SITE INFORMATION AND CORRESPONDENCE

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,Moore Truck Lines - 2 - 22 December 2011 3400 Newton Road, Stockton San Joaquin County Maximum results of groundwater investigations, reported in micrograms per Liter (ug/L), are summarized in the table below. Date Media TPH TPHd B T E X MTBE TBA 1,2-DCA TAME 6-99 grab water 2,400 NA 19 10 13 170 160 NA NA NA 11-99 water 970 NA <0.5 <0.5 <0.5 <0.5 37 <5 NA <1 6-00 water 600 NA 3.8 0.98 <0.5 0.55 13 10 NA <1 2-02 water 420 140 1.0 1.3 <0.5 0.64 10 <1 22 <1 6-02 water 330 210 2.1 0.81 1.0 2.7 180 <50 22 6.4 4-04 grab wate <50 <50 <0.5 <0.5 <0.5 <0.6 <1 <10 <1 <1 6-07 water 700 NA <0.5 <0.5 <0.5 <0.5 630 <10 3.2 45 2/08 water 400 NA <0.5 <0.5 <0.5 <0.5 390 NA <1 <1 2-11 grab water <50 NA <0.5 <0.5 <0.5 <0.5 <0.5 NA NA NA 3-11 water 140 NA <0.5 <0.5 <0.5 <0.5 120 1 NA NA NA 8-11 water4 800 NA <0.5 <0.5 <0.5--F<0.5 590 1 NA NA NA 1 =groundwater results from MW-1 with standard purging. Note MW-1 is often dry while deeper(but screened across water table)adjacent MW-8 water results are non-detect 2=CPT-1 grab water 3=insufficient water in MW-1 to purge, sample taken as grab 4=MW-1 purged dry at 0.4 gallons,took over 1 hour to recharge up 1 foot in well. One of the two Site domestic wells, DW-1 (140' northeast of MW-1) was sampled from 2000 to 2008, and all results were non-detect for petroleum hydrocarbons. The second Site domestic well, DW-2 (60' east of MW-1) reported low levels of TPHd (280 ug/L), toluene (1 ug/L), and xylenes (1.1 ug.L) in October 2000. DW-2 was properly destroyed in December 2000. The seven monitoring wells around MW-1 (MW-2 through MW-8) and onsite domestic well (DW-1) sample results were non-detect when sampled, indicative of a limited source of contamination in soil at MW-1. MW-1 has reportedly been dry or contained inadequate water to purge through much of the investigation, due to a drop in water levels since installation in 1999. MW-1 is screened from 44' bgs to 63' bgs in silty clay, and does not recharge quickly when dewatered; resulting in elevated groundwater concentrations when compared to adjacent (10' to the southeast of MW-1) MW-8 (screened 60' to 70' bgs) which had been non- detect for petroleum hydrocarbons from 2008 to present. The extent of the groundwater plume is defined as 10' to the northwest of non-detect MW-8 to 30' to the east of MW-1, based on groundwater results from nearby borings and monitoring wells MW-2, MW-3, MW-6, and MW-7. Groundwater monitoring since 1999 shows the MTBE plume (the TPHg is primarily MTBE, with no B-T-E-X reported since August 2002) around MW-1 is stable though very slowly declining in concentration. Monitoring continued until June 2009, when all work stopped due to the financial hardship of the responsible party (RP). On 20 December 2010, the San Joaquin County Environmental Health Department referred the Site to the Regional Board for recalcitrance. Regional Board staff (Staff) met with the representative (son) of the RP on 4 January 2011. Groundwater monitoring resumed in February 2011 and ended with Staff approval in August 2011. It was determined that additional work to conduct limited remediation was no longer cost effective, nor was it necessary to continue monitoring the small stable plume that 11 years of groundwater monitoring show is not threatening sensitive receptors.