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<br /> soil sampling at desired intervals. Soil samples are collected analysis(voA)vials,with Teflon"septa,are used as sa+nple
<br /> r containers.
<br /> by either hammering{with a 14a-pound drop hammer)or
<br /> f� hydraulically pushing a conventional split-barrel sampler The groundwater sample is decanted into each VOA vial in
<br /> containing pre-cleaned 2-inch-diameter brass tubes. A
<br /> geologist or engineer from Apex EnvroteCh,Inc.,continuously such A capimanner tsquicklytsecured to the top no#the vial The vial is then
<br /> j togs each borehole wring drilling and
<br /> constantly checks drift inverted and gently tapped to see if air bubbles are present. if
<br /> cuttings for indication of Moth the first recognizable
<br /> none are present,the vial is labeled and refrigerated for
<br /> occurrence of grour}dwater~and volatile hydrocarbons using, delive 'under strict chain-of custody,to the analytical
<br /> either a portable ph detector,Rome ionization laboratory. Mabel information should include a unique sample;
<br /> detector;or an e*6simeter. The sampler is rinsed between identification number,job identification number,date,time,type
<br /> samples and either,steam cleaned or washed with all other
<br /> drilling equipment between borings minimize the potential for of analysis requested,and the sampler's
<br /> ;name,
<br /> 1 cross-contamination. For quality control purposes a duplicate water sample is
<br /> it Monitoring wells are cased with threaded,factory-perforated collected from each well This sampie may also be analyzed or
<br /> and blank SchedulelO PVC. The perforated interval consists put on hold at the laboratory= When required,a trip blank
<br /> -inch vide by 1.v-inch prepared at the laboratory,is placed in the transport cooler. It
<br /> of slotted casing,generally with O.CYto the
<br /> tong slots,with 42 slots per toot. A PVC cap may be secured islabeledsimilar and s anlasamples,
<br /> ed by sthe aabo atary along with
<br /> to the bottom of the casing with stainless steel screws;noduring k
<br /> '
<br /> solvents or cements are used: Genkering devices may be the groundwater samples. In addition,a field blank may be
<br /> fastened to the casing to ensure even dlstributlon 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 batter
<br /> casing is thoroughly washed andtor steam cleaned,or maybe has been either steam cleaned or properly washed,prior to use
<br /> purchased as pre-cieaned,prior to installation, in the next wail,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 1
<br /> boring bottom to generally 1 foot above the perforated interval. To minimize the potential for cross contamsnatiorl between
<br /> A 1-to 2-foot thick bentonite plug is set above this filter material wells,ail well development and water sampling equipment not
<br /> to prevent grout from infiltrating the filter pack. Either,neat dedicated to a well is either steam cleaned or properly washed
<br /> cement,containing about 5 percent bentonite,or sand-cement between use. As a secondary precautionary measure,wells
<br /> grout is then tremmked into the annular space from the top of are sampled in order of least to highest concentrations as
<br /> the bentonite 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 tats
<br /> or driveways,while steel"stovepipes"are usually set over to thealy cal labor water samples cannot be are 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 j
<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 /> l` performance byremovtng fine material from the filter pack that Ape)es office.
<br /> may pass into the well. Weil development techniques uses!
<br /> may include pumping,surging,bailing,swabbing,jetting. `-+ P
<br /> flushing,and air-lifting. All developmentwateris collected MEASURING LiQUID LEVELS 'irllSING
<br /> either in drumsortanks for temporary storage,and properly WATER LEVEL METER OR INTERFACE
<br /> disposed of depending on laboratory analytical results, To PROBE
<br /> w minimize the potential for cross-contamination between webs,
<br /> ail development equipment is either steam cleaned or properly Field equipment used for liquid-level gauging typically includes
<br /> washed prior to use. Fallowing 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 kit also includes cleaning
<br /> its first sampiingi supplies(buckets,solution,spray bodies,and deionized water)
<br /> ' to be used in cleaning the equipment between wells.
<br /> lir SOP - 7
<br /> GROUNDWATER PURGING AND Prior to measurement,the instrument tip is lowered into the well:
<br /> SAMPLING until it 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:treasuring tape(graduated in
<br /> minimum of three wetted well-casing volumes of groundwater. hundredths of a foat)is used to determine the distance;
<br /> When required,purging will continue until either the discharge between the probe and and the marking on the cord. This
<br /> water temperature,conductivkty,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 well is bailed dry. When practical,the a
<br /> groundwater sample should be collected when the water level When necessary in using the interface probe to measure liquid
<br /> l in the well 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 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 batter is usually"Teflon"but the bladder pump is PVC with
<br /> a potypropylene'bladder. In general and depending on the
<br /> intended laboratory analysis,AO-miliiliter glass,volatile organic
<br /> } SOP- Monitoring Wells ".
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