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<br /> soil sampling at desired intervals, sail samples are collected analysts(VOA)vials,rith'Teflon'septa;are used as sample t
<br /> by either hammering(with a 140-pound drop hammer)or containers.
<br /> hydrauRally pushing a conventional spot-barrel sampler `
<br /> containing pre-cleaned 2-inch-diameter brass tubes. A The groundvrater sample is decanted into each VOA vial in'
<br /> geologist or engineer from Apex Envirdech,Inc.,continuously such a manner that there is no meniscus at the top of the vial.
<br /> logs each borehole during drilling and constantly checks drill A cap is quickly secured to the top of the vial. The vial is then
<br /> cuttings for indications of both the first recognizable inverted and gently tapped to see if air bubbles are present. It }
<br /> occurrence of groundwater and volatile hydrocarbons using none are present,the vial is labeled and refrigerated for #
<br /> either a portable photoianization detector,Rama ionization delivery,under strict chairs-af-custody,to the analytical
<br /> detector,or an exptasimeter. The sampler is rinsed between laboratory. Label information should include a unique sample
<br /> samples and either steam cleared or washed with all other identification number,job identification number,date,time,type
<br />! drilling equipment beGveen borings to minimize the potential for of analysis requested,and the samplers name.
<br /> crass-contamination.
<br /> For qualty control purposes,a duplicate veater sample is
<br /> Monitoring wells are cased with threaded,factory-perforated collected tram each v-vll. This sample may also be analyzed or
<br /> and blank Schedule 40 PVC. The perforated interval consists put on hold at the laboratory, When required,a trip blank,
<br /> of slotted casing,generally with 0.020-inch wide by 1.5-€rich prepared at the laboratory.is laced in the transport P p ri cooler. h
<br /> long slots,With 42 slots per fact. A PVC cap may be secured is labeled similar to the well samples,remains in the cooler
<br /> to the bottom of the casing with stainless steel screws;no during transport,and is'analyzed bythe laboratory along with
<br /> solvents or cements are used. Centering devices may be the groundwater samples. In addtion,a field blank may be
<br /> fastened to the casing to ensure even distribution of filter prepared'
<br /> �n the held when
<br /> . P P rh n sampling equipment o
<br /> P t not
<br /> g� P
<br /> material and grout%sithln the borehole annulus. The well dedicated, The held blank is prepared after a pump or bailer
<br /> casing is thorough/ washed and/or steam cleaned or may be
<br /> Y y has been either
<br /> steam cleaned or properly washed,prior to use
<br /> purchased as pre-cleaned,prior to installation. in the need well,and is analyzed along with the other samples.
<br /> The field blank analysis demonstrates the effectiveness of the
<br /> After setting the casing inside the hallow-stem auger,sand or in-held cleaning procedures to pre%snt crass-contamination.
<br /> gravel hater material is poured into the annular space to fill from
<br /> baring bottom to generally 1 fact above the perforated interval. To minimize the potential for cross contamination between
<br /> A i-to 2-foot thick bentonite plug is set above this filter material wells,all welt development and vrater sampling equipment not
<br /> to prevent grout from infiltrating the filter pack. Either neat dedicated to a well is either steam cleaned or properlywashed
<br /> cement,containing about 5 percent bentonite,or sand-cement between use. As a secondary precautionary measure,wells
<br /> grout is then tremmied into the annular space from the top of are same;ed in order of least to highest concentrations as
<br /> the bentonite plug to near surface. A trafFc-rated vault Is established by availabte previous analytical'data,
<br /> installed around each wellhead for wells located in parking lots
<br /> or driveways,while steel"stovepipes"are usually set over In the event the water samples cannot be submitted to the
<br /> wellheads In landscaped areas, analytical laboratory on the same day they are collected(e.g..
<br /> due to wEekends or holidays),the samples are temporarily
<br /> After installation,the yells are thoroughly developed to remove stored until the first opportunity for submittal either on water ice
<br /> residual drilling materials from the wellbore,and to improve well in a cooler,such as when in the Feld,or in refrigerator at
<br /> performance by removing fine material from the filter pack that Apes office, y
<br /> may pass into the well. Well development techniques used
<br /> may include pumping,surging,bailing,swabbing.jetting, SOP
<br /> flushing,and air-lifting. All deve-lopment water is collected ME& URING LiQ'UID LEVELS USING
<br /> either in drums or tanks for temporary storage.and properly WATERER LEVEL METER OR INTERFACE i
<br /> disposed of depending on laboratoryanaVica[results, To PROLE ,
<br /> minimize the potential for crass-corrtamination between wells,
<br />' all development equipment is a„her steam cleaned or properly Field equipment used forTiquiddewl gauging typically includes
<br /> washed prior to use. Following development,the well is the measuring instrument(water-level meter or interface probe)
<br /> allowed to stand undisturbed for a minimum of 24 hours before and product bailer(s). The held Idt also includes cleaning
<br /> its first sampling, supplies(buckets,solution,spray bottles,and delanized water)
<br /> to be used in cleaninghe equipment t mens behrree wells
<br /> SOP . 7 q P n
<br /> GROUNDWATER PURGING AND Prior to measurement,theinstrument tip islowered into the well
<br /> SAMPLING until it touches bottom. Using the previously established top-of- x
<br /> casing or top-of-box(i.e.,wellhead vauR)paint,the probe card
<br /> Prior to water sampling,each w-ell is purged by evacuating a (or halyard)is marked and a measuring tape(graduated in
<br /> minimum of three wetted well-casing volumes of groundwater, hundredths of a foci)is used to detenn€ria the distance
<br /> When required,purging will continue until either the discharge between the probe and and the mardng on the card. This
<br /> water temperature,conductivity,or pH stabilize,a maximum of measurement Is then recorded on the liquid-level data sheet as
<br /> ten wetted-casing volumes of groundwater have been the"Measured Total Depth”of the well.
<br /> recovered or the YmIl is bailed dry. When practical,the M
<br /> groundwater sample should be collected when the water level When necessary In using'the interface probe to measure liquid
<br /> In the wetl recovers to at least 80 percent of its static level, levels,the probe is first electrically grounded to either the metal
<br /> stave Pipe or another metal object nearby. When no ground Is }
<br /> The sampling equipment consists of either a"Teflon"bailer, available,reproducible measurements can ba obtained by
<br /> PVC bailer,or stainless steel bladder pump with a'Teflon" clipping the ground lead to the handle of the interface probe
<br /> bladder. If the sampling system is dedicated to the well.then case.
<br /> the bailer is usuaIly'"T-erion,'but the bladder pump Is PVC with
<br /> k a polypropylene bladder. In general and depending on the
<br /> intended laboratory analysis,43-milliliter giass,volatile organic
<br /> 50P- Monitoring Wells
<br />
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