ARCHIVED REPORTS_XR0013013 - Laserfiche WebLink

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CHAPTER 5 SITE CLOSURE ACTiVJTIES 111 } As discussed in Chapter 3, the soil was demonstrated to be nonhazardous and the hydrocarbons to be nonleachable. As7wel-, the lack of destruction of- the hydrocarbons`by- obioreinediatior , -as discussed in Chapter 4, further demonstrates the stability of the long chain hydrocarbons `and the unlikelihood of their mobility: Therefore, Brown and Caldwell (BC) recommended that the excavation be backfilled with the soil (Attachment F). Prior to backfilling, { BC recommended collecting additional soil samples to document the amount of petroleum hydrocarbon in the soil to be left in place. The County verbally agreed with this recommendation } and the specific site closure activities occurred. The 1993 work conducted by BC was done in accordance with the Site Safety and Health Plan included as Attachment H. I Once the physical limits of the excavation had been reached, 10 confirmation soil samples were collected from the sidewalls and bottom of the excavation. The samples were collected by BC on September 20, 1993, under the direct supervision of the San Joaquin County Public Health Services Department (County), at locations mutually agreed upon by BC and the County. Sampling followed the procedures outlined in the September 3, 1993, BC Status Report for Kent's Oil Remediation Project, included in Attachment F. The samples were analyzed for total petroleum hydrocarbons as diesel (TPHd) and total petroleum hydrocarbons as motor oil (TPHmo) following the procedures outlined above. Samples were also analyzed for TPHd and TPHmo following the toxicity characteristic leaching procedure (TCLP) (EPA Method 1310). TPHd and TPHmo were identified in one of the 10 confirmation samples collected from the excavation at concentrations of 37 milligrams per kilogram (mg/Kg) and 38 mg/Kg, respectively. I e However, the results of the 10 confirmation samples analyzed for TPHd and TPHmo following the TCLP method indicated that these petroleum hydrocarbons were not leachable from the soil. The locations of the confirmation samples are shown on Figure 5-1, and Table 5-1 presents the analytical results. 3 On September 20, 1993, BC also collected under the supervision of the County, 32 soil samples from the stockpiled material for laboratory analysis. The samples were composited by { the analytical laboratory at a ratio of 2 to 1 and the resulting 16 composite samples were analyzed for the presence of TPHd and TPHmo, following the TCLP procedures described above. In addition, five of the composite samples were also analyzed for TPHd and TPHmo following EPA Method 8015 modified. Analytical results of the EPA 8015 modified analysis identified TPHd and TPHmo concentrations ranging from 180 mg/kg to 2100 mg/kg, and 480 mg/kg to 3600 mg/kg, respectively. Results of the TCLP analysis indicated that the TPHd and TPHmo identified in the soil is not leachable. Table 5-2 summarizes the results of the stockpile confirmation soil samples. The complete laboratory reports and chain-of-custody documentation l Use or disclosure of data contained on this sheet is subject to the restriction specified at the beginning of this doctunent. 12n Z9 SIC\760M M10RTSKEYr-0ILCLO Q�1SPSi00 F