Laserfiche WebLink
.1 . <br /> Mr Jeff Wong <br /> July 18, 2001 <br /> • Page 3 of 3 <br /> CONCLUSIONS <br /> The lateral extent of groundwater contamination beneath the site has been essentially defined, with the <br /> exception of the northern extent of the dissolved contaminant plume Dissolved contamination in the <br /> upper water-bearing zone does not appear to extend to deeper zones based upon the absence of TPHg, <br /> benzene, and MTBE in well MW9(B), although low levels of toluene, ethylbenzene, and xylenes were <br /> detected in the deeper well for the second consecutive quarter The very low detection of aromatic <br /> hydrocarbons may be due to field or laboratory error <br /> The apparent groundwater depression near well MW4 may have resulted from operation of the facility <br /> well However, it could be an indicator that some vertical leakage of the shallow aquifer is occurring <br /> through the water supply well <br /> RECOMMENDATIONS <br /> Based upon the results of subsurface investigations conducted to date, Ground Zero makes the <br /> following recommendations <br /> Install a new water supply well to replace the existing water supply well, which has <br /> apparently been impacted by petroleum hydrocarbons, <br /> . . Destroy the existing water supply well in order to eliminate it as a potential vertical migration <br /> pathway to underlying aquifers, <br /> Install additional groundwater monitoring wells to further define the lateral extent of dissolved <br /> MTBE contamination north and northeast of well MW6, <br /> Please contact Ground Zero at (209) 838-9888 it you have any questions or require additional. <br /> information <br /> Respectfully, <br /> Ground Zero Analysis, Inc <br /> Sean Garvey �O <br /> Staff Geologist jaNrJ P O�"�, <br /> LANE <br /> No G795 <br /> John P Lane <br /> CA Registered Geologist No 6795 �t�r <br /> Attachments <br /> cc Mr Ray Baglietto/Mr Frank Rauzi <br /> Mr Marty Hartzell, CA RWQCB <br /> ti n it1( RI11 fili�7_117lJLCNUlz(.1R�pntcl(,}\IRi2�1\t2luhl dui <br />