Laserfiche WebLink
Addendum to Work Plan for Additional Subsurface Investigation February 5, 1992 <br /> J B Terminal, 6700 Grantline Road, Tracy, CA W0322 <br /> Task 1. Installation of Two Groundwater Monitoring Wells <br /> Two soil borings will be advanced in the downgradient direction of the former underground <br /> gasoline storage tank. The boring/wells will be drilled to a total depth of 30 feet below grade, <br /> 10 feet beyond hydrocarbon impaction, or to auger refusal, whichever occurs first. Soil samples <br /> will be collected at five-foot intervals and will described and logged continuously according to <br /> the Unified Soil Classification System. Hydrocarbon concentration of the soil samples will be <br /> estimated in the field utilizing a photoionization detector (PID) The concentrations detected by <br /> the PID will be recorded by the geologist. The drill cuttings will be stockpiled on site, covered <br /> and underlain by 6 mil plastic, and disposed of appropriately, pending laboratory analysis. The <br /> two bonngs will be completed as groundwater monitoring wells using 2-inch diameter PVC <br /> screen and casing. The proposed well locations are shown on Figure 2. Typical well <br /> construction is shown on Figure 3. <br /> Task 2. Well Development and Sampling <br /> Well development and sampling will consist of the following a) Survey the top of the well <br /> heads and measure depths to water in the wells to evaluate the direction and magnitude of the <br /> groundwater gradient beneath the site b) Purge and sample the existing and two new <br /> monitoring wells to evaluate the extent of gasoline hydrocarbons in the first-encountered <br /> groundwater at the site Purge water from the monitoring wells will be contained in 55 gallon <br /> drums pending laboratory analysis. If sample results indicate concentrations below state MCLS, <br /> discharge of water to the ground surface is proposed. <br /> Task 3. Laboratory Analysis <br /> Soil and groundwater samples will be collected and submitted for analysis to a state certified <br /> laboratory as follows• Submit, using chain of custody protocol, one soil sample selected from <br /> each boring/well collected immediately above the saturated zone, to a State-certified laboratory <br /> for analysis of total petroleum hydrocarbons as gasoline (TPHG) and benzene, toluene, <br /> ethylbenzene, and xylenes (BTEX) using EPA methods modified 8015 and 5030/8020 Two <br /> water samples, one from each well, will also be submitted, using chain of custody protocol to <br /> a State-certified Iaboratory for analysis of total petroleum hydrocarbons as gasoline (TPHG) and <br /> benzene, toluene, ethylbenzene, and xylenes (BTEX) using EPA methods modified 8015 and <br /> 5030/8020. <br /> WPM0392 SAY 2 <br />