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California6gional Water Quality Co 41 Board : ;> <br /> Central Valley Region <br /> Karl E. Longley,ScD,P.E.,Chair <br /> Linda S.Adams Sacramento Main Office Arnold <br /> Secreraryyfor 11020 Sun Center Drive#200.Rancho Cordova,California 9567(}6114 Schwarzenegger <br /> Environmental Governor <br /> Proreaion Phone(916)464-3291 •FAX(916)4644645 <br /> http.//www.waterbo'atrds^.ca.@ Io�Iv/cve'ntralvla�tley <br /> RE�VEE tv <br /> 17 January 2008 ,l4N y 2 2008 <br /> Mr. Dan Schreiner, P.G. ENVIRONtr9ENT HEALTH <br /> SECOR PERMIT/SERVICES <br /> 3017 Kilgore Road, Suite 100 <br /> Rancho Cordova, CA 95670 <br /> 3RD QUARTER MONITORING REPORT, L & M OPERABLE UNIT, SAN JOAQUIN COUNTY <br /> Staff of Region 5 Water Quality Control Board has reviewed your submittal entitled Third <br /> Quarter 2007 Site Status, Remedial Summary prepared by SECOR International dated 30 <br /> October 2007. We appreciate the opportunity to review the report and have the following <br /> comments: <br /> General Comments <br /> The site is not characterized as thoroughly as it needs to be for effective remediation. <br /> • Figure 17 (C/D Zone Chemical Concentration Map) illustrates MW-54 and MW-55 <br /> as being the only wells monitoring these deeper groundwater zones. The wells both <br /> show that the deeper zones are polluted with petroleum hydrocarbons (MW-54: <br /> TPHd=2.1 mg/L, TPHg=0.75 mg/L and MW-55: TPHd=1.6 mg/L, TPHg=0.76 mg/L). <br /> Hydrocarbon pollution in C and D groundwater zones require further <br /> characterization. A work plan for additional characterization of C and D zones is <br /> required to be submitted by 14 March 2008. <br /> • Figure 2 (Shallow A Zone Groundwater Contour Map) depicts a gradient of 0.005 <br /> ft/ft in the easterly direction. The iso-concentration maps (for example, see <br /> Attachment 1) show an undefined groundwater plume migrating in that direction. <br /> There are an insufficient number of wells along the east side of Parcel 2A and west <br /> sides of Parcels 3 and 4 to define the contamination plume. A work plan is required <br /> by 14 March 2008 to investigate and monitor these areas. <br /> • The monitoring wells located in the parking lot on the north side of Weber Avenue <br /> (see the area identified in Attachment 2) continue to exhibit high levels of separate <br /> phase hydrocarbons. Monitoring wells 19, 43, 47, 48, and 49 were not sampled due <br /> to the presence of "Sheen" or "SPH". It is apparent that additional remedial <br /> measures need to be implemented in that area to more quickly and efficiently <br /> remove the separate phase product. A work plan for implementing additional <br /> remedial activities in the parking area is required to be submitted by 14 March 2008. <br /> California Environmental Protection Agency <br /> �d Recfrled Paper <br />