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Aft U gradier� Environments"I•�G f '§ j ° ' "�.t November 21 , 1995 Mr. Michael Infurna, REHS Public Health Services J Division of Environmental Health San Joaquin County 304 E . Weber Street Stockton, CA 95201 Subject: Results of November 4, 1995 Investigation Swett & Crawford Building 711 N. Pershing Avenue Stockton, CA Project No. 95025 Dear Mr. Infurna: The purpose of this letter is. to summarize a limited investigation that was performed by Upgradient Environmental at the referenced property on November 4, 1995 . 'The purpose of the investigation was to locate and re-sample that area of the property where pesticides had- been detected in the soil in. 1993 . Upgradient attempted to use the small-scale site map that' was included in RESNA' s 1993 report to locate the target area. However, based on your recollection of the work area in , 1993, the location shown on the RESNA map was too far to the east (too near Pershing Avenue) . After approximately '.one-half hour , of. discussion, V & W Drilling attempted to move their drilling rig onto the property to the- location marked by you. However, the turf was too soft- and wet, causing the rig .to form deep ruts in th,egrass . .We then elected to drill three borings by hand, using V & W' s hand augering equipment. The location of the borings is shown in 'Figure 1 . .All three were augered to a depth of 5 feet, and a sample was collected by placing two 2 x 6-inch brass tubes into the auger and continuing to drill until the tubes were filled with soil . The tubes were then removed, and the bottom tube was sealed and labelled for transport to Sequoia Analytical Laboratories . The samples were analyzed using EPA method 8080 for pesticides . The .laboratory report is attached. dane and 4 , 4-.DDT were ec Chlordetted in sample SP-8 . .Both of these 3 compounds had been• previously detected�. by RESNA in boring ' B-4, indicating that SP-8 is probably located close to this ' boring. -detected in B-4 were approximately However, the concentrations 1 , 000 times greater than those in SP-8 . { Upgradient intends to continue thisinvestigation by hand augering an additional boring near SP-8, collecting samples at 5-foot intervals, beginning at 7 . 5 feet. Upgradient will use its portable Beaver auger . rig, which utilizes 3-inch-diameter hollow-stem augers, a stainless -steel core barrel, and 1-inch-diameter plastic roundwater, which is to � sample sleeves . The boring will be drilled g estimated to be 20 feet or less . A 1-inch-diameter plastic bailer 4111 82nd Street 3369 Kimberly Road Sacramento, CA 95826 Cameron Park, CA 95681 (916) 452-2891 (916) 67-7-3055 1 B "' Fax: 457-1817 Fax: 677-3055