SITE INFORMATION AND CORRESPONDENCE

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CLEARWA TER G 'R O U P, I N C. EPA Test Method for Evaluating Solid Wastes (SW 846) This EPA sampling methodology uses data generated during,previous sampling .activity and applies a statistical analysis to determine the number of samples needed to evaluate. the stockpile. Using this method and the "April 1993 analyticaldata,-,a- minimum number of four samples for analysis may be calculated (calculations'attached EPA method suggests taking slightly more than the minimum. Using this method, Clearwater would take six samples to be analyzed. It should be noted, however, that the assumptions required by-this method may be rendered.invalid by your .assertion that soil was added to the stockpile. One .Sa_mole,/25--Ya-rds - PH-S/EHD-also-suggests=the --collectio-ii=.of' orie-`sample: for every 25 cubic yards in.the January 12 letter. Clearwater personnel visited'the site on January 31'r 1995 and estimatedthe volume of soil at 800 to 900 cubic yards. This would require 32 to 36 discrete samples for the stockpiled soil:at 7735 S. Hwy. 99, and additional samples from the small stockpile at 1111 N. Union. While this may be a PHS/EHD preference, it should again be noted that the'Tile was- Y s-sampled previously Cummings, that the Cummings methods have not been determined be invalid._ �eS and that subsequent sample analysis ' indicated .'the presence- of no detectable- concentrations of petroleum hydrocarbons.' ' The.PHS/EHD also includedguidance concerning sampling of pipi g trenches one S sample per 20 lineal feet). If is:unclear_ how- this sampling protocol could be applied in the current situation. �^x One Composite/25 Yards - An alternative ,to the two PHS`/EHD options that were offered in your letter that may, prove to 'be a reasonable involves sample compositing. This approach involves the collection of a single sample per 25 cubic " yards of soil and.the in-lab compositing`of groups of four samples associated with 100 yard blocks of the pile: If any :of.,the .requested analytes' test .positive , it concentrations exceeding those acceptable to the PHS/EHD in any of:the;comvosites, then each discrete sample comprising the'r composite,will be tested for 'the specific analyteof concern. This method involves the' collection of 32 - 36.discrete samples and the creation of 8 - 9 composites (more samples .than the EPA plan, less than the 1 per 25 plan). Recommendation Clearwater recommends the composite-sampling plan alternative. Based on the pile characterization completed to date and the needs_ of this_ sampling, effort, it is anticipated that the results of this approach .will provide the PHS/EHD with appropriate information." A grid.will be-laid out upon,the pile with string or marker tape, enabling the sampling of pre-measured blocks of 25 cubic .yards. Samples will be collected with a hand auger or slide hammer .lined with brass sleeves. -The brass liners will be driven into :the .designated sampling .1ocations'r removed from the y _ t