COMPLIANCE INFO_1990-1998 - Laserfiche WebLink

Home Browse Search

Mr. Vaughn 2 1 March 1995 numbers referenced in Figure 1, Appendix 3, of the workplan appear to correspond with what we approved, but do not match the sample numbers referenced in the Report. These discrepancies made it difficult to evaluate the results of the sampling. The Report states the City of Tracy's intention to reuse the subject soils in road construction projects at the following locations: 1-205 Corridor Corral Hollow Road construction of Naglee Road roadway improvements for Grant Line Road and 1-205 Interchange, including ramps. However, no information on the soil types, depth to groundwater, or geology is given regarding these areas, as the City agreed to do, and as stated in findings 12 and 13 of WDR Order No. 94- 216. Specification BA.b of Order No. 94-216 states the standards that the soils must meet in order to be regarded as inert and suitable for reuse in construction projects. Those standards are: "low" levels of Total Oil and Grease, and non -detection for gasoline, diesel, and BTEX This specification was referenced in the staff letter dated 2 September 1994, which spelled out the applicable requirements, and explained that staff cannot change the contents of a Board Order. Staff's 3 October 1994 letter to Mr. Verma specifies that analytical detection limits shall be as close as possible to the USEPA Method Detection Limit. This is the specification contained in the Tri -Regional Boards' Staff Recommendations for Preliminary Investigation and Evaluation of Underground Tank Sites. For soils, the appropriate detection limits (PQLs) for the analyses specified above are: for gasoline: 1.0 ppm for diesel: 1.0 ppm. for BTEX: 0.005 ppm for TOG: 50 ppin. In the absence of matrix interferences, these limits are achievable by most labs. These limits are lower than the limits referenced in the California LUFT Manual, a document that this office does not use or recommend. Both the consultants and the analytical laboratory for this project have been apprised of our procedures by staff prior to this project. Although the field and laboratory analytical records and chain of custody records submitted with the Report are incomplete and inadequate, (for example, holding times and method of sample handling are not clearly stated, and the chain of custody does not indicate the analyses requested) the analytical results as reported appear to indicate that the detection limits used by the lab (Friedman and Bruya of Seattle, WA) were too high. For example, although the lab reports do not state the detection limit, results are reported as "lower than 0.04ppm " for benzene, toluene, and etheylene, and as "lower than 0.08 ppm" for xylenes. This suggests that the limit used was 0.04 ppm or higher, significantly higher than the recommended 0.005 ppm. The lab should explain