COMPLIANCE INFO - Laserfiche WebLink

Home Browse Search

k`■ KLEINFELDER 7 CONCLUSIONS AND RECOMMENDATIONS 7.1 GEOPHYSICAL SURVEY A geophysical survey was conducted and a magnetic contour map created for the proposed March Lane Extension within the building area of Blossom Ranch. Although the buildings, equipment, and debris in the area limited the interpretation of magnetic contours, four areas of interest were noted. Two of the four areas of interest were evaluated as potential UST locations, and included the area north of the hulling shed and southeast of a cinder block addition (See Plate 3). A limited soil assessment was conducted in these two areas. 7.2 ORCHARD AREA The analyte 4,4'-DDE was detected in five shallow soil samples within the proposed March Lane Extension. The concentrations of 4,4-DDE ranged from 7.32 to 25.5 µg/kg. These concentrations of 4,4 DDE detected does not exceed the Total Threshold Limit Concentration (TTLC) Regulated Level for classification of a DDE-containing hazardous waste per 22CCR§66261.24. That regulated level for 4,4'-DDE is 1,000 µg/kg for the sum total of DDD, DDE and DDT. Additionally, the concentrations of 4,4'-DDE detected were all less than 10-times the Soluble Threshold Limit Concentration (STLC) Regulated Level as expressed in 22CCR§66261.24. The factor of 10-times the STLC Regulated Level is commonly used as an indicator as to whether or not a STLC analysis is appropriate to be ran on the sample. Therefore, in summary, none of the samples analyzed contained hazardous waste levels of 4,4'-DDE. Additionally, the concentrations of 4,4'-DDE encountered are below the U.S. EPA Region IX Preliminary Remediation Goals (PRGs) for Residential Property dated August 1, 1996 and therefore do not appear to warrant any further investigation or mitigation. It is Kleinfelder's experience that the concentrations of 4,4'-DDE are likely residual and not the result of a spill. Therefore, based on the concentrations present in the samples analyzed, and the conclusions noted above, Kleinfelder does not believe that any further investigation or mitigation is warranted with regards to the 4,4'-DDE in the areas sampled. 7.3 BUILDING AREA The eight soil samples were collected from two exploratory soil borings advanced within the building area of Blossom Ranch in suspect UST areas noted from a geophysical survey and from Kleinfelder's field observations. A total of eight soil samples were collected between 6 and 31Y2 feet bgs in the two borings. Each of the eight soil samples analyzed were found to be below 20-3712-08.E02/2018R 1090 Page 14 of 17 ©1998,Kleinfelder,Inc. December 23, 1998