COMPLIANCE INFO - Laserfiche WebLink

Home Browse Search

ATC Associates Inc. YVATC 1117 Lone Palm Avenue,Suite B Modesto,California 95351 209-579-2221 ASSOCIATE S I N C . fax:209-579-2225 the eastern boundary of the site near the railroad tracks, two borings will be advanced along the southern property boundary near existing groundwater monitoring wells located in the roadway right-of-way, one boring will be advanced in the central area of the site, and one boring will be advanced near the western boundary of the site. During the drilling, a continuous soil core will be collected in utilizing direct push technology. An ATC geologist will inspect the each soil core in the field for physical evidence of impact such as staining, odors, free product, etc. The soil core will be screened using a photo-ionization detector (PID) to assess the potential for the presence of volatile organic compounds (VOCs) in the subsurface. Proposed boring locations are shown on Figure 2. The six borings will be advanced using truck mounted Geoprobe® narrow diameter, direct push technology. Drilling will be conducted by a State-licensed (C57) drilling company. A field geologist will be present to log the soil cores. Descriptions of soil types encountered and sample collection intervals will be recorded on boring logs. Soil samples submitted for laboratory analyses from each boring will be chosen at the ATC scientist's or engineer's discretion, based on physical evidence of impact and/or measured VOCs. Generally, if evidence of impact is not encountered, a sample from directly above the soil/groundwater interface or a sample from the middle of the boring will be submitted for analyses. One groundwater sample will be collected from each boring at the depth groundwater is first encountered, anticipated to be approximately 25 feet bgs. A Geoprobe° Screen Point 15 Groundwater Sampler will be threaded onto the leading end of the Geoprobe when the groundwater is encountered. While the sampler is advanced, O-ring seals and an expendable drive point will provide a watertight system to ensure sample integrity. When the tool has been advanced to the desired depth, extension rods will be sent downhole to brace the bottom of the sample screen as the tool casing is retracted. When the casing is retracted, up to 41-inches of screen with slot sizes of 0.004 inches will be exposed. Teflon® tubing with a check valve attached to one end will be inserted down the casing until it is immersed in groundwater. Water will then be pumped through the tubing and to the ground surface by oscillating the tubing up and down. Following soil and groundwater sample collection, the borings will be backfilled with neat cement grout to the ground surface. Drill cuttings, if any, will be stored on-site in a 55-gallon container pending laboratory results Shallow Soil Sample Collection In order to evaluate the potential presence of agricultural chemicals that may have been applied at the site, seven shallow soil samples will be collected from fallow areas of the site. The shallow soil sampling locations will be determined in the field. The soil samples will be collected by digging with hand tools to a depth of approximately one foot bgs. A discrete soil sample will be collected at each of the seven sample locations at approximately one foot bgs and placed in a laboratory supplied container. The samples will be labeled and immediately placed in a cooler chilled with ice. This sampling scheme will provide a limited screening of a representative area of the actual site, and it will not preclude the possibility of localized spills or leaks of quantities of pesticides or elevated concentrations of herbicides in areas of the site that will not be sampled. s:\environmental\75112-Pi1ot\Roth Road\phasellwp.doc 2