AgdaPkt 2007-04-09 - Laserfiche WebLink

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9A Pag�ge 64 RTD Test !?e�!�!±�, 2006 RTD tested nine locations an the project site at 8-, 10-, 12- and 15-foot depths, which are summarized in Table 1 of RTD's repart (Attachment B to the IS/MND). The results show that all of the samp[es collected from 8-, 10- and 12-foot depths were below the laboratory reparting limits for gasoline-related petroleum hydrocarbons. Trace levels of Ethyl-benzar�e, Xylenes and MTBE were detected at the 15-foot dep±h at only five of the nine locations. None of these concentrations were abave the Environmental Screening Level established by the San �rancisco Bay Regional Water Quality Control Board (SFBRWQCB}. Geomega lnc. Numar� Health Risk Assessment, 2�Q? The San Mateo County Health Department requested a Human Health Risk Assessment be conducted for the proposed development at the project site. The Risk Assessmen#was prepared by Geomega inc. and daied tviarcn 2, 2007. This repuri 5uppien�ents �xist�ng information on soil and water contaminants. The report focused on the potential for cantamination in groundwater originating from spills at the Gas & Shop site that has traveled beneath the project site to enter the air within the underground parking garage. The report states that based on consistently conservative estimates, with a large margin of sa#ety, that migration of toxics from groundwater info the parking garage will not be of concern for future onsite residents. Conclusions The proposed project will require excavation down to 10.5 feet below grade for #he basement, and 12.5 feet below grade for the eleva#or pit. Because there are no toxics detectabie until a depth of 15 feet, and even at that dep#h the measured toxics are within acceptable limits provided by SFBRWQCB and are focated in the groundwater, there are no significant negative impacts from toxics in the sail or groundwater associated with construction or occupancy of the propased project. The proposed projec# is also bound by the mitigation adopted with the Planning Commission's approval of the !S/MND.