WORK PLANS - Laserfiche WebLink

Home Browse Search

BLEW B-2 through B-4: Located laterally approximately 15-feet to the east, south and west of B-1. Advanced to a depth of approximately 15 to 20 feet-bgs. Soil samples collected at depth intervals of 2, 5, 10 and 15 feet-bgs (deepest sample dependent on depth to groundwater). Temporary soil vapor probe installed at five feet-bgs. Soil and soil vapor samples analyzed for BTEX. Contingency: Should field observations indicate obvious impact, advance additional step-out lateral borings. Soil Sampling Methodology Soil will be logged by Blew field personnel in accordance with the Unified Soil Classification System (USCS). Soil will be screened for VOCs using a photo-ionization detector (PID). Soil samples will be collected directly from acetate liners according to 5035 methodology and placed in laboratory-provided sample containers, sealed, labeled, and placed in a cooler with wet ice for subsequent transportation along with standard chain-of-custody documentation to a California-certified laboratory. Soil samples will be analyzed for BTEX via EPA Method 8260B. Groundwater Sampling Methodology Upon encountering groundwater,a temporary PVC well screen and casing will be placed into the borehole. The temporary well will be purged and sampled utilizing a peristaltic pump at a low-flow rate of less than 500 milliliters per minute (mL/min). Blew will attempt to purge at least one well volume, dependent on recharge. Following purging, a groundwater sample will be collected via a peristaltic pump and tubing. The groundwater sample will be collected directly into laboratory-provided containers, sealed, labeled, and stored in a cooler with wet ice for subsequent transport to a California-certified laboratory under standard chain-of-custody protocols.The groundwater sample will be submitted for analysis for BTEX by EPA Method 8260B. Soil Vapor Sampling Methodology The temporary soil vapor wells shall generally consist of approximately 3/8" x 1.5" polyethylene vapor implants, '/4"Teflon tubing, and '/4"polycarbonate sample valves.The soil vapor well construction details will generally be as follows: the vapor implant will be embedded within an approximate V sand pack, followed by approximately V of dry granular bentonite, and a hydrated bentonite annular seal. The temporary soil vapor wells will be allowed to equilibrate for at least two hours prior to purging and sampling activities. Prior to sampling, a shut-in test will be conducted to check for leaks in the above- ground sampling system, and three volumes of air will be purged from the soil vapor well and sampling train. The purging rate will be set between 100 to 200 milliliters/minute (mL/min). Prior to and during purging and sampling, a leak test shall be performed utilizing helium and a shroud. Soil vapor well installation and sampling will be conducted in general accordance with the Advisory— Active Soil Gas Investigations, California Department of Toxic Substances Control (DTSC),July 2015. INDOOR AIR SAMPLING Indoor air sampling is proposed at the following addresses: 594, 582, 568, 556, 534 and 522 Buena Vida Court. Indoor air sampling is contingent upon timely receipt of access agreements. Blew requests that Work Plan for Additional Investigation 2546 French Camp Turnpike,Stockton,CA 95206 3