SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

Mr. M. Scott Mansholt—CEMC March 31,2005 Site Investigation Work Plan, Mountain House Site#6 Page 3 of 5 PERMITTING AND ACCESS Prior to conducting field activities, SAIC will obtain soil boring permits from the San Joaquin County Public Health Services(SJCPHS). Access to advance any borings located in the Mountain House Community Services District(MHCSD) ROW will require an encroachment permit and traffic control. SAIC will prepare the encroachment permit application and traffic control plan and submit both documents to MHCSD for approval. If required, CEMC will post a performance bond for work conducted in the MHCSD ROW. The proposed borings are likely to be located on private property and will require an access agreement. CEMC will secure access to these properties prior to any fieldwork. A site-specific health and safety plan (HASP) will be prepared prior to any field activities. The HASP will include driving directions to the nearest hospital, a hospital route map, and job safety analysis of the work activities to be performed. The HASP will be kept on site, reviewed daily with all on-site personnel, and made available for review during investigation activities. While marking proposed boring locations, potential safety concerns and obstacles to the proposed scope of work will be observed and noted, such as overhead lines, marked and unmarked underground lines, and pedestrians and automobile traffic. Underground Service Alert(USA) will be notified of all proposed boring locations at least 48 hours prior to any intrusive field activities. All USA ticket alerts will be 3 confirmed and cleared prior to any intrusive field activities. In addition, SAIC will subcontract a private utility locator to clear the proposed boring locations for underground utilities. All fieldwork will be conducted in accordance with SAIC's standard operating procedures (SOPS). WATER WELL SEARCH SAIC will conduct a search of DWR files to obtain information on water production wells used for domestic, irrigation, municipal, and/or other uses within a 2,000-foot radius of the site. A copy of the Well Completion Report Release Agreement—Agency Form will be forwarded to the RWQCB for authorization and signature. Following this search SAIC will prepare a table containing the State Well Number, location, and water use (if available), which will be included in the soil and grab groundwater investigation report. SOIL BORINGS Based on the results presented in the Condor report(2001), soil borings will be advanced to a targeted depth of 30 feet bgs and a maximum of 35 feet bgs. Direct-push technology will be used to advance the proposed soil borings. The borings will be continuously cored and field screened using a photoionization detector to detect the presence of residual petroleum in soil. The soil will be logged in general accordance with the Unified Soil Classification System as presented in ASTM 2488-90 and under the supervision of a California Registered Geologist. All down-hole equipment will be cleaned using a Liquinox/water solution to prevent the possibility of cross contamination between consecutive boring locations. The proposed boring objectives presented in Table 1 outline the areas of investigation adjacent to the former OVP ROW and purpose of the proposed soil boring locations shown on Figure 2. SAIC proposes to collect soil samples from selected borings for use in a future human health risk assessment(HHRA). These soil samples will be collected from an approximate depth shallower than 10 3 feet bgs from the proposed soil borings. SAIC will submit a minimum of one soil sample from the upper 10 feet of borehole at either the 1 foot or 5 feet-bgs interval if no impacted soil is observed to the depth of 10 feet bgs, or above groundwater if water is observed shallower than 10 feet bgs. However, if affected soil is observed above 10 feet bgs, SAIC will collect a soil sample for HHRA purposes from the most affected interval. Soil samples collected for the HHRA will be analyzed for the same constituents as all other samples. However, soil samples collected for HHRA purposes will be analyzed using a detection limit that is sensitive (low)enough to detect concentrations of constituents that are not of human health concern.