FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

' Confirmation samples were collected for every 25-by 25-foot area(every 625 square feet) ' within the limits of excavation(bottom samples)and at discrete locations approximately every 25-linear feet along the perimeter of the excavation(sidewall samples). Samples were generally collected at the surface to a depth of three inches. Sample locations were marked with flags prior ' to sample collection. Confirmation sample locations were sketched in field notes,with approximate distances to each sample point measured from the existing fence line east of the ' excavation. Approximate confirmation sample locations and March 2017 excavation limits are depicted on Figure 2. ' Confirmation samples were collected with a stainless-steel trowel. Prior to collection of the sample,the area to be sampled was scraped with a decontaminated trowel to expose a fresh ' surface. Samples were collected in pre-cleaned glass jars. Glass jars were filled completely with soil from the exposed sampling face using a decontaminated stainless-steel trowel. A sample label was attached to each sample container. Sample jars were packaged in zip-closure plastic ' bags and then placed on ice in a cooler for storage and transport to the analytical laboratory under chain-of-custody procedures. Reusable sampling equipment was cleaned prior to and after each use by washing with Liquinox (or equivalent non-phosphate containing detergent)solution in water and subsequent rinsing with ' clean water. 3.1.1 March 2017 Analytical Results Confirmation samples(63samples total) were analyzed by Asset Laboratories for total lead by ' EPA Method 6010B. A total of 15 samples(-25%of the confirmation samples) were analyzed for California Assessment Manual (CAM)Metals by EPA Method 601013/7471A and ' polynuclear aromatic hydrocarbons(PAHs)by EPA Method 8270C/SIM. Analytical results for lead and CAM metals are summarized on Table 1 and analytical results for ' PAHs are summarized on Table 2. Analytical reports and chain-of-custody documentation for the March 2017 confirmation samples are included in Appendix D. The cleanup goal for lead(80 mg/kg)was exceeded in four samples(MFR-B-9,MFR-B-11, MFR-SW-9, AND MFR-SW-10). All other metal concentrations were below cleanup goals. ' Cleanup goals were not established in the SREW for PAHs. PAHs were only detected at low ' concentrations in six of the 15 samples analyzed. While most organic chemicals are considered to be man-made and not naturally occurring,there is historical evidence that PAHs are found in surface soils throughout California. A background study for carcinogenic PAHs in Northern ' Alift PACIFIC EDGE ENGINEERING 3 Closure Report_final.doc ' (949)470-1937;(949)470-0943(FARC)