Laserfiche WebLink
1 <br /> ENVIRONMENTAL HEALTH .DEPARTMENT <br /> SAN JOAQUIN COUNTY Unit Supervisors - <br /> ' Donna K.Heran,R.E H 5 304 East Weber Avenue,Tlurd Floor Carl Horgman,R E H S <br /> Director �i Mike Huggins,RX H S,R D 1 <br /> • ` Al Olsen,RE H 5 Stockton, California 95202 Douglas W Wilson,R E H 5 <br /> cel, ,P • Program Manager Telephone (209) 468-3420 Margaret Lagono,R E H S <br /> �4 f F o a Laurie A Cotulla,R.E ILS Robert Mr.Clellon,R E H S <br /> Program Manager Fax (209)464-0138 Mark Rarcellos,R_E H S <br /> PAUL SUPPLE B 42002 - --- <br /> ARCO PRODUCTS COMPANY <br /> P O BOX 6549 <br /> �t? FEB 1 2002 r1 <br /> ' MORAGA CA 9547 0 <br /> RE* ARCO Station #4932 SITE CODE 113P,"" <br /> ' 16 E Harding Way <br /> Stockton CA 95204 <br /> ' San Joaquin County Environmental Health Department (SJC/EHD) has reviewed the <br /> "Response to SJC/PHS Letter dated December 7, 2001 and Work Plan for Additional Site <br /> Assessment and Feasibility Testing" dated January 15, 2001 that was submitted on your <br /> behalf by SECOR International Incorporated (SECOR)and has the following comments <br /> In response to the Responses the issue of deadlines was discussed Both work plans <br /> that had been submitted by SECOR on your behalf had stated approximate deadlines for <br /> submittal of the reports of findings following completion of the proposed work Both work <br /> plans were approved in whole by SJCIEHD, no conditions modifying the proposed <br /> approximate deadlines for submittal of the reports of findings were made by SJCIEHD As <br /> such, SJCIEHD expected the reports would be submitted by the latest of the approximate <br /> dates proposed by SECOR and approved by SJCIEHD <br /> ' As concerns the pumping test that was performed but not reported SECOR stated that <br /> the test was not formal aquifer testing, but was done to give SECOR an idea of <br /> approximate flow rates to enable them to design a formal aquifer test However, the <br /> performance of a formal aquifer test at a later date was not proposed in the work plan <br /> Though the work should have been addressed with an addendum, SJC/EHD recognizes <br /> that at times changes in field conditions require changes in investigative procedures The <br /> pumping test simply should have been reported <br /> One item that SECOR did not respond to was the lack of comparison of groundwater <br /> contaminant concentrations following the MPE test to the concentrations from before the <br /> ' test was conducted This was a task that SECOR had proposed to complete <br /> The Work Plan for Additional Site Assessment and Feasibility Testing proposes the <br /> installation of three additional shallow groundwater monitoring wells, the installation of <br /> three deep groundwater monitoring wells, the installation of one groundwater extraction <br /> well, and the performance of a three-day groundwater extraction feasibility test <br /> The proposed shallow wells will be built to 40-feet below surface grade (bsg)with a <br /> maximum screen Interval of 20 feet They will be located off-site to obtain lateral shallow <br /> plume definition in the down gradient direction The proposed deep wells will be built to <br /> ' 77-feet bsg with a maximum screen interval of 5 feet One deep well will be located on- <br /> site, the other two will be located off-site to the north/north-east Soil samples will be <br /> collected every five feet during the drilling of the boreholes for the wells, selected samples <br /> 1 <br />