WORK PLANS - Laserfiche WebLink

Home Browse Search

tMS Mr. Jim Barton RWQCB July 26, 2012 Page 3 extent of TPHd, one boring will be drilled in the immediate vicinity of Boring B-14 to facilitate the collection of a groundwater grab sample and assess if groundwater has been impacted. Two additional borings will be drilled to the southwest (down gradient) and east of Boring B-14 to assess groundwater conditions in this area. Groundwater samples were not collected in these areas during the previous investigations. Groundwater samples and one soil sample from each boring will be analyzed for TPHg, TPHd, and VOCs. Boring B-15 Area (Southeast Portion of the Site) Three Shallow Borings Previous investigations conducted at Boring B-15 found TPHd in soil at 25,000 mg/kg in the sample collected from 15 feet bgs in August 2005. To further characterize the lateral extent of TPHd, one boring will be drilled in the immediate vicinity of Boring B-15 to facilitate the collection of a groundwater grab sample and assess if groundwater has been impacted. Two additional borings will be drilled to the southwest (down gradient) and south of Boring B-15 to assess groundwater conditions in this area. Groundwater samples were not collected in this area during the previous investigations. Groundwater samples and one soil sample from each boring will be analyzed for TPHg, TPHd, and VOCs. Groundwater Sampling Four Groundwater Monitoring Wells URS will attempt to locate and once found, sample the four groundwater monitoring wells (MW-1, 2, 3, and 4) in the vicinity of Boring B-15, where TPHd was reported in soil at 25,000 milligrams per kilogram (mg/kg) at 15 feet below ground surface (bgs). Groundwater samples collected from the wells will be submitted for analysis of TPH as gasoline (TPHg), TPHd, and VOCs. Monitoring wells will be bailed to remove sediments prior to purging and sampling. Groundwater samples will be collected with a low flow purge and sampling method following stabilization of water quality parameters. LABORATORY ANALYSIS All soil and groundwater samples will be tested for total petroleum hydrocarbons as diesel and as motor oil using EPA Method 8015B, and VOCs using EPA method 8260B. Select soil samples will also be tested for nitrate, sulfate and sulfide using EPA Method 300, manganese, iron using EPA Method 200.7, and TDS using EPA Method 160.1. All samples will be placed in a cooled insulated ice chest pending transport to Torrent Laboratory, Inc., in Milpitas, California; a State of California certified analytical laboratory. A Chain of Custody form will accompany all transported samples. QUALITY CONTROL Blind duplicate soil and groundwater samples will be collected during field activities at a rate of approximately 10%. One equipment blank will be collected during each day of field activities. Trip blanks will be prepared by the lab and accompany the sample containers during transport. One trip blank will be tested daily for VOCs using EPA method 8260B.