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• Pp Mary Environmental Assessment Report <br /> Pittman Elementary School,Stockton,CA <br /> December 10,2003 <br /> Page 3 <br /> • the site. The site and surrounding properties were observed to be generally level. Mixed residential and <br /> commercial land surrounds the site. Ingestion of soil is a potential exposure pathway <br /> 4.2 POTENTIAL EXPOSURE RELATED TO WATER PATHWAYS <br /> Because pesticide applications are typically restricted to the soil surface, the potential for these materials <br /> to impact groundwater at the site is considered to be minimal. Residual concentrations of pesticides are <br /> likely to be confined to the upper 6 to 12 inches of soil as a result of surficial application. Depth to <br /> groundwater is approximately 40 feet below ground surface (bgs). Groundwater is not anticipated to be <br /> used for drinking water at the site.Therefore water does not appear to be a potential exposure pathway. <br /> 4.3 POTENTIAL EXPOSURE RELATED TO AIR PATHWAYS <br /> Inhalation of chemicals is a potential exposure pathway. However, since pesticides are typically mixed <br /> with water and applied as a liquid, these materials are relatively heavy and are not likely to volatilize and <br /> become airborne. Any volatile fractions associated with the past use of chemicals at the site are likely to <br /> have dissipated at the surface, but may be present in the subsurface. Inhalation of chemically impacted <br /> dust and inhalation of volatile organic compounds from soil are potential exposure pathways. The <br /> possible volatilization of volatile organic contaminants in the subsurface and subsequent migration of <br /> these vapors into indoor spaces is a potential inhalation exposure pathway. . <br /> 5.0 SAMPLING PROCEDURE <br /> Condor personnel collected soil, groundwater, soil vapor, and paint chip samples at the site between <br /> . August 6 and 20, 2003. The sampling procedures were conducted in general accordance with the <br /> sampling plans described in the Work Plan. <br /> 5.1 LAWN AREA SAMPLES <br /> The approximately 14.5-acre site was divided into 15 approximately one-acre-sized sub-parcels. A <br /> discrete surface sample (sample numbers L1-S through 1,15-S) was collected from the approximate <br /> center of each sub-parcel from a depth of approximately 0 to 6 inches bgs, and a discrete subsurface <br /> sample (sample numbers Ll-D through L15-D) was collected from beneath each surface sample location <br /> at a depth of approximately 2.0 to 2.5 feet bgs. The 15 surface samples were analyzed for organochlorine <br /> pesticides. The deeper subsurface samples were frozen and archived by the laboratory, pending the <br /> surface sample results. <br /> Five discrete surface samples (Ll-S, L3-S, L7-S, L9-S, and 1,15-S) were analyzed for CAM 17 Metals. <br /> Three additional discrete surface soil samples (L5-S, L11-S, L13-S) were analyzed for arsenic. Surface <br /> samples L1-S, 1.3-S, L7-S, and L9-S were also analyzed for hexavalent chromium. <br /> Based on the surface sample results, selected subsurface samples were also analyzed. One discrete <br /> subsurface sample (L9-D) was analyzed for organochlorine pesticides. Two discrete subsurface samples <br /> (L3-D and L9-D) were analyzed for CAM 17 Metals. Two discrete subsurface samples (L1-D and L7-D) <br /> were analyzed for arsenic. Two discrete subsurface samples (L3-D and L7-D) were analyzed for <br /> hexavalent chromium. The sample locations are shown on Figure 3, Appendix A. <br /> • <br /> to CONDOR <br />