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PUBLIC Y4EALTH R� CE p.. ..�
<br /> SAN JOAQUIN COUNTY
<br /> # y
<br /> ENVIRONMENTAL HEALTH DIVISION
<br /> i Ernest M. Fujimoto, M.D., M.P.H., Acting Health Officer �. p
<br /> 445 N. San Joaquin Street • P.O. Box 388 • Stockton,CA 95201-0388
<br /> (209) 468-3420
<br /> GORDON MARTS I'l
<br /> CALTRANS 'I
<br /> PO BOX 2048 [
<br /> STOCKTON CA 95201 "JAN 0 1995
<br /> Re: Caltrans Shop 10 p Site Code: 10193
<br /> 1603 South "B" Street
<br /> 'Stockton CA 95205
<br /> i
<br /> San Joaquin County, Public Health Services, Environm Intal Health Division PHS/EHD
<br /> has completed review of the "Groundwater Monitoring Well Activities and Groundwater
<br /> Monitoring Report" dated September 23, 1994 and prepared i'�by Ninyo and Moore
<br /> Geotechnical and Environmental Sciences Consultants.;;' PHS/EHD has the following
<br /> comments for your consideration.
<br /> The report indicated that monitoring wells, MW1, MW2, MW3,i MW4, MW5, MW6, MW7,
<br /> MW8, and MW1 were destroyed during May and June1994?f Monitoring wells,
<br /> MW1 - iMW6 were reportedly dry. MW7, MW8 and MW10 we're requested by Caltrans
<br /> to be destroyed because these wells had very little water. Also to accommodate the
<br /> grading of the site for future development,p Caltrans requested that monitoring wells,
<br /> MW9, MW11, MW1 3, MW1 4, MW1 6, MW1 9, MW20 and MW24 be temporarily lowered.
<br /> These wells were lowered approximately 6 feet below grade, a slip cap placed upon
<br /> the welland backfilled with sand to approximately 1.5 feet below grade where a
<br /> bentonite/neat cement sea[ was placed. Monitoring welly MW12, remained unchanged.
<br /> j.
<br /> The last groundwater sampling event occurred on May 25 and 26, 1994, during which
<br /> samples were collected from MW10, MW1 1, MW1 2, MW13, MW14, MW16, MW19,
<br /> MW20, and MW24. For some reason, groundwater samples were not collected from
<br /> f MW7, MW8, and MW9, despite the fact that these wells should have had sufficient tI
<br /> groundwater to sample. Significant groundwater contaminatioin was detected in wells I
<br /> which were destroyed and wells which were lowered. In'!order to evaluate the historic
<br /> groundwater contamination levels, please prepare a summary�of all groundwater
<br /> sample.results and submit the summary by February 8,11
<br /> 995
<br /> Also, you should be aware that adequate time has elapsed, since PH
<br /> p , , S/EHD agreed to
<br /> allow the temporary lowering of some of the monitoring well, to re-grade the site.
<br /> These wells should be uncovered and g brought to rade i'mmediatel '
<br /> 9 y, surveyed by a 3
<br /> California licensed surveyor and the wells sampled to verify that the extent of
<br /> groundwater contamination is defined. Please contact Mary Mheays by February 28,
<br /> 1995 to ;arrange a site inspection to verify that the wells have been adequately
<br /> repaired and to schedule a sampling inspection. #
<br /> i
<br /> A Division of Sun ,loaq"in cipunty Health Care Senices
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