ARCHIVED REPORTS XR0011047 - Laserfiche WebLink

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plume exists to the north which is centered on the Darpetro site to the northwest of the Morita property Monitoring well data from that project, taken on January 19 , 1995 was reviewed by our staff and indicated that some, if not all, of the contamination measured in the groundwater from the Morita site is from that source. Refer to the WJH quarterly groundwater monitoring report dated May 26, 1995 for more details A summary of all of the laboratory analyzes of water samples taken since monitoring began in October, 1992 , is included as TABLE I It reveals that MW-1 has consistently shown the lowest levels of benzene, (ND except for the 2/94 sampling. ) Benzene levels have been the highest in MW-2 since the 10/93 sampling TPH as gasoline has shown the highest levels in MW-2 & MW-3 , but there does not appear to be any readily identifiable pattern to explain the variations Levels of toluene, ethylbenzene, & xylene detected in the three wells since monitoring began vary widely; again, no definite pattern is apparent The water table had risen slightly over 3 feet since the March, 1995 sampling, (to an average depth of 45 . 00 , bgl , ) the highest . level since monitoring began This is due primarily to the unusually heavy rainfall this past season, which has raised water levels throughout the area The change in direction of the potentiometric surface measured during the July, 1995, (from NE to NW, ) and variations in the levels of contamination in the water samples obtained from the three wells suggests that there may be a source of groundwater withdrawal to the northwest of this site . We have not been furnished current data on the Darpetro project, so we are unable to determine if remediation has begun If a "pump & treat" system has been installed there, that could account for the changes noted during the latest sampling event The next monitoring event for the Morita property is due this month We would appreciate receiving recent data on activities associated with the Darpetro project so that we can review all the relevant data to enable us to provide a more complete analysis Since ely Wm nter & Associates cc ank Morita WiLLU1M 1 BUNTER CVRWQCB • � y 4r NOO860 ,# OFC 2