SITE INFORMATION AND CORRESPONDENCE

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Attachment U.S. Environmental Protection Agency Comments on the Gramdwater Assessment Plan fcr the Kearney-KPF Facility in Stockton, California Page q Camment 8 Paragraph 3 indicates that waste oil and spent TCA were stoned in the former dnmmied waste storage area fon approximately two years. The final date of hazardous waste storage in this unit should have been stated. 11 The first paragraph refers to the excavation of test pits by Canonie Engineers in 1986. Although discussed in the referenced Canonie report, the locations of these test pits should have been indicated on one of the facility illustrations. 13 While the last paragraph roughly defines the boundary between the intermediate and deep hydrogeologic zones, the boundary between the shallow and intermediate zones is not mentioned. 18 The first paragraph indicates that the effect of p1miping at the CWS wells on the site groundwater flaw pattern will be analyzed. Is it the intent of "analyzed" that groundwater flora modelling will be performed? Please explain. 18 Paragraphs 2 and 3 provide transmissivity ranges for the shallow and deep portions of the aquifer, respectively, but no data is given for the intermediate zone. It is unclear whether this data was singly anitted on never determined. Please explain. 18 While Section 3.3.4 discusses the groundwater quality at the site, there is no canparable discussion of soil contamination. Since soil contamination data is provided in Appendix A, a discussion of these results shculd have been included. 23 Section 4.2.1 indicates that soil samples will be collected at 5' intervals at each of the three deep soil borings. Continuous care sampling shculd be undertaken at one of these locations, hawever, in order to obtain an additiaial control point for projecting stratigraphic data. 24 Section 4.2.2 proposes to discard the uppermost 1.5' of soil prion to surface soil sampling because (presumably) of the aeration and hanogenization of soil that occurs during di.scing. While any volatile constituents that may have originally been present prior to discing have probably been driven-off, other organics and/or metals may be present. As such, this upper 1.5' of soil should be sampled and analyzed for the same analytes as the soil below 1.51 . 25 Section 4.3 proposes that continucus cone sampling be perfcxmed at only one of the exploration borings. As these two borings are at opposite extremes of the facility and represent excellent control points, continuous core should be collected at both locations.