COMPLIANCE INFO_FILE 2 - Laserfiche WebLink

Home Browse Search

laboratory. Chain -of -custody forms and shipping information were not provided to PRC in the final report from Testing and Technology. Analytical methods are not explained in the Testing and tTechnology final report; only results were provided. At the time of soil -gas sampling, 0.19 inches of water was measured in tank 81713-1 (Appendix A, Photo 10). 4.0 RESULTS This section presents the results of field sampling performed at NCS Stockton for tank 81713-2 and tank testing results for 81713-1 and 81713-3. Laboratory reports for all soil samples are presented in Appendix C and tank testing documentation in Appendix D. This section also presents a discussion of the nature and extent of contamination. Soil Sample Analytical Results A review of the analytical results received from Compu Chem Western Division (Chem West) of Sacramento, California, indicates that holding times for organic lead analyses under DHS LUFT and EPA method 7420 may be questionable for samples NCS -3 and NCS -4. As stated in the Quality Assurance/Quality Control (QA/QC) Data Review Summary by PRC dated June 26, 1992, (Appendix C) there is no specified holding time for organic lead under the DHS LUFT method; however, the holding time had approached 18 days by the time the analyses were performed, thus leaving the non- detected analyte estimated and usable for limited purposes only. All other data appear to be acceptable upon a cursory review. ® Methods and specific values for each analyses are listed in Table 1. Analysis for ethylene dibromide were originally requested under EPA method 504 but were substituted with analysis for 1,2-dibromoethane under EPA method 8010. This was done because EPA method 8010 is more applicable to hazardous materials investigations in soils; The compound is the same with different names. Although only organic lead was originally requested, using EPA method 7420, total lead was also analyzed by EPA method 6010 even though it was not originally requested. In sample NCS -3, collected from the west end of the UST excavation immediately after tank removal, TPH as gasoline was reported at a concentration of 3,500 mg/kg. Other organic compounds reported above laboratory detection limits in sample NCS -3 were 30 mg/kg benzene, 140 mg/kg toluene, 330 mg/kg total xylenes, and 77 mg/kg ethylbenzene. 11 12