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3ROl, NDWATER TECHNOLOGY I`;C <br /> STANDARD OPERATING PROCEDURE NO 8 <br /> GROUNDWATER MONITORING <br /> -rounatirater monctorinq cr weds az the site snarl be conaucted using an ORS Environmental <br /> Equipment (ORS) INTERFACE PROBE' or SURFACE Sr' NIPLER"' The INTERFACE PROBE— is a <br /> hand-held battery-operated device tor measurinq aeotn to oetroleum product and depth to <br /> .(ater as measures from an estaoleshed datum (i e top or the well casing wnich has been <br /> surveyed) Floating separate-pnase hydrocarbon (proouctl thickness is then calculated by <br /> subtracting the depth to product from the depth to water In addition, water elevations are <br /> adjusted for the presence of floating product with the following calculation <br /> (Product Thickness) x (0 8) + (Water Elevation) = Corrected Water Elevation <br /> Note The factor of 0 8 accounts for the oens,ty dirference between water and <br /> petroleum hydrocarbons <br /> The thickness of dense non-aqueous phase liquids (DNAPLs) is calculated by subtracting the <br /> depth at which the DNAPL is encountered from the total depth of the well Water-level <br /> elevations are not typically corrected for the presence of DNAPLs <br /> The INTERFACE PROBE' consistsf <br /> o adual-sensing probe which utilizes an optical !quid sensor <br /> and electrical conductivity to distinguish between water and petroleum products. A coated <br /> steel measuring tape transmits the sensor's signals to the reel assembly where an audible alarm <br /> sounds a continuous tone when the sensor is immersed in petroleum product and an oscillating <br /> tone when immersed in water The INTERFACE PROBE' is accurate to 0 01 inch <br /> A SURFACE SAMPLER' shall be used for visual inspection of the groundwater to note sheens <br /> (difficult to detect with the INTERFACE PR08E"`), odors, microbial action, etc. <br /> The SURFACE SAMPLER' used consists of a 12-inch-long case acrylic tube with a Delnn ball <br /> which closes onto a conical surface creating a seal as the sampler is pulled up The sampler is <br /> calibrated in inches and centimeters for visual inspection of product thickness <br /> To reduce the potential for cross contamination between wells, the monitoring shall take }dace <br /> in order from the least to the most contaminated wells Wells containing separate-phase <br /> hydrocarbons Ifree product) should be monitored last Between each monitoring the equipment <br /> shall be washed with laboratory-grade detergent and double rinsed with distilled water <br /> CONCORD SOP Chea! <br /> _ GROUNDWATER <br /> TECHNOLOGY INC <br />