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iROUNDVIATER TECHNOLOGY I`;C <br /> STANDARD OPERATING PROCEDURE NO 8 . <br /> GROUNDWATER MONITORING <br /> ;rounowater monitonnrz or *­cils at Inc site snail be conauctea using an URS Environmental <br /> Equroment (ORS) INTERFACE PROBE— or SURFACE SAMPLER' The INTERFACE PROBE' 1s a <br /> hand-held battery-operated device ror measurenq acorn to perroleum product and depth to <br /> rater as measured from an estaolisheo datum (f a top or the well casing wnrch has been <br /> Surveyed) Floating separate-phase hydrocarbon (proauct) thickness 1s 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 10 8) + (Water Elevation) = Corrected Water Elevation <br /> Note The factor or 0 8 accounts tar the aensity altrerence 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 1s 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' consists of a dual-sensing probe which utilizes an optica( liquid 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 to petroleum product and an oscillating <br /> tone when_tmmersed=in=water.The 1NTERFAC-E=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 PROBE'), 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 place <br /> ,n order from the least to the most contaminated wells Wells containing separate-phase <br /> hydrocarbons (free 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 /> , <br /> CONCORD SOP QM41 <br /> An GROUNDWATER <br /> TECHNOLOGY, INC <br />