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w GROUNDWATER TEcHNowGY <br /> STa1NDARD OPERATING PROCEDURE <br /> CONCERNING GROUNDWATER MON1TGRING <br /> SOP 8 <br /> Groundwater monitoring of Wells at the site mhall be <br /> conducted using an ORS Interface Probe and Surface <br /> - :gampler. The Interface Probe ig a hand geld, battery <br /> operr.ted device for Measuring depth to petroleum product <br /> Mrd depth to water as Near from an established datum <br /> (.i.e., top of the well casing which has been surveyed) . <br /> Product thickness is then calculated by subt.aar.cting the <br /> ��epth to 1pe':4-juct from the depth to water. In addition, <br /> dater elevations are adjusted for the presence of fuel <br /> with the following calculation: <br /> (Product Thickness) (.$)+(Water Elevation) <br /> Corrected Water Elevation <br /> Note: The factor of 4.8 accounts for the density <br /> difference between water and petroleum <br /> hydrocarbons. <br /> The Interface Probe consists of a dual aaensing probe <br /> Utilizing an optical liquid sensor and electrical con- <br /> ductivity to distinguish between water and petroleum <br /> products. A coated steel measuring tape transmits the <br /> sensor's sig,ials to the reel assembly, where an audible <br /> alarm sounds a continuous tone when the sensor is <br /> Immersed in petroleum product and an oscillating tone <br /> when immersed in water. The Interface Probe is accurate <br /> L0 1/16-inch. <br /> A Surface Sampler shall be used for visual Inspection of <br /> the groundwat+or to note sheens (difficult to detect with <br /> the Interface Probe) , odors, Microbial action, etc. <br /> The Surface Sampler used consists sof a 12-inch long cast <br /> acrylic tube with a Delrin ball which closes onto a <br /> conical surface creating a seal as the sampler is pulled <br /> Up. The sampler is calibrated in inches and centimeters <br /> for visual Inspection of product thickness. <br /> To reduce the potential for cross contamination between <br /> Wells the monitorings shall take place in order from the <br /> least to Most Contaminated Wells. Wells containing free <br /> product should be monitor6d last. Between each monitoring <br /> the equipment shall be washed with laboratory grade <br /> detergent and double rinsed with distilled water. <br /> GROUNDNATER <br /> ,� TEC'Hh0L C1.INC <br />