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tl <br /> ` J. H. KLEINFELD R &ASSOCI'TES <br /> ' Two samples from each boring, those which exhibited the highest PID <br /> c .4.4 readings during: qualitative field screening, were also analyzed for <br /> aromatic hydrocarbons (BTX) by EPA Method 8020. <br /> Falling head permeability tests were performed on six soil samples to <br /> understand the general infiltration rates at the site and the feasitility <br /> of using an underground soil--vapor extraction system and/or an in-situ <br /> biological treatment method for site remediation. <br /> 3.5 FINDINGS <br /> 'j The data from the chemical analysis of 44 soil samples collected in this <br /> phase of the investigation and of 6 soil samples collected duringPhase e 1 <br /> are summarized in Tables 1 through 4. Table 1 contains the laboratory <br /> h data on total petroleum hydrocarbon concentrations and Tables 2, 3 and 4 <br /> t <br /> sv-,amarize the detected concentrations of benzene, toluene and.xylene <br /> [I respectively. The high detection limit for some of: the constituents <br /> �y <br /> (i.e., benzene) are due to matrix interference caused by higher <br /> contaminant levels present in some of the samples. The chemical data was <br /> also used to prepare 19 contour maps (?slates 27 through 45) displaying the <br /> approximate areal extent of contamination at five sampling depths and at <br /> two cross-sections across the site (Plates 46 through 49). Each map shows <br /> the concentration of either total petroleum hydrocarbons, benzene, <br /> tolueae, or xylene in parts per million (ppm) at a single depth below the <br /> f surface or along a . vertical cross-section through the site at the <br /> imn <br /> indicated location. <br /> A review of the data presented on the contour maps indicate thzt the size <br /> anO shape of the contaminated zine seems to be fairly consistent with <br /> ;j depth. The zones of high total petroleum hydrocarbons, benzene, toluene, <br /> w' and xylene concentrations correlate well with one another. <br /> ae At_--the----shallowest-- depth, --11---feet---below—the ground__-surface- tile___ __--- - --__-.- <br /> contaminated zone appears to be elongated in the northeasterly direction <br /> 4 and is about 40 ft long by 20 ft wide. At 16 and 21 feet below ground <br /> surface, the contaminated zone is almost circular with a diameter of <br /> approximately 35 feet. Contaminant concentrations are probably higher <br /> 38-87-437 <br />