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LIMITED GROUNDWATER INVESTIGATION WORK PLAN APN 111-110-420 3314 N.DELAWARE AVENUE STOCKTON, SAN JOAQUIN COUNTY, CALIFORNIA November 5, 2024 1.0 INTRODUCTION This work plan was prepared by Condor Earth(Condor)to describe proposed Phase II Environmental Site Assessment (ESA) investigation activities at 3314 North Delaware Avenue, Stockton, California (Site) (Figures 1, 2, and 3, Appendix A). The purpose of the work is to investigate groundwater at the Site to evaluate potential impact to groundwater from a former dry cleaner. The Phase 11 ESA Investigation Work Plan will be conducted for the Robbins Family Limited Partnership(Client). 2.0 PROJECT BACKGROUND The Site comprises approximately 1.027 acres designated as APN 111-110-420, located at 3314 North Delaware Avenue, in Stockton, San Joaquin County, California. Condor reviewed Parter's Sub-Slab Soil Gas and Indoor Air Quality Investigation Report, 3314 Delaware Avenue, Stockton, California 95204, dated August 26, 2024 (Partner Report). The Partner Report identified that the Site was historically occupied by various dry-cleaning operations from as early as 1955 to at least 2012. As part of Partner's investigation, three (3) sub-slab soil gas samples, three (3) indoor air samples, and one (1) ambient air sample were collected and analyzed for volatile organic compounds (VOCs) by Method TO-15. Laboratory analytical results indicated that tetrachloroethane (PCE) was detected in soil gas beneath the Site at concentrations exceeding regulatory screening criteria. PCE was not detected in the indoor air samples at concentrations exceeding regulatory screening criteria. Partner's findings indicate that there is the possibility that soil and/or groundwater has been adversely impacted by a release from the former on- Site dry-cleaning operations. Condor's proposed scope of work includes advancing a total of three (3) direct push borings to collect groundwater samples for laboratory analyses. Work will be performed by a State-licensed (C-57 drilling license) drilling contractor under supervision of a Condor geologist. The Partner Report anticipated the depth to groundwater at approximately 15 feet below ground surface(bgs). 3.0 SUBSURFACE INVESTIGATION PLAN Condor will conduct the Phase II ESA based upon the findings of the Partner Report. A utility's location service subcontractor will be used to identify the position of underground utilities and evidence of tank excavation backfill and/or any underground storage tanks (USTs) that may remain buried at the Site. Condor will advance up to three (3) borings to an estimated depth of approximately 20-30 feet bgs to investigate whether subsurface soil and/or groundwater contamination is evident at the Site. Three groundwater samples will be collected. Condor will utilize a State-licensed (C-57 drilling license) drilling contractor to conduct the drilling. We anticipate using a drilling rig equipped with direct push capability, which will minimize soil cuttings generated during the investigation. Any soil cuttings generated during the investigation will be placed in a 55-gallon drum or lidded plastic bucket, sealed, labeled, and left on-site pending laboratory analyses for 40 CONDOR