Laserfiche WebLink
r <br /> 00, <br /> Work Plan September 5, 1990 <br /> Arco Service Station 2076, Lodi, California AGS 30008-1W <br /> egg <br /> of afield geologist,and the earth materials will be logged as drilled using the Unified Soil <br /> Classificatior,System. <br /> We will drill the first boring approximately 2-1/2 feet from the edge of the tank area,near <br /> the fill ends of the product tanks, to 30 feet below grade, ground water, or auger refusal, <br /> whichever is encountered first. A photoionization detector (PID)will be used to evaluate <br /> soil samples for gasoline hydrocarbons. Field instruments such as the PID are useful for <br /> indicating relative levels of gasoline hydrocarbon vapors but do not detect the concentration <br /> of gasoline hydrocarbons preserit with the precision of laboratory analyses. If the PID <br /> reading of the soil sample collected at 30 feet below grade is greater than 50 parts per <br /> a million by volume(ppmv),we will drill until:(1)two consecutive samples collected at 5-foot <br /> 4{ ` intervals produce PID readings of less than 50 ppmv, (2) until we encounter ground water, <br /> or (3).auger refusal. Any additional subjective evidence of gasoline hydrocarbons such as <br /> soil discoloration or obvious odor will be noted. <br /> If the first boring is terminated above 30 feet below grade,three additional soil borings will s <br /> f <br /> be drilled approximately 2-1/2 feet from the edge of the tank area, equally spaced around <br /> the tank perimeter. If the first boring is drilled deeper than 30 feet, two more borings will <br /> : be drilled around.the existing tank cavity using the above criteria until two consecutive a <br /> a <br /> 7 <br /> r;,x <br /> , PP1leap° 000SysOems <br />