COMPLIANCE INFO_2019 - Laserfiche WebLink

Home Browse Search

EnviroTech Consultants, Inc. Page 16 Site Investigation: Sampling Report Louise Avenue Water Treatment Facility 4.2 Secondary Sampling Soil Analytical Results Summary (September 12, 2018) Table 1 summarizes the soil sample analytical results and includes the SFBRWQCB ESLs for Direct Exposure Soil for Construction/Trench Worker and the EPA Carcinogenic Target Risk Dermal Screening Levels for comparison. The complete laboratory reports are included in Attachment 3. The resample collected from surface to 6 inches at COL2-1 had an arsenic concentration of 2.7 mg/kg, which is below the SFBRWQCB ESL threshold of 10 mg/kg and the EPA dermal screening level of 17 mg/kg. The second background sample collected northwest of the retention pond had an arsenic concentration of 6.7 mg/kg. Samples collected from COL3-4 had arsenic concentrations below the SFBRWQCB ESL threshold and the EPA dermal screening level. Arsenic was detected above the SFBRWQCB ESL in samples collected from the surface to 6 inches at sample location COL3-6 and COL3-7 and in the sample collected from 2 to 3 feet at sample location COL3-8. Arsenic was detected at 46 mg/kg in the sample collected from the surface to 6 inches at sample location COL3-8. This arsenic concentration is above the SFBWRQCB ESL and the EPA dermal screening level.All other samples collected had arsenic concentrations below the SFBRWQCB ESL and the EPA dermal screen level. 5.0 EXCAVATION AND DISPOSAL 5.1 Excavation Environmental Waste Minimization, Inc (EWMI) was contracted to excavate the affected soil from the retention pond and store the soil in roll-off bins. Samples collected from COL3-10 through COL3-13 had arsenic concentrations below the SFBRWQCB ESL threshold of 10 mg/kg and the EPA dermal screening level of 17 mg/kg. After discussion with the San Joaquin County Environmental Health Department, the area with these sample locations was determined to be not included in the excavation. The proposed excavation is shown in Figure 9. During excavation, the concrete apron surrounding the drainage inlet was cleaned, and the soil in proximity was removed using shovels and a broom with care not to break/damage the structure. On December 27-28, 2018 approximately 260 yards of soil was excavated and stored in 12 roll-off bins on Site. Figure 10 shows the approximate boundaries of the excavation area including the former sample locations.The excavation extended south and east of sample location COL3-9 and extended up to the base of the concrete apron. Photographs of the excavation area are included in the photographic logs in Attachment 1. 5400 Rosedale Highway Bakersfield, CA 93308 Tel 661.377.0073 Fax 661.377.0074