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• <br /> Mr. Charles A. McLaughlin - 2 - April 10, 1987 <br /> Our next task includes installation of six groundwater monitoring wells. During drilling of <br /> these wells, soil samples will be collected in order to assess whether the oily dirt <br /> constitutes a hazardous or non-hazardous waste. The following analyses will be performed <br /> on samples from approximate depths of 2 and 8 feet at the two locations shown on <br /> Plate 1: <br /> EPA Method 8240 <br /> EPA Method 8270 <br /> CAM Metals <br /> Sulfide Reactivity <br /> Ignitability <br /> Oil and Grease. <br /> One of these locations constitutes a background sample. <br /> In addition, two samples will be collected from the locations labeled 3 and 11 shown on <br /> Plate 1. Samples were collected at these two locations by Kennedy/Jenks/Chilton in <br /> 1986. At location 3, analyses by Kennedy/Jenks/Chilton indicated the presence of <br /> methylene chloride and chloroform at levels of 10 and 1.5 mg/kg, respectively. At <br /> location 11, several semi-volatile organics were detected. These included eight PNA's at <br /> levels ranging from 15 to 110 mg/kg, isophorone at 6.3 mg/kg, and N-nitrosodiphenylamine <br /> at 50 mg/kg. <br /> Neither methylene chloride nor chloroform are typical constituents of petroleum <br /> products. These results may have been the result of contamination introduced during <br /> laboratory handling. The presence of N-nitrosodiphenylamine and isophorone is also <br /> questionable because sample spectra did not match reference spectra for these <br /> compounds. We therefore believe that additional sampling is required to evaluate <br /> whether these contaminants are indeed present before the hazardous/non-hazardous <br /> determination can be made. Dames and Moore will be collecting the samples and Acurex <br /> Laboratories of Mountain View will perform the analyses. When the analyses are <br /> complete, we will forward the results to the Department of Health Services. <br /> We have included the Kennedy/Jenks/Chilton Phase I Site Assessment Report and the <br /> Dames and Moore Phase II Site Assessment work plan for your information. Should you <br /> have further questions regarding this investigation, please contact Ms. M. E. Metcalf at <br /> (415) 894-9320 or Mr. L. J. Siebert at (415) 894-9325. <br /> Very truly yours, <br /> 1 <br /> V <br /> MEM:bw/c <br /> Attachments <br /> cc: Mr. Tony J. Landis, DOHS (w/o attach.) - Per telecon 4/10/87, we are sending this <br /> letter to Mr. McLaughlin as discussed. <br /> Mr. Michael E. Locke, Tracy City Manager (w/o attach.) <br /> IVis. Laurie Cb7tulla;San Joaquin Local Health District (w/o attach.) <br /> Mr. Davi&L_._Brent1 entral Valley RWQCB (w/o attach.) <br />