitonng wells at the site I'he Repoi t - Additional Soil and Gi oundwater InvIcsfi alron, dated December 11, 1997, was prepared by Condor to describe, the, investigation results Laboratory analysis indicated that `1 PH-G, B"I I-X constituents, MTBE, tertiary butanol, and tertiary amyl methyl ether (TAME) were detected in some of the soil and groundwater samples collected during the investigation Groundwater elevation data indicated that groundwater flow at the site was probably controlled by the very active island drainage pumping adjacent to the site The above referenced report recommended quarterly groundwater monitoring, surface water sampling, and Risk Based Corrective Action(R-BCA) to further characterize the site and to evaluate options for remediation or site closure f In a telephone conversation on March 23, 1998, Mr Ronald Rowe of the San Joaquin County Public Health Services/Environmental Health Department (PHS/EHD) indicated that based on his review of the report dated December 11, 1997, referenced above, he was requesting that quarterly groundwater monitoring continue at the site Furthermore, he was requiring that a work plan be prepared for conducting quarterly surface water sampling and further investigating the gasoline oxygenate/additive plume to the east of site monitor well MW-2 Condor prepared a Ietter, dated March 23, 1998, documenting the conversation A work plan, as described above, is currently being prepared by Condor A comprehensive site background is included as Appendix B L� CONDOR