Reso PC16-23 PC 0116 Reso CEQA - Sandpiper

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Section 4.0— Environmental Setting and Discarssion oflmpacts evidence of hazardous materials spills were observed during the site reconnaissance. There were no substantial quantities of hazardous materials observed on the project site that, if accidentally released, could result in soil and/or groundwater contamination beneath the site. Soil Quality The US Environmental Protection Agency (EPA) developed Regional Screening Levels (RSLs) to screen sites for potential human health concerns where releases of chemicals to soil have occurred. The RSLs are recommended for use by the Department of Toxic Substances Control (DTSC). RSLs are considered to be protective for humans (including sensitive groups) over a lifetime. Under most circumstances, the presence of a chemical in soil below the corresponding RSL can be assumed not to pose a significant risk to human health. Soil samples were collected in 2013 from four locations on the project site. The samples were analyzed for gasoline, diesel and oil range petroleum hydrocarbons, organochlorine pesticides, chlorinated herbicides, organophosphorus pesticides, PCBs, VOCs, semi -VOCs, 17 California Assessment Manual (CAM) metals, hexavalent chromium, and naturally occurring asbestos (NOA). The samples also were analyzed for selected soluble metals. Laboratory analyses of the samples did not detect gasoline range petroleum hydrocarbons, chlorinated herbicides, organophosphorus pesticides, PCBs, volatile organic compounds (VOCs), semi -VOCs, or hexavalent chromium. Meta] concentrations were detected at typical natural background levels. The only organochlorine pesticide detected was DDE. DDE was detected in one sample at a concentration of 0.0014 milligrams per kilogram (mg/kg), which is well below the 1.6 mg/kg residential RSL for DDE. Diesel and oil range petroleum hydrocarbons were detected at up to 4.5 and 15 mg/kg, respectively. The detected diesel and oil range petroleum hydrocarbon levels are well below the Regional Water Quality Control Board's (RWQCB) 100 mg/kg residential Environmental Screening Level (ESL). Naturally occurring asbestos (NOA) was also detected. The detected NOA concentration in three of the four samples were below the DTSC's asbestos screening level of 0.01 percent. Therefore, per DTSC guidelines, NOA levels at the project site are not considered significant. Based on the results of the soil sample analysis, soil quality at the project site does not appear to have been substantially affected by hazardous material contamination. Building Materials Asbestos was commonly used in building materials until 1981, and the use of lead in paint and polychlorinated biphenyls (PCBs) in fluorescent in ballasts was not regulated until 1978. Sandpiper Elementary School was constructed in the 1990's; therefore, it is unlikely that asbestos containing materials (ACMs), lead-based paint, or other hazardous materials are present in building materials on the campus. City of Redwood City 50 Initial Study/Mitigated Negative Declaration Sandpiper Elementary Schoo! FaeiGties Expansion November 2016