FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

Sr Mr. Michael Infurna Ip December 19, 1995 EI Page 3 'f Task 2: Domestic Drinking Water Well Sampling If f SECOR will sample three domestic drinking water wells located on the subject property and a fourth, currently unused well presumed to be a domestic well. The construction of the wells is currently unknown. Samples collected from the wells will be analyzed for total petroleum hydrocarbons (TPH) and benzene, toluene, f ethylbenzene and xylenes (BTEX) by EPA Method 801518020. - EG �t �F The three active wells will also be sampled to comply with the County's yearly testing requirements. Water samples collected from the three active wells will also be analyzed for nitrates and nitrites. Two of the three wells will be analyzed for general minerals and fluoride. !3 Tack 3: Field Investigation The scope of the field investigation phase includes drilling sixteen soil borings in the areas of concern listed above and shown on Figure 2. The drilling subcontractor will be V &W Drilling of Rancho Cordova (C47- 658786). All borings will be drilled to a depth of approximately 10 feet below ground surface (bgs) or until groundwater is encountered. I ,E Boreholes will be drilled using a truck-mounted drill rig equipped with 8-inch and 10-inch diameter hollow- stem augers. Boreholes will be drilled to approximately 10 feet below the first encountered groundwater or five feet into any continuous clay layer located below the first encountered groundwater. Relatively undisturbed soil samples will be collected continuously during drilling using either continuous coring equipment or a Modified California Split-Spoon Sampler lined with 3-inch long brass tubes. r !I If groundwater is encountered, the boring will be advanced approximately two feet into the saturated soil, and a 2-inch diameter PVC well casing will be inserted into the open borehole. Groundwater will be allowed to flow into the well casing and a groundwater sample will be collected from the temporary well by lowering a ! clean stainless steel bailer into the well. After grab groundwater samples are collected from the wells, the well casings will be removed and the boreholes filled with cement/bentonite grout. Between borings, all drilling equipment contacting subsurface soils will be decontaminated to prevent cross-contamination. i, a SECOR personnel will describe the soils encountered using the Unified Soil Classification System (USCS) and will maintain a boring log of soil lithology. A representative sample from each sampling interval will be screened in the field for the presence of total volatile organic compounds (VOCs) using a Photoionization Detector(PID). Using this procedure, approximately 100 grams of soil will be placed in a ziploc bag. After approximately 10 minutes, the tip of the PID instrument will be inserted into the bag and a headspace concentration (measured in parts per million) will be recorded. The results of the PID screening will be recorded directly on the boring log. One soil sample from each borehole will be selected for chemical analysis on the basis of depth, lithology, PID field screening results, and other pertinent field observations. Selected soil samples will be transported under Chain-of-Custody documentation to a California state-certified laboratory for analysis for total fuel scan using EPA Method 8015-M/8020 and 5520 (including TPHd, TPHg, BTEX, and oil and grease). Er h:�weatreclsHm[i." i E� y 1