FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

Limited Site Investigation Corral Hollow sho in center,Tracy,California front of the OSH store at the Corral Hollow shopping center.Soil boring locations were selected based on the information obtained from these sources,which are listed in the References section. Investigation Activities General Approach The soil investigation was performed between 10 p.m. and 6 a.m.on June 4 and 5, 2013, and included collection and analysis of representative soil samples at the Site.Soil samples were analyzed forTPHc„TPH as diesel(TPHd),and PAHs. Sample locations were selected to systematically cover the area within 75 feet of the front of the OSH store. Shallow soil samples were collected at eight locations from three depth intervals between one and eight feet below ground surface(bgs).The two shallow soil samples from each soil boring location were submitted for laboratory analysis. Preparatory Activities Terraphase prepared and submitted a soil boring permit application to the San Joaquin County Environmental Health Department.Terraphase contracted and oversaw a private utility locating company to identify and mark subsurface utilities at the Site prior to the investigation. Underground Services Alert was notified more than 48 hours priorto commencing the work.Terraphase prepared a site-specific Health and Safety Plan (HASP)for the investigation activities. Sampling Methods Soil samples were collected using a hand auger and a hydraulic direct-push drill rig.Terraphase subcontracted Gregg Drilling and Testing, a California-licensed drilling contractor to advance the soil borings under the supervision of a Terraphase California Professional Geologist. Due to the location of the Site, in front of an active retail store,the soil sampling activities were conducted during the hours of 10 p.m. and 6 a.m.to minimize disturbance during store hours. Soil samples were collected from eight soil borings spaced at approximately 100-foot intervals across the investigation area (Figure 2).The soil borings were advanced to a depth of eight feet bgs. Soil samples for laboratory analysis were collected from each boring location at four depth intervals. At each soil boring location,soil samples were collected at the following approximate depth intervals: 1-1.5 feet bgs,3-3.5 feet bgs, 5.5-6 feet bgs,and 7.5-8 feet bgs.The surface soil sample (1-1.5 feet bgs)was initially collected using a hand auger.The boring location was then hand-cleared to approximately 3 feet bgs using the decontaminated hand auger,and the 3-3.5 foot bgs sample was collected.The samples collected using a hand auger were immediately transferred into laboratory-supplied glass jars.The direct-push rig was then used to advance the boring to a depth of eight feet bgs. The core barrel was lined with a new, plastic liner to facilitate lithologic logging.The 5.5-6 foot bgs and 7.5-8 foot bgs soil samples were collected by cutting 0.5-foot sections of the intact core in the plastic liner and capping the ends of the liner with Teflon-lined caps.The samples were labeled and placed in a cooler for transportation to a California-certified analytical laboratory following chain-of custody protocols. Boring logs were prepared in the field and completed under the supervision of a California Professional Geologist. In addition to standard descriptors(e.g.,soil types, moisture,grain size) other pertinent field observations were recorded including organic vapor field readings (using a Terraphase Engineering Inc. Page 2 of 5