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<br /> soil sampling at desired intervals. Soil samples are collected analysis(VOA)vials,with"1-exon'septa,are used as sample
<br /> by either hammering(with a 140-pound drop hammer)or containers.
<br /> hydraulically pushing a conventional split-barrel sampler
<br /> containing pre-cleaned 2-inch-diameter brass tubes. A The groundwater sample is decanted into each VOA trial in
<br /> geologist or engineer from Apex Envirotech,Inc.,continuously such a manner that there is no meniscus at the top of the tial.
<br /> togs 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. If
<br /> occurrence of groundwater and volatile hydrocarbons using none are present,the via[is labeled and refrigerated for
<br /> ether a portable photoionization detector,flame ionization delivery,under strict chain-of-custody,to the analytical .
<br /> detector,or an explosimeter. 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 between borings to minimize the potential for
<br /> 9 pot of analysis requested,and the samplers name
<br /> cross-contaminatian.
<br /> For qualty control purposes,a duplicate water sample is
<br /> Monitoring wells are cased with threaded,factory-perforated collected from each well. 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-Inch prepared at the laboratory,is placed in the transport cooler. It
<br /> long slats,with 42 slots per foot. A PVC cap maybe 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 by the laboratory along with k
<br /> solvents or cements are used. Centering devices may be the groundwater samples. In addition,afield blank maybe I
<br /> fastened to the casing to ensure even distribution of fliter prepared in the field when sampling equipment is not {
<br /> material and grout within the bcreholo annulus. The well dedicated. The field blank is prepared after a pump or bailer
<br /> casing Is thoroughly washed and/or steam cleaned,or may be has been either steam cleaned or properlywashed,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 hollow-stem auger,sand or in-field cleaning procedures to prevent crass-contamination.
<br /> gravel finer material is poured into the annular space to fill from
<br /> boring bottom to generally I fact above the perforated interval. To minimize the potential for crass-contamination between s
<br /> A I-to 2-foot thick bentonite plug is set above this filter material %yells,all well development and water sampling equipment not
<br /> to prevent grout from infiltrating the fitter pack Either neat dedicated to a well is ether steam cleaned or property washed
<br /> cement,containing about 5 percent bentonte,or sand-cement between use. As a secondary precautionary measure,wells l
<br /> grout is then tremmied into the annular space from the top of are sampled in order of leas'to highest concentrations as
<br /> the bentonite plug to near surface. A traffic-rated vault is . established by availableP revious analytical data.
<br /> installed around each wellhead for vreils located in parking lots Y
<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 an the same day they are collected(e.g..
<br /> due to weekends or holidays),the samples are temporarily
<br /> After installation,the wells are thoroughly developed to remove stored until the first opportunity for submittal ether on water ice
<br /> residual drilling materials from the wellbore,and to improve well in a cooler,such as when in the field,or in refrigerator at
<br /> performance by removing fine material from the filter pack that Apex`s office.
<br /> May p q development pass into the well. Well develo techniques used
<br /> may include pumping,surging,bailing,srrabbing,jetting, SOP_ IP-
<br /> flushing,
<br /> 2flushing,and air-lifting. All development water is collected MEASURING LIQUID LEVELS USING
<br /> either In drums or tanks for temporary storage,and properly WATER LEVEL*METER OR INTERFACE i
<br /> disposed of depending on laboratory analytical results. To PRO13E
<br /> minimize the potential for cross-contamination between wells, k
<br /> all development equipment Is either steam cleaned or properly Field equipment used for liquid-level gauging typically includes
<br /> wrashed 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 field kt also includes cleaning
<br /> Its first sampling. supplies(buckets,solution,spray bodies,and deionized water)
<br /> SOP - 7
<br /> to be used in cleaning the equipment between wells.
<br /> GROUNDWATER PURGING AND Prior to measurement.the Instrument Up is lowered into the well
<br /> SAMPLING until it touches bottom. Using the previously established top-0f-
<br /> casing or top-of-box(i.e.,wellhead vauit)point,the probe cord
<br /> Prior to water sampling,each well is purged by evacuating a (or halyard)is marked and a measuring tape(graduated In
<br /> minimum of three wetted veli-casing volumes of groundwater. hundredths of a foot)Is used to determine the distance 1
<br /> When required,purging will continue until either the discharge between the probe end and the marking on the cord.*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
<br /> the'Measured Total Depth"of the well.
<br /> recovered,or the veli is bailed dry. When Pf acticaf the t
<br /> groundwater sample should be collected%hien the water level When necessary in using the Interface probe to measure liquid
<br /> In the well recovers to at least 80 percent of its static level. levels,the probe is first aloWcally grounded to either the metal
<br /> . stave pipe or another metal object nearby. When no ground Is
<br /> The sampling equipment consis`s of ether a'Teflon"bailer. available,reproducible measurements can be 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. It the sampling system is dedicated to the well,then case. 1
<br /> the bailer is usually"Toflon,'but the bladder pump Is PVC with t
<br /> a polypropylene bladder. In general and depending on the
<br /> Intended laboratory analysts,44milliliter glass,volab'le organic
<br /> SOP- Monitoring Wells
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