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Q Limited Phase 11 Subsurface Investigation Report 902-908 East Scotts Avenue Stockton,California a ntea g ro u p Antea Group Project No. UPR82572A 3.3.6 Pesticides The laboratory tested a total of 8 soil samples for pesticides. None of the samples submitted had concentration detected above the LRL. Table 4 includes a summary of the analytical data for pesticides. 3.4 Quality Assurance/Quality Control (QA/QC) QA/QC measures included laboratory method blanks and quality control (QC)samples and a QA/QC data validation check on the laboratory's analytical results for the samples collected on April 12-13, 2012. The laboratory report is included as Appendix C. The following table summarizes Antea Group's review of the QA/QC results. Laboratory QA/QC Performed: Yes Laboratory method blanks and quality control Yes,two data qualifiers were noted^ samples analyzed: Are the data valid for their intended purpose? Yes Explanations: ^Qualifier"X"=Surrogate is outside control limits ^Qualifier"D"=Surrogate or matrix spike recoveries were not obtained because the extract was diluted for analysis;also compounds analyzed at a dilution may be flagged with a D. Based on a review of the laboratory's analytical reports, including the laboratory QA/QC procedures and those implemented by Antea Group, we conclude that the laboratory data obtained during this soil sampling event are valid and usable for their intended purpose. 4.0 CONCLUSIONS AND RECOMMENDATIONS On April 12-13,2012,Antea Group and subcontractors completed a limited,shallow soil sampling event at the 902- 908 East Scotts Avenue property located in Stockton, California. Antea Group's subcontractor advanced a total of 20 soil test borings by hand auger and direct-push rig at the locations depicted on Figure 3. Antea Group field-screened soil samples and collected a minimum one sample from each boring for submittal to a state- certified laboratory for analysis by one or more of the contaminants of concern listed in Section 3.2.3. • Field screening of shallow soils indicated elevated PID readings at B3, B6, B7, and B15. Laboratory data indicated that certain soil contaminants, including VOCs and petroleum constituents, are present at concentrations greater than industrial screening criteria in shallow soils at B3 and B7, coinciding with the higher PID readings. • Laboratory analytical results indicate that VOCs, PCBs, and pesticides do not appear to be a significant or widespread environmental concern at the site. However, a trace level of PCBs reported in B7 could indicate a greater concern in that area of the property. The PCB detection coincides with the highest levels of petroleum reported in this investigation. • Trace to low-level PAH concentrations appear scattered across the site in shallow soils. This may be an artifact of the historical industrial usage of the property or a condition of shallow soils used for site 9 www.anteagroup.com