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California *gional Water Quality Conijl Board <br /> Central Valley Region 1 r <br /> Robert Schneider,Chair <br /> Linda S. Adams _ P"f7� .l rnuld <br /> r <br /> Sacramento Main 011-ice <br /> D � <br /> �L�rhw ui icne;,� r <br /> ivr•mnrmad I10'_G Sun Center Drive i:200.li mcho lordova,Calll'omia <br /> Phone(916)464-1291 •FAX 19161464-4645 q C <br /> help/hvww w mrhoards.ca.gov/ccntralvallec NOV _ I <br /> 31 October 2006 ER\ARO,4MFNTHEALTH <br /> pERMIT1S <br /> CERTIFIED MAIL CERTIFIED MAIL <br /> 7006 0100 00006 5887 0466 7006 0100 00006 5887 0459 <br /> Mr. Don Pratt, Environmental Business Manager Mr. Gurpreet and Ms. Kuldeep Dhat <br /> Atlantic Richfield Company 501 S. Cherokee Avenue <br /> P.O. Box 1257 Lodi 35240 <br /> San Ramon 94583 <br /> CHANGE OF LEAD AGENCY, FILE REVIEW, AND REQUEST FOR WORK PLAN, <br /> ARCO 30760, 225 S. CHEROKEE LANE, LODI, SAN JOAQUIN COUNTY (REGIONAL <br /> BOARD CASE # 390330) <br /> In a letter dated 6 October 2006, San Joaquin County Environmental Health Department <br /> (SJCEHD) transferred the regulatory agency lead to the Regional Board for the cleanup of <br /> petroleum hydrocarbons at the ARCO #0760, 225 S. Cherokee Lane, Lodi (Site, Figure 1) <br /> Attached is a site chronology prepared by SJCEHD. Please address all future <br /> correspondence to the address in the header of this letter, and continue to send copies of <br /> written correspondence (excluding work plans and reports) to SJCEHD. <br /> Enclosed are: 1) the non-concurrence letter to SJCEHD from the Regional Board Executive <br /> Officer, and 2) the Regional Board staff memo, dated 14 September 2006, which provides a <br /> chronology of the Site. In preparing the memo, I conducted a preliminary case review and <br /> disagreed with the closure recommendation given by SJCEHD. Specifically, the Site <br /> characterization is incomplete for all petroleum hydrocarbons, including 1,2-Dichloroethane <br /> (1,2-DCA). <br /> 1. Concentrations of 1 ,2-DCA do not show a definite declining trend, indicative of an <br /> ongoing discharge to groundwater from residual soil contamination. <br /> 2. The lateral extent of groundwater pollution has not been defined to the northwest <br /> (TPHg), and south (TPHg, benzene, MtBE, and 1 ,2-DCA) of the Site. <br /> 3. The groundwater plume may not be stable, and may be moving offsite towards the <br /> south or southwest. An additional groundwater investigation and monitoring are <br /> necessary to define the lateral extent of the plume and evaluate the stability of the <br /> groundwater plume. <br /> 4. Constituents of concern detected in groundwater exceed Water Quality Objectives. <br /> Case #1 residual soil concentration estimates showed that a considerable mass,of <br /> TPHg and TPHd remains in soil. While Case #2 confirmation results after over- <br /> excavation were much lower than what would be expected from Case #1 residual mass <br /> California Environmental Protection Agency <br /> 0 Recrclod Paper <br />