CORRESPONDENCE_2017 - Laserfiche WebLink

Home Browse Search

21 December 2017 AGE-Project No. 14-3154 Page 4 of 23 4.0. PREVIOUS INVESTIGATIONS AND FINDINGS The following is a summary of the previous investigations performed at the subject property between December 2014 and November 2017. Also included is a limited summary of the findings and a comparison of the results to the appropriate environmental screening levels. Soil and waste data are compared to: the August 2017 Human and Ecological Risk Office (HERO), Human Health Risk Assessment (HHRA)-Note 3 screening levels for commercial properties, published by the California Department of Toxic Substance Control (herein referred to as DTSC-SLs); to the May 2016 Environmental Protection Agency (EPA) Region 9 Screening Levels for industrial soil (herein referred to as RSLs); and to the San Francisco Bay RWQCB Environmental Screening Levels (TPH only) for commercial/industrial shallow soil exposure (herein referred to as ESLs). Additionally, water data is compared to the July 2014 State of California Maximum Contaminant Levels (herein referred to as MCLs). 4.1. PRELIMINARY INVESTIGATION A preliminary investigation of the subject property was performed in December 2014 as part of a pre-purchase due-diligence inspection. The following is a summary of the investigation.  On 05 and 08 December 2014, soil borings AB8 through AB21 (boring AB8 was the first boring advanced at the subject property) were advanced at the subject property. Borings AB8 through AB21 were advanced to 15 and 20 feet below surface grade (bsg) in and around the waste/glass handling area in the northwest corner of the parcel (Figure 3). Selected soil and groundwater samples were collected and analyzed for total petroleum hydrocarbons quantified as gasoline, diesel and oil range compounds (TPH-g/d/o); volatile organic compounds (VOCs); polychlorinated bi-phenols (PCBs); polynuclear aromatic hydrocarbons (PNA); polycyclic aromatic hydrocarbons (PAH) or semi-volatile organic compounds (SVOCs); and California Assessment Metals (CAM 17). Additionally, a total of four (4) groundwater samples were collected from borings AB8, AB10, AB12, and AB16 and submitted for selected analysis. Glass waste was only observed in one soil sample collected at a depth of approximately five feet bsg in AB18; the remainder of the borings did not encounter waste materials. Saturated soil was observed from the borings at depths of 15 feet bsg; and groundwater was encountered at approximately 20 feet bsg. Soil boring logs are presented in Appendix A. Constituents of concern were not detected above laboratory reporting limits in any of the analyzed soil and water samples collected from the borings. Various metals were detected in the soil samples at concentrations below the DTSC-SLs and RSLs or at levels consistent with background concentrations in California soils. (Tables 1, 4, 5, and 6).