ARCHIVED REPORTS XR0001892 - Laserfiche WebLink

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Phase II Environmental Site Assessment 1645 Cherokee Lane,Stockton,CA ' Hydro-Environmental Technologies, Inc ' 2.0 SUBSURFACE SOIL AND GRAB GROUND WATER INVESTIGATION The field investigation and sample analysis was conducted in accordance with approved U S Environmental Protection Agency (USEPA) methods, California Code of Regulations (CCR) Title 23 procedures, and guidelines from the PHD/EHD This subsurface investigation was conducted under the ' direct supervision of a California Registered Geologist (R G ) HETI personnel conducted an initial on site subsurface soil and grab ground water exploration near previous known contaminant hot spots as determined from the initial URSGWC investigation 2.1 Health and Safety Plan ' For this investigation, HETI personnel prepared a site specific health and safety (H&S) plan in accordance with the requirements of the USEPA 29 CFR 1910 120 and California Cal-OSHA GISO 5192 All on-site HETI and subcontractor personnel were required to adhere to the H&S plan and were ' required to have had 29 CFR 1910 120 training and its annual update The HETI project manager had the appropriate 29 CFR 1910 120 and California GISO 5192 eight-hour supervisor's course 2.2 Geophysical Survey/Utility Clearance Prior to any soil boring, digging, trenching, or subsurface investigation,gatron, HETI contacted Underground ' Service Alert (USA) to clear the areas for utilities or other unknown buried obstructions (USA Nos 190962, 209079, and 250064) On July 5, 2000, Norcal Geophysical Consultants, Inc a private geophysical locating service, contracted by HETI cleared areas within the subject property ' 2.3 Direct Push Drilling On July 12, 2000, HETI contracted with Transglobal Environmental Geocher ustry (TEG) to bore through ' the surface soil in six direct push (DP) borings using a Strataprobe DP drilling rig to the unconfined to semi-confined ground water table Soil samples were collected at 5 0-foot intervals beginning at 10 feet bsg (the approximate bottom of the UST excavation) to 50 feet bsg (assunung that the shallow ground water table is approximately 40 feet bsg) Boring logs are included in Appendix B TEG then installed a temporary PVC casing with the screened interval from 40 to 50 feet bsg to collect a ' ground water sample One grab ground water sample was collected from each of the six DP locations through a stainless steel bailer Ground water samples submitted for analysis were collected in six unpreserved 40-milliliter (mL) volatile organic analysis (VOA) vials The samples were unpreserved 1 because the calcium carbonate-rich ground water would react with nitric acid producing carbon dioxide gas bubbles, thereby invalidating the sample The VOA vials were properly labeled inside of a Ziplock- type plastic bag to lessen possible outside contamination Each boring was grouted to the surface with a 1 cement-bentonite mixture 2