ARCHIVED REPORTS_XR0006931 - Laserfiche WebLink

Home Browse Search

. Page 6 Based upon the analytical results for the ground water samples collected from wells MW10 through MW13 on June 3 , 1992 , KEI recommended the implementation of a monitoring and sampling program at the site Documentation of the well .installation procedures, sampling techniques, and the analytical results are presented in KEI ' s report (KEI-P88-1013 R2) dated July 15, 1992 . On July 13 and 14 , 1994 , two additional two-inch diameter monitor- ing wells (designated as MW14 and MW15 on the attached Figure 1) were installed at the site The wells were each drilled, con- structed, and completed in accordance with the guidelines of the RWQCB and the California Well Standards (per Bulletin 74-90) On July 14 , 1994, off-site monitoring well MW6 was destroyed by pressure grouting the well casing with neat cement The former well was destroyed (replaced by MW15) because it was dry and extended to a depth of only 48 feet below grade Monitoring wells MW14 and MW15 were each drilled and completed to a total depth of 69 feet below grade Ground water was encountered at a depth of 61 feet below grade during drilling. Selected soil samples collected from the boring of monitoring wells MW14 and MW15 were analyzed for TPH as gasoline and BTEX, and the analytical • results are summarized in Table 5 The new wells were developed on July 18 and 19 , 1994 , and all of the Unocal wells , including the newly installed wells MW14 and MW15 , were monitored and sampled on September 14 , 1994, by MPDS Services , Inc , of Concord, California The ground water samples were analyzed for TPH as gasoline, BTEX, and EPA method 8010 constituents , and the analytical results are summarized in Table 3 . Based on the analytical results of the ground water samples collected and evaluated through September of 1994, KEI concluded that the extent of the petroleum hydrocarbons in ground water had not been defined Therefore, it appeared that an additional monitoring well would be necessary in order to define the extent of the petroleum hydrocarbons in ground water However, at that time four additional monitoring wells were proposed at the adjacent Montgomery Ward site One of the monitoring wells proposed to be installed by Montgomery Ward was located downgradrent of the former Unocal site (southeast corner of Pacific Avenue and Robi.nhood Drive) Thus , recommendations for additional wells would be made based on the results of the ground water samples collected from the proposed Montgomery Ward wells Documentation of the well installation and destruction procedures , sampling techniques, and the analytical results are presented in KEI ' s report (KEI-P88- 1013 R4) dated October 27 , 1994 KBI-PBS-1013 APA