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Soo <br /> L. Ripon Milling Inc. Page 4 <br /> Monitoring Well Installation Work Plan <br /> Appendix A <br /> Project No.253.2 <br /> February 3,1995 <br /> ` A chain of custody document is filled out which listed all samples collected, their date of collection, <br /> transfers of custody, and laboratory analyses requested. This document is used to track the samples <br /> and to ensure their integrity. <br /> Groundwater physical parameters including temperature, conductivity (EC), and pH are measured <br /> LW and recorded in the field and are provided in report as field logs. <br /> The groundwater samples may be analyzed by Sherwood Laboratories of Hilmar, California and <br /> 6.0 tested for benzene, toluene, ethylbenzene, and total xylenes (BTEX) by EPA method 602 and total <br /> petroleum hydrocarbons as diesel(TPH-Diesel)by EPA method 3510/8015m. <br /> LO The detection limits for these analyses are as follows:benzene,toluene,ethylbenzene,total xylenes 0.3 <br /> µg/1,and TPH-Diesel 50 gg/l. <br /> 2.8 Soil Boring Installation <br /> LO <br /> The soil borings will be drilled using a continuous flight hollow stem auger to a total depth to be <br /> determined but not to intercept the groundwater. Soil cuttings will either be containerized in DOT <br /> i. approved 55 gallon drums,labeled or lain on and covered by plastic sheeting,and stored on site until <br /> their proper disposition can be arranged. Soil samples will be collected for geological and analytical <br /> evaluation at five foot intervals. Soil samples will be collected in 6.0 inch brass liners using a 2.0 inch <br /> modified California split spoon sampler. All soil samples will be sealed with aluminum foil,capped, <br /> labeled and placed in a cooler at 4"Celsius for transport to the laboratory following Chain of Custody <br /> protocol. <br /> Because every soil sample collected will not be submitted for laboratory analysis,a screening process <br /> will be used to gather additional information through field observation noting sediment type, <br /> especially grain size and clay content;moisture content; visible evidence of contamination,i.e.,color <br /> change due to reduction of iron or discoloration from hydrocarbons and other pollutants, and the <br /> readings above background on a organic vapor meter (OVM). The OVM is a field portable photo <br /> ionization detector that uses a 10.0 eV lamp to detect compounds with ionization potential below 10.0 <br /> L. eV(hydrocarbon range). <br /> The soil borings will be closed as follows:after the last soil sample has been collected the augers will <br /> be lifted 3 feet and 50 pounds of bentonite will be poured through the hollow stem of the augers and <br /> L. hydrated with clean tap water. A tremie pipe of sufficient length to reach the total depth of the <br /> boring will be installed through the center of the hollow stem augers and then the augers will be <br /> withdrawn from the hole. The borehole annulus will be closed by pumping a neat cement grout <br /> (<4%bentonite/cement)through the tremie tube up to grade. <br /> 2.9 Monitoring Well Construction <br /> The monitoring wells will be constructed with 4.0 inch diameter, schedule 40 PVC casing with flush <br /> threaded joints. A screened interval will consist of 0.020 inch perforations extending from <br /> approximately 15 feet below and 5 feet above the water table. <br /> W <br /> A number three sand will be used to form a filter pack about the saturated zone(0.020")perforations <br /> and will extend two feet above this screened interval. An annular seal will be constructed by <br /> 4r <br />