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• sod sampling at desired intervals Sod samples are collected analysis(VOA)vials,wrth'Tefon"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 pro-cleaned 2-inch-diameter brass tubes A The groundwater sample is decanted into each VOA vial in
<br /> geologist or engineer from Apex Enmrotech,Inc,continuously such a manner that there is no meniscus at the top of the Hal
<br /> logs each borehole during dnlAng and constantly checks drill A cap is quickly secured to the top of the Hat The vial is then
<br /> cuttings for indications of both the first recognizable inverted and gently tapped to see it air bubbles are present If
<br /> occurrence of groundwater and volatile hydrocarbons using none are present,the mal is labeled and refrigerated for
<br /> either a portable photownization 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 cleaned or washed with all other identification number,lob identification number,date,time,type
<br /> drilling equipment between borings to minimize the potential for of analysis requested,and the sampler's name
<br /> cross-contamination
<br /> For quality 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 cinch prepared at the laboratory is placed in the transport cooler It
<br /> long slots,with 42 slots per foot 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 by the laboratory along with
<br /> solvents or cements are used Centering devices may be the groundwater samples In addition afield blank may be
<br /> fastened to the casing to ensure even distribution of filter prepared in the field when sampling equipment Is not
<br /> material and grout within the borehole annulus The well dedicated The field blank is prepared after a pump or baiter
<br /> casing is thoroughly washed and/or steam cleaned,or may be has been either steam cleaned or properly washed,prior to use
<br /> purchased as pre-cleaned,prior to installation in the next 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 cross-contamination
<br /> gravel filter material is poured into the annular space to fill from
<br /> boring bottom to generally 1 foot above the perforated interval To minimize the potential for cross-contamination between
<br /> A 1-to 2-foot thick bentonte plug is set above this filter material wells,all well development and water sampling equipment not
<br /> to prevent grout from infiltrating the filter pack. Ether neat dedicated to a well is either steam cleaned or properly washed
<br /> cement containing about 5 percent bentonte,or sand-cement between use Asa secondaryprecautionary measure,wells
<br /> grout is then tremmied into the annular space from the top of are sampled in order of least to highest concentrations as
<br /> the bentonte plug to near surface A traffic-rated vault is established by available 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 field or in refrigerator at
<br /> performance by removing fine material from the filter pack that Apex s office
<br /> may pass into the well Well development techniques used
<br /> may include pumping,surging,bailing swabbing letting, $Op _ 10
<br /> flushing 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
<br /> disposed of depending on laboratory analytical results To PRO BE
<br /> minimize the potential for cross-contamination between wells,
<br /> all development equipment is ether steam cleaned or properly Field equipment used for liquid level 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 boiler(s) The field kit also includes cleaning
<br /> As first sampling supplies(buckets solution spray bottles and deionized water)
<br /> SOP - 7 to be used in cleaning the equipment between wells
<br /> GROUNDWATER PURGING AND Prior to measurement the instrument tip is lowered into the well
<br /> SAMPLING until 9 touches bottom Using the previously established top-of-
<br /> casing or top-of-box(i e,wellhead vault)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 well-casing volumes of groundwater hundredths of a foot)is used to determine the distance
<br /> When required,purging will continue until ether 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 weded-casing volumes of groundwater have been the"Measured Total Depth"of the well
<br /> recovered or the welt is bailed dry When practical,the
<br /> groundwater sample should be collected when the water level When necessary in using the interface probe to measure liquid
<br /> in the well recovers to at least 80 percent of is static level levels,the probe is first electrically grounded to ether the metal
<br /> stove pipe or another metal object nearby When no ground is
<br /> The sampling equipment consists of either 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 If the sampling system is dedicated to the well,then case
<br /> the baiter is usually'Teflon,"but the bladder pump is PVC with
<br /> a polypropylene bladder In general and depending on the
<br /> intended laboratory analysis,40-milliliter glass,volatile organic
<br /> SOP- Mondonng Wells
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