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ULTRAMAR FIELD PROCEDURES The following section describes procedures used by Ultramar field Personnel in the performance of ground water sampling. Ground Water level and Total De th Determination A water level indicator is lowered down the well and a measurement o reference paint on the casing is taken. f the depth to water from an established rrme reference t the total depth is the The indicator well is taken. probe is used to sound the bottom of the well and a to the nearest O.U1-foot. Both the water level and total depth measurements are taken Visual Anal sis of round Water Prior to purging and sampling P g ground water monitoring wells, a water sample is collected from each subjective analysis. The visual analysis involves approximately one-half the bailer length gently lowering a clean, die h well for gt past the water table interface. The bailer Is retrieved y contained within the bailer is examined for floating , Polyethylene bailer to measurable free product is Hated in the bailer} awater/product interface row retrieved, the sample product or the appearance of a petroleum product sheen, If of the free product to the nearest 0.09-foot. The thickness u free to product from the depth to water. p is used to determine the thickness Product is determined by subtracting the depth Monitorin Welip ur in and Sam fin Monitoring wells are purged by removing approximately four casing volumes of water from the well using a clean disposable bailer or electrical submersible purge Purging the temperature, pH, and electric pump. Purge volumes are casing volumes have been remav conductrvity are monitored. calculated prior to purging. During initial readings; and the ground water bhe temperature The well is suffrciently purged when: the four water levels are allowed to stabilize to within rem of and conductivity have stabilized to within f0% of the g moved is relatively free of suspended solids. After Purging, from each well with a clean, disposable the initial water level reading. p g 9, ground volume of water, the ground water is allowed to recharge. if the well has A water sample is then collected po ethylene bailer. if the well is bailed d reading within two hours, the welt will continue to be dry prior to removing the rnlnimum If the wet!has not recharged to at least 80% ofthe initial reading within ni recharged to within s be of the initial Purged until the minimum volume Of water has been removed. formational water and a ground water sample is collected. gallon drams at the site and labeled Pending disposal. °h°urs, the wet€is considered to contain Ground water removed from the well is stored in 55- In wells where free product is detected, the wells will be bailed to remove volume of product and water will be recorded. measurable thickness is no longer Present in the well, a ground watt a the free product. An estimate of the If the free product thickness is reduced to the Persists throughout bailing, a final free r point where a will not be collected. Product thickness measurement sample taken ani collected, Ifa ground free water Product sample Samples are stored in 4t}-milliliter vials so that air passage through the sample ' the sample). The vial is tilted and filled slow The Teflon side of the septum (in cap) is then placed against the meniscus p e is rninirrrized to iY until an upward convex meniscus forms { Prevent volatilizing sample is then inverted and the bottle is to rrrrs over the mouth of the vial. vial, the cap is removed and mare sample is starred from the bailer. ' and the cap is screwed on tightly. The tightly to check for air bubbles, if an air bubble is Present in the for air bubbles. The sample is then a The vial is then resealed and rechecked time of delivery to the laboratory appropriately labeled and stored on ice from the time of collection through the rY• AChain-of-Custody form is Completed to ensure sample integrity.samples are transported to astate-certified laboratory and analyzed within the EPA requested analyses. 9 ty. Ground water -specified holding times for the UV3mar Field PrpcedureWQMR-94