Laserfiche WebLink
Technical Memorandum — Additional Subsurface Investigation Work Plan, September 11, 2018 <br />705 Carlton Avenue, Stockton, California <br />EFI Global Project Number 9836003958 <br />FIELDWORK <br />The proposed soil sam pling and methodologies are describ ed below. The in vestigative scope of work <br />includes advancement of eight direct push soil borings for the collection of soil and groundwater samples. <br />Six borings will be advanced to a maximum depth of 10 feet bgs in the areas of the clar ifier, the paint <br />spray booth, a vehicle wash area, and across the foot print of the warehouse structure. Two borings will <br />be advanced to am aximum depth of 3 feet bgs in the area of the former rail road spurs. A qualified <br />scientist working under the direct supervision of an EFI Global California Professional Geologist will <br />direct the drilling and prepare the field documentation as described below. <br />UNDERGROUND UTILITY CLEARANCE <br />Underground Service Alert (USA) will be notified of intent to conduct subsurface investigati ons at least <br />48 hours prior to the initiation of intrusi ye field tasks. All proposed soil boring locations will be clearly <br />marked with white paint as required by USA. USA w ill contact all utility owners of record within the <br />vicinity and notif y them of the intention to conduc t subsurface investigations in proxim ity to b tried <br />utilities. <br />Additionally, if necessary as indicated by in-field observations, borings where utility clearance methods <br />were inconclusive will be additionall y cleared to a depth of approxim ately 5 feet bgs using hand tools <br />(such as a hand-auger and post-hole digger) to ensure that no shallow obstructions are present. <br />SOIL SAMPLING <br />The prop osed soil boring location is provided on F igure 2. Ad ditional soil samples may be collected <br />based on observed field conditions. The table below summarizes the soil sampling program: <br />Boring IDs Area/Rationale <br />Total Number of <br />Field Samples / <br />Analysis <br />Soil Sample <br />Depths (ft bgs) <br />Sample Analytical <br />Method (Analytes) <br />B I —B6 <br />Assess areas of <br />clarifier, paint spray <br />booth, car wash, and <br />warehouse interior <br />6 <br />One sample per <br />boring above <br />groundwater (if <br />encountered) <br />EPA 8260B (VOCs) <br />B7 — B8 Assess area of former <br />railroad spurs <br />EPA 6010B (0CPs), <br />41 ,3 EPA 8081 (lead and <br />arsenic) <br />ft bgs —feet below ground surface <br />VOC — volatile organic compounds <br />OCP — organochlorine pesticides <br />The soil borings will be advanced using an direct push drill rig operated by a contractor holding a State of <br />California C-57 Well Drilling License. The borings will be advanced with a 2. 25 inch in di ameter steel <br />drive rod to terminal depths of 10 feet bgs in borings B1 through B6 and 3 feet bgs in borings B7 and B8. <br />Soil samples from borings B1 through B6 will be collected above groundwater (if encou ntered) using <br />acetate lined steel sample rods. Upon r etrieval of the sam pier, the sleeve con esponding to the desired <br />sampling depth will be selected and sealed with in ert tape and tight-fitting pl astic caps for chem ical <br />analysis. <br />Soil lithology will be observed fro m unused soil collected in the split-spoon sam pier. Soil will be <br />described on soil boring logs in accordance with th e Unified Soil Classifica tion Sy stem (USCS). In <br />addition, the samples will be observed for color, texture, moisture content, plasticity, visible evidence of <br />soil contamination (i.e., odor, discoloration), and any other notable characteristics. <br />To identify and manage samples obtained in the fiel d, a sam pie label will be affixed to each sample <br />container. The sam pie labels will incl ude the following information: company name, site name, boring <br />EFI Global Page 2 of 5 <br /> <br />Engineering, Fire & <br />Environmental Services